Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal

Pull generic execve() changes from Al Viro:
 "This introduces the generic kernel_thread() and kernel_execve()
  functions, and switches x86, arm, alpha, um and s390 over to them."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (26 commits)
  s390: convert to generic kernel_execve()
  s390: switch to generic kernel_thread()
  s390: fold kernel_thread_helper() into ret_from_fork()
  s390: fold execve_tail() into start_thread(), convert to generic sys_execve()
  um: switch to generic kernel_thread()
  x86, um/x86: switch to generic sys_execve and kernel_execve
  x86: split ret_from_fork
  alpha: introduce ret_from_kernel_execve(), switch to generic kernel_execve()
  alpha: switch to generic kernel_thread()
  alpha: switch to generic sys_execve()
  arm: get rid of execve wrapper, switch to generic execve() implementation
  arm: optimized current_pt_regs()
  arm: introduce ret_from_kernel_execve(), switch to generic kernel_execve()
  arm: split ret_from_fork, simplify kernel_thread() [based on patch by rmk]
  generic sys_execve()
  generic kernel_execve()
  new helper: current_pt_regs()
  preparation for generic kernel_thread()
  um: kill thread->forking
  um: let signal_delivered() do SIGTRAP on singlestepping into handler
  ...

96 files changed, 390 insertions, 899 deletions

diff --git a/arch/Kconfig b/arch/Kconfig
index 550cce4dd648..26a28419cafc 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -271,6 +271,9 @@ config ARCH_WANT_OLD_COMPAT_IPC
         select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
         bool
 
+config GENERIC_KERNEL_THREAD
+        bool
+
 config HAVE_ARCH_SECCOMP_FILTER
         bool
         help
diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index 9944dedee5b1..7da91246e279 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -20,6 +20,7 @@ config ALPHA
         select GENERIC_CMOS_UPDATE
         select GENERIC_STRNCPY_FROM_USER
         select GENERIC_STRNLEN_USER
+        select GENERIC_KERNEL_THREAD
         help
           The Alpha is a 64-bit general-purpose processor designed and
           marketed by the Digital Equipment Corporation of blessed memory,
diff --git a/arch/alpha/include/asm/Kbuild b/arch/alpha/include/asm/Kbuild
index d97d66334e6f..64ffc9e9e548 100644
--- a/arch/alpha/include/asm/Kbuild
+++ b/arch/alpha/include/asm/Kbuild
@@ -10,3 +10,4 @@ header-y += pal.h
 header-y += reg.h
 header-y += regdef.h
 header-y += sysinfo.h
+generic-y += exec.h
diff --git a/arch/alpha/include/asm/exec.h b/arch/alpha/include/asm/exec.h
deleted file mode 100644
index 4a5a41f30779..000000000000
--- a/arch/alpha/include/asm/exec.h
+++ /dev/null
@@ -1,6 +0,0 @@
-#ifndef __ALPHA_EXEC_H
-#define __ALPHA_EXEC_H
-
-#define arch_align_stack(x) (x)
-
-#endif /* __ALPHA_EXEC_H */
diff --git a/arch/alpha/include/asm/processor.h b/arch/alpha/include/asm/processor.h
index e37b887b3d9f..6cb7fe85c4b5 100644
--- a/arch/alpha/include/asm/processor.h
+++ b/arch/alpha/include/asm/processor.h
@@ -49,9 +49,6 @@ extern void start_thread(struct pt_regs *, unsigned long, unsigned long);
 /* Free all resources held by a thread. */
 extern void release_thread(struct task_struct *);
 
-/* Create a kernel thread without removing it from tasklists.  */
-extern long kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
-
 unsigned long get_wchan(struct task_struct *p);
 
 #define KSTK_EIP(tsk) (task_pt_regs(tsk)->pc)
diff --git a/arch/alpha/include/asm/unistd.h b/arch/alpha/include/asm/unistd.h
index a31a78eac9b9..3cb6c1188984 100644
--- a/arch/alpha/include/asm/unistd.h
+++ b/arch/alpha/include/asm/unistd.h
@@ -481,6 +481,8 @@
 #define __ARCH_WANT_SYS_OLDUMOUNT
 #define __ARCH_WANT_SYS_SIGPENDING
 #define __ARCH_WANT_SYS_RT_SIGSUSPEND
+#define __ARCH_WANT_SYS_EXECVE
+#define __ARCH_WANT_KERNEL_EXECVE
 
 /* "Conditional" syscalls.  What we want is
 
diff --git a/arch/alpha/kernel/alpha_ksyms.c b/arch/alpha/kernel/alpha_ksyms.c
index 15fa821d09cd..89566b346c0f 100644
--- a/arch/alpha/kernel/alpha_ksyms.c
+++ b/arch/alpha/kernel/alpha_ksyms.c
@@ -50,9 +50,6 @@ EXPORT_SYMBOL(alpha_read_fp_reg_s);
 EXPORT_SYMBOL(alpha_write_fp_reg);
 EXPORT_SYMBOL(alpha_write_fp_reg_s);
 
-/* entry.S */
-EXPORT_SYMBOL(kernel_thread);
-
 /* Networking helper routines. */
 EXPORT_SYMBOL(csum_tcpudp_magic);
 EXPORT_SYMBOL(ip_compute_csum);
diff --git a/arch/alpha/kernel/entry.S b/arch/alpha/kernel/entry.S
index ec0da0567ab5..7e43e1156d10 100644
--- a/arch/alpha/kernel/entry.S
+++ b/arch/alpha/kernel/entry.S
@@ -609,59 +609,35 @@ ret_from_fork:
 .end ret_from_fork
 
 /*
- * kernel_thread(fn, arg, clone_flags)
+ * ... and new kernel threads - here
  */
         .align 4
-        .globl  kernel_thread
-        .ent    kernel_thread
-kernel_thread:
-        /* We can be called from a module.  */
-        ldgp    $gp, 0($27)
-        .prologue 1
-        subq    $sp, SP_OFF+6*8, $sp
-        br      $1, 2f          /* load start address */
-
-        /* We've now "returned" from a fake system call.  */
-        unop
-        blt     $0, 1f          /* error?  */
-        ldi     $1, 0x3fff
-        beq     $20, 1f         /* parent or child?  */
-
-        bic     $sp, $1, $8     /* in child.  */
-        jsr     $26, ($27)
+        .globl  ret_from_kernel_thread
+        .ent    ret_from_kernel_thread
+ret_from_kernel_thread:
+        mov     $17, $16
+        jsr     $26, schedule_tail
+        mov     $9, $27
+        mov     $10, $16
+        jsr     $26, ($9)
         ldgp    $gp, 0($26)
         mov     $0, $16
         mov     $31, $26
         jmp     $31, sys_exit
+.end ret_from_kernel_thread
 
-1:      ret                     /* in parent.  */
-
-        .align 4
-2:      /* Fake a system call stack frame, as we can't do system calls
-           from kernel space.  Note that we store FN and ARG as they
-           need to be set up in the child for the call.  Also store $8
-           and $26 for use in the parent.  */
-        stq     $31, SP_OFF($sp)        /* ps */
-        stq     $1, SP_OFF+8($sp)       /* pc */
-        stq     $gp, SP_OFF+16($sp)     /* gp */
-        stq     $16, 136($sp)           /* $27; FN for child */
-        stq     $17, SP_OFF+24($sp)     /* $16; ARG for child */
-        stq     $8, 64($sp)             /* $8 */
-        stq     $26, 128($sp)           /* $26 */
+        .globl  ret_from_kernel_execve
+        .align  4
+        .ent    ret_from_kernel_execve
+ret_from_kernel_execve:
+        mov     $16, $sp
         /* Avoid the HAE being gratuitously wrong, to avoid restoring it.  */
         ldq     $2, alpha_mv+HAE_CACHE
         stq     $2, 152($sp)            /* HAE */
+        mov     $31, $19                /* to disable syscall restarts */
+        br      $31, ret_to_user
 
-        /* Shuffle FLAGS to the front; add CLONE_VM.  */
-        ldi     $1, CLONE_VM|CLONE_UNTRACED
-        or      $18, $1, $16
-        bsr     $26, sys_clone
-
-        /* We don't actually care for a3 success widgetry in the kernel.
-           Not for positive errno values.  */
-        stq     $0, 0($sp)              /* $0 */
-        br      ret_to_kernel
-.end kernel_thread
+.end    ret_from_kernel_execve
 
 
 /*
@@ -745,15 +721,6 @@ sys_rt_sigreturn:
 .end sys_rt_sigreturn
 
         .align  4
-        .globl  sys_execve
-        .ent    sys_execve
-sys_execve:
-        .prologue 0
-        mov     $sp, $19
-        jmp     $31, do_sys_execve
-.end sys_execve
-
-        .align  4
         .globl  alpha_ni_syscall
         .ent    alpha_ni_syscall
 alpha_ni_syscall:
diff --git a/arch/alpha/kernel/process.c b/arch/alpha/kernel/process.c
index 83638aa096d5..4054e0ffe2b2 100644
--- a/arch/alpha/kernel/process.c
+++ b/arch/alpha/kernel/process.c
@@ -263,33 +263,35 @@ alpha_vfork(struct pt_regs *regs)
 
 /*
  * Copy an alpha thread..
- *
- * Note the "stack_offset" stuff: when returning to kernel mode, we need
- * to have some extra stack-space for the kernel stack that still exists
- * after the "ret_from_fork".  When returning to user mode, we only want
- * the space needed by the syscall stack frame (ie "struct pt_regs").
- * Use the passed "regs" pointer to determine how much space we need
- * for a kernel fork().
  */
 
 int
 copy_thread(unsigned long clone_flags, unsigned long usp,
-            unsigned long unused,
+            unsigned long arg,
             struct task_struct * p, struct pt_regs * regs)
 {
         extern void ret_from_fork(void);
+        extern void ret_from_kernel_thread(void);
 
         struct thread_info *childti = task_thread_info(p);
-        struct pt_regs * childregs;
-        struct switch_stack * childstack, *stack;
-        unsigned long stack_offset, settls;
-
-        stack_offset = PAGE_SIZE - sizeof(struct pt_regs);
-        if (!(regs->ps & 8))
-                stack_offset = (PAGE_SIZE-1) & (unsigned long) regs;
-        childregs = (struct pt_regs *)
-          (stack_offset + PAGE_SIZE + task_stack_page(p));
-                
+        struct pt_regs *childregs = task_pt_regs(p);
+        struct switch_stack *childstack, *stack;
+        unsigned long settls;
+
+        childstack = ((struct switch_stack *) childregs) - 1;
+        if (unlikely(!regs)) {
+                /* kernel thread */
+                memset(childstack, 0,
+                        sizeof(struct switch_stack) + sizeof(struct pt_regs));
+                childstack->r26 = (unsigned long) ret_from_kernel_thread;
+                childstack->r9 = usp;   /* function */
+                childstack->r10 = arg;
+                childregs->hae = alpha_mv.hae_cache,
+                childti->pcb.usp = 0;
+                childti->pcb.ksp = (unsigned long) childstack;
+                childti->pcb.flags = 1; /* set FEN, clear everything else */
+                return 0;
+        }
         *childregs = *regs;
         settls = regs->r20;
         childregs->r0 = 0;
@@ -297,7 +299,6 @@ copy_thread(unsigned long clone_flags, unsigned long usp,
         childregs->r20 = 1;     /* OSF/1 has some strange fork() semantics.  */
         regs->r20 = 0;
         stack = ((struct switch_stack *) regs) - 1;
-        childstack = ((struct switch_stack *) childregs) - 1;
         *childstack = *stack;
         childstack->r26 = (unsigned long) ret_from_fork;
         childti->pcb.usp = usp;
@@ -386,27 +387,6 @@ dump_elf_task_fp(elf_fpreg_t *dest, struct task_struct *task)
 EXPORT_SYMBOL(dump_elf_task_fp);
 
 /*
- * sys_execve() executes a new program.
- */
-asmlinkage int
-do_sys_execve(const char __user *ufilename,
-              const char __user *const __user *argv,
-              const char __user *const __user *envp, struct pt_regs *regs)
-{
-        int error;
-        char *filename;
-
-        filename = getname(ufilename);
-        error = PTR_ERR(filename);
-        if (IS_ERR(filename))
-                goto out;
-        error = do_execve(filename, argv, envp, regs);
-        putname(filename);
-out:
-        return error;
-}
-
-/*
  * Return saved PC of a blocked thread.  This assumes the frame
  * pointer is the 6th saved long on the kernel stack and that the
  * saved return address is the first long in the frame.  This all
@@ -459,22 +439,3 @@ get_wchan(struct task_struct *p)
         }
         return pc;
 }
-
-int kernel_execve(const char *path, const char *const argv[], const char *const envp[])
-{
-        /* Avoid the HAE being gratuitously wrong, which would cause us
-           to do the whole turn off interrupts thing and restore it.  */
-        struct pt_regs regs = {.hae = alpha_mv.hae_cache};
-        int err = do_execve(path, argv, envp, &regs);
-        if (!err) {
-                struct pt_regs *p = current_pt_regs();
-                /* copy regs to normal position and off to userland we go... */
-                *p = regs;
-                __asm__ __volatile__ (
-                        "mov    %0, $sp;"
-                        "br     $31, ret_from_sys_call"
-                        : : "r"(p));
-        }
-        return err;
-}
-EXPORT_SYMBOL(kernel_execve);
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 2867a7742306..e40eefb5d32d 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -52,6 +52,7 @@ config ARM
         select GENERIC_STRNCPY_FROM_USER
         select GENERIC_STRNLEN_USER
         select DCACHE_WORD_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && !CPU_BIG_ENDIAN
+        select GENERIC_KERNEL_THREAD
         help
           The ARM series is a line of low-power-consumption RISC chip designs
           licensed by ARM Ltd and targeted at embedded applications and
diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h
index 99afa7498260..06e7d509eaac 100644
--- a/arch/arm/include/asm/processor.h
+++ b/arch/arm/include/asm/processor.h
@@ -85,11 +85,6 @@ unsigned long get_wchan(struct task_struct *p);
 #define cpu_relax()                     barrier()
 #endif
 
-/*
- * Create a new kernel thread
- */
-extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
-
 #define task_pt_regs(p) \
         ((struct pt_regs *)(THREAD_START_SP + task_stack_page(p)) - 1)
 
diff --git a/arch/arm/include/asm/ptrace.h b/arch/arm/include/asm/ptrace.h
index 355ece523f41..44fe998269d9 100644
--- a/arch/arm/include/asm/ptrace.h
+++ b/arch/arm/include/asm/ptrace.h
@@ -254,6 +254,11 @@ static inline unsigned long user_stack_pointer(struct pt_regs *regs)
         return regs->ARM_sp;
 }
 
+#define current_pt_regs(void) ({                                \
+        register unsigned long sp asm ("sp");                   \
+        (struct pt_regs *)((sp | (THREAD_SIZE - 1)) - 7) - 1;   \
+})
+
 #endif /* __KERNEL__ */
 
 #endif /* __ASSEMBLY__ */
diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h
index 74542c52f9be..368165e33c1c 100644
--- a/arch/arm/include/asm/system.h
+++ b/arch/arm/include/asm/system.h
@@ -2,7 +2,6 @@
 #include <asm/barrier.h>
 #include <asm/compiler.h>
 #include <asm/cmpxchg.h>
-#include <asm/exec.h>
 #include <asm/switch_to.h>
 #include <asm/system_info.h>
 #include <asm/system_misc.h>
diff --git a/arch/arm/include/asm/unistd.h b/arch/arm/include/asm/unistd.h
index d9ff5cc3a506..f259921edfe9 100644
--- a/arch/arm/include/asm/unistd.h
+++ b/arch/arm/include/asm/unistd.h
@@ -478,6 +478,8 @@
 #define __ARCH_WANT_OLD_READDIR
 #define __ARCH_WANT_SYS_SOCKETCALL
 #endif
+#define __ARCH_WANT_SYS_EXECVE
+#define __ARCH_WANT_KERNEL_EXECVE
 
 /*
  * "Conditional" syscalls
diff --git a/arch/arm/kernel/calls.S b/arch/arm/kernel/calls.S
index e337879595e5..831cd38c8d99 100644
--- a/arch/arm/kernel/calls.S
+++ b/arch/arm/kernel/calls.S
@@ -20,7 +20,7 @@
                 CALL(sys_creat)
                 CALL(sys_link)
 /* 10 */        CALL(sys_unlink)
-                CALL(sys_execve_wrapper)
+                CALL(sys_execve)
                 CALL(sys_chdir)
                 CALL(OBSOLETE(sys_time))        /* used by libc4 */
                 CALL(sys_mknod)
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index f45987037bf1..e340fa1db203 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -91,6 +91,30 @@ ENTRY(ret_from_fork)
         b       ret_slow_syscall
 ENDPROC(ret_from_fork)
 
+ENTRY(ret_from_kernel_thread)
+ UNWIND(.fnstart)
+ UNWIND(.cantunwind)
+        bl      schedule_tail
+        mov     r0, r4
+        adr     lr, BSYM(1f)    @ kernel threads should not exit
+        mov     pc, r5
+1:      bl      do_exit
+        nop
+ UNWIND(.fnend)
+ENDPROC(ret_from_kernel_thread)
+
+/*
+ * turn a kernel thread into userland process
+ * use: ret_from_kernel_execve(struct pt_regs *normal)
+ */
+ENTRY(ret_from_kernel_execve)
+        mov     why, #0                 @ not a syscall
+        str     why, [r0, #S_R0]        @ ... and we want 0 in ->ARM_r0 as well
+        get_thread_info tsk             @ thread structure
+        mov     sp, r0                  @ stack pointer just under pt_regs
+        b       ret_slow_syscall
+ENDPROC(ret_from_kernel_execve)
+
         .equ NR_syscalls,0
 #define CALL(x) .equ NR_syscalls,NR_syscalls+1
 #include "calls.S"
@@ -517,11 +541,6 @@ sys_vfork_wrapper:
                 b       sys_vfork
 ENDPROC(sys_vfork_wrapper)
 
-sys_execve_wrapper:
-                add     r3, sp, #S_OFF
-                b       sys_execve
-ENDPROC(sys_execve_wrapper)
-
 sys_clone_wrapper:
                 add     ip, sp, #S_OFF
                 str     ip, [sp, #4]
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 04eea22d7958..f98c17ff1957 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -373,6 +373,7 @@ void release_thread(struct task_struct *dead_task)
 }
 
 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
+asmlinkage void ret_from_kernel_thread(void) __asm__("ret_from_kernel_thread");
 
 int
 copy_thread(unsigned long clone_flags, unsigned long stack_start,
@@ -381,13 +382,20 @@ copy_thread(unsigned long clone_flags, unsigned long stack_start,
         struct thread_info *thread = task_thread_info(p);
         struct pt_regs *childregs = task_pt_regs(p);
 
-        *childregs = *regs;
-        childregs->ARM_r0 = 0;
-        childregs->ARM_sp = stack_start;
-
         memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
+
+        if (likely(regs)) {
+                *childregs = *regs;
+                childregs->ARM_r0 = 0;
+                childregs->ARM_sp = stack_start;
+                thread->cpu_context.pc = (unsigned long)ret_from_fork;
+        } else {
+                thread->cpu_context.r4 = stk_sz;
+                thread->cpu_context.r5 = stack_start;
+                thread->cpu_context.pc = (unsigned long)ret_from_kernel_thread;
+                childregs->ARM_cpsr = SVC_MODE;
+        }
         thread->cpu_context.sp = (unsigned long)childregs;
-        thread->cpu_context.pc = (unsigned long)ret_from_fork;
 
         clear_ptrace_hw_breakpoint(p);
 
@@ -423,63 +431,6 @@ int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
 }
 EXPORT_SYMBOL(dump_fpu);
 
-/*
- * Shuffle the argument into the correct register before calling the
- * thread function.  r4 is the thread argument, r5 is the pointer to
- * the thread function, and r6 points to the exit function.
- */
-extern void kernel_thread_helper(void);
-asm(    ".pushsection .text\n"
-"       .align\n"
-"       .type   kernel_thread_helper, #function\n"
-"kernel_thread_helper:\n"
-#ifdef CONFIG_TRACE_IRQFLAGS
-"       bl      trace_hardirqs_on\n"
-#endif
-"       msr     cpsr_c, r7\n"
-"       mov     r0, r4\n"
-"       mov     lr, r6\n"
-"       mov     pc, r5\n"
-"       .size   kernel_thread_helper, . - kernel_thread_helper\n"
-"       .popsection");
-
-#ifdef CONFIG_ARM_UNWIND
-extern void kernel_thread_exit(long code);
-asm(    ".pushsection .text\n"
-"       .align\n"
-"       .type   kernel_thread_exit, #function\n"
-"kernel_thread_exit:\n"
-"       .fnstart\n"
-"       .cantunwind\n"
-"       bl      do_exit\n"
-"       nop\n"
-"       .fnend\n"
-"       .size   kernel_thread_exit, . - kernel_thread_exit\n"
-"       .popsection");
-#else
-#define kernel_thread_exit      do_exit
-#endif
-
-/*
- * Create a kernel thread.
- */
-pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-        struct pt_regs regs;
-
-        memset(&regs, 0, sizeof(regs));
-
-        regs.ARM_r4 = (unsigned long)arg;
-        regs.ARM_r5 = (unsigned long)fn;
-        regs.ARM_r6 = (unsigned long)kernel_thread_exit;
-        regs.ARM_r7 = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE;
-        regs.ARM_pc = (unsigned long)kernel_thread_helper;
-        regs.ARM_cpsr = regs.ARM_r7 | PSR_I_BIT;
-
-        return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
-
 unsigned long get_wchan(struct task_struct *p)
 {
         struct stackframe frame;
diff --git a/arch/arm/kernel/sys_arm.c b/arch/arm/kernel/sys_arm.c
index 76cbb055dd05..c2a898aa57aa 100644
--- a/arch/arm/kernel/sys_arm.c
+++ b/arch/arm/kernel/sys_arm.c
@@ -59,69 +59,6 @@ asmlinkage int sys_vfork(struct pt_regs *regs)
         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->ARM_sp, regs, 0, NULL, NULL);
 }
 
-/* sys_execve() executes a new program.
- * This is called indirectly via a small wrapper
- */
-asmlinkage int sys_execve(const char __user *filenamei,
-                          const char __user *const __user *argv,
-                          const char __user *const __user *envp, struct pt_regs *regs)
-{
-        int error;
-        char * filename;
-
-        filename = getname(filenamei);
-        error = PTR_ERR(filename);
-        if (IS_ERR(filename))
-                goto out;
-        error = do_execve(filename, argv, envp, regs);
-        putname(filename);
-out:
-        return error;
-}
-
-int kernel_execve(const char *filename,
-                  const char *const argv[],
-                  const char *const envp[])
-{
-        struct pt_regs regs;
-        int ret;
-
-        memset(&regs, 0, sizeof(struct pt_regs));
-        ret = do_execve(filename,
-                        (const char __user *const __user *)argv,
-                        (const char __user *const __user *)envp, &regs);
-        if (ret < 0)
-                goto out;
-
-        /*
-         * Save argc to the register structure for userspace.
-         */
-        regs.ARM_r0 = ret;
-
-        /*
-         * We were successful.  We won't be returning to our caller, but
-         * instead to user space by manipulating the kernel stack.
-         */
-        asm(    "add    r0, %0, %1\n\t"
-                "mov    r1, %2\n\t"
-                "mov    r2, %3\n\t"
-                "bl     memmove\n\t"    /* copy regs to top of stack */
-                "mov    r8, #0\n\t"     /* not a syscall */
-                "mov    r9, %0\n\t"     /* thread structure */
-                "mov    sp, r0\n\t"     /* reposition stack pointer */
-                "b      ret_to_user"
-                :
-                : "r" (current_thread_info()),
-                  "Ir" (THREAD_START_SP - sizeof(regs)),
-                  "r" (&regs),
-                  "Ir" (sizeof(regs))
-                : "r0", "r1", "r2", "r3", "r8", "r9", "ip", "lr", "memory");
-
- out:
-        return ret;
-}
-EXPORT_SYMBOL(kernel_execve);
-
 /*
  * Since loff_t is a 64 bit type we avoid a lot of ABI hassle
  * with a different argument ordering.
diff --git a/arch/avr32/include/asm/Kbuild b/arch/avr32/include/asm/Kbuild
index e3ba7bca06fa..be0433ee5a8e 100644
--- a/arch/avr32/include/asm/Kbuild
+++ b/arch/avr32/include/asm/Kbuild
@@ -1,5 +1,6 @@
 include include/asm-generic/Kbuild.asm
 
 generic-y       += clkdev.h
+generic-y       += exec.h
 
 header-y        += cachectl.h
diff --git a/arch/avr32/include/asm/exec.h b/arch/avr32/include/asm/exec.h
deleted file mode 100644
index f467be8bf823..000000000000
--- a/arch/avr32/include/asm/exec.h
+++ /dev/null
@@ -1,13 +0,0 @@
-/*
- * Copyright (C) 2004-2006 Atmel Corporation
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-#ifndef __ASM_AVR32_EXEC_H
-#define __ASM_AVR32_EXEC_H
-
-#define arch_align_stack(x)     (x)
-
-#endif /* __ASM_AVR32_EXEC_H */
diff --git a/arch/c6x/include/asm/Kbuild b/arch/c6x/include/asm/Kbuild
index 277f1a4ecb09..4e4e98da8192 100644
--- a/arch/c6x/include/asm/Kbuild
+++ b/arch/c6x/include/asm/Kbuild
@@ -12,6 +12,7 @@ generic-y += div64.h
 generic-y += dma.h
 generic-y += emergency-restart.h
 generic-y += errno.h
+generic-y += exec.h
 generic-y += fb.h
 generic-y += fcntl.h
 generic-y += futex.h
diff --git a/arch/c6x/include/asm/exec.h b/arch/c6x/include/asm/exec.h
deleted file mode 100644
index 0fea482cdc84..000000000000
--- a/arch/c6x/include/asm/exec.h
+++ /dev/null
@@ -1,6 +0,0 @@
-#ifndef _ASM_C6X_EXEC_H
-#define _ASM_C6X_EXEC_H
-
-#define arch_align_stack(x) (x)
-
-#endif /* _ASM_C6X_EXEC_H */
diff --git a/arch/cris/include/asm/Kbuild b/arch/cris/include/asm/Kbuild
index a8eab26a1ec7..ff1bf7fcae8e 100644
--- a/arch/cris/include/asm/Kbuild
+++ b/arch/cris/include/asm/Kbuild
@@ -9,3 +9,4 @@ header-y += rs485.h
 header-y += sync_serial.h
 
 generic-y += clkdev.h
+generic-y += exec.h
diff --git a/arch/cris/include/asm/exec.h b/arch/cris/include/asm/exec.h
deleted file mode 100644
index 9665dab7e25b..000000000000
--- a/arch/cris/include/asm/exec.h
+++ /dev/null
@@ -1,6 +0,0 @@
-#ifndef __ASM_CRIS_EXEC_H
-#define __ASM_CRIS_EXEC_H
-
-#define arch_align_stack(x) (x)
-
-#endif /* __ASM_CRIS_EXEC_H */
diff --git a/arch/frv/include/asm/Kbuild b/arch/frv/include/asm/Kbuild
index 13cd044aabdf..251bd7125576 100644
--- a/arch/frv/include/asm/Kbuild
+++ b/arch/frv/include/asm/Kbuild
@@ -3,3 +3,4 @@ include include/asm-generic/Kbuild.asm
 header-y += registers.h
 header-y += termios.h
 generic-y += clkdev.h
+generic-y += exec.h
diff --git a/arch/frv/include/asm/exec.h b/arch/frv/include/asm/exec.h
deleted file mode 100644
index 65c91305d4a7..000000000000
--- a/arch/frv/include/asm/exec.h
+++ /dev/null
@@ -1,17 +0,0 @@
-/* FR-V CPU executable handling
- *
- * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
- */
-
-#ifndef _ASM_EXEC_H
-#define _ASM_EXEC_H
-
-#define arch_align_stack(x) (x)
-
-#endif /* _ASM_EXEC_H */
diff --git a/arch/h8300/include/asm/Kbuild b/arch/h8300/include/asm/Kbuild
index 0e152a93c125..fccd81eddff1 100644
--- a/arch/h8300/include/asm/Kbuild
+++ b/arch/h8300/include/asm/Kbuild
@@ -1,3 +1,4 @@
 include include/asm-generic/Kbuild.asm
 
-generic-y       += clkdev.h
+generic-y += clkdev.h
+generic-y += exec.h
diff --git a/arch/h8300/include/asm/exec.h b/arch/h8300/include/asm/exec.h
deleted file mode 100644
index c01c45ccadf9..000000000000
--- a/arch/h8300/include/asm/exec.h
+++ /dev/null
@@ -1,6 +0,0 @@
-#ifndef _H8300_EXEC_H
-#define _H8300_EXEC_H
-
-#define arch_align_stack(x) (x)
-
-#endif /* _H8300_EXEC_H */
diff --git a/arch/hexagon/kernel/syscall.c b/arch/hexagon/kernel/syscall.c
index 620dd18197a0..553cd60ee659 100644
--- a/arch/hexagon/kernel/syscall.c
+++ b/arch/hexagon/kernel/syscall.c
@@ -87,4 +87,3 @@ int kernel_execve(const char *filename,
 
         return retval;
 }
-EXPORT_SYMBOL(kernel_execve);
diff --git a/arch/ia64/include/asm/Kbuild b/arch/ia64/include/asm/Kbuild
index 58f3d14a6cd4..562f59315847 100644
--- a/arch/ia64/include/asm/Kbuild
+++ b/arch/ia64/include/asm/Kbuild
@@ -14,3 +14,4 @@ header-y += rse.h
 header-y += ucontext.h
 header-y += ustack.h
 generic-y += clkdev.h
+generic-y += exec.h
diff --git a/arch/ia64/include/asm/exec.h b/arch/ia64/include/asm/exec.h
deleted file mode 100644
index b26242490e36..000000000000
--- a/arch/ia64/include/asm/exec.h
+++ /dev/null
@@ -1,14 +0,0 @@
-/*
- * Process execution defines.
- *
- * Copyright (C) 1998-2003 Hewlett-Packard Co
- *      David Mosberger-Tang <davidm@hpl.hp.com>
- * Copyright (C) 1999 Asit Mallick <asit.k.mallick@intel.com>
- * Copyright (C) 1999 Don Dugger <don.dugger@intel.com>
- */
-#ifndef _ASM_IA64_EXEC_H
-#define _ASM_IA64_EXEC_H
-
-#define arch_align_stack(x) (x)
-
-#endif /* _ASM_IA64_EXEC_H */
diff --git a/arch/m32r/include/asm/Kbuild b/arch/m32r/include/asm/Kbuild
index 0e152a93c125..fccd81eddff1 100644
--- a/arch/m32r/include/asm/Kbuild
+++ b/arch/m32r/include/asm/Kbuild
@@ -1,3 +1,4 @@
 include include/asm-generic/Kbuild.asm
 
-generic-y       += clkdev.h
+generic-y += clkdev.h
+generic-y += exec.h
diff --git a/arch/m32r/include/asm/exec.h b/arch/m32r/include/asm/exec.h
deleted file mode 100644
index c805dbd75b5d..000000000000
--- a/arch/m32r/include/asm/exec.h
+++ /dev/null
@@ -1,14 +0,0 @@
-/*
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 2001  Hiroyuki Kondo, Hirokazu Takata, and Hitoshi Yamamoto
- * Copyright (C) 2004, 2006  Hirokazu Takata <takata at linux-m32r.org>
- */
-#ifndef _ASM_M32R_EXEC_H
-#define _ASM_M32R_EXEC_H
-
-#define arch_align_stack(x) (x)
-
-#endif /* _ASM_M32R_EXEC_H */
diff --git a/arch/m68k/include/asm/Kbuild b/arch/m68k/include/asm/Kbuild
index bfe675f0faee..ecb540810ab3 100644
--- a/arch/m68k/include/asm/Kbuild
+++ b/arch/m68k/include/asm/Kbuild
@@ -7,6 +7,7 @@ generic-y += cputime.h
 generic-y += device.h
 generic-y += emergency-restart.h
 generic-y += errno.h
+generic-y += exec.h
 generic-y += futex.h
 generic-y += ioctl.h
 generic-y += ipcbuf.h
diff --git a/arch/m68k/include/asm/exec.h b/arch/m68k/include/asm/exec.h
deleted file mode 100644
index 0499adf90230..000000000000
--- a/arch/m68k/include/asm/exec.h
+++ /dev/null
@@ -1,6 +0,0 @@
-#ifndef _M68K_EXEC_H
-#define _M68K_EXEC_H
-
-#define arch_align_stack(x) (x)
-
-#endif /* _M68K_EXEC_H */
diff --git a/arch/microblaze/include/asm/Kbuild b/arch/microblaze/include/asm/Kbuild
index 48510f6cec8f..8653072d7e9f 100644
--- a/arch/microblaze/include/asm/Kbuild
+++ b/arch/microblaze/include/asm/Kbuild
@@ -2,3 +2,4 @@ include include/asm-generic/Kbuild.asm
 
 header-y  += elf.h
 generic-y += clkdev.h
+generic-y += exec.h
diff --git a/arch/microblaze/include/asm/exec.h b/arch/microblaze/include/asm/exec.h
deleted file mode 100644
index e750de1fe8fb..000000000000
--- a/arch/microblaze/include/asm/exec.h
+++ /dev/null
@@ -1,14 +0,0 @@
-/*
- * Copyright (C) 2006 Atmark Techno, Inc.
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License. See the file "COPYING" in the main directory of this archive
- * for more details.
- */
-
-#ifndef _ASM_MICROBLAZE_EXEC_H
-#define _ASM_MICROBLAZE_EXEC_H
-
-#define arch_align_stack(x) (x)
-
-#endif /* _ASM_MICROBLAZE_EXEC_H */
diff --git a/arch/mn10300/include/asm/Kbuild b/arch/mn10300/include/asm/Kbuild
index 0d20f5526dd8..fccd81eddff1 100644
--- a/arch/mn10300/include/asm/Kbuild
+++ b/arch/mn10300/include/asm/Kbuild
@@ -1,3 +1,4 @@
 include include/asm-generic/Kbuild.asm
 
 generic-y += clkdev.h
+generic-y += exec.h
diff --git a/arch/mn10300/include/asm/exec.h b/arch/mn10300/include/asm/exec.h
deleted file mode 100644
index c74e367f4b9d..000000000000
--- a/arch/mn10300/include/asm/exec.h
+++ /dev/null
@@ -1,16 +0,0 @@
-/* MN10300 process execution definitions
- *
- * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- */
-#ifndef _ASM_EXEC_H
-#define _ASM_EXEC_H
-
-#define arch_align_stack(x) (x)
-
-#endif /* _ASM_EXEC_H */
diff --git a/arch/parisc/include/asm/Kbuild b/arch/parisc/include/asm/Kbuild
index 0587f62e5b76..458371a1565a 100644
--- a/arch/parisc/include/asm/Kbuild
+++ b/arch/parisc/include/asm/Kbuild
@@ -3,3 +3,4 @@ include include/asm-generic/Kbuild.asm
 header-y += pdc.h
 generic-y += clkdev.h
 generic-y += word-at-a-time.h
+generic-y += exec.h
diff --git a/arch/parisc/include/asm/exec.h b/arch/parisc/include/asm/exec.h
deleted file mode 100644
index 6bb5af75b17a..000000000000
--- a/arch/parisc/include/asm/exec.h
+++ /dev/null
@@ -1,6 +0,0 @@
-#ifndef __PARISC_EXEC_H
-#define __PARISC_EXEC_H
-
-#define arch_align_stack(x) (x)
-
-#endif /* __PARISC_EXEC_H */
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index ceff7aef2477..99d2d790d152 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -135,6 +135,7 @@ config S390
         select GENERIC_CLOCKEVENTS
         select KTIME_SCALAR if 32BIT
         select HAVE_ARCH_SECCOMP_FILTER
+        select GENERIC_KERNEL_THREAD
 
 config SCHED_OMIT_FRAME_POINTER
         def_bool y
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 56831dfa9198..94e749c90230 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -35,6 +35,7 @@ static inline void get_cpu_id(struct cpuid *ptr)
 extern void s390_adjust_jiffies(void);
 extern const struct seq_operations cpuinfo_op;
 extern int sysctl_ieee_emulation_warnings;
+extern void execve_tail(void);
 
 /*
  * User space process size: 2GB for 31 bit, 4TB or 8PT for 64 bit.
@@ -126,6 +127,7 @@ struct stack_frame {
         regs->psw.mask  = psw_user_bits | PSW_MASK_EA | PSW_MASK_BA;    \
         regs->psw.addr  = new_psw | PSW_ADDR_AMODE;                     \
         regs->gprs[15]  = new_stackp;                                   \
+        execve_tail();                                                  \
 } while (0)
 
 #define start_thread31(regs, new_psw, new_stackp) do {                  \
@@ -135,6 +137,7 @@ struct stack_frame {
         __tlb_flush_mm(current->mm);                                    \
         crst_table_downgrade(current->mm, 1UL << 31);                   \
         update_mm(current->mm, current);                                \
+        execve_tail();                                                  \
 } while (0)
 
 /* Forward declaration, a strange C thing */
@@ -150,7 +153,6 @@ static inline void show_cacheinfo(struct seq_file *m) { }
 
 /* Free all resources held by a thread. */
 extern void release_thread(struct task_struct *);
-extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
 
 /*
  * Return saved PC of a blocked thread.
diff --git a/arch/s390/include/asm/unistd.h b/arch/s390/include/asm/unistd.h
index 4e64b5cd1558..8192e292753a 100644
--- a/arch/s390/include/asm/unistd.h
+++ b/arch/s390/include/asm/unistd.h
@@ -417,6 +417,8 @@
 #   define __ARCH_WANT_COMPAT_SYS_TIME
 #   define __ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND
 # endif
+#define __ARCH_WANT_SYS_EXECVE
+#define __ARCH_WANT_KERNEL_EXECVE
 
 /*
  * "Conditional" syscalls
diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
index 189963c90c6e..65cca95843e1 100644
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -432,32 +432,6 @@ sys32_rt_sigqueueinfo(int pid, int sig, compat_siginfo_t __user *uinfo)
         return ret;
 }
 
-/*
- * sys32_execve() executes a new program after the asm stub has set
- * things up for us.  This should basically do what I want it to.
- */
-asmlinkage long sys32_execve(const char __user *name, compat_uptr_t __user *argv,
-                             compat_uptr_t __user *envp)
-{
-        struct pt_regs *regs = task_pt_regs(current);
-        char *filename;
-        long rc;
-
-        filename = getname(name);
-        rc = PTR_ERR(filename);
-        if (IS_ERR(filename))
-                return rc;
-        rc = compat_do_execve(filename, argv, envp, regs);
-        if (rc)
-                goto out;
-        current->thread.fp_regs.fpc=0;
-        asm volatile("sfpc %0,0" : : "d" (0));
-        rc = regs->gprs[2];
-out:
-        putname(filename);
-        return rc;
-}
-
 asmlinkage long sys32_pread64(unsigned int fd, char __user *ubuf,
                                 size_t count, u32 poshi, u32 poslo)
 {
diff --git a/arch/s390/kernel/compat_linux.h b/arch/s390/kernel/compat_linux.h
index 90887bd98cf0..d4d0239970ac 100644
--- a/arch/s390/kernel/compat_linux.h
+++ b/arch/s390/kernel/compat_linux.h
@@ -125,8 +125,6 @@ long sys32_rt_sigprocmask(int how, compat_sigset_t __user *set,
                           compat_sigset_t __user *oset, size_t sigsetsize);
 long sys32_rt_sigpending(compat_sigset_t __user *set, size_t sigsetsize);
 long sys32_rt_sigqueueinfo(int pid, int sig, compat_siginfo_t __user *uinfo);
-long sys32_execve(const char __user *name, compat_uptr_t __user *argv,
-                  compat_uptr_t __user *envp);
 long sys32_init_module(void __user *umod, unsigned long len,
                        const char __user *uargs);
 long sys32_delete_module(const char __user *name_user, unsigned int flags);
diff --git a/arch/s390/kernel/compat_wrapper.S b/arch/s390/kernel/compat_wrapper.S
index 3afba804fe97..ad79b846535c 100644
--- a/arch/s390/kernel/compat_wrapper.S
+++ b/arch/s390/kernel/compat_wrapper.S
@@ -1576,7 +1576,7 @@ ENTRY(sys32_execve_wrapper)
         llgtr   %r2,%r2                 # char *
         llgtr   %r3,%r3                 # compat_uptr_t *
         llgtr   %r4,%r4                 # compat_uptr_t *
-        jg      sys32_execve            # branch to system call
+        jg      compat_sys_execve       # branch to system call
 
 ENTRY(sys_fanotify_init_wrapper)
         llgfr   %r2,%r2                 # unsigned int
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 870bad6d56fc..ef46f66bc0d6 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -331,45 +331,38 @@ ENTRY(ret_from_fork)
         l       %r12,__LC_THREAD_INFO
         l       %r13,__LC_SVC_NEW_PSW+4
         tm      __PT_PSW+1(%r11),0x01   # forking a kernel thread ?
-        jo      0f
-        st      %r15,__PT_R15(%r11)     # store stack pointer for new kthread
-0:      l       %r1,BASED(.Lschedule_tail)
+        je      1f
+        l       %r1,BASED(.Lschedule_tail)
         basr    %r14,%r1                # call schedule_tail
         TRACE_IRQS_ON
         ssm     __LC_SVC_NEW_PSW        # reenable interrupts
         j       sysc_tracenogo
 
+1:      # it's a kernel thread
+        st      %r15,__PT_R15(%r11)     # store stack pointer for new kthread
+        l       %r1,BASED(.Lschedule_tail)
+        basr    %r14,%r1                # call schedule_tail
+        TRACE_IRQS_ON
+        ssm     __LC_SVC_NEW_PSW        # reenable interrupts
+        lm      %r9,%r11,__PT_R9(%r11)  # load gprs
+ENTRY(kernel_thread_starter)
+        la      %r2,0(%r10)
+        basr    %r14,%r9
+        la      %r2,0
+        br      %r11                    # do_exit
+
 #
 # kernel_execve function needs to deal with pt_regs that is not
 # at the usual place
 #
-ENTRY(kernel_execve)
-        stm     %r12,%r15,48(%r15)
-        lr      %r14,%r15
-        l       %r13,__LC_SVC_NEW_PSW+4
-        ahi     %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
-        st      %r14,__SF_BACKCHAIN(%r15)
-        la      %r12,STACK_FRAME_OVERHEAD(%r15)
-        xc      0(__PT_SIZE,%r12),0(%r12)
-        l       %r1,BASED(.Ldo_execve)
-        lr      %r5,%r12
-        basr    %r14,%r1                # call do_execve
-        ltr     %r2,%r2
-        je      0f
-        ahi     %r15,(STACK_FRAME_OVERHEAD + __PT_SIZE)
-        lm      %r12,%r15,48(%r15)
-        br      %r14
-        # execve succeeded.
-0:      ssm     __LC_PGM_NEW_PSW        # disable I/O and ext. interrupts
-        l       %r15,__LC_KERNEL_STACK  # load ksp
-        ahi     %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
-        la      %r11,STACK_FRAME_OVERHEAD(%r15)
-        mvc     0(__PT_SIZE,%r11),0(%r12)       # copy pt_regs
-        l       %r12,__LC_THREAD_INFO
+ENTRY(ret_from_kernel_execve)
+        ssm     __LC_PGM_NEW_PSW        # disable I/O and ext. interrupts
+        lr      %r15,%r2
+        lr      %r11,%r2
+        ahi     %r15,-STACK_FRAME_OVERHEAD
         xc      __SF_BACKCHAIN(4,%r15),__SF_BACKCHAIN(%r15)
+        l       %r12,__LC_THREAD_INFO
         ssm     __LC_SVC_NEW_PSW        # reenable interrupts
-        l       %r1,BASED(.Lexecve_tail)
-        basr    %r14,%r1                # call execve_tail
         j       sysc_return
 
 /*
@@ -931,8 +924,6 @@ cleanup_idle_wait:
 .Ldo_signal:            .long   do_signal
 .Ldo_notify_resume:     .long   do_notify_resume
 .Ldo_per_trap:          .long   do_per_trap
-.Ldo_execve:            .long   do_execve
-.Lexecve_tail:          .long   execve_tail
 .Ljump_table:           .long   pgm_check_table
 .Lschedule:             .long   schedule
 #ifdef CONFIG_PREEMPT
diff --git a/arch/s390/kernel/entry.h b/arch/s390/kernel/entry.h
index a5f4dc42a5db..d0d3f69a7346 100644
--- a/arch/s390/kernel/entry.h
+++ b/arch/s390/kernel/entry.h
@@ -58,9 +58,6 @@ long sys_fork(void);
 long sys_clone(unsigned long newsp, unsigned long clone_flags,
                int __user *parent_tidptr, int __user *child_tidptr);
 long sys_vfork(void);
-void execve_tail(void);
-long sys_execve(const char __user *name, const char __user *const __user *argv,
-                const char __user *const __user *envp);
 long sys_sigsuspend(int history0, int history1, old_sigset_t mask);
 long sys_sigaction(int sig, const struct old_sigaction __user *act,
                    struct old_sigaction __user *oact);
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index 7549985402f7..f9761f806c9e 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -353,41 +353,31 @@ ENTRY(ret_from_fork)
         la      %r11,STACK_FRAME_OVERHEAD(%r15)
         lg      %r12,__LC_THREAD_INFO
         tm      __PT_PSW+1(%r11),0x01   # forking a kernel thread ?
-        jo      0f
-        stg     %r15,__PT_R15(%r11)     # store stack pointer for new kthread
-0:      brasl   %r14,schedule_tail
+        je      1f
+        brasl   %r14,schedule_tail
         TRACE_IRQS_ON
         ssm     __LC_SVC_NEW_PSW        # reenable interrupts
         j       sysc_tracenogo
-
-#
-# kernel_execve function needs to deal with pt_regs that is not
-# at the usual place
-#
-ENTRY(kernel_execve)
-        stmg    %r12,%r15,96(%r15)
-        lgr     %r14,%r15
-        aghi    %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
-        stg     %r14,__SF_BACKCHAIN(%r15)
-        la      %r12,STACK_FRAME_OVERHEAD(%r15)
-        xc      0(__PT_SIZE,%r12),0(%r12)
-        lgr     %r5,%r12
-        brasl   %r14,do_execve
-        ltgfr   %r2,%r2
-        je      0f
-        aghi    %r15,(STACK_FRAME_OVERHEAD + __PT_SIZE)
-        lmg     %r12,%r15,96(%r15)
-        br      %r14
-        # execve succeeded.
-0:      ssm     __LC_PGM_NEW_PSW        # disable I/O and ext. interrupts
-        lg      %r15,__LC_KERNEL_STACK  # load ksp
-        aghi    %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
-        la      %r11,STACK_FRAME_OVERHEAD(%r15)
-        mvc     0(__PT_SIZE,%r11),0(%r12)       # copy pt_regs
-        lg      %r12,__LC_THREAD_INFO
+1:      # it's a kernel thread
+        stg     %r15,__PT_R15(%r11)     # store stack pointer for new kthread
+        brasl   %r14,schedule_tail
+        TRACE_IRQS_ON
+        ssm     __LC_SVC_NEW_PSW        # reenable interrupts
+        lmg     %r9,%r11,__PT_R9(%r11)  # load gprs
+ENTRY(kernel_thread_starter)
+        la      %r2,0(%r10)
+        basr    %r14,%r9
+        la      %r2,0
+        br      %r11                    # do_exit
+
+ENTRY(ret_from_kernel_execve)
+        ssm     __LC_PGM_NEW_PSW        # disable I/O and ext. interrupts
+        lgr     %r15,%r2
+        lgr     %r11,%r2
+        aghi    %r15,-STACK_FRAME_OVERHEAD
         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
+        lg      %r12,__LC_THREAD_INFO
         ssm     __LC_SVC_NEW_PSW        # reenable interrupts
-        brasl   %r14,execve_tail
         j       sysc_return
 
 /*
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 5024be27df44..cd31ad457a9b 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -100,35 +100,6 @@ void cpu_idle(void)
 
 extern void __kprobes kernel_thread_starter(void);
 
-asm(
-        ".section .kprobes.text, \"ax\"\n"
-        ".global kernel_thread_starter\n"
-        "kernel_thread_starter:\n"
-        "    la    2,0(10)\n"
-        "    basr  14,9\n"
-        "    la    2,0\n"
-        "    br    11\n"
-        ".previous\n");
-
-int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
-{
-        struct pt_regs regs;
-
-        memset(&regs, 0, sizeof(regs));
-        regs.psw.mask = psw_kernel_bits |
-                PSW_MASK_DAT | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
-        regs.psw.addr = (unsigned long) kernel_thread_starter | PSW_ADDR_AMODE;
-        regs.gprs[9] = (unsigned long) fn;
-        regs.gprs[10] = (unsigned long) arg;
-        regs.gprs[11] = (unsigned long) do_exit;
-        regs.orig_gpr2 = -1;
-
-        /* Ok, create the new process.. */
-        return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
-                       0, &regs, 0, NULL, NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
-
 /*
  * Free current thread data structures etc..
  */
@@ -146,7 +117,7 @@ void release_thread(struct task_struct *dead_task)
 }
 
 int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
-                unsigned long unused,
+                unsigned long arg,
                 struct task_struct *p, struct pt_regs *regs)
 {
         struct thread_info *ti;
@@ -158,20 +129,44 @@ int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
 
         frame = container_of(task_pt_regs(p), struct fake_frame, childregs);
         p->thread.ksp = (unsigned long) frame;
-        /* Store access registers to kernel stack of new process. */
-        frame->childregs = *regs;
-        frame->childregs.gprs[2] = 0;   /* child returns 0 on fork. */
-        frame->childregs.gprs[15] = new_stackp;
-        frame->sf.back_chain = 0;
+        /* Save access registers to new thread structure. */
+        save_access_regs(&p->thread.acrs[0]);
+        /* start new process with ar4 pointing to the correct address space */
+        p->thread.mm_segment = get_fs();
+        /* Don't copy debug registers */
+        memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
+        memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
+        clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
+        clear_tsk_thread_flag(p, TIF_PER_TRAP);
+        /* Initialize per thread user and system timer values */
+        ti = task_thread_info(p);
+        ti->user_timer = 0;
+        ti->system_timer = 0;
 
+        frame->sf.back_chain = 0;
         /* new return point is ret_from_fork */
         frame->sf.gprs[8] = (unsigned long) ret_from_fork;
-
         /* fake return stack for resume(), don't go back to schedule */
         frame->sf.gprs[9] = (unsigned long) frame;
 
-        /* Save access registers to new thread structure. */
-        save_access_regs(&p->thread.acrs[0]);
+        /* Store access registers to kernel stack of new process. */
+        if (unlikely(!regs)) {
+                /* kernel thread */
+                memset(&frame->childregs, 0, sizeof(struct pt_regs));
+                frame->childregs.psw.mask = psw_kernel_bits | PSW_MASK_DAT |
+                                PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
+                frame->childregs.psw.addr = PSW_ADDR_AMODE |
+                                (unsigned long) kernel_thread_starter;
+                frame->childregs.gprs[9] = new_stackp; /* function */
+                frame->childregs.gprs[10] = arg;
+                frame->childregs.gprs[11] = (unsigned long) do_exit;
+                frame->childregs.orig_gpr2 = -1;
+
+                return 0;
+        }
+        frame->childregs = *regs;
+        frame->childregs.gprs[2] = 0;   /* child returns 0 on fork. */
+        frame->childregs.gprs[15] = new_stackp;
 
         /* Don't copy runtime instrumentation info */
         p->thread.ri_cb = NULL;
@@ -202,17 +197,6 @@ int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
                 }
         }
 #endif /* CONFIG_64BIT */
-        /* start new process with ar4 pointing to the correct address space */
-        p->thread.mm_segment = get_fs();
-        /* Don't copy debug registers */
-        memset(&p->thread.per_user, 0, sizeof(p->thread.per_user));
-        memset(&p->thread.per_event, 0, sizeof(p->thread.per_event));
-        clear_tsk_thread_flag(p, TIF_SINGLE_STEP);
-        clear_tsk_thread_flag(p, TIF_PER_TRAP);
-        /* Initialize per thread user and system timer values */
-        ti = task_thread_info(p);
-        ti->user_timer = 0;
-        ti->system_timer = 0;
         return 0;
 }
 
@@ -258,31 +242,6 @@ asmlinkage void execve_tail(void)
 }
 
 /*
- * sys_execve() executes a new program.
- */
-SYSCALL_DEFINE3(execve, const char __user *, name,
-                const char __user *const __user *, argv,
-                const char __user *const __user *, envp)
-{
-        struct pt_regs *regs = task_pt_regs(current);
-        char *filename;
-        long rc;
-
-        filename = getname(name);
-        rc = PTR_ERR(filename);
-        if (IS_ERR(filename))
-                return rc;
-        rc = do_execve(filename, argv, envp, regs);
-        if (rc)
-                goto out;
-        execve_tail();
-        rc = regs->gprs[2];
-out:
-        putname(filename);
-        return rc;
-}
-
-/*
  * fill in the FPU structure for a core dump.
  */
 int dump_fpu (struct pt_regs * regs, s390_fp_regs *fpregs)
diff --git a/arch/sh/include/asm/Kbuild b/arch/sh/include/asm/Kbuild
index 7b673ddcd555..86eadceff097 100644
--- a/arch/sh/include/asm/Kbuild
+++ b/arch/sh/include/asm/Kbuild
@@ -7,6 +7,7 @@ generic-y += delay.h
 generic-y += div64.h
 generic-y += emergency-restart.h
 generic-y += errno.h
+generic-y += exec.h
 generic-y += fcntl.h
 generic-y += ioctl.h
 generic-y += ipcbuf.h
diff --git a/arch/sh/include/asm/exec.h b/arch/sh/include/asm/exec.h
deleted file mode 100644
index 69486a9497f7..000000000000
--- a/arch/sh/include/asm/exec.h
+++ /dev/null
@@ -1,10 +0,0 @@
-/*
- * Copyright (C) 1999, 2000  Niibe Yutaka  &  Kaz Kojima
- * Copyright (C) 2002 Paul Mundt
- */
-#ifndef __ASM_SH_EXEC_H
-#define __ASM_SH_EXEC_H
-
-#define arch_align_stack(x) (x)
-
-#endif /* __ASM_SH_EXEC_H */
diff --git a/arch/sparc/include/asm/Kbuild b/arch/sparc/include/asm/Kbuild
index 61d41c11ee0a..10d54e5e37f5 100644
--- a/arch/sparc/include/asm/Kbuild
+++ b/arch/sparc/include/asm/Kbuild
@@ -3,6 +3,7 @@
 
 generic-y += clkdev.h
 generic-y += div64.h
+generic-y += exec.h
 generic-y += local64.h
 generic-y += irq_regs.h
 generic-y += local.h
diff --git a/arch/sparc/include/asm/exec.h b/arch/sparc/include/asm/exec.h
deleted file mode 100644
index 2e085881e0d1..000000000000
--- a/arch/sparc/include/asm/exec.h
+++ /dev/null
@@ -1,6 +0,0 @@
-#ifndef __SPARC_EXEC_H
-#define __SPARC_EXEC_H
-
-#define arch_align_stack(x) (x)
-
-#endif /* __SPARC_EXEC_H */
diff --git a/arch/tile/include/asm/Kbuild b/arch/tile/include/asm/Kbuild
index ea2e8ea3eb61..5cd98fac9899 100644
--- a/arch/tile/include/asm/Kbuild
+++ b/arch/tile/include/asm/Kbuild
@@ -13,6 +13,7 @@ generic-y += cputime.h
 generic-y += div64.h
 generic-y += emergency-restart.h
 generic-y += errno.h
+generic-y += exec.h
 generic-y += fb.h
 generic-y += fcntl.h
 generic-y += ioctl.h
diff --git a/arch/tile/include/asm/exec.h b/arch/tile/include/asm/exec.h
deleted file mode 100644
index a714e1950867..000000000000
--- a/arch/tile/include/asm/exec.h
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * Copyright 2010 Tilera Corporation. All Rights Reserved.
- *
- *   This program is free software; you can redistribute it and/or
- *   modify it under the terms of the GNU General Public License
- *   as published by the Free Software Foundation, version 2.
- *
- *   This program is distributed in the hope that it will be useful, but
- *   WITHOUT ANY WARRANTY; without even the implied warranty of
- *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
- *   NON INFRINGEMENT.  See the GNU General Public License for
- *   more details.
- */
-
-#ifndef _ASM_TILE_EXEC_H
-#define _ASM_TILE_EXEC_H
-
-#define arch_align_stack(x) (x)
-
-#endif /* _ASM_TILE_EXEC_H */
diff --git a/arch/um/include/asm/processor-generic.h b/arch/um/include/asm/processor-generic.h
index 24e97be814bc..1e82e954e978 100644
--- a/arch/um/include/asm/processor-generic.h
+++ b/arch/um/include/asm/processor-generic.h
@@ -63,8 +63,6 @@ static inline void release_thread(struct task_struct *task)
 {
 }
 
-extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
-
 extern unsigned long thread_saved_pc(struct task_struct *t);
 
 static inline void mm_copy_segments(struct mm_struct *from_mm,
diff --git a/arch/um/kernel/exec.c b/arch/um/kernel/exec.c
index de66c421ae9d..ab019c7f0b57 100644
--- a/arch/um/kernel/exec.c
+++ b/arch/um/kernel/exec.c
@@ -16,7 +16,6 @@
 #include <mem_user.h>
 #include <skas.h>
 #include <os.h>
-#include "internal.h"
 
 void flush_thread(void)
 {
@@ -49,27 +48,7 @@ void start_thread(struct pt_regs *regs, unsigned long eip, unsigned long esp)
 }
 EXPORT_SYMBOL(start_thread);
 
-long um_execve(const char *file, const char __user *const __user *argv, const char __user *const __user *env)
+void __noreturn ret_from_kernel_execve(struct pt_regs *unused)
 {
-        long err;
-
-        err = do_execve(file, argv, env, &current->thread.regs);
-        if (!err)
-                UML_LONGJMP(current->thread.exec_buf, 1);
-        return err;
-}
-
-long sys_execve(const char __user *file, const char __user *const __user *argv,
-                const char __user *const __user *env)
-{
-        long error;
-        char *filename;
-
-        filename = getname(file);
-        error = PTR_ERR(filename);
-        if (IS_ERR(filename)) goto out;
-        error = do_execve(filename, argv, env, &current->thread.regs);
-        putname(filename);
- out:
-        return error;
+        UML_LONGJMP(current->thread.exec_buf, 1);
 }
diff --git a/arch/um/kernel/internal.h b/arch/um/kernel/internal.h
deleted file mode 100644
index 5bf97db24a04..000000000000
--- a/arch/um/kernel/internal.h
+++ /dev/null
@@ -1 +0,0 @@
-extern long um_execve(const char *file, const char __user *const __user *argv, const char __user *const __user *env);
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index 41f53240e794..30629783b3e0 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -69,18 +69,6 @@ unsigned long alloc_stack(int order, int atomic)
         return page;
 }
 
-int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
-{
-        int pid;
-
-        current->thread.request.u.thread.proc = fn;
-        current->thread.request.u.thread.arg = arg;
-        pid = do_fork(CLONE_VM | CLONE_UNTRACED | flags, 0,
-                      &current->thread.regs, 0, NULL, NULL);
-        return pid;
-}
-EXPORT_SYMBOL(kernel_thread);
-
 static inline void set_current(struct task_struct *task)
 {
         cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task)
@@ -177,7 +165,7 @@ void fork_handler(void)
 }
 
 int copy_thread(unsigned long clone_flags, unsigned long sp,
-                unsigned long stack_top, struct task_struct * p,
+                unsigned long arg, struct task_struct * p,
                 struct pt_regs *regs)
 {
         void (*handler)(void);
@@ -198,7 +186,8 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
                 arch_copy_thread(&current->thread.arch, &p->thread.arch);
         } else {
                 get_safe_registers(p->thread.regs.regs.gp, p->thread.regs.regs.fp);
-                p->thread.request.u.thread = current->thread.request.u.thread;
+                p->thread.request.u.thread.proc = (int (*)(void *))sp;
+                p->thread.request.u.thread.arg = (void *)arg;
                 handler = new_thread_handler;
         }
 
diff --git a/arch/um/kernel/syscall.c b/arch/um/kernel/syscall.c
index 10808bda3671..a81f3705e90f 100644
--- a/arch/um/kernel/syscall.c
+++ b/arch/um/kernel/syscall.c
@@ -13,7 +13,6 @@
 #include <asm/mman.h>
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
-#include "internal.h"
 
 long sys_fork(void)
 {
@@ -50,19 +49,3 @@ long old_mmap(unsigned long addr, unsigned long len,
  out:
         return err;
 }
-
-int kernel_execve(const char *filename,
-                  const char *const argv[],
-                  const char *const envp[])
-{
-        mm_segment_t fs;
-        int ret;
-
-        fs = get_fs();
-        set_fs(KERNEL_DS);
-        ret = um_execve(filename, (const char __user *const __user *)argv,
-                        (const char __user *const __user *) envp);
-        set_fs(fs);
-
-        return ret;
-}
diff --git a/arch/unicore32/include/asm/Kbuild b/arch/unicore32/include/asm/Kbuild
index 123c59a06c14..c910c9857e11 100644
--- a/arch/unicore32/include/asm/Kbuild
+++ b/arch/unicore32/include/asm/Kbuild
@@ -11,6 +11,7 @@ generic-y += device.h
 generic-y += div64.h
 generic-y += emergency-restart.h
 generic-y += errno.h
+generic-y += exec.h
 generic-y += fb.h
 generic-y += fcntl.h
 generic-y += ftrace.h
diff --git a/arch/unicore32/include/asm/exec.h b/arch/unicore32/include/asm/exec.h
deleted file mode 100644
index 06d1f0f57888..000000000000
--- a/arch/unicore32/include/asm/exec.h
+++ /dev/null
@@ -1,15 +0,0 @@
-/*
- * Process execution bits for PKUnity SoC and UniCore ISA
- *
- * Copyright (C) 2001-2012 GUAN Xue-tao
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-#ifndef __UNICORE_EXEC_H__
-#define __UNICORE_EXEC_H__
-
-#define arch_align_stack(x)             (x)
-
-#endif /* __UNICORE_EXEC_H__ */
diff --git a/arch/unicore32/kernel/sys.c b/arch/unicore32/kernel/sys.c
index 3afe60a39ac9..5fd9af773e15 100644
--- a/arch/unicore32/kernel/sys.c
+++ b/arch/unicore32/kernel/sys.c
@@ -104,7 +104,6 @@ int kernel_execve(const char *filename,
  out:
         return ret;
 }
-EXPORT_SYMBOL(kernel_execve);
 
 /* Note: used by the compat code even in 64-bit Linux. */
 SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len,
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1ae94bcae5d9..42d2c35a5bbd 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -108,6 +108,7 @@ config X86
         select GENERIC_STRNLEN_USER
         select HAVE_RCU_USER_QS if X86_64
         select HAVE_IRQ_TIME_ACCOUNTING
+        select GENERIC_KERNEL_THREAD
 
 config INSTRUCTION_DECODER
         def_bool y
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 9c289504e680..076745fc8045 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -465,7 +465,7 @@ GLOBAL(\label)
         PTREGSCALL stub32_rt_sigreturn, sys32_rt_sigreturn, %rdi
         PTREGSCALL stub32_sigreturn, sys32_sigreturn, %rdi
         PTREGSCALL stub32_sigaltstack, sys32_sigaltstack, %rdx
-        PTREGSCALL stub32_execve, sys32_execve, %rcx
+        PTREGSCALL stub32_execve, compat_sys_execve, %rcx
         PTREGSCALL stub32_fork, sys_fork, %rdi
         PTREGSCALL stub32_clone, sys32_clone, %rdx
         PTREGSCALL stub32_vfork, sys_vfork, %rdi
diff --git a/arch/x86/ia32/sys_ia32.c b/arch/x86/ia32/sys_ia32.c
index c5b938d92eab..86d68d1c8806 100644
--- a/arch/x86/ia32/sys_ia32.c
+++ b/arch/x86/ia32/sys_ia32.c
@@ -385,21 +385,6 @@ asmlinkage long sys32_sendfile(int out_fd, int in_fd,
         return ret;
 }
 
-asmlinkage long sys32_execve(const char __user *name, compat_uptr_t __user *argv,
-                             compat_uptr_t __user *envp, struct pt_regs *regs)
-{
-        long error;
-        char *filename;
-
-        filename = getname(name);
-        error = PTR_ERR(filename);
-        if (IS_ERR(filename))
-                return error;
-        error = compat_do_execve(filename, argv, envp, regs);
-        putname(filename);
-        return error;
-}
-
 asmlinkage long sys32_clone(unsigned int clone_flags, unsigned int newsp,
                             struct pt_regs *regs)
 {
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index b98c0d958ebb..ad1fc8511674 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -588,11 +588,6 @@ typedef struct {
 } mm_segment_t;
 
 
-/*
- * create a kernel thread without removing it from tasklists
- */
-extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
-
 /* Free all resources held by a thread. */
 extern void release_thread(struct task_struct *);
 
diff --git a/arch/x86/include/asm/sys_ia32.h b/arch/x86/include/asm/sys_ia32.h
index 4ca1c611b552..a9a8cf3da49d 100644
--- a/arch/x86/include/asm/sys_ia32.h
+++ b/arch/x86/include/asm/sys_ia32.h
@@ -54,8 +54,6 @@ asmlinkage long sys32_pwrite(unsigned int, const char __user *, u32, u32, u32);
 asmlinkage long sys32_personality(unsigned long);
 asmlinkage long sys32_sendfile(int, int, compat_off_t __user *, s32);
 
-asmlinkage long sys32_execve(const char __user *, compat_uptr_t __user *,
-                             compat_uptr_t __user *, struct pt_regs *);
 asmlinkage long sys32_clone(unsigned int, unsigned int, struct pt_regs *);
 
 long sys32_lseek(unsigned int, int, unsigned int);
diff --git a/arch/x86/include/asm/syscalls.h b/arch/x86/include/asm/syscalls.h
index f1d8b441fc77..2be0b880417e 100644
--- a/arch/x86/include/asm/syscalls.h
+++ b/arch/x86/include/asm/syscalls.h
@@ -25,7 +25,7 @@ int sys_fork(struct pt_regs *);
 int sys_vfork(struct pt_regs *);
 long sys_execve(const char __user *,
                 const char __user *const __user *,
-                const char __user *const __user *, struct pt_regs *);
+                const char __user *const __user *);
 long sys_clone(unsigned long, unsigned long, void __user *,
                void __user *, struct pt_regs *);
 
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index c535d847e3b5..2d946e63ee82 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -79,7 +79,6 @@ struct thread_info {
 #define TIF_SIGPENDING          2       /* signal pending */
 #define TIF_NEED_RESCHED        3       /* rescheduling necessary */
 #define TIF_SINGLESTEP          4       /* reenable singlestep on user return*/
-#define TIF_IRET                5       /* force IRET */
 #define TIF_SYSCALL_EMU         6       /* syscall emulation active */
 #define TIF_SYSCALL_AUDIT       7       /* syscall auditing active */
 #define TIF_SECCOMP             8       /* secure computing */
@@ -105,7 +104,6 @@ struct thread_info {
 #define _TIF_SIGPENDING         (1 << TIF_SIGPENDING)
 #define _TIF_SINGLESTEP         (1 << TIF_SINGLESTEP)
 #define _TIF_NEED_RESCHED       (1 << TIF_NEED_RESCHED)
-#define _TIF_IRET               (1 << TIF_IRET)
 #define _TIF_SYSCALL_EMU        (1 << TIF_SYSCALL_EMU)
 #define _TIF_SYSCALL_AUDIT      (1 << TIF_SYSCALL_AUDIT)
 #define _TIF_SECCOMP            (1 << TIF_SECCOMP)
diff --git a/arch/x86/include/asm/unistd.h b/arch/x86/include/asm/unistd.h
index 0d9776e9e2dc..55d155560fdf 100644
--- a/arch/x86/include/asm/unistd.h
+++ b/arch/x86/include/asm/unistd.h
@@ -50,6 +50,8 @@
 # define __ARCH_WANT_SYS_TIME
 # define __ARCH_WANT_SYS_UTIME
 # define __ARCH_WANT_SYS_WAITPID
+# define __ARCH_WANT_SYS_EXECVE
+# define __ARCH_WANT_KERNEL_EXECVE
 
 /*
  * "Conditional" syscalls
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index a48ea05157d3..91ce48f05f9f 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -23,7 +23,7 @@ obj-y			+= time.o ioport.o ldt.o dumpstack.o nmi.o
 obj-y                   += setup.o x86_init.o i8259.o irqinit.o jump_label.o
 obj-$(CONFIG_IRQ_WORK)  += irq_work.o
 obj-y                   += probe_roms.o
-obj-$(CONFIG_X86_32)    += sys_i386_32.o i386_ksyms_32.o
+obj-$(CONFIG_X86_32)    += i386_ksyms_32.o
 obj-$(CONFIG_X86_64)    += sys_x86_64.o x8664_ksyms_64.o
 obj-y                   += syscall_$(BITS).o
 obj-$(CONFIG_X86_64)    += vsyscall_64.o
diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index 68de2dc962ec..28610822fb3c 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -69,4 +69,7 @@ void common(void) {
         OFFSET(BP_kernel_alignment, boot_params, hdr.kernel_alignment);
         OFFSET(BP_pref_address, boot_params, hdr.pref_address);
         OFFSET(BP_code32_start, boot_params, hdr.code32_start);
+
+        BLANK();
+        DEFINE(PTREGS_SIZE, sizeof(struct pt_regs));
 }
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 0750e3ba87c0..8f9ed1afde8f 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -299,6 +299,13 @@ ENTRY(ret_from_fork)
         CFI_ENDPROC
 END(ret_from_fork)
 
+ENTRY(ret_from_kernel_execve)
+        movl %eax, %esp
+        movl $0,PT_EAX(%esp)
+        GET_THREAD_INFO(%ebp)
+        jmp syscall_exit
+END(ret_from_kernel_execve)
+
 /*
  * Interrupt exit functions should be protected against kprobes
  */
@@ -323,8 +330,7 @@ ret_from_intr:
         andl $(X86_EFLAGS_VM | SEGMENT_RPL_MASK), %eax
 #else
         /*
-         * We can be coming here from a syscall done in the kernel space,
-         * e.g. a failed kernel_execve().
+         * We can be coming here from child spawned by kernel_thread().
          */
         movl PT_CS(%esp), %eax
         andl $SEGMENT_RPL_MASK, %eax
@@ -732,7 +738,6 @@ ENDPROC(ptregs_##name)
 PTREGSCALL1(iopl)
 PTREGSCALL0(fork)
 PTREGSCALL0(vfork)
-PTREGSCALL3(execve)
 PTREGSCALL2(sigaltstack)
 PTREGSCALL0(sigreturn)
 PTREGSCALL0(rt_sigreturn)
@@ -1015,15 +1020,20 @@ END(spurious_interrupt_bug)
  */
         .popsection
 
-ENTRY(kernel_thread_helper)
-        pushl $0                # fake return address for unwinder
+ENTRY(ret_from_kernel_thread)
         CFI_STARTPROC
-        movl %edi,%eax
-        call *%esi
+        pushl_cfi %eax
+        call schedule_tail
+        GET_THREAD_INFO(%ebp)
+        popl_cfi %eax
+        pushl_cfi $0x0202               # Reset kernel eflags
+        popfl_cfi
+        movl PT_EBP(%esp),%eax
+        call *PT_EBX(%esp)
         call do_exit
         ud2                     # padding for call trace
         CFI_ENDPROC
-ENDPROC(kernel_thread_helper)
+ENDPROC(ret_from_kernel_thread)
 
 #ifdef CONFIG_XEN
 /* Xen doesn't set %esp to be precisely what the normal sysenter
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 44531acd9a81..cdc790c78f32 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -554,7 +554,7 @@ ENTRY(ret_from_fork)
         RESTORE_REST
 
         testl $3, CS-ARGOFFSET(%rsp)            # from kernel_thread?
-        jz   retint_restore_args
+        jz   1f
 
         testl $_TIF_IA32, TI_flags(%rcx)        # 32-bit compat task needs IRET
         jnz  int_ret_from_sys_call
@@ -562,6 +562,16 @@ ENTRY(ret_from_fork)
         RESTORE_TOP_OF_STACK %rdi, -ARGOFFSET
         jmp ret_from_sys_call                   # go to the SYSRET fastpath
 
+1:
+        subq $REST_SKIP, %rsp   # move the stack pointer back
+        CFI_ADJUST_CFA_OFFSET   REST_SKIP
+        movq %rbp, %rdi
+        call *%rbx
+        # exit
+        mov %eax, %edi
+        call do_exit
+        ud2                     # padding for call trace
+
         CFI_ENDPROC
 END(ret_from_fork)
 
@@ -862,7 +872,6 @@ ENTRY(stub_execve)
         PARTIAL_FRAME 0
         SAVE_REST
         FIXUP_TOP_OF_STACK %r11
-        movq %rsp, %rcx
         call sys_execve
         RESTORE_TOP_OF_STACK %r11
         movq %rax,RAX(%rsp)
@@ -912,8 +921,7 @@ ENTRY(stub_x32_execve)
         PARTIAL_FRAME 0
         SAVE_REST
         FIXUP_TOP_OF_STACK %r11
-        movq %rsp, %rcx
-        call sys32_execve
+        call compat_sys_execve
         RESTORE_TOP_OF_STACK %r11
         movq %rax,RAX(%rsp)
         RESTORE_REST
@@ -1318,51 +1326,19 @@ bad_gs:
         jmp  2b
         .previous
 
-ENTRY(kernel_thread_helper)
-        pushq $0                # fake return address
-        CFI_STARTPROC
-        /*
-         * Here we are in the child and the registers are set as they were
-         * at kernel_thread() invocation in the parent.
-         */
-        call *%rsi
-        # exit
-        mov %eax, %edi
-        call do_exit
-        ud2                     # padding for call trace
-        CFI_ENDPROC
-END(kernel_thread_helper)
-
-/*
- * execve(). This function needs to use IRET, not SYSRET, to set up all state properly.
- *
- * C extern interface:
- *       extern long execve(const char *name, char **argv, char **envp)
- *
- * asm input arguments:
- *      rdi: name, rsi: argv, rdx: envp
- *
- * We want to fallback into:
- *      extern long sys_execve(const char *name, char **argv,char **envp, struct pt_regs *regs)
- *
- * do_sys_execve asm fallback arguments:
- *      rdi: name, rsi: argv, rdx: envp, rcx: fake frame on the stack
- */
-ENTRY(kernel_execve)
-        CFI_STARTPROC
-        FAKE_STACK_FRAME $0
-        SAVE_ALL
-        movq %rsp,%rcx
-        call sys_execve
-        movq %rax, RAX(%rsp)
-        RESTORE_REST
-        testq %rax,%rax
-        je int_ret_from_sys_call
-        RESTORE_ARGS
-        UNFAKE_STACK_FRAME
-        ret
-        CFI_ENDPROC
-END(kernel_execve)
+ENTRY(ret_from_kernel_execve)
+        movq %rdi, %rsp
+        movl $0, RAX(%rsp)
+        // RESTORE_REST
+        movq 0*8(%rsp), %r15
+        movq 1*8(%rsp), %r14
+        movq 2*8(%rsp), %r13
+        movq 3*8(%rsp), %r12
+        movq 4*8(%rsp), %rbp
+        movq 5*8(%rsp), %rbx
+        addq $(6*8), %rsp
+        jmp int_ret_from_sys_call
+END(ret_from_kernel_execve)
 
 /* Call softirq on interrupt stack. Interrupts are off. */
 ENTRY(call_softirq)
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index dc3567e083f9..b644e1c765dc 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -293,71 +293,6 @@ sys_clone(unsigned long clone_flags, unsigned long newsp,
 }
 
 /*
- * This gets run with %si containing the
- * function to call, and %di containing
- * the "args".
- */
-extern void kernel_thread_helper(void);
-
-/*
- * Create a kernel thread
- */
-int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-        struct pt_regs regs;
-
-        memset(&regs, 0, sizeof(regs));
-
-        regs.si = (unsigned long) fn;
-        regs.di = (unsigned long) arg;
-
-#ifdef CONFIG_X86_32
-        regs.ds = __USER_DS;
-        regs.es = __USER_DS;
-        regs.fs = __KERNEL_PERCPU;
-        regs.gs = __KERNEL_STACK_CANARY;
-#else
-        regs.ss = __KERNEL_DS;
-#endif
-
-        regs.orig_ax = -1;
-        regs.ip = (unsigned long) kernel_thread_helper;
-        regs.cs = __KERNEL_CS | get_kernel_rpl();
-        regs.flags = X86_EFLAGS_IF | X86_EFLAGS_BIT1;
-
-        /* Ok, create the new process.. */
-        return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
-}
-EXPORT_SYMBOL(kernel_thread);
-
-/*
- * sys_execve() executes a new program.
- */
-long sys_execve(const char __user *name,
-                const char __user *const __user *argv,
-                const char __user *const __user *envp, struct pt_regs *regs)
-{
-        long error;
-        char *filename;
-
-        filename = getname(name);
-        error = PTR_ERR(filename);
-        if (IS_ERR(filename))
-                return error;
-        error = do_execve(filename, argv, envp, regs);
-
-#ifdef CONFIG_X86_32
-        if (error == 0) {
-                /* Make sure we don't return using sysenter.. */
-                set_thread_flag(TIF_IRET);
-        }
-#endif
-
-        putname(filename);
-        return error;
-}
-
-/*
  * Idle related variables and functions
  */
 unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE;
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index b9ff83c7135b..44e0bff38e72 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -57,6 +57,7 @@
 #include <asm/switch_to.h>
 
 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
+asmlinkage void ret_from_kernel_thread(void) __asm__("ret_from_kernel_thread");
 
 /*
  * Return saved PC of a blocked thread.
@@ -127,23 +128,39 @@ void release_thread(struct task_struct *dead_task)
 }
 
 int copy_thread(unsigned long clone_flags, unsigned long sp,
-        unsigned long unused,
+        unsigned long arg,
         struct task_struct *p, struct pt_regs *regs)
 {
-        struct pt_regs *childregs;
+        struct pt_regs *childregs = task_pt_regs(p);
         struct task_struct *tsk;
         int err;
 
-        childregs = task_pt_regs(p);
+        p->thread.sp = (unsigned long) childregs;
+        p->thread.sp0 = (unsigned long) (childregs+1);
+
+        if (unlikely(!regs)) {
+                /* kernel thread */
+                memset(childregs, 0, sizeof(struct pt_regs));
+                p->thread.ip = (unsigned long) ret_from_kernel_thread;
+                task_user_gs(p) = __KERNEL_STACK_CANARY;
+                childregs->ds = __USER_DS;
+                childregs->es = __USER_DS;
+                childregs->fs = __KERNEL_PERCPU;
+                childregs->bx = sp;     /* function */
+                childregs->bp = arg;
+                childregs->orig_ax = -1;
+                childregs->cs = __KERNEL_CS | get_kernel_rpl();
+                childregs->flags = X86_EFLAGS_IF | X86_EFLAGS_BIT1;
+                p->fpu_counter = 0;
+                p->thread.io_bitmap_ptr = NULL;
+                memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
+                return 0;
+        }
         *childregs = *regs;
         childregs->ax = 0;
         childregs->sp = sp;
 
-        p->thread.sp = (unsigned long) childregs;
-        p->thread.sp0 = (unsigned long) (childregs+1);
-
         p->thread.ip = (unsigned long) ret_from_fork;
-
         task_user_gs(p) = get_user_gs(regs);
 
         p->fpu_counter = 0;
@@ -190,6 +207,12 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
         regs->cs                = __USER_CS;
         regs->ip                = new_ip;
         regs->sp                = new_sp;
+        regs->flags             = X86_EFLAGS_IF;
+        /*
+         * force it to the iret return path by making it look as if there was
+         * some work pending.
+         */
+        set_thread_flag(TIF_NOTIFY_RESUME);
 }
 EXPORT_SYMBOL_GPL(start_thread);
 
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 8a6d20ce1978..16c6365e2b86 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -146,29 +146,18 @@ static inline u32 read_32bit_tls(struct task_struct *t, int tls)
 }
 
 int copy_thread(unsigned long clone_flags, unsigned long sp,
-                unsigned long unused,
+                unsigned long arg,
         struct task_struct *p, struct pt_regs *regs)
 {
         int err;
         struct pt_regs *childregs;
         struct task_struct *me = current;
 
-        childregs = ((struct pt_regs *)
-                        (THREAD_SIZE + task_stack_page(p))) - 1;
-        *childregs = *regs;
-
-        childregs->ax = 0;
-        if (user_mode(regs))
-                childregs->sp = sp;
-        else
-                childregs->sp = (unsigned long)childregs;
-
+        p->thread.sp0 = (unsigned long)task_stack_page(p) + THREAD_SIZE;
+        childregs = task_pt_regs(p);
         p->thread.sp = (unsigned long) childregs;
-        p->thread.sp0 = (unsigned long) (childregs+1);
         p->thread.usersp = me->thread.usersp;
-
         set_tsk_thread_flag(p, TIF_FORK);
-
         p->fpu_counter = 0;
         p->thread.io_bitmap_ptr = NULL;
 
@@ -178,6 +167,24 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
         p->thread.fs = p->thread.fsindex ? 0 : me->thread.fs;
         savesegment(es, p->thread.es);
         savesegment(ds, p->thread.ds);
+        memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
+
+        if (unlikely(!regs)) {
+                /* kernel thread */
+                memset(childregs, 0, sizeof(struct pt_regs));
+                childregs->sp = (unsigned long)childregs;
+                childregs->ss = __KERNEL_DS;
+                childregs->bx = sp; /* function */
+                childregs->bp = arg;
+                childregs->orig_ax = -1;
+                childregs->cs = __KERNEL_CS | get_kernel_rpl();
+                childregs->flags = X86_EFLAGS_IF | X86_EFLAGS_BIT1;
+                return 0;
+        }
+        *childregs = *regs;
+
+        childregs->ax = 0;
+        childregs->sp = sp;
 
         err = -ENOMEM;
         memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index b33144c8b309..29ad351804e9 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -840,10 +840,6 @@ do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
         if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
                 fire_user_return_notifiers();
 
-#ifdef CONFIG_X86_32
-        clear_thread_flag(TIF_IRET);
-#endif /* CONFIG_X86_32 */
-
         rcu_user_enter();
 }
 
diff --git a/arch/x86/kernel/sys_i386_32.c b/arch/x86/kernel/sys_i386_32.c
deleted file mode 100644
index 0b0cb5fede19..000000000000
--- a/arch/x86/kernel/sys_i386_32.c
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
- * This file contains various random system calls that
- * have a non-standard calling sequence on the Linux/i386
- * platform.
- */
-
-#include <linux/errno.h>
-#include <linux/sched.h>
-#include <linux/mm.h>
-#include <linux/fs.h>
-#include <linux/smp.h>
-#include <linux/sem.h>
-#include <linux/msg.h>
-#include <linux/shm.h>
-#include <linux/stat.h>
-#include <linux/syscalls.h>
-#include <linux/mman.h>
-#include <linux/file.h>
-#include <linux/utsname.h>
-#include <linux/ipc.h>
-
-#include <linux/uaccess.h>
-#include <linux/unistd.h>
-
-#include <asm/syscalls.h>
-
-/*
- * Do a system call from kernel instead of calling sys_execve so we
- * end up with proper pt_regs.
- */
-int kernel_execve(const char *filename,
-                  const char *const argv[],
-                  const char *const envp[])
-{
-        long __res;
-        asm volatile ("int $0x80"
-        : "=a" (__res)
-        : "0" (__NR_execve), "b" (filename), "c" (argv), "d" (envp) : "memory");
-        return __res;
-}
diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index 54abcc0baf23..5c9687b1bde6 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -561,9 +561,9 @@ int handle_vm86_trap(struct kernel_vm86_regs *regs, long error_code, int trapno)
                 if ((trapno == 3) || (trapno == 1)) {
                         KVM86->regs32->ax = VM86_TRAP + (trapno << 8);
                         /* setting this flag forces the code in entry_32.S to
-                           call save_v86_state() and change the stack pointer
-                           to KVM86->regs32 */
-                        set_thread_flag(TIF_IRET);
+                           the path where we call save_v86_state() and change
+                           the stack pointer to KVM86->regs32 */
+                        set_thread_flag(TIF_NOTIFY_RESUME);
                         return 0;
                 }
                 do_int(regs, trapno, (unsigned char __user *) (regs->pt.ss << 4), SP(regs));
diff --git a/arch/x86/syscalls/syscall_32.tbl b/arch/x86/syscalls/syscall_32.tbl
index 7a35a6e71d44..a47103fbc692 100644
--- a/arch/x86/syscalls/syscall_32.tbl
+++ b/arch/x86/syscalls/syscall_32.tbl
@@ -17,7 +17,7 @@
 8       i386    creat                   sys_creat
 9       i386    link                    sys_link
 10      i386    unlink                  sys_unlink
-11      i386    execve                  ptregs_execve                   stub32_execve
+11      i386    execve                  sys_execve                      stub32_execve
 12      i386    chdir                   sys_chdir
 13      i386    time                    sys_time                        compat_sys_time
 14      i386    mknod                   sys_mknod
diff --git a/arch/x86/um/Kconfig b/arch/x86/um/Kconfig
index aeaff8bef2f1..30c4eec033af 100644
--- a/arch/x86/um/Kconfig
+++ b/arch/x86/um/Kconfig
@@ -13,6 +13,7 @@ endmenu
 config UML_X86
         def_bool y
         select GENERIC_FIND_FIRST_BIT
+        select GENERIC_KERNEL_THREAD
 
 config 64BIT
         bool "64-bit kernel" if SUBARCH = "x86"
diff --git a/arch/x86/um/sys_call_table_32.c b/arch/x86/um/sys_call_table_32.c
index b5408cecac6c..232e60504b3a 100644
--- a/arch/x86/um/sys_call_table_32.c
+++ b/arch/x86/um/sys_call_table_32.c
@@ -25,7 +25,6 @@
 #define old_mmap sys_old_mmap
 
 #define ptregs_fork sys_fork
-#define ptregs_execve sys_execve
 #define ptregs_iopl sys_iopl
 #define ptregs_vm86old sys_vm86old
 #define ptregs_clone i386_clone
diff --git a/arch/xtensa/include/asm/Kbuild b/arch/xtensa/include/asm/Kbuild
index 0d20f5526dd8..fccd81eddff1 100644
--- a/arch/xtensa/include/asm/Kbuild
+++ b/arch/xtensa/include/asm/Kbuild
@@ -1,3 +1,4 @@
 include include/asm-generic/Kbuild.asm
 
 generic-y += clkdev.h
+generic-y += exec.h
diff --git a/arch/xtensa/include/asm/exec.h b/arch/xtensa/include/asm/exec.h
deleted file mode 100644
index af949e28cb32..000000000000
--- a/arch/xtensa/include/asm/exec.h
+++ /dev/null
@@ -1,14 +0,0 @@
-/*
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 2001 - 2005 Tensilica Inc.
- */
-
-#ifndef _XTENSA_EXEC_H
-#define _XTENSA_EXEC_H
-
-#define arch_align_stack(x) (x)
-
-#endif /* _XTENSA_EXEC_H */
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index e800dec958c3..fbd9f60bd763 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -36,7 +36,6 @@
 #include <asm/uaccess.h>
 #include <asm/param.h>
 #include <asm/page.h>
-#include <asm/exec.h>
 
 #ifndef user_long_t
 #define user_long_t long
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 262db114ff01..a46049154107 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -39,7 +39,6 @@
 #include <asm/uaccess.h>
 #include <asm/param.h>
 #include <asm/pgalloc.h>
-#include <asm/exec.h>
 
 typedef char *elf_caddr_t;
 
diff --git a/fs/exec.c b/fs/exec.c
index 4f2bebc276c5..ca434534ae9a 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -59,7 +59,6 @@
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
 #include <asm/tlb.h>
-#include <asm/exec.h>
 
 #include <trace/events/task.h>
 #include "internal.h"
@@ -392,7 +391,7 @@ struct user_arg_ptr {
         union {
                 const char __user *const __user *native;
 #ifdef CONFIG_COMPAT
-                compat_uptr_t __user *compat;
+                const compat_uptr_t __user *compat;
 #endif
         } ptr;
 };
@@ -1574,9 +1573,9 @@ int do_execve(const char *filename,
 }
 
 #ifdef CONFIG_COMPAT
-int compat_do_execve(char *filename,
-        compat_uptr_t __user *__argv,
-        compat_uptr_t __user *__envp,
+int compat_do_execve(const char *filename,
+        const compat_uptr_t __user *__argv,
+        const compat_uptr_t __user *__envp,
         struct pt_regs *regs)
 {
         struct user_arg_ptr argv = {
@@ -1658,3 +1657,55 @@ int get_dumpable(struct mm_struct *mm)
 {
         return __get_dumpable(mm->flags);
 }
+
+#ifdef __ARCH_WANT_SYS_EXECVE
+SYSCALL_DEFINE3(execve,
+                const char __user *, filename,
+                const char __user *const __user *, argv,
+                const char __user *const __user *, envp)
+{
+        const char *path = getname(filename);
+        int error = PTR_ERR(path);
+        if (!IS_ERR(path)) {
+                error = do_execve(path, argv, envp, current_pt_regs());
+                putname(path);
+        }
+        return error;
+}
+#ifdef CONFIG_COMPAT
+asmlinkage long compat_sys_execve(const char __user * filename,
+        const compat_uptr_t __user * argv,
+        const compat_uptr_t __user * envp)
+{
+        const char *path = getname(filename);
+        int error = PTR_ERR(path);
+        if (!IS_ERR(path)) {
+                error = compat_do_execve(path, argv, envp, current_pt_regs());
+                putname(path);
+        }
+        return error;
+}
+#endif
+#endif
+
+#ifdef __ARCH_WANT_KERNEL_EXECVE
+int kernel_execve(const char *filename,
+                  const char *const argv[],
+                  const char *const envp[])
+{
+        struct pt_regs *p = current_pt_regs();
+        int ret;
+
+        ret = do_execve(filename,
+                        (const char __user *const __user *)argv,
+                        (const char __user *const __user *)envp, p);
+        if (ret < 0)
+                return ret;
+
+        /*
+         * We were successful.  We won't be returning to our caller, but
+         * instead to user space by manipulating the kernel stack.
+         */
+        ret_from_kernel_execve(p);
+}
+#endif
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index 37935c2d2e8f..26531f32bbb2 100644
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -19,6 +19,8 @@ struct pt_regs;
 
 #ifdef __KERNEL__
 #include <linux/sched.h>
+#include <linux/unistd.h>
+#include <asm/exec.h>
 
 #define CORENAME_MAX_SIZE 128
 
@@ -135,5 +137,9 @@ extern void install_exec_creds(struct linux_binprm *bprm);
 extern void set_binfmt(struct linux_binfmt *new);
 extern void free_bprm(struct linux_binprm *);
 
+#ifdef __ARCH_WANT_KERNEL_EXECVE
+extern void ret_from_kernel_execve(struct pt_regs *normal) __noreturn;
+#endif
+
 #endif /* __KERNEL__ */
 #endif /* _LINUX_BINFMTS_H */
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 3f53d002c7c5..d0ced1011f2f 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -284,8 +284,12 @@ asmlinkage ssize_t compat_sys_pwritev(unsigned long fd,
                 const struct compat_iovec __user *vec,
                 unsigned long vlen, u32 pos_low, u32 pos_high);
 
-int compat_do_execve(char *filename, compat_uptr_t __user *argv,
-                     compat_uptr_t __user *envp, struct pt_regs *regs);
+int compat_do_execve(const char *filename, const compat_uptr_t __user *argv,
+                     const compat_uptr_t __user *envp, struct pt_regs *regs);
+#ifdef __ARCH_WANT_SYS_EXECVE
+asmlinkage long compat_sys_execve(const char __user *filename, const compat_uptr_t __user *argv,
+                     const compat_uptr_t __user *envp);
+#endif
 
 asmlinkage long compat_sys_select(int n, compat_ulong_t __user *inp,
                 compat_ulong_t __user *outp, compat_ulong_t __user *exp,
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 3db698aee34c..1d24ffad59c5 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -401,6 +401,10 @@ static inline void user_single_step_siginfo(struct task_struct *tsk,
 #define arch_ptrace_stop(code, info)            do { } while (0)
 #endif
 
+#ifndef current_pt_regs
+#define current_pt_regs() task_pt_regs(current)
+#endif
+
 extern int task_current_syscall(struct task_struct *target, long *callno,
                                 unsigned long args[6], unsigned int maxargs,
                                 unsigned long *sp, unsigned long *pc);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index c2070e92a9d6..a83ca5816ecb 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2332,6 +2332,9 @@ extern int do_execve(const char *,
                      const char __user * const __user *, struct pt_regs *);
 extern long do_fork(unsigned long, unsigned long, struct pt_regs *, unsigned long, int __user *, int __user *);
 struct task_struct *fork_idle(int);
+#ifdef CONFIG_GENERIC_KERNEL_THREAD
+extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
+#endif
 
 extern void set_task_comm(struct task_struct *tsk, char *from);
 extern char *get_task_comm(char *to, struct task_struct *tsk);
diff --git a/kernel/fork.c b/kernel/fork.c
index 1cd7d581b3b2..8b20ab7d3aa2 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1584,7 +1584,7 @@ long do_fork(unsigned long clone_flags,
          * requested, no event is reported; otherwise, report if the event
          * for the type of forking is enabled.
          */
-        if (likely(user_mode(regs)) && !(clone_flags & CLONE_UNTRACED)) {
+        if (!(clone_flags & CLONE_UNTRACED) && likely(user_mode(regs))) {
                 if (clone_flags & CLONE_VFORK)
                         trace = PTRACE_EVENT_VFORK;
                 else if ((clone_flags & CSIGNAL) != SIGCHLD)
@@ -1634,6 +1634,17 @@ long do_fork(unsigned long clone_flags,
         return nr;
 }
 
+#ifdef CONFIG_GENERIC_KERNEL_THREAD
+/*
+ * Create a kernel thread.
+ */
+pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
+{
+        return do_fork(flags|CLONE_VM|CLONE_UNTRACED, (unsigned long)fn, NULL,
+                (unsigned long)arg, NULL, NULL);
+}
+#endif
+
 #ifndef ARCH_MIN_MMSTRUCT_ALIGN
 #define ARCH_MIN_MMSTRUCT_ALIGN 0
 #endif