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

Pull big execve/kernel_thread/fork unification series from Al Viro:
 "All architectures are converted to new model.  Quite a bit of that
  stuff is actually shared with architecture trees; in such cases it's
  literally shared branch pulled by both, not a cherry-pick.

  A lot of ugliness and black magic is gone (-3KLoC total in this one):

   - kernel_thread()/kernel_execve()/sys_execve() redesign.

     We don't do syscalls from kernel anymore for either kernel_thread()
     or kernel_execve():

     kernel_thread() is essentially clone(2) with callback run before we
     return to userland, the callbacks either never return or do
     successful do_execve() before returning.

     kernel_execve() is a wrapper for do_execve() - it doesn't need to
     do transition to user mode anymore.

     As a result kernel_thread() and kernel_execve() are
     arch-independent now - they live in kernel/fork.c and fs/exec.c
     resp.  sys_execve() is also in fs/exec.c and it's completely
     architecture-independent.

   - daemonize() is gone, along with its parts in fs/*.c

   - struct pt_regs * is no longer passed to do_fork/copy_process/
     copy_thread/do_execve/search_binary_handler/->load_binary/do_coredump.

   - sys_fork()/sys_vfork()/sys_clone() unified; some architectures
     still need wrappers (ones with callee-saved registers not saved in
     pt_regs on syscall entry), but the main part of those suckers is in
     kernel/fork.c now."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (113 commits)
  do_coredump(): get rid of pt_regs argument
  print_fatal_signal(): get rid of pt_regs argument
  ptrace_signal(): get rid of unused arguments
  get rid of ptrace_signal_deliver() arguments
  new helper: signal_pt_regs()
  unify default ptrace_signal_deliver
  flagday: kill pt_regs argument of do_fork()
  death to idle_regs()
  don't pass regs to copy_process()
  flagday: don't pass regs to copy_thread()
  bfin: switch to generic vfork, get rid of pointless wrappers
  xtensa: switch to generic clone()
  openrisc: switch to use of generic fork and clone
  unicore32: switch to generic clone(2)
  score: switch to generic fork/vfork/clone
  c6x: sanitize copy_thread(), get rid of clone(2) wrapper, switch to generic clone()
  take sys_fork/sys_vfork/sys_clone prototypes to linux/syscalls.h
  mn10300: switch to generic fork/vfork/clone
  h8300: switch to generic fork/vfork/clone
  tile: switch to generic clone()
  ...

Conflicts:
	arch/microblaze/include/asm/Kbuild

10 files changed, 52 insertions, 193 deletions

diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig
index 4cba7439f9de..4bcf89148f3c 100644
--- a/arch/microblaze/Kconfig
+++ b/arch/microblaze/Kconfig
@@ -26,6 +26,9 @@ config MICROBLAZE
         select GENERIC_ATOMIC64
         select GENERIC_CLOCKEVENTS
         select MODULES_USE_ELF_RELA
+        select GENERIC_KERNEL_THREAD
+        select GENERIC_KERNEL_EXECVE
+        select CLONE_BACKWARDS
 
 config SWAP
         def_bool n
diff --git a/arch/microblaze/include/asm/Kbuild b/arch/microblaze/include/asm/Kbuild
index 2957fcc71764..eb3a46c096fe 100644
--- a/arch/microblaze/include/asm/Kbuild
+++ b/arch/microblaze/include/asm/Kbuild
@@ -4,3 +4,4 @@ header-y  += elf.h
 generic-y += clkdev.h
 generic-y += exec.h
 generic-y += trace_clock.h
+generic-y += syscalls.h
diff --git a/arch/microblaze/include/asm/processor.h b/arch/microblaze/include/asm/processor.h
index af2bb9652392..0759153e8117 100644
--- a/arch/microblaze/include/asm/processor.h
+++ b/arch/microblaze/include/asm/processor.h
@@ -31,6 +31,7 @@ extern const struct seq_operations cpuinfo_op;
 void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp);
 
 extern void ret_from_fork(void);
+extern void ret_from_kernel_thread(void);
 
 # endif /* __ASSEMBLY__ */
 
@@ -78,11 +79,6 @@ extern unsigned long thread_saved_pc(struct task_struct *t);
 
 extern unsigned long get_wchan(struct task_struct *p);
 
-/*
- * create a kernel thread without removing it from tasklists
- */
-extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
-
 # define KSTK_EIP(tsk)  (0)
 # define KSTK_ESP(tsk)  (0)
 
@@ -131,8 +127,6 @@ extern inline void release_thread(struct task_struct *dead_task)
 {
 }
 
-extern int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
-
 /* Free current thread data structures etc.  */
 static inline void exit_thread(void)
 {
diff --git a/arch/microblaze/include/asm/syscalls.h b/arch/microblaze/include/asm/syscalls.h
deleted file mode 100644
index 27f2f4c0f39f..000000000000
--- a/arch/microblaze/include/asm/syscalls.h
+++ /dev/null
@@ -1,16 +0,0 @@
-#ifndef __ASM_MICROBLAZE_SYSCALLS_H
-
-asmlinkage long microblaze_vfork(struct pt_regs *regs);
-asmlinkage long microblaze_clone(int flags, unsigned long stack,
-                                                        struct pt_regs *regs);
-asmlinkage long microblaze_execve(const char __user *filenamei,
-                                  const char __user *const __user *argv,
-                                  const char __user *const __user *envp,
-                                  struct pt_regs *regs);
-
-asmlinkage long sys_clone(int flags, unsigned long stack, struct pt_regs *regs);
-#define sys_clone sys_clone
-
-#include <asm-generic/syscalls.h>
-
-#endif /* __ASM_MICROBLAZE_SYSCALLS_H */
diff --git a/arch/microblaze/include/asm/unistd.h b/arch/microblaze/include/asm/unistd.h
index 6985e6e9d826..94d978986b75 100644
--- a/arch/microblaze/include/asm/unistd.h
+++ b/arch/microblaze/include/asm/unistd.h
@@ -422,6 +422,12 @@
 #define __ARCH_WANT_SYS_SIGPROCMASK
 #define __ARCH_WANT_SYS_RT_SIGACTION
 #define __ARCH_WANT_SYS_RT_SIGSUSPEND
+#define __ARCH_WANT_SYS_EXECVE
+#define __ARCH_WANT_SYS_CLONE
+#define __ARCH_WANT_SYS_VFORK
+#ifdef CONFIG_MMU
+#define __ARCH_WANT_SYS_FORK
+#endif
 
 /*
  * "Conditional" syscalls
diff --git a/arch/microblaze/kernel/entry-nommu.S b/arch/microblaze/kernel/entry-nommu.S
index 75c3ea1f48a1..cb0327f204ab 100644
--- a/arch/microblaze/kernel/entry-nommu.S
+++ b/arch/microblaze/kernel/entry-nommu.S
@@ -474,6 +474,14 @@ ENTRY(ret_from_fork)
         brid    ret_to_user
         nop
 
+ENTRY(ret_from_kernel_thread)
+        brlid   r15, schedule_tail
+        addk    r5, r0, r3
+        brald   r15, r20
+        addk    r5, r0, r19
+        brid    ret_to_user
+        addk    r3, r0, r0
+
 work_pending:
         enable_irq
 
@@ -551,18 +559,6 @@ no_work_pending:
         rtid    r14, 0
         nop
 
-sys_vfork:
-        brid    microblaze_vfork
-        addk    r5, r1, r0
-
-sys_clone:
-        brid    microblaze_clone
-        addk    r7, r1, r0
-
-sys_execve:
-        brid    microblaze_execve
-        addk    r8, r1, r0
-
 sys_rt_sigreturn_wrapper:
         brid    sys_rt_sigreturn
         addk    r5, r1, r0
diff --git a/arch/microblaze/kernel/entry.S b/arch/microblaze/kernel/entry.S
index 03f7b8ce6b6b..c217367dfc7b 100644
--- a/arch/microblaze/kernel/entry.S
+++ b/arch/microblaze/kernel/entry.S
@@ -293,24 +293,6 @@ C_ENTRY(_user_exception):
         swi     r1, r0, TOPHYS(PER_CPU(ENTRY_SP)) /* save stack */
         addi    r14, r14, 4     /* return address is 4 byte after call */
 
-        mfs     r1, rmsr
-        nop
-        andi    r1, r1, MSR_UMS
-        bnei    r1, 1f
-
-/* Kernel-mode state save - kernel execve */
-        lwi     r1, r0, TOPHYS(PER_CPU(ENTRY_SP)); /* Reload kernel stack-ptr*/
-        tophys(r1,r1);
-
-        addik   r1, r1, -PT_SIZE; /* Make room on the stack. */
-        SAVE_REGS
-
-        swi     r1, r1, PT_MODE; /* pt_regs -> kernel mode */
-        brid    2f;
-        nop;                            /* Fill delay slot */
-
-/* User-mode state save.  */
-1:
         lwi     r1, r0, TOPHYS(PER_CPU(CURRENT_SAVE)); /* get saved current */
         tophys(r1,r1);
         lwi     r1, r1, TS_THREAD_INFO; /* get stack from task_struct */
@@ -460,18 +442,6 @@ TRAP_return:		/* Make global symbol for debugging */
         nop;
 
 
-/* These syscalls need access to the struct pt_regs on the stack, so we
-   implement them in assembly (they're basically all wrappers anyway).  */
-
-C_ENTRY(sys_fork_wrapper):
-        addi    r5, r0, SIGCHLD                 /* Arg 0: flags */
-        lwi     r6, r1, PT_R1   /* Arg 1: child SP (use parent's) */
-        addik   r7, r1, 0                       /* Arg 2: parent context */
-        add     r8, r0, r0                      /* Arg 3: (unused) */
-        add     r9, r0, r0;                     /* Arg 4: (unused) */
-        brid    do_fork         /* Do real work (tail-call) */
-        add     r10, r0, r0;                    /* Arg 5: (unused) */
-
 /* This the initial entry point for a new child thread, with an appropriate
    stack in place that makes it look the the child is in the middle of an
    syscall.  This function is actually `returned to' from switch_thread
@@ -479,28 +449,19 @@ C_ENTRY(sys_fork_wrapper):
    saved context).  */
 C_ENTRY(ret_from_fork):
         bralid  r15, schedule_tail; /* ...which is schedule_tail's arg */
-        add     r3, r5, r0;     /* switch_thread returns the prev task */
+        add     r5, r3, r0;     /* switch_thread returns the prev task */
                                 /* ( in the delay slot ) */
         brid    ret_from_trap;  /* Do normal trap return */
         add     r3, r0, r0;     /* Child's fork call should return 0. */
 
-C_ENTRY(sys_vfork):
-        brid    microblaze_vfork        /* Do real work (tail-call) */
-        addik   r5, r1, 0
-
-C_ENTRY(sys_clone):
-        bnei    r6, 1f;                 /* See if child SP arg (arg 1) is 0. */
-        lwi     r6, r1, PT_R1;  /* If so, use paret's stack ptr */
-1:      addik   r7, r1, 0;                      /* Arg 2: parent context */
-        lwi     r9, r1, PT_R8;          /* parent tid.  */
-        lwi     r10, r1, PT_R9;         /* child tid.  */
-        /* do_fork will pick up TLS from regs->r10.  */
-        brid    do_fork         /* Do real work (tail-call) */
-        add     r8, r0, r0;             /* Arg 3: (unused) */
-
-C_ENTRY(sys_execve):
-        brid    microblaze_execve;      /* Do real work (tail-call).*/
-        addik   r8, r1, 0;              /* add user context as 4th arg */
+C_ENTRY(ret_from_kernel_thread):
+        bralid  r15, schedule_tail; /* ...which is schedule_tail's arg */
+        add     r5, r3, r0;     /* switch_thread returns the prev task */
+                                /* ( in the delay slot ) */
+        brald   r15, r20        /* fn was left in r20 */
+        addk    r5, r0, r19     /* ... and argument - in r19 */
+        brid    ret_from_trap
+        add     r3, r0, r0
 
 C_ENTRY(sys_rt_sigreturn_wrapper):
         brid    sys_rt_sigreturn        /* Do real work */
diff --git a/arch/microblaze/kernel/process.c b/arch/microblaze/kernel/process.c
index 1944e00f07e1..40823fd1db0b 100644
--- a/arch/microblaze/kernel/process.c
+++ b/arch/microblaze/kernel/process.c
@@ -13,6 +13,7 @@
 #include <linux/pm.h>
 #include <linux/tick.h>
 #include <linux/bitops.h>
+#include <linux/ptrace.h>
 #include <asm/pgalloc.h>
 #include <asm/uaccess.h> /* for USER_DS macros */
 #include <asm/cacheflush.h>
@@ -119,46 +120,38 @@ void flush_thread(void)
 }
 
 int copy_thread(unsigned long clone_flags, unsigned long usp,
-                unsigned long unused,
-                struct task_struct *p, struct pt_regs *regs)
+                unsigned long arg, struct task_struct *p)
 {
         struct pt_regs *childregs = task_pt_regs(p);
         struct thread_info *ti = task_thread_info(p);
 
-        *childregs = *regs;
-        if (user_mode(regs))
+        if (unlikely(p->flags & PF_KTHREAD)) {
+                /* if we're creating a new kernel thread then just zeroing all
+                 * the registers. That's OK for a brand new thread.*/
+                memset(childregs, 0, sizeof(struct pt_regs));
+                memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
+                ti->cpu_context.r1  = (unsigned long)childregs;
+                ti->cpu_context.r20 = (unsigned long)usp; /* fn */
+                ti->cpu_context.r19 = (unsigned long)arg;
+                childregs->pt_mode = 1;
+                local_save_flags(childregs->msr);
+#ifdef CONFIG_MMU
+                ti->cpu_context.msr = childregs->msr & ~MSR_IE;
+#endif
+                ti->cpu_context.r15 = (unsigned long)ret_from_kernel_thread - 8;
+                return 0;
+        }
+        *childregs = *current_pt_regs();
+        if (usp)
                 childregs->r1 = usp;
-        else
-                childregs->r1 = ((unsigned long) ti) + THREAD_SIZE;
 
-#ifndef CONFIG_MMU
         memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
         ti->cpu_context.r1 = (unsigned long)childregs;
+#ifndef CONFIG_MMU
         ti->cpu_context.msr = (unsigned long)childregs->msr;
 #else
+        childregs->msr |= MSR_UMS;
 
-        /* if creating a kernel thread then update the current reg (we don't
-         * want to use the parent's value when restoring by POP_STATE) */
-        if (kernel_mode(regs))
-                /* save new current on stack to use POP_STATE */
-                childregs->CURRENT_TASK = (unsigned long)p;
-        /* if returning to user then use the parent's value of this register */
-
-        /* if we're creating a new kernel thread then just zeroing all
-         * the registers. That's OK for a brand new thread.*/
-        /* Pls. note that some of them will be restored in POP_STATE */
-        if (kernel_mode(regs))
-                memset(&ti->cpu_context, 0, sizeof(struct cpu_context));
-        /* if this thread is created for fork/vfork/clone, then we want to
-         * restore all the parent's context */
-        /* in addition to the registers which will be restored by POP_STATE */
-        else {
-                ti->cpu_context = *(struct cpu_context *)regs;
-                childregs->msr |= MSR_UMS;
-        }
-
-        /* FIXME STATE_SAVE_PT_OFFSET; */
-        ti->cpu_context.r1  = (unsigned long)childregs;
         /* we should consider the fact that childregs is a copy of the parent
          * regs which were saved immediately after entering the kernel state
          * before enabling VM. This MSR will be restored in switch_to and
@@ -209,29 +202,6 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
 }
 #endif
 
-static void kernel_thread_helper(int (*fn)(void *), void *arg)
-{
-        fn(arg);
-        do_exit(-1);
-}
-
-int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
-{
-        struct pt_regs regs;
-
-        memset(&regs, 0, sizeof(regs));
-        /* store them in non-volatile registers */
-        regs.r5 = (unsigned long)fn;
-        regs.r6 = (unsigned long)arg;
-        local_save_flags(regs.msr);
-        regs.pc = (unsigned long)kernel_thread_helper;
-        regs.pt_mode = 1;
-
-        return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0,
-                        &regs, 0, NULL, NULL);
-}
-EXPORT_SYMBOL_GPL(kernel_thread);
-
 unsigned long get_wchan(struct task_struct *p)
 {
 /* TBD (used by procfs) */
@@ -246,6 +216,7 @@ void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp)
         regs->pt_mode = 0;
 #ifdef CONFIG_MMU
         regs->msr |= MSR_UMS;
+        regs->msr &= ~MSR_VM;
 #endif
 }
 
diff --git a/arch/microblaze/kernel/sys_microblaze.c b/arch/microblaze/kernel/sys_microblaze.c
index 404c0f24bd41..63647c586b43 100644
--- a/arch/microblaze/kernel/sys_microblaze.c
+++ b/arch/microblaze/kernel/sys_microblaze.c
@@ -34,38 +34,6 @@
 
 #include <asm/syscalls.h>
 
-asmlinkage long microblaze_vfork(struct pt_regs *regs)
-{
-        return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->r1,
-                                                regs, 0, NULL, NULL);
-}
-
-asmlinkage long microblaze_clone(int flags, unsigned long stack,
-                                                        struct pt_regs *regs)
-{
-        if (!stack)
-                stack = regs->r1;
-        return do_fork(flags, stack, regs, 0, NULL, NULL);
-}
-
-asmlinkage long microblaze_execve(const char __user *filenamei,
-                                  const char __user *const __user *argv,
-                                  const char __user *const __user *envp,
-                                  struct pt_regs *regs)
-{
-        int error;
-        struct filename *filename;
-
-        filename = getname(filenamei);
-        error = PTR_ERR(filename);
-        if (IS_ERR(filename))
-                goto out;
-        error = do_execve(filename->name, argv, envp, regs);
-        putname(filename);
-out:
-        return error;
-}
-
 asmlinkage long sys_mmap(unsigned long addr, unsigned long len,
                         unsigned long prot, unsigned long flags,
                         unsigned long fd, off_t pgoff)
@@ -75,24 +43,3 @@ asmlinkage long sys_mmap(unsigned long addr, unsigned long len,
 
         return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> PAGE_SHIFT);
 }
-
-/*
- * 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[])
-{
-        register const char *__a __asm__("r5") = filename;
-        register const void *__b __asm__("r6") = argv;
-        register const void *__c __asm__("r7") = envp;
-        register unsigned long __syscall __asm__("r12") = __NR_execve;
-        register unsigned long __ret __asm__("r3");
-        __asm__ __volatile__ ("brki r14, 0x8"
-                        : "=r" (__ret), "=r" (__syscall)
-                        : "1" (__syscall), "r" (__a), "r" (__b), "r" (__c)
-                        : "r4", "r8", "r9",
-                        "r10", "r11", "r14", "cc", "memory");
-        return __ret;
-}
diff --git a/arch/microblaze/kernel/syscall_table.S b/arch/microblaze/kernel/syscall_table.S
index 6a2b294ef6dc..ff6431e54680 100644
--- a/arch/microblaze/kernel/syscall_table.S
+++ b/arch/microblaze/kernel/syscall_table.S
@@ -2,11 +2,7 @@ ENTRY(sys_call_table)
         .long sys_restart_syscall       /* 0 - old "setup()" system call,
                                          * used for restarting */
         .long sys_exit
-#ifdef CONFIG_MMU
-        .long sys_fork_wrapper
-#else
-        .long sys_ni_syscall
-#endif
+        .long sys_fork
         .long sys_read
         .long sys_write
         .long sys_open                  /* 5 */