powerpc: switch to generic sys_execve()/kernel_execve()

the only non-obvious part is that current_pt_regs() is really needed
here - task_pt_regs() is NULL for kernel threads; it's OK for ptrace
uses (the thing task_pt_regs() is intended for), but not for us.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

8 files changed, 21 insertions, 51 deletions

diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
index 9c21ed42aba..f76b88c367d 100644
--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h
@@ -125,6 +125,8 @@ extern unsigned long ptrace_get_reg(struct task_struct *task, int regno);
 extern int ptrace_put_reg(struct task_struct *task, int regno,
                           unsigned long data);
 
+#define current_pt_regs() \
+        ((struct pt_regs *)((unsigned long)current_thread_info() + THREAD_SIZE) - 1)
 /*
  * We use the least-significant bit of the trap field to indicate
  * whether we have saved the full set of registers, or only a
diff --git a/arch/powerpc/include/asm/syscalls.h b/arch/powerpc/include/asm/syscalls.h
index 4084e567d28..329db4ec12c 100644
--- a/arch/powerpc/include/asm/syscalls.h
+++ b/arch/powerpc/include/asm/syscalls.h
@@ -17,9 +17,6 @@ asmlinkage unsigned long sys_mmap(unsigned long addr, size_t len,
 asmlinkage unsigned long sys_mmap2(unsigned long addr, size_t len,
                 unsigned long prot, unsigned long flags,
                 unsigned long fd, unsigned long pgoff);
-asmlinkage int sys_execve(unsigned long a0, unsigned long a1,
-                unsigned long a2, unsigned long a3, unsigned long a4,
-                unsigned long a5, struct pt_regs *regs);
 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long usp,
                 int __user *parent_tidp, void __user *child_threadptr,
                 int __user *child_tidp, int p6, struct pt_regs *regs);
diff --git a/arch/powerpc/include/asm/unistd.h b/arch/powerpc/include/asm/unistd.h
index bd377a36861..26a6825909b 100644
--- a/arch/powerpc/include/asm/unistd.h
+++ b/arch/powerpc/include/asm/unistd.h
@@ -420,6 +420,8 @@
 #define __ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND
 #define __ARCH_WANT_SYS_NEWFSTATAT
 #endif
+#define __ARCH_WANT_SYS_EXECVE
+#define __ARCH_WANT_KERNEL_EXECVE
 
 /*
  * "Conditional" syscalls
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 6eb330a87c3..e6be75fc491 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -446,6 +446,11 @@ ret_from_kernel_thread:
         li      r3,0
         b       do_exit         # no return
 
+        .globl  __ret_from_kernel_execve
+__ret_from_kernel_execve:
+        addi    r1,r3,-STACK_FRAME_OVERHEAD
+        b       ret_from_syscall
+
 /* Traced system call support */
 syscall_dotrace:
         SAVE_NVGPRS(r1)
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index d7f4fafc751..1ca3d9fa48c 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -380,6 +380,12 @@ _GLOBAL(ret_from_kernel_thread)
         li      r3,0
         b       .do_exit        # no return
 
+_GLOBAL(__ret_from_kernel_execve)
+        addi    r1,r3,-STACK_FRAME_OVERHEAD
+        li      r10,1
+        std     r10,SOFTE(r1)
+        b       syscall_exit
+
         .section        ".toc","aw"
 DSCR_DEFAULT:
         .tc dscr_default[TC],dscr_default
diff --git a/arch/powerpc/kernel/misc.S b/arch/powerpc/kernel/misc.S
index ba16874fe29..7ce26d45777 100644
--- a/arch/powerpc/kernel/misc.S
+++ b/arch/powerpc/kernel/misc.S
@@ -54,13 +54,6 @@ _GLOBAL(add_reloc_offset)
         .align  3
 2:      PPC_LONG 1b
 
-_GLOBAL(kernel_execve)
-        li      r0,__NR_execve
-        sc
-        bnslr
-        neg     r3,r3
-        blr
-
 _GLOBAL(setjmp)
         mflr    r0
         PPC_STL r0,0(r3)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 3b06898fa17..6fdf044f475 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1064,26 +1064,13 @@ int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
                         regs, 0, NULL, NULL);
 }
 
-int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
-               unsigned long a3, unsigned long a4, unsigned long a5,
-               struct pt_regs *regs)
+void __ret_from_kernel_execve(struct pt_regs *normal)
+__noreturn;
+
+void ret_from_kernel_execve(struct pt_regs *normal)
 {
-        int error;
-        char *filename;
-
-        filename = getname((const char __user *) a0);
-        error = PTR_ERR(filename);
-        if (IS_ERR(filename))
-                goto out;
-        flush_fp_to_thread(current);
-        flush_altivec_to_thread(current);
-        flush_spe_to_thread(current);
-        error = do_execve(filename,
-                          (const char __user *const __user *) a1,
-                          (const char __user *const __user *) a2, regs);
-        putname(filename);
-out:
-        return error;
+        set_thread_flag(TIF_RESTOREALL);
+        __ret_from_kernel_execve(normal);
 }
 
 static inline int valid_irq_stack(unsigned long sp, struct task_struct *p,
diff --git a/arch/powerpc/kernel/sys_ppc32.c b/arch/powerpc/kernel/sys_ppc32.c
index 81c570633ea..a1ae73a0f35 100644
--- a/arch/powerpc/kernel/sys_ppc32.c
+++ b/arch/powerpc/kernel/sys_ppc32.c
@@ -187,28 +187,6 @@ asmlinkage int compat_sys_sendfile64(int out_fd, int in_fd, compat_loff_t __user
         return ret;
 }
 
-long compat_sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
-                  unsigned long a3, unsigned long a4, unsigned long a5,
-                  struct pt_regs *regs)
-{
-        int error;
-        char * filename;
-        
-        filename = getname((char __user *) a0);
-        error = PTR_ERR(filename);
-        if (IS_ERR(filename))
-                goto out;
-        flush_fp_to_thread(current);
-        flush_altivec_to_thread(current);
-
-        error = compat_do_execve(filename, compat_ptr(a1), compat_ptr(a2), regs);
-
-        putname(filename);
-
-out:
-        return error;
-}
-
 /* Note: it is necessary to treat option as an unsigned int, 
  * with the corresponding cast to a signed int to insure that the 
  * proper conversion (sign extension) between the register representation of a signed int (msr in 32-bit mode)