MIPS: Switch over to generic sys_execve and kernel_execve.

This version contains a few updates by David Daney, in particular it's
now using __builtin_frame_address() instead of asm() which depending
on personal taste, is slightly more appealing.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

7 files changed, 19 insertions, 76 deletions

diff --git a/arch/mips/include/asm/ptrace.h b/arch/mips/include/asm/ptrace.h
index 4f5da948a777..cec5e125f7e4 100644
--- a/arch/mips/include/asm/ptrace.h
+++ b/arch/mips/include/asm/ptrace.h
@@ -61,4 +61,10 @@ static inline void die_if_kernel(const char *str, struct pt_regs *regs)
                 die(str, regs);
 }
 
+#define current_pt_regs()                                               \
+({                                                                      \
+        unsigned long sp = (unsigned long)__builtin_frame_address(0);   \
+        (struct pt_regs *)((sp | (THREAD_SIZE - 1)) + 1 - 32) - 1;      \
+})
+
 #endif /* _ASM_PTRACE_H */
diff --git a/arch/mips/include/asm/unistd.h b/arch/mips/include/asm/unistd.h
index 9e47cc11aa26..8ae908c66e59 100644
--- a/arch/mips/include/asm/unistd.h
+++ b/arch/mips/include/asm/unistd.h
@@ -18,8 +18,10 @@
 #ifndef __ASSEMBLY__
 
 #define __ARCH_OMIT_COMPAT_SYS_GETDENTS64
+#define __ARCH_WANT_KERNEL_EXECVE
 #define __ARCH_WANT_OLD_READDIR
 #define __ARCH_WANT_SYS_ALARM
+#define __ARCH_WANT_SYS_EXECVE
 #define __ARCH_WANT_SYS_GETHOSTNAME
 #define __ARCH_WANT_SYS_IPC
 #define __ARCH_WANT_SYS_PAUSE
diff --git a/arch/mips/kernel/entry.S b/arch/mips/kernel/entry.S
index aab6997b8f47..5dcb5fbbbd53 100644
--- a/arch/mips/kernel/entry.S
+++ b/arch/mips/kernel/entry.S
@@ -192,6 +192,15 @@ syscall_exit_work:
         jal     syscall_trace_leave
         b       resume_userspace
 
+LEAF(ret_from_kernel_execve)
+        move    sp, a0
+        ori     $28,  sp, _THREAD_SIZE - 1
+        xori    $28, $28, _THREAD_SIZE - 1
+        li      v0, 0
+        li      a3, 0
+        j       syscall_exit_partial
+        END(ret_from_kernel_execve)
+
 #if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_MIPS_MT)
 
 /*
diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c
index 3a21acedf882..8796dbc7e358 100644
--- a/arch/mips/kernel/linux32.c
+++ b/arch/mips/kernel/linux32.c
@@ -3,7 +3,6 @@
  *
  * Copyright (C) 2000 Silicon Graphics, Inc.
  * Written by Ulf Carlsson (ulfc@engr.sgi.com)
- * sys32_execve from ia64/ia32 code, Feb 2000, Kanoj Sarcar (kanoj@sgi.com)
  */
 #include <linux/compiler.h>
 #include <linux/mm.h>
@@ -77,26 +76,6 @@ out:
         return error;
 }
 
-/*
- * sys_execve() executes a new program.
- */
-asmlinkage int sys32_execve(nabi_no_regargs struct pt_regs regs)
-{
-        int error;
-        struct filename *filename;
-
-        filename = getname(compat_ptr(regs.regs[4]));
-        error = PTR_ERR(filename);
-        if (IS_ERR(filename))
-                goto out;
-        error = compat_do_execve(filename->name, compat_ptr(regs.regs[5]),
-                                 compat_ptr(regs.regs[6]), &regs);
-        putname(filename);
-
-out:
-        return error;
-}
-
 #define RLIM_INFINITY32 0x7fffffff
 #define RESOURCE32(x) ((x > RLIM_INFINITY32) ? RLIM_INFINITY32 : x)
 
diff --git a/arch/mips/kernel/scall64-n32.S b/arch/mips/kernel/scall64-n32.S
index f6ba8381ee01..d27ca340d46d 100644
--- a/arch/mips/kernel/scall64-n32.S
+++ b/arch/mips/kernel/scall64-n32.S
@@ -167,7 +167,7 @@ EXPORT(sysn32_call_table)
         PTR     sys_getsockopt
         PTR     sys_clone                       /* 6055 */
         PTR     sys_fork
-        PTR     sys32_execve
+        PTR     compat_sys_execve
         PTR     sys_exit
         PTR     compat_sys_wait4
         PTR     sys_kill                        /* 6060 */
diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S
index 53c2d7245764..9601be6afa3d 100644
--- a/arch/mips/kernel/scall64-o32.S
+++ b/arch/mips/kernel/scall64-o32.S
@@ -203,7 +203,7 @@ sys_call_table:
         PTR     sys_creat
         PTR     sys_link
         PTR     sys_unlink                      /* 4010 */
-        PTR     sys32_execve
+        PTR     compat_sys_execve
         PTR     sys_chdir
         PTR     compat_sys_time
         PTR     sys_mknod
diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c
index 2bd561bc05ae..c611e2df7767 100644
--- a/arch/mips/kernel/syscall.c
+++ b/arch/mips/kernel/syscall.c
@@ -127,28 +127,6 @@ _sys_clone(nabi_no_regargs struct pt_regs regs)
                        parent_tidptr, child_tidptr);
 }
 
-/*
- * sys_execve() executes a new program.
- */
-asmlinkage int sys_execve(nabi_no_regargs struct pt_regs regs)
-{
-        int error;
-        struct filename *filename;
-
-        filename = getname((const char __user *) (long)regs.regs[4]);
-        error = PTR_ERR(filename);
-        if (IS_ERR(filename))
-                goto out;
-        error = do_execve(filename->name,
-                          (const char __user *const __user *) (long)regs.regs[5],
-                          (const char __user *const __user *) (long)regs.regs[6],
-                          &regs);
-        putname(filename);
-
-out:
-        return error;
-}
-
 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
 {
         struct thread_info *ti = task_thread_info(current);
@@ -313,34 +291,3 @@ asmlinkage void bad_stack(void)
 {
         do_exit(SIGSEGV);
 }
-
-/*
- * 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 unsigned long __a0 asm("$4") = (unsigned long) filename;
-        register unsigned long __a1 asm("$5") = (unsigned long) argv;
-        register unsigned long __a2 asm("$6") = (unsigned long) envp;
-        register unsigned long __a3 asm("$7");
-        unsigned long __v0;
-
-        __asm__ volatile ("                                     \n"
-        "       .set    noreorder                               \n"
-        "       li      $2, %5          # __NR_execve           \n"
-        "       syscall                                         \n"
-        "       move    %0, $2                                  \n"
-        "       .set    reorder                                 \n"
-        : "=&r" (__v0), "=r" (__a3)
-        : "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
-        : "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",
-          "memory");
-
-        if (__a3 == 0)
-                return __v0;
-
-        return -__v0;
-}