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
  ...

3 files changed, 56 insertions, 7 deletions

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