x86: get rid of TIF_IRET hackery

TIF_NOTIFY_RESUME will work in precisely the same way; all that
is achieved by TIF_IRET is appearing that there's some work to be
done, so we end up on the iret exit path.  Just use NOTIFY_RESUME.
And for execve() do that in 32bit start_thread(), not sys_execve()
itself.

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

5 files changed, 8 insertions, 17 deletions

diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 89f794f007ec..c509d07bdbd7 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 */
@@ -104,7 +103,6 @@ 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/kernel/process.c b/arch/x86/kernel/process.c
index ef6a8456f719..7162e9c1f598 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -351,14 +351,6 @@ long sys_execve(const char __user *name,
         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;
 }
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 516fa186121b..75fcad146def 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -194,6 +194,11 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
          * Free the old FP and other extended state
          */
         free_thread_xstate(current);
+        /*
+         * 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/signal.c b/arch/x86/kernel/signal.c
index b280908a376e..c648fc529872 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -800,10 +800,6 @@ 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 */
 }
 
 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
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));