Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86/asm changes from Ingo Molnar:
 "The one change that stands out is the alternatives patching change
  that prevents us from ever patching back instructions from SMP to UP:
  this simplifies things and speeds up CPU hotplug.

  Other than that it's smaller fixes, cleanups and improvements."

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86: Unspaghettize do_trap()
  x86_64: Work around old GAS bug
  x86: Use REP BSF unconditionally
  x86: Prefer TZCNT over BFS
  x86/64: Adjust types of temporaries used by ffs()/fls()/fls64()
  x86: Drop unnecessary kernel_eflags variable on 64-bit
  x86/smp: Don't ever patch back to UP if we unplug cpus

1 files changed, 29 insertions, 31 deletions

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 378967578f22..cfbe3fc41586 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -108,30 +108,45 @@ static inline void preempt_conditional_cli(struct pt_regs *regs)
         dec_preempt_count();
 }
 
-static void __kprobes
-do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
-        long error_code, siginfo_t *info)
+static int __kprobes
+do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str,
+                  struct pt_regs *regs, long error_code)
 {
-        struct task_struct *tsk = current;
-
 #ifdef CONFIG_X86_32
         if (regs->flags & X86_VM_MASK) {
                 /*
-                 * traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
+                 * Traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
                  * On nmi (interrupt 2), do_trap should not be called.
                  */
-                if (trapnr < X86_TRAP_UD)
-                        goto vm86_trap;
-                goto trap_signal;
+                if (trapnr < X86_TRAP_UD) {
+                        if (!handle_vm86_trap((struct kernel_vm86_regs *) regs,
+                                                error_code, trapnr))
+                                return 0;
+                }
+                return -1;
         }
 #endif
+        if (!user_mode(regs)) {
+                if (!fixup_exception(regs)) {
+                        tsk->thread.error_code = error_code;
+                        tsk->thread.trap_nr = trapnr;
+                        die(str, regs, error_code);
+                }
+                return 0;
+        }
 
-        if (!user_mode(regs))
-                goto kernel_trap;
+        return -1;
+}
 
-#ifdef CONFIG_X86_32
-trap_signal:
-#endif
+static void __kprobes
+do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
+        long error_code, siginfo_t *info)
+{
+        struct task_struct *tsk = current;
+
+
+        if (!do_trap_no_signal(tsk, trapnr, str, regs, error_code))
+                return;
         /*
          * We want error_code and trap_nr set for userspace faults and
          * kernelspace faults which result in die(), but not
@@ -159,23 +174,6 @@ trap_signal:
                 force_sig_info(signr, info, tsk);
         else
                 force_sig(signr, tsk);
-        return;
-
-kernel_trap:
-        if (!fixup_exception(regs)) {
-                tsk->thread.error_code = error_code;
-                tsk->thread.trap_nr = trapnr;
-                die(str, regs, error_code);
-        }
-        return;
-
-#ifdef CONFIG_X86_32
-vm86_trap:
-        if (handle_vm86_trap((struct kernel_vm86_regs *) regs,
-                                                error_code, trapnr))
-                goto trap_signal;
-        return;
-#endif
 }
 
 #define DO_ERROR(trapnr, signr, str, name)                              \