x86: signal: introduce helper align_sigframe()

Impact: cleanup

Introduce helper align_sigframe() to align stack pointer for signal frame.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 15 insertions, 12 deletions

diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 53425c681f2b..dde3f2ae2371 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -191,6 +191,20 @@ setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
 /*
  * Determine which stack to use..
  */
+static unsigned long align_sigframe(unsigned long sp)
+{
+#ifdef CONFIG_X86_32
+        /*
+         * Align the stack pointer according to the i386 ABI,
+         * i.e. so that on function entry ((sp + 4) & 15) == 0.
+         */
+        sp = ((sp + 4) & -16ul) - 4;
+#else /* !CONFIG_X86_32 */
+        sp = round_down(sp, 16) - 8;
+#endif
+        return sp;
+}
+
 static inline void __user *
 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
              void __user **fpstate)
@@ -236,18 +250,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
                         return (void __user *)-1L;
         }
 
-        sp -= frame_size;
-#ifdef CONFIG_X86_32
-        /*
-         * Align the stack pointer according to the i386 ABI,
-         * i.e. so that on function entry ((sp + 4) & 15) == 0.
-         */
-        sp = ((sp + 4) & -16ul) - 4;
-#else /* !CONFIG_X86_32 */
-        sp = round_down(sp, 16) - 8;
-#endif
-
-        return (void __user *) sp;
+        return (void __user *)align_sigframe(sp - frame_size);
 }
 
 #ifdef CONFIG_X86_32