x86/signal: Cleanup get_nr_restart_syscall()

Check for TS_COMPAT instead of TIF_IA32 to distinguish ia32
tasks from 64-bit tasks.

Check for __X32_SYSCALL_BIT iff CONFIG_X86_X32_ABI is defined.

Suggested-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Elvira Khabirova <lineprinter0@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160111145515.GB29007@altlinux.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index cb6282c3638ffbd32bcb33663d8cefc17eac8a8e..c07ff5ddbd477eb44edb9ea960623d17b6d43924 100644 (file)
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -692,12 +692,15 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 
 static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs)
 {
-#if defined(CONFIG_X86_32) || !defined(CONFIG_X86_64)
+#ifdef CONFIG_X86_64
+       if (is_ia32_task())
+               return __NR_ia32_restart_syscall;
+#endif
+#ifdef CONFIG_X86_X32_ABI
+       return __NR_restart_syscall | (regs->orig_ax & __X32_SYSCALL_BIT);
+#else
        return __NR_restart_syscall;
-#else /* !CONFIG_X86_32 && CONFIG_X86_64 */
-       return test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall :
-               __NR_restart_syscall | (regs->orig_ax & __X32_SYSCALL_BIT);
-#endif /* CONFIG_X86_32 || !CONFIG_X86_64 */
+#endif
 }
 
 /*