x86/entry/64: Fix IRQ state confusion and related warning on compat syscalls with CONFIG_AUDITSYSCALL=n

int_ret_from_sys_call now expects IRQs to be enabled.  I got
this right in the real sysexit_audit and sysretl_audit asm
paths, but I missed it in the #defined-away versions when
CONFIG_AUDITSYSCALL=n.  This is a straightforward fix for
CONFIG_AUDITSYSCALL=n

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.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>
Fixes: 29ea1b258b98 ("x86/entry/64: Migrate 64-bit and compat syscalls to the new exit handlers and remove old assembly code")
Link: http://lkml.kernel.org/r/25cf0a01e01c6008118dd8f8d9f043020416700c.1436291493.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/entry/entry_64_compat.S

@@ -22,8 +22,8 @@
 #define __AUDIT_ARCH_LE		0x40000000
 
 #ifndef CONFIG_AUDITSYSCALL
-# define sysexit_audit		ia32_ret_from_sys_call
-# define sysretl_audit		ia32_ret_from_sys_call
+# define sysexit_audit		ia32_ret_from_sys_call_irqs_off
+# define sysretl_audit		ia32_ret_from_sys_call_irqs_off
 #endif
 
 	.section .entry.text, "ax"
@@ -466,6 +466,10 @@ ia32_badarg:
 	/* And exit again. */
 	jmp retint_user
 
+ia32_ret_from_sys_call_irqs_off:
+	TRACE_IRQS_ON
+	ENABLE_INTERRUPTS(CLBR_NONE)
+
 ia32_ret_from_sys_call:
 	xorl	%eax, %eax		/* Do not leak kernel information */
 	movq	%rax, R11(%rsp)