From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Mon, 4 Dec 2017 11:59:57 +0000 (+0100)
Subject: Revert "x86/entry/64: Add missing irqflags tracing to native_load_gs_index()"
X-Git-Tag: v4.14.4~1
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e49d722f26b904015077655bff47cdbde049226a;p=platform%2Fkernel%2Flinux-rpi.git

Revert "x86/entry/64: Add missing irqflags tracing to native_load_gs_index()"

This reverts commit f9a64e23a9da528e7d8aa1bd2c7bb92be4ebb724 which is
commit 0d794d0d018f23fb09c50f6ae26868bd6ae343d6 upstream.

Andy writes:

	I think the thing to do is to revert the patch from -stable.
	The bug it fixes is very minor, and the regression is that it
	made a pre-existing bug in some nearly-undebuggable core resume
	code much easier to hit.  I don't feel comfortable with a
	backport of the latter fix until it has a good long soak in
	Linus' tree.

Reported-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 518d9286..2e956af 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -51,19 +51,15 @@ ENTRY(native_usergs_sysret64)
 END(native_usergs_sysret64)
 #endif /* CONFIG_PARAVIRT */
 
-.macro TRACE_IRQS_FLAGS flags:req
+.macro TRACE_IRQS_IRETQ
 #ifdef CONFIG_TRACE_IRQFLAGS
-	bt	$9, \flags		/* interrupts off? */
+	bt	$9, EFLAGS(%rsp)		/* interrupts off? */
 	jnc	1f
 	TRACE_IRQS_ON
 1:
 #endif
 .endm
 
-.macro TRACE_IRQS_IRETQ
-	TRACE_IRQS_FLAGS EFLAGS(%rsp)
-.endm
-
 /*
  * When dynamic function tracer is enabled it will add a breakpoint
  * to all locations that it is about to modify, sync CPUs, update
@@ -927,13 +923,11 @@ ENTRY(native_load_gs_index)
 	FRAME_BEGIN
 	pushfq
 	DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI)
-	TRACE_IRQS_OFF
 	SWAPGS
 .Lgs_change:
 	movl	%edi, %gs
 2:	ALTERNATIVE "", "mfence", X86_BUG_SWAPGS_FENCE
 	SWAPGS
-	TRACE_IRQS_FLAGS (%rsp)
 	popfq
 	FRAME_END
 	ret