From: Konrad Rzeszutek Wilk <konrad@kernel.org>
Date: Sun, 7 Jan 2018 16:30:51 +0000 (-0500)
Subject: x86/spec: Actually do the check for in_use on ENABLE_IBRS
X-Git-Tag: v4.1.12-124.31.3~1294
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=b66aff637834a1bb791d42ec97c7cb027570eb5c;p=users%2Fjedix%2Flinux-maple.git

x86/spec: Actually do the check for in_use on ENABLE_IBRS

Orabug: 27344012
CVE: CVE-2017-5715
Reported-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad@kernel.org>
Signed-off-by: Kirtikar Kashyap <kirtikar.kashyap@oracle.com>
---

diff --git a/arch/x86/include/asm/spec_ctrl.h b/arch/x86/include/asm/spec_ctrl.h
index 5f7e27644a81..26f1fac1fee9 100644
--- a/arch/x86/include/asm/spec_ctrl.h
+++ b/arch/x86/include/asm/spec_ctrl.h
@@ -128,7 +128,10 @@
 	add $(32*8), %rsp;
 
 .macro ENABLE_IBRS
-ALTERNATIVE "", __stringify(__ASM_ENABLE_IBRS), X86_FEATURE_SPEC_CTRL
+	testl	$SPEC_CTRL_IBRS_INUSE, use_ibrs
+	jz	7f
+	__ASM_ENABLE_IBRS
+7:
 .endm
 
 .macro ENABLE_IBRS_CLOBBER