From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Date: Thu, 1 Feb 2018 16:45:41 +0000 (-0500)
Subject: x86/spectre: Update sysctl values if toggled only by set_{ibrs,ibpb}_disabled
X-Git-Tag: v4.1.12-124.31.3~1166
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=96c806884414eac9e46fafedf9ffa3da1c727eb2;p=users%2Fjedix%2Flinux-maple.git

x86/spectre: Update sysctl values if toggled only by set_{ibrs,ibpb}_disabled

As otherwise we will report the wrong values in the
/sys/kernel/debug/x86/{ibrs,ipbp}_enabled at first
bootup - that is if you have 'noibrs' on the command line.

Orabug: 27477743
CVE: CVE-2017-5715

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@oracle.com>
---

diff --git a/arch/x86/include/asm/spec_ctrl.h b/arch/x86/include/asm/spec_ctrl.h
index b3015fb3e63f..582e116f9eb5 100644
--- a/arch/x86/include/asm/spec_ctrl.h
+++ b/arch/x86/include/asm/spec_ctrl.h
@@ -254,12 +254,16 @@ static inline void set_ibrs_disabled(void)
 	use_ibrs |= SPEC_CTRL_IBRS_ADMIN_DISABLED;
 	if (check_ibrs_inuse())
 		clear_ibrs_inuse();
+	/* Update what sysfs shows. */
+	sysctl_ibrs_enabled = ibrs_inuse ? 1 : 0;
 }
 
 static inline void clear_ibrs_disabled(void)
 {
 	use_ibrs &= ~SPEC_CTRL_IBRS_ADMIN_DISABLED;
 	set_ibrs_inuse();
+	/* Update what sysfs shows. */
+	sysctl_ibrs_enabled = ibrs_inuse ? 1 : 0;
 }
 
 extern u32 sysctl_lfence_enabled;
@@ -320,12 +324,16 @@ static inline void set_ibpb_disabled(void)
 	use_ibpb |= 0x4;
 	if (check_ibpb_inuse())
 		clear_ibpb_inuse();
+	/* Update what sysfs shows. */
+	sysctl_ibpb_enabled = ibpb_inuse ? 1 : 0;
 }
 
 static inline void clear_ibpb_disabled(void)
 {
 	use_ibpb &= ~0x4;
 	set_ibpb_inuse();
+	/* Update what sysfs shows. */
+	sysctl_ibpb_enabled = ibpb_inuse ? 1 : 0;
 }
 
 #endif /* __ASSEMBLY__ */
diff --git a/arch/x86/kernel/cpu/spec_ctrl.c b/arch/x86/kernel/cpu/spec_ctrl.c
index c27c31cea4f0..9450e116bf59 100644
--- a/arch/x86/kernel/cpu/spec_ctrl.c
+++ b/arch/x86/kernel/cpu/spec_ctrl.c
@@ -81,8 +81,6 @@ static ssize_t ibrs_enabled_write(struct file *file,
 		clear_ibrs_disabled();
 	}
 
-	sysctl_ibrs_enabled = enable;
-
 	mutex_unlock(&spec_ctrl_mutex);
 	return count;
 }
@@ -132,8 +130,6 @@ static ssize_t ibpb_enabled_write(struct file *file,
 	else
 		clear_ibpb_disabled();
 
-	sysctl_ibpb_enabled = enable;
-
 	mutex_unlock(&spec_ctrl_mutex);
 	return count;
 }