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Message-Id: <1470071280-78706-3-git-send-email-thgarnie@google.com>
Date: Mon, 1 Aug 2016 10:08:00 -0700
From: Thomas Garnier <thgarnie@...gle.com>
To: Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H . Peter Anvin" <hpa@...or.com>,
Kees Cook <keescook@...omium.org>,
Thomas Garnier <thgarnie@...gle.com>,
Yinghai Lu <yinghai@...nel.org>,
"Rafael J . Wysocki" <rjw@...ysocki.net>,
Pavel Machek <pavel@....cz>
Cc: x86@...nel.org,
linux-kernel@...r.kernel.org,
linux-pm@...r.kernel.org,
kernel-hardening@...ts.openwall.com
Subject: [PATCH v1 2/2] x86/power/64: Fix __PAGE_OFFSET usage on restore
When KASLR memory randomization is used, __PAGE_OFFSET is a global
variable changed during boot. The assembly code was using the variable
as an immediate value to calculate the cr3 physical address. The
physical address was incorrect resulting to a GP fault.
Signed-off-by: Thomas Garnier <thgarnie@...gle.com>
---
arch/x86/power/hibernate_asm_64.S | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/arch/x86/power/hibernate_asm_64.S b/arch/x86/power/hibernate_asm_64.S
index 8eee0e9..8db4905 100644
--- a/arch/x86/power/hibernate_asm_64.S
+++ b/arch/x86/power/hibernate_asm_64.S
@@ -23,6 +23,16 @@
#include <asm/processor-flags.h>
#include <asm/frame.h>
+/*
+ * A global variable holds the page_offset when KASLR memory randomization
+ * is enabled.
+ */
+#ifdef CONFIG_RANDOMIZE_MEMORY
+#define __PAGE_OFFSET_REF __PAGE_OFFSET
+#else
+#define __PAGE_OFFSET_REF $__PAGE_OFFSET
+#endif
+
ENTRY(swsusp_arch_suspend)
movq $saved_context, %rax
movq %rsp, pt_regs_sp(%rax)
@@ -72,7 +82,7 @@ ENTRY(restore_image)
/* code below has been relocated to a safe page */
ENTRY(core_restore_code)
/* switch to temporary page tables */
- movq $__PAGE_OFFSET, %rcx
+ movq __PAGE_OFFSET_REF, %rcx
subq %rcx, %rax
movq %rax, %cr3
/* flush TLB */
--
2.8.0.rc3.226.g39d4020
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