Commit-ID: 9584d98bed7a7a904d0702ad06bbcc94703cb5b4
Gitweb: http://git.kernel.org/tip/9584d98bed7a7a904d0702ad06bbcc94703cb5b4
Author: Andy Lutomirski <luto@xxxxxxxxxx>
AuthorDate: Tue, 1 Aug 2017 07:11:35 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 10 Aug 2017 17:15:13 +0200
x86/fsgsbase/64: Report FSBASE and GSBASE correctly in core dumps
In ELF_COPY_CORE_REGS, we're copying from the current task, so
accessing thread.fsbase and thread.gsbase makes no sense. Just read
the values from the CPU registers.
In practice, the old code would have been correct most of the time
simply because thread.fsbase and thread.gsbase usually matched the
CPU registers.
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Borislav Petkov <bpetkov@xxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Chang Seok <chang.seok.bae@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/include/asm/elf.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index a62a12c..da3250e 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -204,6 +204,7 @@ void set_personality_ia32(bool);
#define ELF_CORE_COPY_REGS(pr_reg, regs) \
do { \
+ unsigned long base; \
unsigned v; \
(pr_reg)[0] = (regs)->r15; \
(pr_reg)[1] = (regs)->r14; \
@@ -226,8 +227,8 @@ do { \
(pr_reg)[18] = (regs)->flags; \
(pr_reg)[19] = (regs)->sp; \
(pr_reg)[20] = (regs)->ss; \
- (pr_reg)[21] = current->thread.fsbase; \
- (pr_reg)[22] = current->thread.gsbase; \
+ rdmsrl(MSR_FS_BASE, base); (pr_reg)[21] = base; \
+ rdmsrl(MSR_KERNEL_GS_BASE, base); (pr_reg)[22] = base; \
asm("movl %%ds,%0" : "=r" (v)); (pr_reg)[23] = v; \
asm("movl %%es,%0" : "=r" (v)); (pr_reg)[24] = v; \
asm("movl %%fs,%0" : "=r" (v)); (pr_reg)[25] = v; \
--
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