2019-05-20 23:21:51

by Thomas Garnier

Subject: [PATCH v7 06/12] x86: pm-trace - Adapt assembly for PIE support

From: Thomas Garnier <[email protected]>

Change assembly to use the new _ASM_MOVABS macro instead of _ASM_MOV for
the assembly to be PIE compatible.

Position Independent Executable (PIE) support will allow to extend the
KASLR randomization range below 0xffffffff80000000.

Signed-off-by: Thomas Garnier <[email protected]>
---
arch/x86/include/asm/pm-trace.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/pm-trace.h b/arch/x86/include/asm/pm-trace.h
index bfa32aa428e5..972070806ce9 100644
--- a/arch/x86/include/asm/pm-trace.h
+++ b/arch/x86/include/asm/pm-trace.h
@@ -8,7 +8,7 @@
do { \
if (pm_trace_enabled) { \
const void *tracedata; \
- asm volatile(_ASM_MOV " $1f,%0\n" \
+ asm volatile(_ASM_MOVABS " $1f,%0\n" \
".section .tracedata,\"a\"\n" \
"1:\t.word %c1\n\t" \
_ASM_PTR " %c2\n" \
--
2.21.0.1020.gf2820cf01a-goog

2019-06-10 21:37:20

by Kees Cook

Subject: Re: [PATCH v7 06/12] x86: pm-trace - Adapt assembly for PIE support

On Mon, May 20, 2019 at 04:19:31PM -0700, Thomas Garnier wrote:
> From: Thomas Garnier <[email protected]>
>
> Change assembly to use the new _ASM_MOVABS macro instead of _ASM_MOV for
> the assembly to be PIE compatible.
>
> Position Independent Executable (PIE) support will allow to extend the
> KASLR randomization range below 0xffffffff80000000.
>
> Signed-off-by: Thomas Garnier <[email protected]>

Reviewed-by: Kees Cook <[email protected]>

-Kees

> ---
> arch/x86/include/asm/pm-trace.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/asm/pm-trace.h b/arch/x86/include/asm/pm-trace.h
> index bfa32aa428e5..972070806ce9 100644
> --- a/arch/x86/include/asm/pm-trace.h
> +++ b/arch/x86/include/asm/pm-trace.h
> @@ -8,7 +8,7 @@
> do { \
> if (pm_trace_enabled) { \
> const void *tracedata; \
> - asm volatile(_ASM_MOV " $1f,%0\n" \
> + asm volatile(_ASM_MOVABS " $1f,%0\n" \
> ".section .tracedata,\"a\"\n" \
> "1:\t.word %c1\n\t" \
> _ASM_PTR " %c2\n" \
> --
> 2.21.0.1020.gf2820cf01a-goog
>

--
Kees Cook