* [PATCH] x86/bugs: Correct RSB terminology in Kconfig
@ 2024-09-13 12:27 Breno Leitao
2024-09-13 12:40 ` Dave Hansen
0 siblings, 1 reply; 2+ messages in thread
From: Breno Leitao @ 2024-09-13 12:27 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, x86,
H. Peter Anvin
Cc: corbet, open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)
RSB stands for "Return Stack Buffer" in industry literature[1]. Update
the kernel Kconfig to use this standard term instead of the current
"Return-Speculation-Buffer".
This change aligns kernel documentation with widely accepted terminology.
The line length reduction triggers text reformatting, but no functional
text is altered.
[1] https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/advisory-guidance/return-stack-buffer-underflow.html
Signed-off-by: Breno Leitao <leitao@debian.org>
---
arch/x86/Kconfig | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 007bab9f2a0e..5d87d5d7c6d0 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2554,15 +2554,14 @@ config MITIGATION_CALL_DEPTH_TRACKING
default y
help
Compile the kernel with call depth tracking to mitigate the Intel
- SKL Return-Speculation-Buffer (RSB) underflow issue. The
- mitigation is off by default and needs to be enabled on the
- kernel command line via the retbleed=stuff option. For
- non-affected systems the overhead of this option is marginal as
- the call depth tracking is using run-time generated call thunks
- in a compiler generated padding area and call patching. This
- increases text size by ~5%. For non affected systems this space
- is unused. On affected SKL systems this results in a significant
- performance gain over the IBRS mitigation.
+ SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off
+ by default and needs to be enabled on the kernel command line via the
+ retbleed=stuff option. For non-affected systems the overhead of this
+ option is marginal as the call depth tracking is using run-time
+ generated call thunks in a compiler generated padding area and call
+ patching. This increases text size by ~5%. For non affected systems
+ this space is unused. On affected SKL systems this results in a
+ significant performance gain over the IBRS mitigation.
config CALL_THUNKS_DEBUG
bool "Enable call thunks and call depth tracking debugging"
--
2.43.5
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] x86/bugs: Correct RSB terminology in Kconfig
2024-09-13 12:27 [PATCH] x86/bugs: Correct RSB terminology in Kconfig Breno Leitao
@ 2024-09-13 12:40 ` Dave Hansen
0 siblings, 0 replies; 2+ messages in thread
From: Dave Hansen @ 2024-09-13 12:40 UTC (permalink / raw)
To: Breno Leitao, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
Dave Hansen, x86, H. Peter Anvin
Cc: corbet, open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)
On 9/13/24 05:27, Breno Leitao wrote:
> RSB stands for "Return Stack Buffer" in industry literature[1]. Update
> the kernel Kconfig to use this standard term instead of the current
> "Return-Speculation-Buffer".
Thanks. I'll throw this in my queue, but I'm too chicken to mess with
the branches that will be going up in this merge window.
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
^ permalink raw reply [flat|nested] 2+ messages in thread
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