tldr; Just FYI, I'm carrying this on the perf tools tree.
Full explanation:
There used to be no copies, with tools/ code using kernel headers
directly. From time to time tools/perf/ broke due to legitimate kernel
hacking. At some point Linus complained about such direct usage. Then we
adopted the current model.
The way these headers are used in perf are not restricted to just
including them to compile something.
There are sometimes used in scripts that convert defines into string
tables, etc, so some change may break one of these scripts, or new MSRs
may use some different #define pattern, etc.
E.g.:
$ ls -1 tools/perf/trace/beauty/*.sh | head -5
tools/perf/trace/beauty/arch_errno_names.sh
tools/perf/trace/beauty/drm_ioctl.sh
tools/perf/trace/beauty/fadvise.sh
tools/perf/trace/beauty/fsconfig.sh
tools/perf/trace/beauty/fsmount.sh
$
$ tools/perf/trace/beauty/fadvise.sh
static const char *fadvise_advices[] = {
[0] = "NORMAL",
[1] = "RANDOM",
[2] = "SEQUENTIAL",
[3] = "WILLNEED",
[4] = "DONTNEED",
[5] = "NOREUSE",
};
$
The tools/perf/check-headers.sh script, part of the tools/ build
process, points out changes in the original files.
So its important not to touch the copies in tools/ when doing changes in
the original kernel headers, that will be done later, when
check-headers.sh inform about the change to the perf tools hackers.
sources
To pick up the changes from these csets:
be482ff9500999f5 ("x86/bhi: Enumerate Branch History Injection (BHI) bug")
0f4a837615ff925b ("x86/bhi: Define SPEC_CTRL_BHI_DIS_S")
That cause no changes to tooling:
$ tools/perf/trace/beauty/tracepoints/x86_msr.sh > x86_msr.before
$ objdump -dS /tmp/build/perf-tools-next/util/amd-sample-raw.o > amd-sample-raw.o.before
$ cp arch/x86/include/asm/msr-index.h tools/arch/x86/include/asm/msr-index.h
$ make -C tools/perf O=/tmp/build/perf-tools-next
<SNIP>
CC /tmp/build/perf-tools-next/trace/beauty/tracepoints/x86_msr.o
<SNIP>
CC /tmp/build/perf-tools-next/util/amd-sample-raw.o
<SNIP>
$ objdump -dS /tmp/build/perf-tools-next/util/amd-sample-raw.o > amd-sample-raw.o.after
$ tools/perf/trace/beauty/tracepoints/x86_msr.sh > x86_msr.after
$ diff -u x86_msr.before x86_msr.after
$ diff -u amd-sample-raw.o.before amd-sample-raw.o.after
Just silences this perf build warning:
Warning: Kernel ABI header differences:
diff -u tools/arch/x86/include/asm/msr-index.h arch/x86/include/asm/msr-index.h
Cc: Adrian Hunter <[email protected]>
Cc: Daniel Sneddon <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Pawan Gupta <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/lkml/
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
tools/arch/x86/include/asm/msr-index.h | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/tools/arch/x86/include/asm/msr-index.h b/tools/arch/x86/include/asm/msr-index.h
index 05956bd8bacf50e3..e72c2b87295799af 100644
--- a/tools/arch/x86/include/asm/msr-index.h
+++ b/tools/arch/x86/include/asm/msr-index.h
@@ -61,10 +61,13 @@
#define SPEC_CTRL_SSBD BIT(SPEC_CTRL_SSBD_SHIFT) /* Speculative Store Bypass Disable */
#define SPEC_CTRL_RRSBA_DIS_S_SHIFT 6 /* Disable RRSBA behavior */
#define SPEC_CTRL_RRSBA_DIS_S BIT(SPEC_CTRL_RRSBA_DIS_S_SHIFT)
+#define SPEC_CTRL_BHI_DIS_S_SHIFT 10 /* Disable Branch History Injection behavior */
+#define SPEC_CTRL_BHI_DIS_S BIT(SPEC_CTRL_BHI_DIS_S_SHIFT)
/* A mask for bits which the kernel toggles when controlling mitigations */
#define SPEC_CTRL_MITIGATIONS_MASK (SPEC_CTRL_IBRS | SPEC_CTRL_STIBP | SPEC_CTRL_SSBD \
- | SPEC_CTRL_RRSBA_DIS_S)
+ | SPEC_CTRL_RRSBA_DIS_S \
+ | SPEC_CTRL_BHI_DIS_S)
#define MSR_IA32_PRED_CMD 0x00000049 /* Prediction Command */
#define PRED_CMD_IBPB BIT(0) /* Indirect Branch Prediction Barrier */
@@ -163,6 +166,10 @@
* are restricted to targets in
* kernel.
*/
+#define ARCH_CAP_BHI_NO BIT(20) /*
+ * CPU is not affected by Branch
+ * History Injection.
+ */
#define ARCH_CAP_PBRSB_NO BIT(24) /*
* Not susceptible to Post-Barrier
* Return Stack Buffer Predictions.
--
2.44.0