The patch titled
Subject: x86: call instrumentation hooks from copy_mc.c
has been added to the -mm mm-nonmm-unstable branch. Its filename is
x86-call-instrumentation-hooks-from-copy_mcc.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/x86-call-instrumentation-hooks-from-copy_mcc.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Alexander Potapenko <glider@xxxxxxxxxx>
Subject: x86: call instrumentation hooks from copy_mc.c
Date: Wed, 20 Mar 2024 11:18:51 +0100
Memory accesses in copy_mc_to_kernel() and copy_mc_to_user() are performed
by assembly routines and are invisible to KASAN, KCSAN, and KMSAN. Add
hooks from instrumentation.h to tell the tools these functions have
memcpy/copy_from_user semantics.
The call to copy_mc_fragile() in copy_mc_fragile_handle_tail() is left
intact, because the latter is only called from the assembly implementation
of copy_mc_fragile(), so the memory accesses in it are covered by the
instrumentation in copy_mc_to_kernel() and copy_mc_to_user().
Link: https://lore.kernel.org/all/3b7dbd88-0861-4638-b2d2-911c97a4cadf@xxxxxxxxxxxxxxxxxxx/
Link: https://lkml.kernel.org/r/20240320101851.2589698-3-glider@xxxxxxxxxx
Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx>
Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/lib/copy_mc.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
--- a/arch/x86/lib/copy_mc.c~x86-call-instrumentation-hooks-from-copy_mcc
+++ a/arch/x86/lib/copy_mc.c
@@ -4,6 +4,7 @@
#include <linux/jump_label.h>
#include <linux/uaccess.h>
#include <linux/export.h>
+#include <linux/instrumented.h>
#include <linux/string.h>
#include <linux/types.h>
@@ -61,10 +62,20 @@ unsigned long copy_mc_enhanced_fast_stri
*/
unsigned long __must_check copy_mc_to_kernel(void *dst, const void *src, unsigned len)
{
- if (copy_mc_fragile_enabled)
- return copy_mc_fragile(dst, src, len);
- if (static_cpu_has(X86_FEATURE_ERMS))
- return copy_mc_enhanced_fast_string(dst, src, len);
+ unsigned long ret;
+
+ if (copy_mc_fragile_enabled) {
+ instrument_memcpy_before(dst, src, len);
+ ret = copy_mc_fragile(dst, src, len);
+ instrument_memcpy_after(dst, src, len, ret);
+ return ret;
+ }
+ if (static_cpu_has(X86_FEATURE_ERMS)) {
+ instrument_memcpy_before(dst, src, len);
+ ret = copy_mc_enhanced_fast_string(dst, src, len);
+ instrument_memcpy_after(dst, src, len, ret);
+ return ret;
+ }
memcpy(dst, src, len);
return 0;
}
@@ -75,6 +86,7 @@ unsigned long __must_check copy_mc_to_us
unsigned long ret;
if (copy_mc_fragile_enabled) {
+ instrument_copy_to_user(dst, src, len);
__uaccess_begin();
ret = copy_mc_fragile((__force void *)dst, src, len);
__uaccess_end();
@@ -82,6 +94,7 @@ unsigned long __must_check copy_mc_to_us
}
if (static_cpu_has(X86_FEATURE_ERMS)) {
+ instrument_copy_to_user(dst, src, len);
__uaccess_begin();
ret = copy_mc_enhanced_fast_string((__force void *)dst, src, len);
__uaccess_end();
_
Patches currently in -mm which might be from glider@xxxxxxxxxx are
mm-kmsan-implement-kmsan_memmove.patch
instrumentedh-add-instrument_memcpy_before-instrument_memcpy_after.patch
x86-call-instrumentation-hooks-from-copy_mcc.patch
