This is a note to let you know that I've just added the patch titled
selftests: Provide local define of __cpuid_count()
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
selftests-provide-local-define-of-__cpuid_count.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a23039c7306f53416ba35d230201398ea34f4640 Mon Sep 17 00:00:00 2001
From: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Date: Mon, 25 Apr 2022 14:01:11 -0700
Subject: selftests: Provide local define of __cpuid_count()
From: Reinette Chatre <reinette.chatre@xxxxxxxxx>
commit a23039c7306f53416ba35d230201398ea34f4640 upstream.
Some selftests depend on information provided by the CPUID instruction.
To support this dependency the selftests implement private wrappers for
CPUID.
Duplication of the CPUID wrappers should be avoided.
Both gcc and clang/LLVM provide __cpuid_count() macros but neither
the macro nor its header file are available in all the compiler
versions that need to be supported by the selftests. __cpuid_count()
as provided by gcc is available starting with gcc v4.4, so it is
not available if the latest tests need to be run in all the
environments required to support kernels v4.9 and v4.14 that
have the minimal required gcc v3.2.
Duplicate gcc's __cpuid_count() macro to provide a centrally defined
macro for __cpuid_count() to help eliminate the duplicate CPUID wrappers
while continuing to compile in older environments.
Suggested-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Signed-off-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
Cc: Kyle Huey <me@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/kselftest.h | 15 +++++++++++++++
1 file changed, 15 insertions(+)
--- a/tools/testing/selftests/kselftest.h
+++ b/tools/testing/selftests/kselftest.h
@@ -52,6 +52,21 @@
#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
#endif
+/*
+ * gcc cpuid.h provides __cpuid_count() since v4.4.
+ * Clang/LLVM cpuid.h provides __cpuid_count() since v3.4.0.
+ *
+ * Provide local define for tests needing __cpuid_count() because
+ * selftests need to work in older environments that do not yet
+ * have __cpuid_count().
+ */
+#ifndef __cpuid_count
+#define __cpuid_count(level, count, a, b, c, d) \
+ __asm__ __volatile__ ("cpuid\n\t" \
+ : "=a" (a), "=b" (b), "=c" (c), "=d" (d) \
+ : "0" (level), "2" (count))
+#endif
+
/* define kselftest exit codes */
#define KSFT_PASS 0
#define KSFT_FAIL 1
Patches currently in stable-queue which might be from reinette.chatre@xxxxxxxxx are
queue-5.15/selftests-provide-local-define-of-__cpuid_count.patch
