Cache information in x86_64 ld.so --list-diagnostics output (RHEL-21997)

Resolves: RHEL-21997
This commit is contained in:
Florian Weimer 2024-01-18 12:49:44 +01:00
parent d1cf4608a0
commit d304f5706a
2 changed files with 117 additions and 1 deletions

112
glibc-RHEL-21997.patch Normal file
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@ -0,0 +1,112 @@
This downstream-only patch compensates for the missing backport of
commit 2d651eb9265d1366d7b9e881bfddd46db9c1ecc4 ("x86: Move
x86 processor cache info to cpu_features"). Without it,
ld.so --list-diagnostics prints values that have not been properly
initalized from CPUID data.
diff --git a/sysdeps/x86/cacheinfo.h b/sysdeps/x86/cacheinfo.h
index 10ebadd819d9efff..d8421fab83ab08ac 100644
--- a/sysdeps/x86/cacheinfo.h
+++ b/sysdeps/x86/cacheinfo.h
@@ -19,31 +19,42 @@
#include <assert.h>
#include <unistd.h>
+/* When building ld.so, do not export any of the variables. They are
+ only used for diagnostics and are not initialized during regular
+ operation. */
+#if IS_IN (rtld)
+# define CACHEINFO_VARIABLE(name, initializer) \
+ static long int name = initializer
+#else
+# define CACHEINFO_VARIABLE(name, initializer) \
+ long int name attribute_hidden = initializer
+#endif
+
/* Data cache size for use in memory and string routines, typically
L1 size, rounded to multiple of 256 bytes. */
-long int __x86_data_cache_size_half attribute_hidden = 32 * 1024 / 2;
-long int __x86_data_cache_size attribute_hidden = 32 * 1024;
+CACHEINFO_VARIABLE (__x86_data_cache_size_half, 32 * 1024 / 2);
+CACHEINFO_VARIABLE (__x86_data_cache_size, 32 * 1024);
/* Similar to __x86_data_cache_size_half, but not rounded. */
-long int __x86_raw_data_cache_size_half attribute_hidden = 32 * 1024 / 2;
+CACHEINFO_VARIABLE (__x86_raw_data_cache_size_half, 32 * 1024 / 2);
/* Similar to __x86_data_cache_size, but not rounded. */
-long int __x86_raw_data_cache_size attribute_hidden = 32 * 1024;
+CACHEINFO_VARIABLE (__x86_raw_data_cache_size, 32 * 1024);
/* Shared cache size for use in memory and string routines, typically
L2 or L3 size, rounded to multiple of 256 bytes. */
-long int __x86_shared_cache_size_half attribute_hidden = 1024 * 1024 / 2;
-long int __x86_shared_cache_size attribute_hidden = 1024 * 1024;
+CACHEINFO_VARIABLE (__x86_shared_cache_size_half, 1024 * 1024 / 2);
+CACHEINFO_VARIABLE (__x86_shared_cache_size, 1024 * 1024);
/* Similar to __x86_shared_cache_size_half, but not rounded. */
-long int __x86_raw_shared_cache_size_half attribute_hidden = 1024 * 1024 / 2;
+CACHEINFO_VARIABLE (__x86_raw_shared_cache_size_half, 1024 * 1024 / 2);
/* Similar to __x86_shared_cache_size, but not rounded. */
-long int __x86_raw_shared_cache_size attribute_hidden = 1024 * 1024;
+CACHEINFO_VARIABLE (__x86_raw_shared_cache_size, 1024 * 1024);
/* Threshold to use non temporal store. */
-long int __x86_shared_non_temporal_threshold attribute_hidden;
+CACHEINFO_VARIABLE (__x86_shared_non_temporal_threshold, 0);
/* Threshold to use Enhanced REP MOVSB. */
-long int __x86_rep_movsb_threshold attribute_hidden = 2048;
+CACHEINFO_VARIABLE (__x86_rep_movsb_threshold, 2048);
/* Threshold to use Enhanced REP STOSB. */
-long int __x86_rep_stosb_threshold attribute_hidden = 2048;
+CACHEINFO_VARIABLE (__x86_rep_stosb_threshold, 2048);
static void
get_common_cache_info (long int *shared_ptr, long int * shared_per_thread_ptr, unsigned int *threads_ptr,
diff --git a/sysdeps/x86/dl-diagnostics-cpu.c b/sysdeps/x86/dl-diagnostics-cpu.c
index 0ba286a828b69937..9215604ecf22344c 100644
--- a/sysdeps/x86/dl-diagnostics-cpu.c
+++ b/sysdeps/x86/dl-diagnostics-cpu.c
@@ -19,6 +19,13 @@
#include <dl-diagnostics.h>
#include <ldsodefs.h>
+#include <assert.h>
+#include <unistd.h>
+#include <cpu-features.h>
+#include <cpuid.h>
+#include <dl-cacheinfo.h>
+#include <cacheinfo.h>
+
static void
print_cpu_features_value (const char *label, uint64_t value)
{
@@ -81,19 +88,21 @@ _dl_diagnostics_cpu (void)
#include "cpu-features-preferred_feature_index_1.def"
#undef BIT
+ /* The cache information variables are only used for diagnostics and
+ are not initialized during startup. The values used at run time
+ are only in libc.so.6. */
+ init_cacheinfo ();
+
print_cpu_features_value ("xsave_state_size",
cpu_features->xsave_state_size);
print_cpu_features_value ("xsave_state_full_size",
cpu_features->xsave_state_full_size);
- print_cpu_features_value ("data_cache_size", cpu_features->data_cache_size);
- print_cpu_features_value ("shared_cache_size",
- cpu_features->shared_cache_size);
+ print_cpu_features_value ("data_cache_size", __x86_data_cache_size);
+ print_cpu_features_value ("shared_cache_size", __x86_shared_cache_size);
print_cpu_features_value ("non_temporal_threshold",
- cpu_features->non_temporal_threshold);
- print_cpu_features_value ("rep_movsb_threshold",
- cpu_features->rep_movsb_threshold);
- print_cpu_features_value ("rep_stosb_threshold",
- cpu_features->rep_stosb_threshold);
+ __x86_shared_non_temporal_threshold);
+ print_cpu_features_value ("rep_movsb_threshold", __x86_rep_movsb_threshold);
+ print_cpu_features_value ("rep_stosb_threshold", __x86_rep_stosb_threshold);
_Static_assert (offsetof (struct cpu_features, rep_stosb_threshold)
+ sizeof (cpu_features->rep_stosb_threshold)
== sizeof (*cpu_features),

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@ -1,6 +1,6 @@
%define glibcsrcdir glibc-2.28
%define glibcversion 2.28
%define glibcrelease 250%{?dist}
%define glibcrelease 251%{?dist}
# Pre-release tarballs are pulled in from git using a command that is
# effectively:
#
@ -1182,6 +1182,7 @@ Patch994: glibc-RHEL-3010-1.patch
Patch995: glibc-RHEL-3010-2.patch
Patch996: glibc-RHEL-3010-3.patch
Patch997: glibc-RHEL-19445.patch
Patch998: glibc-RHEL-21997.patch
##############################################################################
# Continued list of core "glibc" package information:
@ -3013,6 +3014,9 @@ fi
%files -f compat-libpthread-nonshared.filelist -n compat-libpthread-nonshared
%changelog
* Thu Jan 18 2024 Florian Weimer <fweimer@redhat.com> - 2.28-251
- Cache information in x86_64 ld.so --list-diagnostics output (RHEL-21997)
* Wed Jan 10 2024 Arjun Shankar <arjun@redhat.com> - 2.28-250
- getaddrinfo: Return correct error EAI_MEMORY when out-of-memory (RHEL-19445)