[PATCH] Common cpuid wrappers, use SYS_cpuid when available

[PATCH] Common cpuid wrappers, use SYS_cpuid when available

[Piotr Henryk Dabrowski]

	* config.h.in: Check for SYS_cpuid and define HAVE_SYS_CPUID
	* configure: Check for SYS_cpuid and define HAVE_SYS_CPUID
	* configure.ac: Check for SYS_cpuid and define HAVE_SYS_CPUID
	* misc/cpuid.h: Common cpuid wrappers, use SYS_cpuid when available
	* sysdeps/x86/cpu-features.c: Use misc/cpuid.h wrappers
	* sysdeps/x86/fpu/test-fenv-clear-sse.c: Use misc/cpuid.h wrappers
	* sysdeps/x86/fpu/test-fenv-sse-2.c: Use misc/cpuid.h wrappers
	* sysdeps/x86/fpu/test-fenv-sse.c: Use misc/cpuid.h wrappers
	* sysdeps/x86_64/cacheinfo.c: Use misc/cpuid.h wrappers
	* sysdeps/x86_64/tst-audit10.c: Use misc/cpuid.h wrappers
	* sysdeps/x86_64/tst-audit4.c: Use misc/cpuid.h wrappers
	* sysdeps/x86_64/tst-audit6.c: Use misc/cpuid.h wrappers
	* sysdeps/x86_64/tst-auditmod10b.c: Use misc/cpuid.h wrappers
	* sysdeps/x86_64/tst-auditmod4b.c: Use misc/cpuid.h wrappers
	* sysdeps/x86_64/tst-auditmod6b.c: Use misc/cpuid.h wrappers
	* sysdeps/x86_64/tst-auditmod6c.c: Use misc/cpuid.h wrappers
	* sysdeps/x86_64/tst-auditmod7b.c: Use misc/cpuid.h wrappers
---
 ChangeLog                             | 20 +++++++++
 config.h.in                           |  3 ++
 configure                             | 37 ++++++++++++++++
 configure.ac                          | 18 ++++++++
 misc/cpuid.h                          | 82 +++++++++++++++++++++++++++++++++++
 sysdeps/x86/cpu-features.c            | 37 ++++++++--------
 sysdeps/x86/fpu/test-fenv-clear-sse.c |  4 +-
 sysdeps/x86/fpu/test-fenv-sse-2.c     |  4 +-
 sysdeps/x86/fpu/test-fenv-sse.c       |  4 +-
 sysdeps/x86_64/cacheinfo.c            | 24 +++++-----
 sysdeps/x86_64/tst-audit10.c          |  6 +--
 sysdeps/x86_64/tst-audit4.c           |  4 +-
 sysdeps/x86_64/tst-audit6.c           |  4 +-
 sysdeps/x86_64/tst-auditmod10b.c      |  6 +--
 sysdeps/x86_64/tst-auditmod4b.c       |  4 +-
 sysdeps/x86_64/tst-auditmod6b.c       |  4 +-
 sysdeps/x86_64/tst-auditmod6c.c       |  4 +-
 sysdeps/x86_64/tst-auditmod7b.c       |  4 +-
 18 files changed, 215 insertions(+), 54 deletions(-)
 create mode 100644 misc/cpuid.h

diff --git a/ChangeLog b/ChangeLog
index a6be762..3c67632 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,23 @@
+2016-03-07  Piotr Henryk Dabrowski  <ultr@ultr.pl>
+
+	* config.h.in: Check for SYS_cpuid and define HAVE_SYS_CPUID
+	* configure: Check for SYS_cpuid and define HAVE_SYS_CPUID
+	* configure.ac: Check for SYS_cpuid and define HAVE_SYS_CPUID
+	* misc/cpuid.h: Common cpuid wrappers, use SYS_cpuid when available
+	* sysdeps/x86/cpu-features.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86/fpu/test-fenv-clear-sse.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86/fpu/test-fenv-sse-2.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86/fpu/test-fenv-sse.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86_64/cacheinfo.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86_64/tst-audit10.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86_64/tst-audit4.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86_64/tst-audit6.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86_64/tst-auditmod10b.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86_64/tst-auditmod4b.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86_64/tst-auditmod6b.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86_64/tst-auditmod6c.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86_64/tst-auditmod7b.c: Use misc/cpuid.h wrappers
+
 2016-03-09  Joseph Myers  <joseph@codesourcery.com>
 
 	[BZ #19790]
diff --git a/config.h.in b/config.h.in
index 0147ba3..0f2231a 100644
--- a/config.h.in
+++ b/config.h.in
@@ -121,6 +121,9 @@
 /* Mach/i386 specific: define if the `i386_set_gdt' RPC is available.  */
 #undef	HAVE_I386_SET_GDT
 
+/* Define if the x86 kernel supports SYS_cpuid syscall.  */
+#undef HAVE_SYS_CPUID
+
 /* Defined of libidn is available.  */
 #undef HAVE_LIBIDN
 
diff --git a/configure b/configure
index 8fe5937..1138642 100755
--- a/configure
+++ b/configure
@@ -6420,6 +6420,43 @@ ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS
$LDFLAGS conftest.$ac_ext $ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
+# SYS_cpuid syscall
+libc_cv_sys_cpuid=no
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for x86 kernel with
SYS_cpuid support" >&5 +$as_echo_n "checking for x86 kernel with SYS_cpuid
support... " >&6; } +cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+  #if (defined(__i386__) || defined(__x86_64__)) && defined(__linux__)
+  #include <sys/syscall.h>
+  #if !defined(SYS_cpuid) || !defined(__NR_cpuid)
+  #error SYS_cpuid not defined
+  #endif
+  #else
+  #error Not a x86 Linux
+  #endif
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  libc_cv_sys_cpuid=yes
+else
+  libc_cv_sys_cpuid=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+if test "$libc_cv_sys_cpuid" = yes; then
+  $as_echo "#define HAVE_SYS_CPUID 1" >>confdefs.h
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_sys_cpuid" >&5
+$as_echo "$libc_cv_sys_cpuid" >&6; }
+
 ### End of automated tests.
 ### Now run sysdeps configure fragments.
 
diff --git a/configure.ac b/configure.ac
index 3c766b7..89a1779 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1704,6 +1704,24 @@ AC_SUBST(libc_cv_cxx_thread_local)
 AC_LANG_POP([C++])
 dnl End of C++ feature tests.
 
+# SYS_cpuid syscall
+libc_cv_sys_cpuid=no
+AC_MSG_CHECKING(for x86 kernel with SYS_cpuid support)
+AC_TRY_COMPILE([
+  #if (defined(__i386__) || defined(__x86_64__)) && defined(__linux__)
+  #include <sys/syscall.h>
+  #if !defined(SYS_cpuid) || !defined(__NR_cpuid)
+  #error SYS_cpuid not defined
+  #endif
+  #else
+  #error Not a x86 Linux
+  #endif
+], [], [libc_cv_sys_cpuid=yes], [libc_cv_sys_cpuid=no])
+if test "$libc_cv_sys_cpuid" = yes; then
+  AC_DEFINE(HAVE_SYS_CPUID)
+fi
+AC_MSG_RESULT($libc_cv_sys_cpuid)
+
 ### End of automated tests.
 ### Now run sysdeps configure fragments.
 
diff --git a/misc/cpuid.h b/misc/cpuid.h
new file mode 100644
index 0000000..6caea13
--- /dev/null
+++ b/misc/cpuid.h
@@ -0,0 +1,82 @@
+/* CPUID wrapper functions.
+   This file is part of the GNU C Library.
+   Copyright (C) 2016 Piotr Henryk Dabrowski <ultr@ultr.pl>
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _CPUID_H
+#define _CPUID_H 1
+
+/* NOTE: for new Linux kernels these functions try to use kernel-adjusted
+   values for cpuid returned by the SYS_cpuid sys call.
+   Otherwise they fallback to native cpuid implementation. */
+
+#include <config.h>
+
+#include <cpuid.h>
+#include <errno.h>
+#include <stddef.h>
+
+#ifdef HAVE_SYS_CPUID
+#include <sysdep.h>
+#include <sys/syscall.h>
+#endif
+
+#define get_cpuid_max __get_cpuid_max
+
+/* Return cpuid data for requested cpuid level (eax) and count register (ecx),
+   as found in returned eax, ebx, ecx and edx registers.
+   All pointers are required to be non-null. */
+static inline void
+cpuid_count (unsigned int level, unsigned int count,
+	     unsigned int *eax, unsigned int *ebx,
+	     unsigned int *ecx, unsigned int *edx)
+{
+#ifdef HAVE_SYS_CPUID
+	if (INLINE_SYSCALL(cpuid, 6, level, count, eax, ebx, ecx, edx) == 0)
+		return;
+#endif
+	__cpuid_count(level, count, *eax, *ebx, *ecx, *edx);
+}
+
+/* Return cpuid data for requested cpuid level (eax),
+   as found in returned eax, ebx, ecx and edx registers.
+   All pointers are required to be non-null. */
+static inline void
+cpuid (unsigned int level,
+       unsigned int *eax, unsigned int *ebx,
+       unsigned int *ecx, unsigned int *edx)
+{
+	cpuid_count(level, 0, eax, ebx, ecx, edx);
+}
+
+/* Return cpuid data for requested cpuid level (eax),
+   as found in returned eax, ebx, ecx and edx registers.
+   The function checks if cpuid is supported and returns 1 for valid cpuid
+   information or 0 for unsupported cpuid level.
+   All pointers are required to be non-null. */
+static inline int
+get_cpuid (unsigned int level,
+	   unsigned int *eax, unsigned int *ebx,
+	   unsigned int *ecx, unsigned int *edx)
+{
+	unsigned int ext = level & 0x80000000;
+	if (get_cpuid_max (ext, 0) < level)
+		return 0;
+	cpuid (level, eax, ebx, ecx, edx);
+	return 1;
+}
+
+#endif /* cpuid.h */
diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
index 218ff2b..a71c701 100644
--- a/sysdeps/x86/cpu-features.c
+++ b/sysdeps/x86/cpu-features.c
@@ -16,7 +16,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <cpuid.h>
+#include <misc/cpuid.h>
 #include <cpu-features.h>
 
 static inline void
@@ -25,9 +25,9 @@ get_common_indeces (struct cpu_features *cpu_features,
 		    unsigned int *extended_model)
 {
   unsigned int eax;
-  __cpuid (1, eax, cpu_features->cpuid[COMMON_CPUID_INDEX_1].ebx,
-	   cpu_features->cpuid[COMMON_CPUID_INDEX_1].ecx,
-	   cpu_features->cpuid[COMMON_CPUID_INDEX_1].edx);
+  cpuid (1, &eax, &(cpu_features->cpuid[COMMON_CPUID_INDEX_1].ebx),
+	 &(cpu_features->cpuid[COMMON_CPUID_INDEX_1].ecx),
+	 &(cpu_features->cpuid[COMMON_CPUID_INDEX_1].edx));
   GLRO(dl_x86_cpu_features).cpuid[COMMON_CPUID_INDEX_1].eax = eax;
   *family = (eax >> 8) & 0x0f;
   *model = (eax >> 4) & 0x0f;
@@ -42,20 +42,21 @@ get_common_indeces (struct cpu_features *cpu_features,
 static inline void
 init_cpu_features (struct cpu_features *cpu_features)
 {
-  unsigned int ebx, ecx, edx;
+  unsigned int eax, ebx, ecx, edx;
   unsigned int family = 0;
   unsigned int model = 0;
   enum cpu_features_kind kind;
 
 #if !HAS_CPUID
-  if (__get_cpuid_max (0, 0) == 0)
+  if (get_cpuid_max (0, 0) == 0)
     {
       kind = arch_kind_other;
       goto no_cpuid;
     }
 #endif
 
-  __cpuid (0, cpu_features->max_cpuid, ebx, ecx, edx);
+  cpuid (0, &eax, &ebx, &ecx, &edx);
+  cpu_features->max_cpuid = eax;
 
   /* This spells out "GenuineIntel".  */
   if (ebx == 0x756e6547 && ecx == 0x6c65746e && edx == 0x49656e69)
@@ -147,13 +148,13 @@ init_cpu_features (struct cpu_features *cpu_features)
       ecx = cpu_features->cpuid[COMMON_CPUID_INDEX_1].ecx;
 
       unsigned int eax;
-      __cpuid (0x80000000, eax, ebx, ecx, edx);
+      cpuid (0x80000000, &eax, &ebx, &ecx, &edx);
       if (eax >= 0x80000001)
-	__cpuid (0x80000001,
-		 cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].eax,
-		 cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].ebx,
-		 cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].ecx,
-		 cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].edx);
+	cpuid (0x80000001,
+	       &(cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].eax),
+	       &(cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].ebx),
+	       &(cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].ecx),
+	       &(cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].edx));
 
       if (family == 0x15)
 	{
@@ -175,11 +176,11 @@ init_cpu_features (struct cpu_features *cpu_features)
     cpu_features->feature[index_I686] |= bit_I686;
 
   if (cpu_features->max_cpuid >= 7)
-    __cpuid_count (7, 0,
-		   cpu_features->cpuid[COMMON_CPUID_INDEX_7].eax,
-		   cpu_features->cpuid[COMMON_CPUID_INDEX_7].ebx,
-		   cpu_features->cpuid[COMMON_CPUID_INDEX_7].ecx,
-		   cpu_features->cpuid[COMMON_CPUID_INDEX_7].edx);
+    cpuid_count (7, 0,
+		 &(cpu_features->cpuid[COMMON_CPUID_INDEX_7].eax),
+		 &(cpu_features->cpuid[COMMON_CPUID_INDEX_7].ebx),
+		 &(cpu_features->cpuid[COMMON_CPUID_INDEX_7].ecx),
+		 &(cpu_features->cpuid[COMMON_CPUID_INDEX_7].edx));
 
   /* Can we call xgetbv?  */
   if (HAS_CPU_FEATURE (OSXSAVE))
diff --git a/sysdeps/x86/fpu/test-fenv-clear-sse.c
b/sysdeps/x86/fpu/test-fenv-clear-sse.c index cc4b3f0..816470b 100644
--- a/sysdeps/x86/fpu/test-fenv-clear-sse.c
+++ b/sysdeps/x86/fpu/test-fenv-clear-sse.c
@@ -17,7 +17,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <cpuid.h>
+#include <misc/cpuid.h>
 #include <stdbool.h>
 
 static bool
@@ -25,7 +25,7 @@ have_sse2 (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
+  if (!get_cpuid (1, &eax, &ebx, &ecx, &edx))
     return false;
 
   return (edx & bit_SSE2) != 0;
diff --git a/sysdeps/x86/fpu/test-fenv-sse-2.c
b/sysdeps/x86/fpu/test-fenv-sse-2.c index d3197c3..c72d5ad 100644
--- a/sysdeps/x86/fpu/test-fenv-sse-2.c
+++ b/sysdeps/x86/fpu/test-fenv-sse-2.c
@@ -16,7 +16,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <cpuid.h>
+#include <misc/cpuid.h>
 #include <fenv.h>
 #include <float.h>
 #include <stdbool.h>
@@ -28,7 +28,7 @@ have_sse2 (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
+  if (!get_cpuid (1, &eax, &ebx, &ecx, &edx))
     return false;
 
   return (edx & bit_SSE2) != 0;
diff --git a/sysdeps/x86/fpu/test-fenv-sse.c b/sysdeps/x86/fpu/test-fenv-sse.c
index 4f4ff6a..c8f1497 100644
--- a/sysdeps/x86/fpu/test-fenv-sse.c
+++ b/sysdeps/x86/fpu/test-fenv-sse.c
@@ -16,7 +16,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <cpuid.h>
+#include <misc/cpuid.h>
 #include <fenv.h>
 #include <float.h>
 #include <stdbool.h>
@@ -27,7 +27,7 @@ have_sse2 (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
+  if (!get_cpuid (1, &eax, &ebx, &ecx, &edx))
     return false;
 
   return (edx & bit_SSE2) != 0;
diff --git a/sysdeps/x86_64/cacheinfo.c b/sysdeps/x86_64/cacheinfo.c
index 96463df..76cd03d 100644
--- a/sysdeps/x86_64/cacheinfo.c
+++ b/sysdeps/x86_64/cacheinfo.c
@@ -20,7 +20,7 @@
 #include <stdbool.h>
 #include <stdlib.h>
 #include <unistd.h>
-#include <cpuid.h>
+#include <misc/cpuid.h>
 #include <init-arch.h>
 
 #define is_intel GLRO(dl_x86_cpu_features).kind == arch_kind_intel
@@ -162,7 +162,7 @@ intel_check_word (int name, unsigned int value, bool
*has_level_2, unsigned int round = 0;
 	  while (1)
 	    {
-	      __cpuid_count (4, round, eax, ebx, ecx, edx);
+	      cpuid_count (4, round, &eax, &ebx, &ecx, &edx);
 
 	      enum { null = 0, data = 1, inst = 2, uni = 3 } type = eax & 0x1f;
 	      if (type == null)
@@ -275,7 +275,7 @@ handle_intel (int name, unsigned int maxidx)
       unsigned int ebx;
       unsigned int ecx;
       unsigned int edx;
-      __cpuid (2, eax, ebx, ecx, edx);
+      cpuid (2, &eax, &ebx, &ecx, &edx);
 
       /* The low byte of EAX in the first round contain the number of
 	 rounds we have to make.  At least one, the one we are already
@@ -319,7 +319,7 @@ handle_amd (int name)
   unsigned int ebx;
   unsigned int ecx;
   unsigned int edx;
-  __cpuid (0x80000000, eax, ebx, ecx, edx);
+  cpuid (0x80000000, &eax, &ebx, &ecx, &edx);
 
   /* No level 4 cache (yet).  */
   if (name > _SC_LEVEL3_CACHE_LINESIZE)
@@ -329,7 +329,7 @@ handle_amd (int name)
   if (eax < fn)
     return 0;
 
-  __cpuid (fn, eax, ebx, ecx, edx);
+  cpuid (fn, &eax, &ebx, &ecx, &edx);
 
   if (name < _SC_LEVEL1_DCACHE_SIZE)
     {
@@ -479,7 +479,7 @@ init_cacheinfo (void)
   unsigned int ebx;
   unsigned int ecx;
   unsigned int edx;
-  int max_cpuid_ex;
+  unsigned int max_cpuid_ex;
   long int data = -1;
   long int shared = -1;
   unsigned int level;
@@ -512,7 +512,7 @@ init_cacheinfo (void)
 	  /* Query until desired cache level is enumerated.  */
 	  do
 	    {
-	      __cpuid_count (4, i++, eax, ebx, ecx, edx);
+	      cpuid_count (4, i++, &eax, &ebx, &ecx, &edx);
 
 	      /* There seems to be a bug in at least some Pentium Ds
 		 which sometimes fail to iterate all cache parameters.
@@ -536,7 +536,7 @@ init_cacheinfo (void)
 	      i = 0;
 	      while (1)
 		{
-		  __cpuid_count (11, i++, eax, ebx, ecx, edx);
+		  cpuid_count (11, i++, &eax, &ebx, &ecx, &edx);
 
 		  int shipped = ebx & 0xff;
 		  int type = ecx & 0xff0;
@@ -598,7 +598,7 @@ init_cacheinfo (void)
       shared = handle_amd (_SC_LEVEL3_CACHE_SIZE);
 
       /* Get maximum extended function. */
-      __cpuid (0x80000000, max_cpuid_ex, ebx, ecx, edx);
+      cpuid (0x80000000, &max_cpuid_ex, &ebx, &ecx, &edx);
 
       if (shared <= 0)
 	/* No shared L3 cache.  All we have is the L2 cache.  */
@@ -609,7 +609,7 @@ init_cacheinfo (void)
 	  if (max_cpuid_ex >= 0x80000008)
 	    {
 	      /* Get width of APIC ID.  */
-	      __cpuid (0x80000008, max_cpuid_ex, ebx, ecx, edx);
+	      cpuid (0x80000008, &max_cpuid_ex, &ebx, &ecx, &edx);
 	      threads = 1 << ((ecx >> 12) & 0x0f);
 	    }
 
@@ -617,7 +617,7 @@ init_cacheinfo (void)
 	    {
 	      /* If APIC ID width is not available, use logical
 		 processor count.  */
-	      __cpuid (0x00000001, max_cpuid_ex, ebx, ecx, edx);
+	      cpuid (0x00000001, &max_cpuid_ex, &ebx, &ecx, &edx);
 
 	      if ((edx & (1 << 28)) != 0)
 		threads = (ebx >> 16) & 0xff;
@@ -635,7 +635,7 @@ init_cacheinfo (void)
 #ifndef DISABLE_PREFETCHW
       if (max_cpuid_ex >= 0x80000001)
 	{
-	  __cpuid (0x80000001, eax, ebx, ecx, edx);
+	  cpuid (0x80000001, &eax, &ebx, &ecx, &edx);
 	  /*  PREFETCHW     || 3DNow!  */
 	  if ((ecx & 0x100) || (edx & 0x80000000))
 	    __x86_prefetchw = -1;
diff --git a/sysdeps/x86_64/tst-audit10.c b/sysdeps/x86_64/tst-audit10.c
index a487b40..7442f46 100644
--- a/sysdeps/x86_64/tst-audit10.c
+++ b/sysdeps/x86_64/tst-audit10.c
@@ -16,7 +16,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <cpuid.h>
+#include <misc/cpuid.h>
 #include <cpu-features.h>
 
 int tst_audit10_aux (void);
@@ -26,11 +26,11 @@ avx512_enabled (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (__get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
+  if (get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
       || (ecx & (bit_AVX | bit_OSXSAVE)) != (bit_AVX | bit_OSXSAVE))
     return 0;
 
-  __cpuid_count (7, 0, eax, ebx, ecx, edx);
+  cpuid_count (7, 0, &eax, &ebx, &ecx, &edx);
   if (!(ebx & bit_AVX512F))
     return 0;
 
diff --git a/sysdeps/x86_64/tst-audit4.c b/sysdeps/x86_64/tst-audit4.c
index d8e2ab1..5aeaebf 100644
--- a/sysdeps/x86_64/tst-audit4.c
+++ b/sysdeps/x86_64/tst-audit4.c
@@ -16,7 +16,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <cpuid.h>
+#include <misc/cpuid.h>
 
 int tst_audit4_aux (void);
 
@@ -25,7 +25,7 @@ avx_enabled (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (__get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
+  if (get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
       || (ecx & (bit_AVX | bit_OSXSAVE)) != (bit_AVX | bit_OSXSAVE))
     return 0;
 
diff --git a/sysdeps/x86_64/tst-audit6.c b/sysdeps/x86_64/tst-audit6.c
index f2f6a48..e7cc9d6 100644
--- a/sysdeps/x86_64/tst-audit6.c
+++ b/sysdeps/x86_64/tst-audit6.c
@@ -2,7 +2,7 @@
 
 #include <stdlib.h>
 #include <string.h>
-#include <cpuid.h>
+#include <misc/cpuid.h>
 #include <emmintrin.h>
 
 extern __m128i audit_test (__m128i, __m128i, __m128i, __m128i,
@@ -14,7 +14,7 @@ avx_enabled (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (__get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
+  if (get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
       || (ecx & (bit_AVX | bit_OSXSAVE)) != (bit_AVX | bit_OSXSAVE))
     return 0;
 
diff --git a/sysdeps/x86_64/tst-auditmod10b.c b/sysdeps/x86_64/tst-auditmod10b.c
index ad6fcaf..3b050d0 100644
--- a/sysdeps/x86_64/tst-auditmod10b.c
+++ b/sysdeps/x86_64/tst-auditmod10b.c
@@ -125,18 +125,18 @@ la_symbind64 (Elf64_Sym *sym, unsigned int ndx, uintptr_t
*refcook, 
 #ifdef __AVX512F__
 #include <immintrin.h>
-#include <cpuid.h>
+#include <misc/cpuid.h>
 
 static int
 check_avx512 (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (__get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
+  if (get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
       || (ecx & (bit_AVX | bit_OSXSAVE)) != (bit_AVX | bit_OSXSAVE))
     return 0;
 
-  __cpuid_count (7, 0, eax, ebx, ecx, edx);
+  cpuid_count (7, 0, &eax, &ebx, &ecx, &edx);
   if (!(ebx & bit_AVX512F))
     return 0;
 
diff --git a/sysdeps/x86_64/tst-auditmod4b.c b/sysdeps/x86_64/tst-auditmod4b.c
index 2b0d827..c980887 100644
--- a/sysdeps/x86_64/tst-auditmod4b.c
+++ b/sysdeps/x86_64/tst-auditmod4b.c
@@ -108,7 +108,7 @@ la_symbind64 (Elf64_Sym *sym, unsigned int ndx, uintptr_t
*refcook, 
 #ifdef __AVX__
 #include <immintrin.h>
-#include <cpuid.h>
+#include <misc/cpuid.h>
 
 static int avx = -1;
 
@@ -120,7 +120,7 @@ check_avx (void)
     {
       unsigned int eax, ebx, ecx, edx;
 
-      if (__get_cpuid (1, &eax, &ebx, &ecx, &edx)
+      if (get_cpuid (1, &eax, &ebx, &ecx, &edx)
 	  && (ecx & bit_AVX))
 	avx = 1;
       else
diff --git a/sysdeps/x86_64/tst-auditmod6b.c b/sysdeps/x86_64/tst-auditmod6b.c
index 886fc33..d77d949 100644
--- a/sysdeps/x86_64/tst-auditmod6b.c
+++ b/sysdeps/x86_64/tst-auditmod6b.c
@@ -108,7 +108,7 @@ la_symbind64 (Elf64_Sym *sym, unsigned int ndx, uintptr_t
*refcook, 
 #ifdef __AVX__
 #include <immintrin.h>
-#include <cpuid.h>
+#include <misc/cpuid.h>
 
 static int avx = -1;
 
@@ -120,7 +120,7 @@ check_avx (void)
     {
       unsigned int eax, ebx, ecx, edx;
 
-      if (__get_cpuid (1, &eax, &ebx, &ecx, &edx)
+      if (get_cpuid (1, &eax, &ebx, &ecx, &edx)
 	  && (ecx & bit_AVX))
 	avx = 1;
       else
diff --git a/sysdeps/x86_64/tst-auditmod6c.c b/sysdeps/x86_64/tst-auditmod6c.c
index b2ee24d..0a5f143 100644
--- a/sysdeps/x86_64/tst-auditmod6c.c
+++ b/sysdeps/x86_64/tst-auditmod6c.c
@@ -108,7 +108,7 @@ la_symbind64 (Elf64_Sym *sym, unsigned int ndx, uintptr_t
*refcook, 
 #ifdef __AVX__
 #include <immintrin.h>
-#include <cpuid.h>
+#include <misc/cpuid.h>
 
 static int avx = -1;
 
@@ -120,7 +120,7 @@ check_avx (void)
     {
       unsigned int eax, ebx, ecx, edx;
 
-      if (__get_cpuid (1, &eax, &ebx, &ecx, &edx)
+      if (get_cpuid (1, &eax, &ebx, &ecx, &edx)
 	  && (ecx & bit_AVX))
 	avx = 1;
       else
diff --git a/sysdeps/x86_64/tst-auditmod7b.c b/sysdeps/x86_64/tst-auditmod7b.c
index f27076d..72257cd 100644
--- a/sysdeps/x86_64/tst-auditmod7b.c
+++ b/sysdeps/x86_64/tst-auditmod7b.c
@@ -108,7 +108,7 @@ la_symbind64 (Elf64_Sym *sym, unsigned int ndx, uintptr_t
*refcook, 
 #ifdef __AVX__
 #include <immintrin.h>
-#include <cpuid.h>
+#include <misc/cpuid.h>
 
 static int avx = -1;
 
@@ -120,7 +120,7 @@ check_avx (void)
     {
       unsigned int eax, ebx, ecx, edx;
 
-      if (__get_cpuid (1, &eax, &ebx, &ecx, &edx)
+      if (get_cpuid (1, &eax, &ebx, &ecx, &edx)
 	  && (ecx & bit_AVX))
 	avx = 1;
       else
-- 
2.1.4

Re: [PATCH] Common cpuid wrappers, use SYS_cpuid when available

[Piotr Henryk Dabrowski]

Currently there is no way of disabling CPU features reported by the CPUID
instruction. Which sometimes turn out to be broken [1] or undesired [2].
We can assume we will run into similar situations again sooner or later.
The only way to fix this is to do a microcode update (if it is available),
as the BIOS does not provide a way to disable CPUID bits either. When there is
no new microcode, then there is no way to tell your system not to use certain
CPU features. This sometimes leads to an unbootable and/or unusable system.
Plus the ability to quickly disable certain CPU extensions would be handy for
debugging.

This patch aims at providing system-wide support for the kernel-adjusted CPUID:
* The kernel takes a command line parameter (cpu-=...) allowing for an easy way
  to disable any of the known CPUID capability bits [3]. Plus the kernel may
  disable certain features by itself as well.
* Then the kernel provides a system call for obtaining the adjusted data [4]
  (SYS_cpuid, to be used instead of the __cpuid* macros from GCC's cpuid.h).

Since the cpuid instruction is available from the user-space, use of SYS_cpuid
cannot be enforced on programmers. But it can be encouraged, and making glibc
respect it is a good start (and a requirement for this purpose).
The expected impact is, after the new versions of kernel and glibc are widely
adopted, to discourage use of low-level __cpuid* macros for checking supported
CPU features on Linux as a coding issue that workarounds and breaks system
features.
And we may expect users to report bugs for programs that do not respect features
being disabled. Especially that they will be trivial to fix.
It will take time, but if this is introduced now, it may become a widely used
solution in a few years that will finally allow us to easily disable unwanted
CPU features on demand.

This feature is NOT implemented in the Linux kernel yet.
However I would like to ask you to say if you *would* ACK this *if* the
SYS_cpuid system call were to be adopted into the kernel.
Obviously shipping either without the other does not make any sense.

This is also my very first patch for glibc, so please let me know of any code
quality issues or improvement suggestions.

On GitLab you can find trees with both this patch [5] and the latest Linux
kernel patched [6]. And I attach a test program for the SYS_cpuid below [7].

[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=800574
[2] https://devtalk.nvidia.com/default/topic/893325/newest-and-beta-linux-driver-causing-segmentation-fault-core-dumped-on-all-skylake-platforms/
[3] e.g. 'linux ... nosplash quiet cpu-=mmx,sse,sse2'
[4] long sys_cpuid(const u32 level, const u32 count,
                   u32 __user *eax, u32 __user *ebx,
                   u32 __user *ecx, u32 __user *edx);
[5] https://gitlab.com/ultr/glibc/tags/ultr-sys_cpuid
[6] https://gitlab.com/ultr/linux/tags/ultr-sys_cpuid-master
[7] SYS_cpuid test program:
- - - - cut here - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
#include <stdio.h>
#include <stdint.h>

#include <unistd.h>
#include <sys/syscall.h>

#include <cpuid.h>

#ifndef __linux__
    #warning Not a Linux!
#endif

#ifndef SYS_cpuid
    #warning Defining undefined SYS_cpuid!
    #ifdef __x86_64__
        #define SYS_cpuid 327
    #else
        #define SYS_cpuid 378
    #endif
#endif

void get_kernel(const uint32_t level, const uint32_t count) {
    uint32_t eax = 0, ebx = 0, ecx = 0, edx = 0;
    int ret = syscall(SYS_cpuid, level, count, &eax, &ebx, &ecx, &edx);
    printf("sys_cpuid==%d:\t[0x%08lX,%lu] => [0x%08lX,0x%08lX,0x%08lX,0x%08lX]\n", ret, level, count, eax, ebx, ecx, edx);
}

void get_native(const uint32_t level, const uint32_t count) {
    register uint32_t eax = 0, ebx = 0, ecx = 0, edx = 0;
    __cpuid_count(level, count, eax, ebx, ecx, edx);
    printf("native cpuid:\t[0x%08lX,%lu] => [0x%08lX,0x%08lX,0x%08lX,0x%08lX]\n", level, count, eax, ebx, ecx, edx);
}

void get(const uint32_t level, const uint32_t count) {
    get_native(level, count);
    get_kernel(level, count);
}

int main(int argc, char **argv) {
    printf("SYS_cpuid = %d\n", SYS_cpuid);
    get(0x00000001, 0);
    get(0x00000006, 0);
    get(0x00000007, 0);
    get(0x0000000D, 1);
    get(0x0000000F, 0);
    get(0x0000000F, 1);
    get(0x80000001, 0);
    get(0x80000008, 0);
    get(0x8000000A, 0);
    get(0x80860001, 0);
    get(0xC0000001, 0);

    get(0x00000002, 0);
    get(0x00000004, 0);
    get(0x00000004, 1);
    get(0x00000004, 2);
    get(0x00000004, 3);
    return 0;
}
- - - - cut here - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Regards,
Piotr Henryk Dabrowski

Re: [PATCH] Common cpuid wrappers, use SYS_cpuid when available

[Piotr Henryk Dabrowski]

Sorry for the malformed patch in the first post.
Here is a working one.

	* config.h.in: Check for SYS_cpuid and define HAVE_SYS_CPUID
	* configure: Check for SYS_cpuid and define HAVE_SYS_CPUID
	* configure.ac: Check for SYS_cpuid and define HAVE_SYS_CPUID
	* misc/cpuid.h: Common cpuid wrappers, use SYS_cpuid when available
	* sysdeps/x86/cpu-features.c: Use misc/cpuid.h wrappers
	* sysdeps/x86/fpu/test-fenv-clear-sse.c: Use misc/cpuid.h wrappers
	* sysdeps/x86/fpu/test-fenv-sse-2.c: Use misc/cpuid.h wrappers
	* sysdeps/x86/fpu/test-fenv-sse.c: Use misc/cpuid.h wrappers
	* sysdeps/x86_64/cacheinfo.c: Use misc/cpuid.h wrappers
	* sysdeps/x86_64/tst-audit10.c: Use misc/cpuid.h wrappers
	* sysdeps/x86_64/tst-audit4.c: Use misc/cpuid.h wrappers
	* sysdeps/x86_64/tst-audit6.c: Use misc/cpuid.h wrappers
	* sysdeps/x86_64/tst-auditmod10b.c: Use misc/cpuid.h wrappers
	* sysdeps/x86_64/tst-auditmod4b.c: Use misc/cpuid.h wrappers
	* sysdeps/x86_64/tst-auditmod6b.c: Use misc/cpuid.h wrappers
	* sysdeps/x86_64/tst-auditmod6c.c: Use misc/cpuid.h wrappers
	* sysdeps/x86_64/tst-auditmod7b.c: Use misc/cpuid.h wrappers
---
 ChangeLog                             | 20 +++++++++
 config.h.in                           |  3 ++
 configure                             | 37 ++++++++++++++++
 configure.ac                          | 18 ++++++++
 misc/cpuid.h                          | 82 +++++++++++++++++++++++++++++++++++
 sysdeps/x86/cpu-features.c            | 37 ++++++++--------
 sysdeps/x86/fpu/test-fenv-clear-sse.c |  4 +-
 sysdeps/x86/fpu/test-fenv-sse-2.c     |  4 +-
 sysdeps/x86/fpu/test-fenv-sse.c       |  4 +-
 sysdeps/x86_64/cacheinfo.c            | 24 +++++-----
 sysdeps/x86_64/tst-audit10.c          |  6 +--
 sysdeps/x86_64/tst-audit4.c           |  4 +-
 sysdeps/x86_64/tst-audit6.c           |  4 +-
 sysdeps/x86_64/tst-auditmod10b.c      |  6 +--
 sysdeps/x86_64/tst-auditmod4b.c       |  4 +-
 sysdeps/x86_64/tst-auditmod6b.c       |  4 +-
 sysdeps/x86_64/tst-auditmod6c.c       |  4 +-
 sysdeps/x86_64/tst-auditmod7b.c       |  4 +-
 18 files changed, 215 insertions(+), 54 deletions(-)
 create mode 100644 misc/cpuid.h

diff --git a/ChangeLog b/ChangeLog
index a6be762..3c67632 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,23 @@
+2016-03-07  Piotr Henryk Dabrowski  <ultr@ultr.pl>
+
+	* config.h.in: Check for SYS_cpuid and define HAVE_SYS_CPUID
+	* configure: Check for SYS_cpuid and define HAVE_SYS_CPUID
+	* configure.ac: Check for SYS_cpuid and define HAVE_SYS_CPUID
+	* misc/cpuid.h: Common cpuid wrappers, use SYS_cpuid when available
+	* sysdeps/x86/cpu-features.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86/fpu/test-fenv-clear-sse.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86/fpu/test-fenv-sse-2.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86/fpu/test-fenv-sse.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86_64/cacheinfo.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86_64/tst-audit10.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86_64/tst-audit4.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86_64/tst-audit6.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86_64/tst-auditmod10b.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86_64/tst-auditmod4b.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86_64/tst-auditmod6b.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86_64/tst-auditmod6c.c: Use misc/cpuid.h wrappers
+	* sysdeps/x86_64/tst-auditmod7b.c: Use misc/cpuid.h wrappers
+
 2016-03-09  Joseph Myers  <joseph@codesourcery.com>
 
 	[BZ #19790]
diff --git a/config.h.in b/config.h.in
index 0147ba3..0f2231a 100644
--- a/config.h.in
+++ b/config.h.in
@@ -121,6 +121,9 @@
 /* Mach/i386 specific: define if the `i386_set_gdt' RPC is available.  */
 #undef	HAVE_I386_SET_GDT
 
+/* Define if the x86 kernel supports SYS_cpuid syscall.  */
+#undef HAVE_SYS_CPUID
+
 /* Defined of libidn is available.  */
 #undef HAVE_LIBIDN
 
diff --git a/configure b/configure
index 8fe5937..1138642 100755
--- a/configure
+++ b/configure
@@ -6420,6 +6420,43 @@ ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $
 ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
+# SYS_cpuid syscall
+libc_cv_sys_cpuid=no
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for x86 kernel with SYS_cpuid support" >&5
+$as_echo_n "checking for x86 kernel with SYS_cpuid support... " >&6; }
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+  #if (defined(__i386__) || defined(__x86_64__)) && defined(__linux__)
+  #include <sys/syscall.h>
+  #if !defined(SYS_cpuid) || !defined(__NR_cpuid)
+  #error SYS_cpuid not defined
+  #endif
+  #else
+  #error Not a x86 Linux
+  #endif
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  libc_cv_sys_cpuid=yes
+else
+  libc_cv_sys_cpuid=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+if test "$libc_cv_sys_cpuid" = yes; then
+  $as_echo "#define HAVE_SYS_CPUID 1" >>confdefs.h
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_sys_cpuid" >&5
+$as_echo "$libc_cv_sys_cpuid" >&6; }
+
 ### End of automated tests.
 ### Now run sysdeps configure fragments.
 
diff --git a/configure.ac b/configure.ac
index 3c766b7..89a1779 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1704,6 +1704,24 @@ AC_SUBST(libc_cv_cxx_thread_local)
 AC_LANG_POP([C++])
 dnl End of C++ feature tests.
 
+# SYS_cpuid syscall
+libc_cv_sys_cpuid=no
+AC_MSG_CHECKING(for x86 kernel with SYS_cpuid support)
+AC_TRY_COMPILE([
+  #if (defined(__i386__) || defined(__x86_64__)) && defined(__linux__)
+  #include <sys/syscall.h>
+  #if !defined(SYS_cpuid) || !defined(__NR_cpuid)
+  #error SYS_cpuid not defined
+  #endif
+  #else
+  #error Not a x86 Linux
+  #endif
+], [], [libc_cv_sys_cpuid=yes], [libc_cv_sys_cpuid=no])
+if test "$libc_cv_sys_cpuid" = yes; then
+  AC_DEFINE(HAVE_SYS_CPUID)
+fi
+AC_MSG_RESULT($libc_cv_sys_cpuid)
+
 ### End of automated tests.
 ### Now run sysdeps configure fragments.
 
diff --git a/misc/cpuid.h b/misc/cpuid.h
new file mode 100644
index 0000000..6caea13
--- /dev/null
+++ b/misc/cpuid.h
@@ -0,0 +1,82 @@
+/* CPUID wrapper functions.
+   This file is part of the GNU C Library.
+   Copyright (C) 2016 Piotr Henryk Dabrowski <ultr@ultr.pl>
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _CPUID_H
+#define _CPUID_H 1
+
+/* NOTE: for new Linux kernels these functions try to use kernel-adjusted
+   values for cpuid returned by the SYS_cpuid sys call.
+   Otherwise they fallback to native cpuid implementation. */
+
+#include <config.h>
+
+#include <cpuid.h>
+#include <errno.h>
+#include <stddef.h>
+
+#ifdef HAVE_SYS_CPUID
+#include <sysdep.h>
+#include <sys/syscall.h>
+#endif
+
+#define get_cpuid_max __get_cpuid_max
+
+/* Return cpuid data for requested cpuid level (eax) and count register (ecx),
+   as found in returned eax, ebx, ecx and edx registers.
+   All pointers are required to be non-null. */
+static inline void
+cpuid_count (unsigned int level, unsigned int count,
+	     unsigned int *eax, unsigned int *ebx,
+	     unsigned int *ecx, unsigned int *edx)
+{
+#ifdef HAVE_SYS_CPUID
+	if (INLINE_SYSCALL(cpuid, 6, level, count, eax, ebx, ecx, edx) == 0)
+		return;
+#endif
+	__cpuid_count(level, count, *eax, *ebx, *ecx, *edx);
+}
+
+/* Return cpuid data for requested cpuid level (eax),
+   as found in returned eax, ebx, ecx and edx registers.
+   All pointers are required to be non-null. */
+static inline void
+cpuid (unsigned int level,
+       unsigned int *eax, unsigned int *ebx,
+       unsigned int *ecx, unsigned int *edx)
+{
+	cpuid_count(level, 0, eax, ebx, ecx, edx);
+}
+
+/* Return cpuid data for requested cpuid level (eax),
+   as found in returned eax, ebx, ecx and edx registers.
+   The function checks if cpuid is supported and returns 1 for valid cpuid
+   information or 0 for unsupported cpuid level.
+   All pointers are required to be non-null. */
+static inline int
+get_cpuid (unsigned int level,
+	   unsigned int *eax, unsigned int *ebx,
+	   unsigned int *ecx, unsigned int *edx)
+{
+	unsigned int ext = level & 0x80000000;
+	if (get_cpuid_max (ext, 0) < level)
+		return 0;
+	cpuid (level, eax, ebx, ecx, edx);
+	return 1;
+}
+
+#endif /* cpuid.h */
diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
index 218ff2b..a71c701 100644
--- a/sysdeps/x86/cpu-features.c
+++ b/sysdeps/x86/cpu-features.c
@@ -16,7 +16,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <cpuid.h>
+#include <misc/cpuid.h>
 #include <cpu-features.h>
 
 static inline void
@@ -25,9 +25,9 @@ get_common_indeces (struct cpu_features *cpu_features,
 		    unsigned int *extended_model)
 {
   unsigned int eax;
-  __cpuid (1, eax, cpu_features->cpuid[COMMON_CPUID_INDEX_1].ebx,
-	   cpu_features->cpuid[COMMON_CPUID_INDEX_1].ecx,
-	   cpu_features->cpuid[COMMON_CPUID_INDEX_1].edx);
+  cpuid (1, &eax, &(cpu_features->cpuid[COMMON_CPUID_INDEX_1].ebx),
+	 &(cpu_features->cpuid[COMMON_CPUID_INDEX_1].ecx),
+	 &(cpu_features->cpuid[COMMON_CPUID_INDEX_1].edx));
   GLRO(dl_x86_cpu_features).cpuid[COMMON_CPUID_INDEX_1].eax = eax;
   *family = (eax >> 8) & 0x0f;
   *model = (eax >> 4) & 0x0f;
@@ -42,20 +42,21 @@ get_common_indeces (struct cpu_features *cpu_features,
 static inline void
 init_cpu_features (struct cpu_features *cpu_features)
 {
-  unsigned int ebx, ecx, edx;
+  unsigned int eax, ebx, ecx, edx;
   unsigned int family = 0;
   unsigned int model = 0;
   enum cpu_features_kind kind;
 
 #if !HAS_CPUID
-  if (__get_cpuid_max (0, 0) == 0)
+  if (get_cpuid_max (0, 0) == 0)
     {
       kind = arch_kind_other;
       goto no_cpuid;
     }
 #endif
 
-  __cpuid (0, cpu_features->max_cpuid, ebx, ecx, edx);
+  cpuid (0, &eax, &ebx, &ecx, &edx);
+  cpu_features->max_cpuid = eax;
 
   /* This spells out "GenuineIntel".  */
   if (ebx == 0x756e6547 && ecx == 0x6c65746e && edx == 0x49656e69)
@@ -147,13 +148,13 @@ init_cpu_features (struct cpu_features *cpu_features)
       ecx = cpu_features->cpuid[COMMON_CPUID_INDEX_1].ecx;
 
       unsigned int eax;
-      __cpuid (0x80000000, eax, ebx, ecx, edx);
+      cpuid (0x80000000, &eax, &ebx, &ecx, &edx);
       if (eax >= 0x80000001)
-	__cpuid (0x80000001,
-		 cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].eax,
-		 cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].ebx,
-		 cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].ecx,
-		 cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].edx);
+	cpuid (0x80000001,
+	       &(cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].eax),
+	       &(cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].ebx),
+	       &(cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].ecx),
+	       &(cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].edx));
 
       if (family == 0x15)
 	{
@@ -175,11 +176,11 @@ init_cpu_features (struct cpu_features *cpu_features)
     cpu_features->feature[index_I686] |= bit_I686;
 
   if (cpu_features->max_cpuid >= 7)
-    __cpuid_count (7, 0,
-		   cpu_features->cpuid[COMMON_CPUID_INDEX_7].eax,
-		   cpu_features->cpuid[COMMON_CPUID_INDEX_7].ebx,
-		   cpu_features->cpuid[COMMON_CPUID_INDEX_7].ecx,
-		   cpu_features->cpuid[COMMON_CPUID_INDEX_7].edx);
+    cpuid_count (7, 0,
+		 &(cpu_features->cpuid[COMMON_CPUID_INDEX_7].eax),
+		 &(cpu_features->cpuid[COMMON_CPUID_INDEX_7].ebx),
+		 &(cpu_features->cpuid[COMMON_CPUID_INDEX_7].ecx),
+		 &(cpu_features->cpuid[COMMON_CPUID_INDEX_7].edx));
 
   /* Can we call xgetbv?  */
   if (HAS_CPU_FEATURE (OSXSAVE))
diff --git a/sysdeps/x86/fpu/test-fenv-clear-sse.c b/sysdeps/x86/fpu/test-fenv-clear-sse.c
index cc4b3f0..816470b 100644
--- a/sysdeps/x86/fpu/test-fenv-clear-sse.c
+++ b/sysdeps/x86/fpu/test-fenv-clear-sse.c
@@ -17,7 +17,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <cpuid.h>
+#include <misc/cpuid.h>
 #include <stdbool.h>
 
 static bool
@@ -25,7 +25,7 @@ have_sse2 (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
+  if (!get_cpuid (1, &eax, &ebx, &ecx, &edx))
     return false;
 
   return (edx & bit_SSE2) != 0;
diff --git a/sysdeps/x86/fpu/test-fenv-sse-2.c b/sysdeps/x86/fpu/test-fenv-sse-2.c
index d3197c3..c72d5ad 100644
--- a/sysdeps/x86/fpu/test-fenv-sse-2.c
+++ b/sysdeps/x86/fpu/test-fenv-sse-2.c
@@ -16,7 +16,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <cpuid.h>
+#include <misc/cpuid.h>
 #include <fenv.h>
 #include <float.h>
 #include <stdbool.h>
@@ -28,7 +28,7 @@ have_sse2 (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
+  if (!get_cpuid (1, &eax, &ebx, &ecx, &edx))
     return false;
 
   return (edx & bit_SSE2) != 0;
diff --git a/sysdeps/x86/fpu/test-fenv-sse.c b/sysdeps/x86/fpu/test-fenv-sse.c
index 4f4ff6a..c8f1497 100644
--- a/sysdeps/x86/fpu/test-fenv-sse.c
+++ b/sysdeps/x86/fpu/test-fenv-sse.c
@@ -16,7 +16,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <cpuid.h>
+#include <misc/cpuid.h>
 #include <fenv.h>
 #include <float.h>
 #include <stdbool.h>
@@ -27,7 +27,7 @@ have_sse2 (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
+  if (!get_cpuid (1, &eax, &ebx, &ecx, &edx))
     return false;
 
   return (edx & bit_SSE2) != 0;
diff --git a/sysdeps/x86_64/cacheinfo.c b/sysdeps/x86_64/cacheinfo.c
index 96463df..76cd03d 100644
--- a/sysdeps/x86_64/cacheinfo.c
+++ b/sysdeps/x86_64/cacheinfo.c
@@ -20,7 +20,7 @@
 #include <stdbool.h>
 #include <stdlib.h>
 #include <unistd.h>
-#include <cpuid.h>
+#include <misc/cpuid.h>
 #include <init-arch.h>
 
 #define is_intel GLRO(dl_x86_cpu_features).kind == arch_kind_intel
@@ -162,7 +162,7 @@ intel_check_word (int name, unsigned int value, bool *has_level_2,
 	  unsigned int round = 0;
 	  while (1)
 	    {
-	      __cpuid_count (4, round, eax, ebx, ecx, edx);
+	      cpuid_count (4, round, &eax, &ebx, &ecx, &edx);
 
 	      enum { null = 0, data = 1, inst = 2, uni = 3 } type = eax & 0x1f;
 	      if (type == null)
@@ -275,7 +275,7 @@ handle_intel (int name, unsigned int maxidx)
       unsigned int ebx;
       unsigned int ecx;
       unsigned int edx;
-      __cpuid (2, eax, ebx, ecx, edx);
+      cpuid (2, &eax, &ebx, &ecx, &edx);
 
       /* The low byte of EAX in the first round contain the number of
 	 rounds we have to make.  At least one, the one we are already
@@ -319,7 +319,7 @@ handle_amd (int name)
   unsigned int ebx;
   unsigned int ecx;
   unsigned int edx;
-  __cpuid (0x80000000, eax, ebx, ecx, edx);
+  cpuid (0x80000000, &eax, &ebx, &ecx, &edx);
 
   /* No level 4 cache (yet).  */
   if (name > _SC_LEVEL3_CACHE_LINESIZE)
@@ -329,7 +329,7 @@ handle_amd (int name)
   if (eax < fn)
     return 0;
 
-  __cpuid (fn, eax, ebx, ecx, edx);
+  cpuid (fn, &eax, &ebx, &ecx, &edx);
 
   if (name < _SC_LEVEL1_DCACHE_SIZE)
     {
@@ -479,7 +479,7 @@ init_cacheinfo (void)
   unsigned int ebx;
   unsigned int ecx;
   unsigned int edx;
-  int max_cpuid_ex;
+  unsigned int max_cpuid_ex;
   long int data = -1;
   long int shared = -1;
   unsigned int level;
@@ -512,7 +512,7 @@ init_cacheinfo (void)
 	  /* Query until desired cache level is enumerated.  */
 	  do
 	    {
-	      __cpuid_count (4, i++, eax, ebx, ecx, edx);
+	      cpuid_count (4, i++, &eax, &ebx, &ecx, &edx);
 
 	      /* There seems to be a bug in at least some Pentium Ds
 		 which sometimes fail to iterate all cache parameters.
@@ -536,7 +536,7 @@ init_cacheinfo (void)
 	      i = 0;
 	      while (1)
 		{
-		  __cpuid_count (11, i++, eax, ebx, ecx, edx);
+		  cpuid_count (11, i++, &eax, &ebx, &ecx, &edx);
 
 		  int shipped = ebx & 0xff;
 		  int type = ecx & 0xff0;
@@ -598,7 +598,7 @@ init_cacheinfo (void)
       shared = handle_amd (_SC_LEVEL3_CACHE_SIZE);
 
       /* Get maximum extended function. */
-      __cpuid (0x80000000, max_cpuid_ex, ebx, ecx, edx);
+      cpuid (0x80000000, &max_cpuid_ex, &ebx, &ecx, &edx);
 
       if (shared <= 0)
 	/* No shared L3 cache.  All we have is the L2 cache.  */
@@ -609,7 +609,7 @@ init_cacheinfo (void)
 	  if (max_cpuid_ex >= 0x80000008)
 	    {
 	      /* Get width of APIC ID.  */
-	      __cpuid (0x80000008, max_cpuid_ex, ebx, ecx, edx);
+	      cpuid (0x80000008, &max_cpuid_ex, &ebx, &ecx, &edx);
 	      threads = 1 << ((ecx >> 12) & 0x0f);
 	    }
 
@@ -617,7 +617,7 @@ init_cacheinfo (void)
 	    {
 	      /* If APIC ID width is not available, use logical
 		 processor count.  */
-	      __cpuid (0x00000001, max_cpuid_ex, ebx, ecx, edx);
+	      cpuid (0x00000001, &max_cpuid_ex, &ebx, &ecx, &edx);
 
 	      if ((edx & (1 << 28)) != 0)
 		threads = (ebx >> 16) & 0xff;
@@ -635,7 +635,7 @@ init_cacheinfo (void)
 #ifndef DISABLE_PREFETCHW
       if (max_cpuid_ex >= 0x80000001)
 	{
-	  __cpuid (0x80000001, eax, ebx, ecx, edx);
+	  cpuid (0x80000001, &eax, &ebx, &ecx, &edx);
 	  /*  PREFETCHW     || 3DNow!  */
 	  if ((ecx & 0x100) || (edx & 0x80000000))
 	    __x86_prefetchw = -1;
diff --git a/sysdeps/x86_64/tst-audit10.c b/sysdeps/x86_64/tst-audit10.c
index a487b40..7442f46 100644
--- a/sysdeps/x86_64/tst-audit10.c
+++ b/sysdeps/x86_64/tst-audit10.c
@@ -16,7 +16,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <cpuid.h>
+#include <misc/cpuid.h>
 #include <cpu-features.h>
 
 int tst_audit10_aux (void);
@@ -26,11 +26,11 @@ avx512_enabled (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (__get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
+  if (get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
       || (ecx & (bit_AVX | bit_OSXSAVE)) != (bit_AVX | bit_OSXSAVE))
     return 0;
 
-  __cpuid_count (7, 0, eax, ebx, ecx, edx);
+  cpuid_count (7, 0, &eax, &ebx, &ecx, &edx);
   if (!(ebx & bit_AVX512F))
     return 0;
 
diff --git a/sysdeps/x86_64/tst-audit4.c b/sysdeps/x86_64/tst-audit4.c
index d8e2ab1..5aeaebf 100644
--- a/sysdeps/x86_64/tst-audit4.c
+++ b/sysdeps/x86_64/tst-audit4.c
@@ -16,7 +16,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <cpuid.h>
+#include <misc/cpuid.h>
 
 int tst_audit4_aux (void);
 
@@ -25,7 +25,7 @@ avx_enabled (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (__get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
+  if (get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
       || (ecx & (bit_AVX | bit_OSXSAVE)) != (bit_AVX | bit_OSXSAVE))
     return 0;
 
diff --git a/sysdeps/x86_64/tst-audit6.c b/sysdeps/x86_64/tst-audit6.c
index f2f6a48..e7cc9d6 100644
--- a/sysdeps/x86_64/tst-audit6.c
+++ b/sysdeps/x86_64/tst-audit6.c
@@ -2,7 +2,7 @@
 
 #include <stdlib.h>
 #include <string.h>
-#include <cpuid.h>
+#include <misc/cpuid.h>
 #include <emmintrin.h>
 
 extern __m128i audit_test (__m128i, __m128i, __m128i, __m128i,
@@ -14,7 +14,7 @@ avx_enabled (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (__get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
+  if (get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
       || (ecx & (bit_AVX | bit_OSXSAVE)) != (bit_AVX | bit_OSXSAVE))
     return 0;
 
diff --git a/sysdeps/x86_64/tst-auditmod10b.c b/sysdeps/x86_64/tst-auditmod10b.c
index ad6fcaf..3b050d0 100644
--- a/sysdeps/x86_64/tst-auditmod10b.c
+++ b/sysdeps/x86_64/tst-auditmod10b.c
@@ -125,18 +125,18 @@ la_symbind64 (Elf64_Sym *sym, unsigned int ndx, uintptr_t *refcook,
 
 #ifdef __AVX512F__
 #include <immintrin.h>
-#include <cpuid.h>
+#include <misc/cpuid.h>
 
 static int
 check_avx512 (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (__get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
+  if (get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
       || (ecx & (bit_AVX | bit_OSXSAVE)) != (bit_AVX | bit_OSXSAVE))
     return 0;
 
-  __cpuid_count (7, 0, eax, ebx, ecx, edx);
+  cpuid_count (7, 0, &eax, &ebx, &ecx, &edx);
   if (!(ebx & bit_AVX512F))
     return 0;
 
diff --git a/sysdeps/x86_64/tst-auditmod4b.c b/sysdeps/x86_64/tst-auditmod4b.c
index 2b0d827..c980887 100644
--- a/sysdeps/x86_64/tst-auditmod4b.c
+++ b/sysdeps/x86_64/tst-auditmod4b.c
@@ -108,7 +108,7 @@ la_symbind64 (Elf64_Sym *sym, unsigned int ndx, uintptr_t *refcook,
 
 #ifdef __AVX__
 #include <immintrin.h>
-#include <cpuid.h>
+#include <misc/cpuid.h>
 
 static int avx = -1;
 
@@ -120,7 +120,7 @@ check_avx (void)
     {
       unsigned int eax, ebx, ecx, edx;
 
-      if (__get_cpuid (1, &eax, &ebx, &ecx, &edx)
+      if (get_cpuid (1, &eax, &ebx, &ecx, &edx)
 	  && (ecx & bit_AVX))
 	avx = 1;
       else
diff --git a/sysdeps/x86_64/tst-auditmod6b.c b/sysdeps/x86_64/tst-auditmod6b.c
index 886fc33..d77d949 100644
--- a/sysdeps/x86_64/tst-auditmod6b.c
+++ b/sysdeps/x86_64/tst-auditmod6b.c
@@ -108,7 +108,7 @@ la_symbind64 (Elf64_Sym *sym, unsigned int ndx, uintptr_t *refcook,
 
 #ifdef __AVX__
 #include <immintrin.h>
-#include <cpuid.h>
+#include <misc/cpuid.h>
 
 static int avx = -1;
 
@@ -120,7 +120,7 @@ check_avx (void)
     {
       unsigned int eax, ebx, ecx, edx;
 
-      if (__get_cpuid (1, &eax, &ebx, &ecx, &edx)
+      if (get_cpuid (1, &eax, &ebx, &ecx, &edx)
 	  && (ecx & bit_AVX))
 	avx = 1;
       else
diff --git a/sysdeps/x86_64/tst-auditmod6c.c b/sysdeps/x86_64/tst-auditmod6c.c
index b2ee24d..0a5f143 100644
--- a/sysdeps/x86_64/tst-auditmod6c.c
+++ b/sysdeps/x86_64/tst-auditmod6c.c
@@ -108,7 +108,7 @@ la_symbind64 (Elf64_Sym *sym, unsigned int ndx, uintptr_t *refcook,
 
 #ifdef __AVX__
 #include <immintrin.h>
-#include <cpuid.h>
+#include <misc/cpuid.h>
 
 static int avx = -1;
 
@@ -120,7 +120,7 @@ check_avx (void)
     {
       unsigned int eax, ebx, ecx, edx;
 
-      if (__get_cpuid (1, &eax, &ebx, &ecx, &edx)
+      if (get_cpuid (1, &eax, &ebx, &ecx, &edx)
 	  && (ecx & bit_AVX))
 	avx = 1;
       else
diff --git a/sysdeps/x86_64/tst-auditmod7b.c b/sysdeps/x86_64/tst-auditmod7b.c
index f27076d..72257cd 100644
--- a/sysdeps/x86_64/tst-auditmod7b.c
+++ b/sysdeps/x86_64/tst-auditmod7b.c
@@ -108,7 +108,7 @@ la_symbind64 (Elf64_Sym *sym, unsigned int ndx, uintptr_t *refcook,
 
 #ifdef __AVX__
 #include <immintrin.h>
-#include <cpuid.h>
+#include <misc/cpuid.h>
 
 static int avx = -1;
 
@@ -120,7 +120,7 @@ check_avx (void)
     {
       unsigned int eax, ebx, ecx, edx;
 
-      if (__get_cpuid (1, &eax, &ebx, &ecx, &edx)
+      if (get_cpuid (1, &eax, &ebx, &ecx, &edx)
 	  && (ecx & bit_AVX))
 	avx = 1;
       else
-- 
2.1.4

Re: [PATCH] Common cpuid wrappers, use SYS_cpuid when available

[Mike Frysinger]

[-- Attachment #1: Type: text/plain, Size: 1466 bytes --]

On 09 Mar 2016 02:24, Piotr Henryk Dabrowski wrote:
> --- a/configure.ac
> +++ b/configure.ac
> @@ -1704,6 +1704,24 @@ AC_SUBST(libc_cv_cxx_thread_local)
>  AC_LANG_POP([C++])
>  dnl End of C++ feature tests.
>  
> +# SYS_cpuid syscall
> +libc_cv_sys_cpuid=no
> +AC_MSG_CHECKING(for x86 kernel with SYS_cpuid support)
> +AC_TRY_COMPILE([
> +  #if (defined(__i386__) || defined(__x86_64__)) && defined(__linux__)
> +  #include <sys/syscall.h>
> +  #if !defined(SYS_cpuid) || !defined(__NR_cpuid)
> +  #error SYS_cpuid not defined
> +  #endif
> +  #else
> +  #error Not a x86 Linux
> +  #endif
> +], [], [libc_cv_sys_cpuid=yes], [libc_cv_sys_cpuid=no])
> +if test "$libc_cv_sys_cpuid" = yes; then
> +  AC_DEFINE(HAVE_SYS_CPUID)
> +fi
> +AC_MSG_RESULT($libc_cv_sys_cpuid)

don't think you need this here.  you can define __ASSUME_CPUID in
kernel-features.h and use that everywhere.  look at that file and
symbols it defins as an example.

> +   Copyright (C) 2016 Piotr Henryk Dabrowski <ultr@ultr.pl>

nope -- you'll need to sign copyright papers w/the FSF

> +/* NOTE: for new Linux kernels these functions try to use kernel-adjusted
> +   values for cpuid returned by the SYS_cpuid sys call.
> +   Otherwise they fallback to native cpuid implementation. */

GNU style: two spaces after periods

> +	if (INLINE_SYSCALL(cpuid, 6, level, count, eax, ebx, ecx, edx) == 0)

GNU style: put spaces before the ( w/func calls
-mike

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

Re: [PATCH] Common cpuid wrappers, use SYS_cpuid when available

[Adhemerval Zanella]

On 09-03-2016 08:27, Piotr Henryk Dabrowski wrote:
> 
> This feature is NOT implemented in the Linux kernel yet.
> However I would like to ask you to say if you *would* ACK this *if* the
> SYS_cpuid system call were to be adopted into the kernel.
> Obviously shipping either without the other does not make any sense.

If such functionality is indeed accepted upstream in Linux I see no reason
on not possible ack this patch (the ack it self will depend on patch
quality and architecture maintainer feedback). I see the idea is reasonable,
the only drawback is a slight large latency on program startup (due syscall
issuing in cacheinfo.c).

Before start to ask for patch revision, you need to sort out the copyright
by signing the papers with the FSF as pointed out by Mike Frysinger.

Re: [PATCH] Common cpuid wrappers, use SYS_cpuid when available

[Andreas Schwab]

Piotr Henryk Dabrowski <ultr@ultr.pl> writes:

> +# SYS_cpuid syscall
> +libc_cv_sys_cpuid=no
> +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for x86 kernel with
> SYS_cpuid support" >&5 +$as_echo_n "checking for x86 kernel with SYS_cpuid
> support... " >&6; } +cat confdefs.h - <<_ACEOF >conftest.$ac_ext
> +/* end confdefs.h.  */
> +
> +  #if (defined(__i386__) || defined(__x86_64__)) && defined(__linux__)
> +  #include <sys/syscall.h>

You cannot use the host libc to check for features.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

Re: [PATCH] Common cpuid wrappers, use SYS_cpuid when available

[Joseph Myers]

On Wed, 9 Mar 2016, Piotr Henryk Dabrowski wrote:

> Sorry for the malformed patch in the first post.
> Here is a working one.
> 
> 	* config.h.in: Check for SYS_cpuid and define HAVE_SYS_CPUID
> 	* configure: Check for SYS_cpuid and define HAVE_SYS_CPUID
> 	* configure.ac: Check for SYS_cpuid and define HAVE_SYS_CPUID
> 	* misc/cpuid.h: Common cpuid wrappers, use SYS_cpuid when available

Non-sysdeps files should not have anything architecture-specific.

Now, *if* you need a configure test, you can't avoid changing the 
architecture-independent config.h.in (we don't yet have a way to split 
that by architecture).  But the rest can be avoided by using sysdeps 
configure fragments and headers.  And you don't need a configure test 
anyway - the code can use #ifdef __NR_cpuid to test if the syscall is 
available at compile time, and __ASSUME_CPUID to test if the syscall can 
be presumed to work (if the runtime kernel is known to be recent enough, 
since the kernel headers used to build glibc may be more recent than the 
kernel used by glibc at runtime).  Finally, misc/cpuid.h should go under a 
sysdeps directory, suitably named not to conflict with the compiler's 
<cpuid.h>.

There's a complication: sysdeps/x86 shouldn't contain anything 
Linux-specific either.  So what that suggests is that you have e.g. 
sysdeps/x86/x86-cpuid.h that uses just the cpuid instruction but that can 
be overridden by an OS-specific header that supports the syscall - and 
then have such an OS-specific version in sysdeps/unix/sysv/linux/x86 (you 
can also do more complicated schemes to avoid duplicating the code to use 
the instruction).

-- 
Joseph S. Myers
joseph@codesourcery.com

Re: [PATCH] Common cpuid wrappers, use SYS_cpuid when available

[Florian Weimer]

* Piotr Henryk Dabrowski:

> However I would like to ask you to say if you *would* ACK this *if* the
> SYS_cpuid system call were to be adopted into the kernel.

<cpuid.h> is provided by GCC, it would have to change as well.  The
real challenge is the pervasive use of inline assembly, though.

Currently, you cannot invoke system calls from IFUNC selectors.  This
means that one major application for IFUNC selectors cannot use the
system call.

I also wonder if the relevant CPUID flags should rather be part of
auxv, or if this functionality should be a vsyscall instead.  Both
would avoid circularity issues (you may need to do a CPUID before
doing a system call, and vice versa).

[PATCH v2] Common cpuid wrappers, use SYS_cpuid when available

[Piotr Henryk Dabrowski]

Thank you for your comments. I have modified the patch to include most of them.
Please let me know if the v2 [1] is closer to something that could pass a
review.


Florian Weimer <fw@deneb.enyo.de> writes:

> <cpuid.h> is provided by GCC, it would have to change as well.

I don't think <cpuid.h> would *have to* change.
Especially that all the original __cpuid* macros need to stay as they are, as
they are used even in the Linux kernel itself and would cause a circular
recursion here.
Of course providing kernel-adjusted cpuid* functions besides the standard asm
__cpuid* macros would solve a lot of problems when modifying programs to use
this feature.
Including the glibc, but here that would require bumping the minimum required
GCC version (to one with updated cpuid.h), so I guess this is not a possible
solution (yet).

> The real challenge is the pervasive use of inline assembly, though.
>
> Currently, you cannot invoke system calls from IFUNC selectors.  This
> means that one major application for IFUNC selectors cannot use the
> system call.

Is this really a big drawback? This is a feature that may have its own
limitations. You don't call to cpuid op that much after all. Obviously this
will never be as portable as the simple __cpuid* asm macros from <cpuid.h>.

> I also wonder if the relevant CPUID flags should rather be part of auxv

Thank you for these suggestions.

But wouldn't providing auxv entries make this feature ELF-only?

And how could we decide which flags are relevant? There are at least 11
different relevant op/count cpuid calls, returning 4 u32 registers each [2].

Plus it takes us far away from the original idea of simply replacing cpuid calls
within the application [3]. This would require switching the detection of CPU
features to a completely new model, which programmers might find hard to adapt
to. Which, in turn, would ruin the whole plan of making kernel-adjusted cpuid
widely adopted.
Just my opinion though :-)

> or if this functionality should be a vsyscall instead.

vsyscall or vdso? I will look into this idea.

> (you may need to do a CPUID before doing a system call, and vice versa).

Why? You mean checking the cpuid bits if we have syscall/sysret features?
Still you can easily call the original asm __cpuid macro in such case.


Joseph Myers <joseph@codesourcery.com> writes:

> Non-sysdeps files should not have anything architecture-specific.
>
> Now, *if* you need a configure test, you can't avoid changing the 
> architecture-independent config.h.in (we don't yet have a way to split 
> that by architecture).  But the rest can be avoided by using sysdeps 
> configure fragments and headers.  And you don't need a configure test 
> anyway - the code can use #ifdef __NR_cpuid to test if the syscall is 
> available at compile time, and __ASSUME_CPUID to test if the syscall can 
> be presumed to work (if the runtime kernel is known to be recent enough, 
> since the kernel headers used to build glibc may be more recent than the 
> kernel used by glibc at runtime).  Finally, misc/cpuid.h should go under a 
> sysdeps directory, suitably named not to conflict with the compiler's 
> <cpuid.h>.
>
> There's a complication: sysdeps/x86 shouldn't contain anything 
> Linux-specific either.  So what that suggests is that you have e.g. 
> sysdeps/x86/x86-cpuid.h that uses just the cpuid instruction but that can 
> be overridden by an OS-specific header that supports the syscall - and 
> then have such an OS-specific version in sysdeps/unix/sysv/linux/x86 (you 
> can also do more complicated schemes to avoid duplicating the code to use 
> the instruction).

The configure test was removed. It wasn't really necessary, although maybe it
might be a good idea to somehow log which version of cpuid is being used
during the compile time.

And with the current code the __ASSUME_CPUID should not be necessary either.


Mike Frysinger <vapier@gentoo.org> writes:

> don't think you need this here.  you can define __ASSUME_CPUID in
> kernel-features.h and use that everywhere.  look at that file and
> symbols it defins as an example.

Removed with the configure checks.

> nope -- you'll need to sign copyright papers w/the FSF

So the copyright attribution line must display the FSF only, plus I need to sign
the legal papers, right?
How can I obtain a copy for signing? Just in case.


Andreas Schwab <schwab@suse.de> writes:

> You cannot use the host libc to check for features.

Removed with the configure checks.


[1] https://gitlab.com/ultr/glibc/tags/ultr-sys_cpuid-v2
[2]
    0x00000001, 0
    0x00000006, 0
    0x00000007, 0
    0x0000000D, 1
    0x0000000F, 0
    0x0000000F, 1
    0x80000001, 0
    0x80000008, 0
    0x8000000A, 0
    0x80860001, 0
    0xC0000001, 0
[3]
    __cpuid_count(level, count, eax, ebx, ecx, edx);
    vs
    int ret = syscall(SYS_cpuid, level, count, &eax, &ebx, &ecx, &edx);


Regards,
Piotr Henryk Dabrowski


--

Common cpuid wrappers, use SYS_cpuid when available

	* misc/common_cpuid.h: Common cpuid wrappers
	* sysdeps/generic/local_cpuid.h: Common cpuid wrappers
	* sysdeps/unix/sysv/linux/x86/local_cpuid.h: use SYS_cpuid if available
	* sysdeps/x86/cpu-features.c: Use local_cpuid.h
	* sysdeps/x86/fpu/test-fenv-clear-sse.c: Use local_cpuid.h
	* sysdeps/x86/fpu/test-fenv-sse-2.c: Use local_cpuid.h
	* sysdeps/x86/fpu/test-fenv-sse.c: Use local_cpuid.h
	* sysdeps/x86_64/cacheinfo.c: Use local_cpuid.h
	* sysdeps/x86_64/tst-audit10.c: Use local_cpuid.h
	* sysdeps/x86_64/tst-audit4.c: Use local_cpuid.h
	* sysdeps/x86_64/tst-audit6.c: Use local_cpuid.h
	* sysdeps/x86_64/tst-auditmod10b.c: Use local_cpuid.h
	* sysdeps/x86_64/tst-auditmod4b.c: Use local_cpuid.h
	* sysdeps/x86_64/tst-auditmod6b.c: Use local_cpuid.h
	* sysdeps/x86_64/tst-auditmod6c.c: Use local_cpuid.h
	* sysdeps/x86_64/tst-auditmod7b.c: Use local_cpuid.h
---
 ChangeLog                                 | 19 ++++++++
 misc/common_cpuid.h                       | 73 +++++++++++++++++++++++++++++++
 sysdeps/generic/local_cpuid.h             | 33 ++++++++++++++
 sysdeps/unix/sysv/linux/x86/local_cpuid.h | 40 +++++++++++++++++
 sysdeps/x86/cpu-features.c                | 37 ++++++++--------
 sysdeps/x86/fpu/test-fenv-clear-sse.c     |  4 +-
 sysdeps/x86/fpu/test-fenv-sse-2.c         |  4 +-
 sysdeps/x86/fpu/test-fenv-sse.c           |  4 +-
 sysdeps/x86_64/cacheinfo.c                | 24 +++++-----
 sysdeps/x86_64/tst-audit10.c              |  6 +--
 sysdeps/x86_64/tst-audit4.c               |  4 +-
 sysdeps/x86_64/tst-audit6.c               |  4 +-
 sysdeps/x86_64/tst-auditmod10b.c          |  6 +--
 sysdeps/x86_64/tst-auditmod4b.c           |  4 +-
 sysdeps/x86_64/tst-auditmod6b.c           |  4 +-
 sysdeps/x86_64/tst-auditmod6c.c           |  4 +-
 sysdeps/x86_64/tst-auditmod7b.c           |  4 +-
 17 files changed, 220 insertions(+), 54 deletions(-)
 create mode 100644 misc/common_cpuid.h
 create mode 100644 sysdeps/generic/local_cpuid.h
 create mode 100644 sysdeps/unix/sysv/linux/x86/local_cpuid.h

diff --git a/ChangeLog b/ChangeLog
index 727516e..d17e167 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,22 @@
+2016-03-10  Piotr Henryk Dabrowski  <ultr@ultr.pl>
+
+	* misc/common_cpuid.h: Common cpuid wrappers
+	* sysdeps/generic/local_cpuid.h: Common cpuid wrappers
+	* sysdeps/unix/sysv/linux/x86/local_cpuid.h: use SYS_cpuid if available
+	* sysdeps/x86/cpu-features.c: Use local_cpuid.h
+	* sysdeps/x86/fpu/test-fenv-clear-sse.c: Use local_cpuid.h
+	* sysdeps/x86/fpu/test-fenv-sse-2.c: Use local_cpuid.h
+	* sysdeps/x86/fpu/test-fenv-sse.c: Use local_cpuid.h
+	* sysdeps/x86_64/cacheinfo.c: Use local_cpuid.h
+	* sysdeps/x86_64/tst-audit10.c: Use local_cpuid.h
+	* sysdeps/x86_64/tst-audit4.c: Use local_cpuid.h
+	* sysdeps/x86_64/tst-audit6.c: Use local_cpuid.h
+	* sysdeps/x86_64/tst-auditmod10b.c: Use local_cpuid.h
+	* sysdeps/x86_64/tst-auditmod4b.c: Use local_cpuid.h
+	* sysdeps/x86_64/tst-auditmod6b.c: Use local_cpuid.h
+	* sysdeps/x86_64/tst-auditmod6c.c: Use local_cpuid.h
+	* sysdeps/x86_64/tst-auditmod7b.c: Use local_cpuid.h
+
 2016-03-09  Aurelien Jarno  <aurelien@aurel32.net>
 
 	[BZ #19792]
diff --git a/misc/common_cpuid.h b/misc/common_cpuid.h
new file mode 100644
index 0000000..89b7e93
--- /dev/null
+++ b/misc/common_cpuid.h
@@ -0,0 +1,73 @@
+/* CPUID wrapper functions.
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Piotr Henryk Dabrowski (ultr@ultr.pl), 2016.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _LOCAL_CPUID_H
+# error "Do not use <misc/common_cpuid.h> directly; include <local_cpuid.h> instead."
+#endif
+
+#ifndef _COMMON_CPUID_H
+#define _COMMON_CPUID_H 1
+
+#include <cpuid.h>
+#include <errno.h>
+
+#define get_cpuid_max __get_cpuid_max
+
+/* NOTE: for new Linux kernels these functions try to use kernel-adjusted
+   values for cpuid returned by the SYS_cpuid sys call.
+   Otherwise they fallback to native cpuid implementation.  */
+
+/* Return cpuid data for requested cpuid level (eax) and count register (ecx),
+   as found in returned eax, ebx, ecx and edx registers.
+   All pointers are required to be non-null.
+   Implementation is system dependant.  */
+static inline void
+cpuid_count (unsigned int level, unsigned int count,
+	     unsigned int *eax, unsigned int *ebx,
+	     unsigned int *ecx, unsigned int *edx);
+
+/* Return cpuid data for requested cpuid level (eax),
+   as found in returned eax, ebx, ecx and edx registers.
+   All pointers are required to be non-null.  */
+static inline void
+cpuid (unsigned int level,
+       unsigned int *eax, unsigned int *ebx,
+       unsigned int *ecx, unsigned int *edx)
+{
+	cpuid_count (level, 0, eax, ebx, ecx, edx);
+}
+
+/* Return cpuid data for requested cpuid level (eax),
+   as found in returned eax, ebx, ecx and edx registers.
+   The function checks if cpuid is supported and returns 1 for valid cpuid
+   information or 0 for unsupported cpuid level.
+   All pointers are required to be non-null.  */
+static inline int
+get_cpuid (unsigned int level,
+	   unsigned int *eax, unsigned int *ebx,
+	   unsigned int *ecx, unsigned int *edx)
+{
+	unsigned int ext = level & 0x80000000;
+	if (get_cpuid_max (ext, 0) < level)
+		return 0;
+	cpuid (level, eax, ebx, ecx, edx);
+	return 1;
+}
+
+#endif /* common_cpuid.h */
diff --git a/sysdeps/generic/local_cpuid.h b/sysdeps/generic/local_cpuid.h
new file mode 100644
index 0000000..7350293
--- /dev/null
+++ b/sysdeps/generic/local_cpuid.h
@@ -0,0 +1,33 @@
+/* CPUID wrapper functions.
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Piotr Henryk Dabrowski (ultr@ultr.pl), 2016.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _LOCAL_CPUID_H
+#define _LOCAL_CPUID_H 1
+
+#include <misc/common_cpuid.h>
+
+static inline void
+cpuid_count (unsigned int level, unsigned int count,
+	     unsigned int *eax, unsigned int *ebx,
+	     unsigned int *ecx, unsigned int *edx)
+{
+	__cpuid_count (level, count, *eax, *ebx, *ecx, *edx);
+}
+
+#endif /* local_cpuid.h */
diff --git a/sysdeps/unix/sysv/linux/x86/local_cpuid.h b/sysdeps/unix/sysv/linux/x86/local_cpuid.h
new file mode 100644
index 0000000..8a459d4
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86/local_cpuid.h
@@ -0,0 +1,40 @@
+/* CPUID wrapper functions.
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Piotr Henryk Dabrowski (ultr@ultr.pl), 2016.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _LOCAL_CPUID_H
+#define _LOCAL_CPUID_H 1
+
+#include <misc/common_cpuid.h>
+
+#include <sysdep.h>
+#include <sys/syscall.h>
+
+static inline void
+cpuid_count (unsigned int level, unsigned int count,
+	     unsigned int *eax, unsigned int *ebx,
+	     unsigned int *ecx, unsigned int *edx)
+{
+#ifdef __NR_cpuid
+	if (INLINE_SYSCALL (cpuid, 6, level, count, eax, ebx, ecx, edx) == 0)
+		return;
+#endif
+	__cpuid_count (level, count, *eax, *ebx, *ecx, *edx);
+}
+
+#endif /* local_cpuid.h */
diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
index 218ff2b..dc5be3f 100644
--- a/sysdeps/x86/cpu-features.c
+++ b/sysdeps/x86/cpu-features.c
@@ -16,7 +16,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <cpuid.h>
+#include <local_cpuid.h>
 #include <cpu-features.h>
 
 static inline void
@@ -25,9 +25,9 @@ get_common_indeces (struct cpu_features *cpu_features,
 		    unsigned int *extended_model)
 {
   unsigned int eax;
-  __cpuid (1, eax, cpu_features->cpuid[COMMON_CPUID_INDEX_1].ebx,
-	   cpu_features->cpuid[COMMON_CPUID_INDEX_1].ecx,
-	   cpu_features->cpuid[COMMON_CPUID_INDEX_1].edx);
+  cpuid (1, &eax, &(cpu_features->cpuid[COMMON_CPUID_INDEX_1].ebx),
+	 &(cpu_features->cpuid[COMMON_CPUID_INDEX_1].ecx),
+	 &(cpu_features->cpuid[COMMON_CPUID_INDEX_1].edx));
   GLRO(dl_x86_cpu_features).cpuid[COMMON_CPUID_INDEX_1].eax = eax;
   *family = (eax >> 8) & 0x0f;
   *model = (eax >> 4) & 0x0f;
@@ -42,20 +42,21 @@ get_common_indeces (struct cpu_features *cpu_features,
 static inline void
 init_cpu_features (struct cpu_features *cpu_features)
 {
-  unsigned int ebx, ecx, edx;
+  unsigned int eax, ebx, ecx, edx;
   unsigned int family = 0;
   unsigned int model = 0;
   enum cpu_features_kind kind;
 
 #if !HAS_CPUID
-  if (__get_cpuid_max (0, 0) == 0)
+  if (get_cpuid_max (0, 0) == 0)
     {
       kind = arch_kind_other;
       goto no_cpuid;
     }
 #endif
 
-  __cpuid (0, cpu_features->max_cpuid, ebx, ecx, edx);
+  cpuid (0, &eax, &ebx, &ecx, &edx);
+  cpu_features->max_cpuid = eax;
 
   /* This spells out "GenuineIntel".  */
   if (ebx == 0x756e6547 && ecx == 0x6c65746e && edx == 0x49656e69)
@@ -147,13 +148,13 @@ init_cpu_features (struct cpu_features *cpu_features)
       ecx = cpu_features->cpuid[COMMON_CPUID_INDEX_1].ecx;
 
       unsigned int eax;
-      __cpuid (0x80000000, eax, ebx, ecx, edx);
+      cpuid (0x80000000, &eax, &ebx, &ecx, &edx);
       if (eax >= 0x80000001)
-	__cpuid (0x80000001,
-		 cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].eax,
-		 cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].ebx,
-		 cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].ecx,
-		 cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].edx);
+	cpuid (0x80000001,
+	       &(cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].eax),
+	       &(cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].ebx),
+	       &(cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].ecx),
+	       &(cpu_features->cpuid[COMMON_CPUID_INDEX_80000001].edx));
 
       if (family == 0x15)
 	{
@@ -175,11 +176,11 @@ init_cpu_features (struct cpu_features *cpu_features)
     cpu_features->feature[index_I686] |= bit_I686;
 
   if (cpu_features->max_cpuid >= 7)
-    __cpuid_count (7, 0,
-		   cpu_features->cpuid[COMMON_CPUID_INDEX_7].eax,
-		   cpu_features->cpuid[COMMON_CPUID_INDEX_7].ebx,
-		   cpu_features->cpuid[COMMON_CPUID_INDEX_7].ecx,
-		   cpu_features->cpuid[COMMON_CPUID_INDEX_7].edx);
+    cpuid_count (7, 0,
+		 &(cpu_features->cpuid[COMMON_CPUID_INDEX_7].eax),
+		 &(cpu_features->cpuid[COMMON_CPUID_INDEX_7].ebx),
+		 &(cpu_features->cpuid[COMMON_CPUID_INDEX_7].ecx),
+		 &(cpu_features->cpuid[COMMON_CPUID_INDEX_7].edx));
 
   /* Can we call xgetbv?  */
   if (HAS_CPU_FEATURE (OSXSAVE))
diff --git a/sysdeps/x86/fpu/test-fenv-clear-sse.c b/sysdeps/x86/fpu/test-fenv-clear-sse.c
index cc4b3f0..45de9eb 100644
--- a/sysdeps/x86/fpu/test-fenv-clear-sse.c
+++ b/sysdeps/x86/fpu/test-fenv-clear-sse.c
@@ -17,7 +17,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <cpuid.h>
+#include <local_cpuid.h>
 #include <stdbool.h>
 
 static bool
@@ -25,7 +25,7 @@ have_sse2 (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
+  if (!get_cpuid (1, &eax, &ebx, &ecx, &edx))
     return false;
 
   return (edx & bit_SSE2) != 0;
diff --git a/sysdeps/x86/fpu/test-fenv-sse-2.c b/sysdeps/x86/fpu/test-fenv-sse-2.c
index d3197c3..92ee3f2 100644
--- a/sysdeps/x86/fpu/test-fenv-sse-2.c
+++ b/sysdeps/x86/fpu/test-fenv-sse-2.c
@@ -16,7 +16,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <cpuid.h>
+#include <local_cpuid.h>
 #include <fenv.h>
 #include <float.h>
 #include <stdbool.h>
@@ -28,7 +28,7 @@ have_sse2 (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
+  if (!get_cpuid (1, &eax, &ebx, &ecx, &edx))
     return false;
 
   return (edx & bit_SSE2) != 0;
diff --git a/sysdeps/x86/fpu/test-fenv-sse.c b/sysdeps/x86/fpu/test-fenv-sse.c
index 4f4ff6a..5836b95 100644
--- a/sysdeps/x86/fpu/test-fenv-sse.c
+++ b/sysdeps/x86/fpu/test-fenv-sse.c
@@ -16,7 +16,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <cpuid.h>
+#include <local_cpuid.h>
 #include <fenv.h>
 #include <float.h>
 #include <stdbool.h>
@@ -27,7 +27,7 @@ have_sse2 (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
+  if (!get_cpuid (1, &eax, &ebx, &ecx, &edx))
     return false;
 
   return (edx & bit_SSE2) != 0;
diff --git a/sysdeps/x86_64/cacheinfo.c b/sysdeps/x86_64/cacheinfo.c
index 96463df..18da742 100644
--- a/sysdeps/x86_64/cacheinfo.c
+++ b/sysdeps/x86_64/cacheinfo.c
@@ -20,7 +20,7 @@
 #include <stdbool.h>
 #include <stdlib.h>
 #include <unistd.h>
-#include <cpuid.h>
+#include <local_cpuid.h>
 #include <init-arch.h>
 
 #define is_intel GLRO(dl_x86_cpu_features).kind == arch_kind_intel
@@ -162,7 +162,7 @@ intel_check_word (int name, unsigned int value, bool *has_level_2,
 	  unsigned int round = 0;
 	  while (1)
 	    {
-	      __cpuid_count (4, round, eax, ebx, ecx, edx);
+	      cpuid_count (4, round, &eax, &ebx, &ecx, &edx);
 
 	      enum { null = 0, data = 1, inst = 2, uni = 3 } type = eax & 0x1f;
 	      if (type == null)
@@ -275,7 +275,7 @@ handle_intel (int name, unsigned int maxidx)
       unsigned int ebx;
       unsigned int ecx;
       unsigned int edx;
-      __cpuid (2, eax, ebx, ecx, edx);
+      cpuid (2, &eax, &ebx, &ecx, &edx);
 
       /* The low byte of EAX in the first round contain the number of
 	 rounds we have to make.  At least one, the one we are already
@@ -319,7 +319,7 @@ handle_amd (int name)
   unsigned int ebx;
   unsigned int ecx;
   unsigned int edx;
-  __cpuid (0x80000000, eax, ebx, ecx, edx);
+  cpuid (0x80000000, &eax, &ebx, &ecx, &edx);
 
   /* No level 4 cache (yet).  */
   if (name > _SC_LEVEL3_CACHE_LINESIZE)
@@ -329,7 +329,7 @@ handle_amd (int name)
   if (eax < fn)
     return 0;
 
-  __cpuid (fn, eax, ebx, ecx, edx);
+  cpuid (fn, &eax, &ebx, &ecx, &edx);
 
   if (name < _SC_LEVEL1_DCACHE_SIZE)
     {
@@ -479,7 +479,7 @@ init_cacheinfo (void)
   unsigned int ebx;
   unsigned int ecx;
   unsigned int edx;
-  int max_cpuid_ex;
+  unsigned int max_cpuid_ex;
   long int data = -1;
   long int shared = -1;
   unsigned int level;
@@ -512,7 +512,7 @@ init_cacheinfo (void)
 	  /* Query until desired cache level is enumerated.  */
 	  do
 	    {
-	      __cpuid_count (4, i++, eax, ebx, ecx, edx);
+	      cpuid_count (4, i++, &eax, &ebx, &ecx, &edx);
 
 	      /* There seems to be a bug in at least some Pentium Ds
 		 which sometimes fail to iterate all cache parameters.
@@ -536,7 +536,7 @@ init_cacheinfo (void)
 	      i = 0;
 	      while (1)
 		{
-		  __cpuid_count (11, i++, eax, ebx, ecx, edx);
+		  cpuid_count (11, i++, &eax, &ebx, &ecx, &edx);
 
 		  int shipped = ebx & 0xff;
 		  int type = ecx & 0xff0;
@@ -598,7 +598,7 @@ init_cacheinfo (void)
       shared = handle_amd (_SC_LEVEL3_CACHE_SIZE);
 
       /* Get maximum extended function. */
-      __cpuid (0x80000000, max_cpuid_ex, ebx, ecx, edx);
+      cpuid (0x80000000, &max_cpuid_ex, &ebx, &ecx, &edx);
 
       if (shared <= 0)
 	/* No shared L3 cache.  All we have is the L2 cache.  */
@@ -609,7 +609,7 @@ init_cacheinfo (void)
 	  if (max_cpuid_ex >= 0x80000008)
 	    {
 	      /* Get width of APIC ID.  */
-	      __cpuid (0x80000008, max_cpuid_ex, ebx, ecx, edx);
+	      cpuid (0x80000008, &max_cpuid_ex, &ebx, &ecx, &edx);
 	      threads = 1 << ((ecx >> 12) & 0x0f);
 	    }
 
@@ -617,7 +617,7 @@ init_cacheinfo (void)
 	    {
 	      /* If APIC ID width is not available, use logical
 		 processor count.  */
-	      __cpuid (0x00000001, max_cpuid_ex, ebx, ecx, edx);
+	      cpuid (0x00000001, &max_cpuid_ex, &ebx, &ecx, &edx);
 
 	      if ((edx & (1 << 28)) != 0)
 		threads = (ebx >> 16) & 0xff;
@@ -635,7 +635,7 @@ init_cacheinfo (void)
 #ifndef DISABLE_PREFETCHW
       if (max_cpuid_ex >= 0x80000001)
 	{
-	  __cpuid (0x80000001, eax, ebx, ecx, edx);
+	  cpuid (0x80000001, &eax, &ebx, &ecx, &edx);
 	  /*  PREFETCHW     || 3DNow!  */
 	  if ((ecx & 0x100) || (edx & 0x80000000))
 	    __x86_prefetchw = -1;
diff --git a/sysdeps/x86_64/tst-audit10.c b/sysdeps/x86_64/tst-audit10.c
index a487b40..5a23774 100644
--- a/sysdeps/x86_64/tst-audit10.c
+++ b/sysdeps/x86_64/tst-audit10.c
@@ -16,7 +16,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <cpuid.h>
+#include <local_cpuid.h>
 #include <cpu-features.h>
 
 int tst_audit10_aux (void);
@@ -26,11 +26,11 @@ avx512_enabled (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (__get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
+  if (get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
       || (ecx & (bit_AVX | bit_OSXSAVE)) != (bit_AVX | bit_OSXSAVE))
     return 0;
 
-  __cpuid_count (7, 0, eax, ebx, ecx, edx);
+  cpuid_count (7, 0, &eax, &ebx, &ecx, &edx);
   if (!(ebx & bit_AVX512F))
     return 0;
 
diff --git a/sysdeps/x86_64/tst-audit4.c b/sysdeps/x86_64/tst-audit4.c
index d8e2ab1..0ab51ed 100644
--- a/sysdeps/x86_64/tst-audit4.c
+++ b/sysdeps/x86_64/tst-audit4.c
@@ -16,7 +16,7 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <cpuid.h>
+#include <local_cpuid.h>
 
 int tst_audit4_aux (void);
 
@@ -25,7 +25,7 @@ avx_enabled (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (__get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
+  if (get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
       || (ecx & (bit_AVX | bit_OSXSAVE)) != (bit_AVX | bit_OSXSAVE))
     return 0;
 
diff --git a/sysdeps/x86_64/tst-audit6.c b/sysdeps/x86_64/tst-audit6.c
index f2f6a48..85689a0 100644
--- a/sysdeps/x86_64/tst-audit6.c
+++ b/sysdeps/x86_64/tst-audit6.c
@@ -2,7 +2,7 @@
 
 #include <stdlib.h>
 #include <string.h>
-#include <cpuid.h>
+#include <local_cpuid.h>
 #include <emmintrin.h>
 
 extern __m128i audit_test (__m128i, __m128i, __m128i, __m128i,
@@ -14,7 +14,7 @@ avx_enabled (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (__get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
+  if (get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
       || (ecx & (bit_AVX | bit_OSXSAVE)) != (bit_AVX | bit_OSXSAVE))
     return 0;
 
diff --git a/sysdeps/x86_64/tst-auditmod10b.c b/sysdeps/x86_64/tst-auditmod10b.c
index ad6fcaf..9c3093f 100644
--- a/sysdeps/x86_64/tst-auditmod10b.c
+++ b/sysdeps/x86_64/tst-auditmod10b.c
@@ -125,18 +125,18 @@ la_symbind64 (Elf64_Sym *sym, unsigned int ndx, uintptr_t *refcook,
 
 #ifdef __AVX512F__
 #include <immintrin.h>
-#include <cpuid.h>
+#include <local_cpuid.h>
 
 static int
 check_avx512 (void)
 {
   unsigned int eax, ebx, ecx, edx;
 
-  if (__get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
+  if (get_cpuid (1, &eax, &ebx, &ecx, &edx) == 0
       || (ecx & (bit_AVX | bit_OSXSAVE)) != (bit_AVX | bit_OSXSAVE))
     return 0;
 
-  __cpuid_count (7, 0, eax, ebx, ecx, edx);
+  cpuid_count (7, 0, &eax, &ebx, &ecx, &edx);
   if (!(ebx & bit_AVX512F))
     return 0;
 
diff --git a/sysdeps/x86_64/tst-auditmod4b.c b/sysdeps/x86_64/tst-auditmod4b.c
index 2b0d827..df74ea3 100644
--- a/sysdeps/x86_64/tst-auditmod4b.c
+++ b/sysdeps/x86_64/tst-auditmod4b.c
@@ -108,7 +108,7 @@ la_symbind64 (Elf64_Sym *sym, unsigned int ndx, uintptr_t *refcook,
 
 #ifdef __AVX__
 #include <immintrin.h>
-#include <cpuid.h>
+#include <local_cpuid.h>
 
 static int avx = -1;
 
@@ -120,7 +120,7 @@ check_avx (void)
     {
       unsigned int eax, ebx, ecx, edx;
 
-      if (__get_cpuid (1, &eax, &ebx, &ecx, &edx)
+      if (get_cpuid (1, &eax, &ebx, &ecx, &edx)
 	  && (ecx & bit_AVX))
 	avx = 1;
       else
diff --git a/sysdeps/x86_64/tst-auditmod6b.c b/sysdeps/x86_64/tst-auditmod6b.c
index 886fc33..521441c 100644
--- a/sysdeps/x86_64/tst-auditmod6b.c
+++ b/sysdeps/x86_64/tst-auditmod6b.c
@@ -108,7 +108,7 @@ la_symbind64 (Elf64_Sym *sym, unsigned int ndx, uintptr_t *refcook,
 
 #ifdef __AVX__
 #include <immintrin.h>
-#include <cpuid.h>
+#include <local_cpuid.h>
 
 static int avx = -1;
 
@@ -120,7 +120,7 @@ check_avx (void)
     {
       unsigned int eax, ebx, ecx, edx;
 
-      if (__get_cpuid (1, &eax, &ebx, &ecx, &edx)
+      if (get_cpuid (1, &eax, &ebx, &ecx, &edx)
 	  && (ecx & bit_AVX))
 	avx = 1;
       else
diff --git a/sysdeps/x86_64/tst-auditmod6c.c b/sysdeps/x86_64/tst-auditmod6c.c
index b2ee24d..d4ca5c8 100644
--- a/sysdeps/x86_64/tst-auditmod6c.c
+++ b/sysdeps/x86_64/tst-auditmod6c.c
@@ -108,7 +108,7 @@ la_symbind64 (Elf64_Sym *sym, unsigned int ndx, uintptr_t *refcook,
 
 #ifdef __AVX__
 #include <immintrin.h>
-#include <cpuid.h>
+#include <local_cpuid.h>
 
 static int avx = -1;
 
@@ -120,7 +120,7 @@ check_avx (void)
     {
       unsigned int eax, ebx, ecx, edx;
 
-      if (__get_cpuid (1, &eax, &ebx, &ecx, &edx)
+      if (get_cpuid (1, &eax, &ebx, &ecx, &edx)
 	  && (ecx & bit_AVX))
 	avx = 1;
       else
diff --git a/sysdeps/x86_64/tst-auditmod7b.c b/sysdeps/x86_64/tst-auditmod7b.c
index f27076d..343a27e 100644
--- a/sysdeps/x86_64/tst-auditmod7b.c
+++ b/sysdeps/x86_64/tst-auditmod7b.c
@@ -108,7 +108,7 @@ la_symbind64 (Elf64_Sym *sym, unsigned int ndx, uintptr_t *refcook,
 
 #ifdef __AVX__
 #include <immintrin.h>
-#include <cpuid.h>
+#include <local_cpuid.h>
 
 static int avx = -1;
 
@@ -120,7 +120,7 @@ check_avx (void)
     {
       unsigned int eax, ebx, ecx, edx;
 
-      if (__get_cpuid (1, &eax, &ebx, &ecx, &edx)
+      if (get_cpuid (1, &eax, &ebx, &ecx, &edx)
 	  && (ecx & bit_AVX))
 	avx = 1;
       else
-- 
2.1.4

Re: [PATCH v2] Common cpuid wrappers, use SYS_cpuid when available

[Joseph Myers]

On Thu, 10 Mar 2016, Piotr Henryk Dabrowski wrote:

> 	* misc/common_cpuid.h: Common cpuid wrappers
> 	* sysdeps/generic/local_cpuid.h: Common cpuid wrappers

The cpuid concept is x86-specific.  Thus, nothing should go in misc/ or 
sysdeps/generic/.  Use sysdeps/x86/.

> +{
> +	cpuid_count (level, 0, eax, ebx, ecx, edx);

Formatting of course needs to be in GNU style (so two-column indents).

> +#ifdef __NR_cpuid
> +	if (INLINE_SYSCALL (cpuid, 6, level, count, eax, ebx, ecx, edx) == 0)
> +		return;
> +#endif
> +	__cpuid_count (level, count, *eax, *ebx, *ecx, *edx);

If the kernel used at runtime supports the syscall, is it ever possible 
for it to fail?  If not, you should have __ASSUME_CPUID to disable the 
fallback.

-- 
Joseph S. Myers
joseph@codesourcery.com

Re: [PATCH v2] Common cpuid wrappers, use SYS_cpuid when available

[Mike Frysinger]

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On 10 Mar 2016 21:12, Piotr Henryk Dabrowski wrote:
> > or if this functionality should be a vsyscall instead.
> 
> vsyscall or vdso? I will look into this idea.

vdso.  vsyscall is an old synonym now for it.  see `man 7 vdso`.

> > nope -- you'll need to sign copyright papers w/the FSF
> 
> So the copyright attribution line must display the FSF only, plus I need to sign
> the legal papers, right?

yes, you must do both

> How can I obtain a copy for signing? Just in case.

see this page:
https://sourceware.org/glibc/wiki/Contribution%20checklist#FSF_copyright_Assignment
-mike

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