x86: Install <sys/platform/x86.h> [BZ #26124]

Install <sys/platform/x86.h> so that programmers can do

 #if __has_include(<sys/platform/x86.h>)
 #include <sys/platform/x86.h>
 #endif
 ...

   if (CPU_FEATURE_USABLE (SSE2))
 ...
   if (CPU_FEATURE_USABLE (AVX2))
 ...

<sys/platform/x86.h> exports only:

enum
{
  COMMON_CPUID_INDEX_1 = 0,
  COMMON_CPUID_INDEX_7,
  COMMON_CPUID_INDEX_80000001,
  COMMON_CPUID_INDEX_D_ECX_1,
  COMMON_CPUID_INDEX_80000007,
  COMMON_CPUID_INDEX_80000008,
  COMMON_CPUID_INDEX_7_ECX_1,
  /* Keep the following line at the end.  */
  COMMON_CPUID_INDEX_MAX
};

struct cpuid_features
{
  struct cpuid_registers cpuid;
  struct cpuid_registers usable;
};

struct cpu_features
{
  struct cpu_features_basic basic;
  struct cpuid_features features[COMMON_CPUID_INDEX_MAX];
};

/* Get a pointer to the CPU features structure.  */
extern const struct cpu_features *__x86_get_cpu_features
  (unsigned int max) __attribute__ ((const));

Since all feature checks are done through macros, programs compiled with
a newer <sys/platform/x86.h> are compatible with the older glibc binaries
as long as the layout of struct cpu_features is identical.  The features
array can be expanded with backward binary compatibility for both .o and
.so files.  When COMMON_CPUID_INDEX_MAX is increased to support new
processor features, __x86_get_cpu_features in the older glibc binaries
returns NULL and HAS_CPU_FEATURE/CPU_FEATURE_USABLE return false on the
new processor feature.  No new symbol version is neeeded.

Both CPU_FEATURE_USABLE and HAS_CPU_FEATURE are provided.  HAS_CPU_FEATURE
can be used to identify processor features.

Note: Although GCC has __builtin_cpu_supports, it only supports a subset
of <sys/platform/x86.h> and it is equivalent to CPU_FEATURE_USABLE.  It
doesn't support HAS_CPU_FEATURE.

1 files changed, 250 insertions, 0 deletions

diff --git a/sysdeps/x86/tst-cpu-features-cpuinfo.c b/sysdeps/x86/tst-cpu-features-cpuinfo.c
new file mode 100644
index 0000000000..96277284d1
--- /dev/null
+++ b/sysdeps/x86/tst-cpu-features-cpuinfo.c
@@ -0,0 +1,250 @@
+/* Test CPU feature data against /proc/cpuinfo.
+   This file is part of the GNU C Library.
+   Copyright (C) 2012-2020 Free Software Foundation, Inc.
+
+   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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <sys/platform/x86.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static char *cpu_flags;
+
+/* Search for flags in /proc/cpuinfo and store line
+   in cpu_flags.  */
+void
+get_cpuinfo (void)
+{
+  FILE *f;
+  char *line = NULL;
+  size_t len = 0;
+  ssize_t read;
+
+  f = fopen ("/proc/cpuinfo", "r");
+  if (f == NULL)
+    {
+      printf ("cannot open /proc/cpuinfo\n");
+      exit (1);
+    }
+
+  while ((read = getline (&line, &len, f)) != -1)
+    {
+      if (strncmp (line, "flags", 5) == 0)
+       {
+         cpu_flags = strdup (line);
+         break;
+       }
+    }
+  fclose (f);
+  free (line);
+}
+
+int
+check_proc (const char *proc_name, int flag, int usable, const char *name)
+{
+  int found = 0;
+
+  printf ("Checking %s:\n", name);
+  if (!usable)
+    {
+      printf ("  %s: insufficient usable info, skipped\n", name);
+      return 0;
+    }
+  printf ("  %s: %d\n", name, flag);
+  if (strstr (cpu_flags, proc_name) != NULL)
+    found = 1;
+  printf ("  cpuinfo (%s): %d\n", proc_name, found);
+
+  if (found != flag)
+    printf (" *** failure ***\n");
+
+  return (found != flag);
+}
+
+#define CHECK_PROC(str, name) \
+  check_proc (#str, HAS_CPU_FEATURE (name), CPU_FEATURE_USABLE (name), \
+	      "HAS_CPU_FEATURE (" #name ")");
+
+static int
+do_test (int argc, char **argv)
+{
+  int fails = 0;
+
+  get_cpuinfo ();
+  fails += CHECK_PROC (acpi, ACPI);
+  fails += CHECK_PROC (adx, ADX);
+  fails += CHECK_PROC (apic, APIC);
+  fails += CHECK_PROC (aes, AES);
+  fails += CHECK_PROC (amx_bf16, AMX_BF16);
+  fails += CHECK_PROC (amx_int8, AMX_INT8);
+  fails += CHECK_PROC (amx_tile, AMX_TILE);
+  fails += CHECK_PROC (arch_capabilities, ARCH_CAPABILITIES);
+  fails += CHECK_PROC (avx, AVX);
+  fails += CHECK_PROC (avx2, AVX2);
+  fails += CHECK_PROC (avx512_4fmaps, AVX512_4FMAPS);
+  fails += CHECK_PROC (avx512_4vnniw, AVX512_4VNNIW);
+  fails += CHECK_PROC (avx512_bf16, AVX512_BF16);
+  fails += CHECK_PROC (avx512_bitalg, AVX512_BITALG);
+  fails += CHECK_PROC (avx512ifma, AVX512_IFMA);
+  fails += CHECK_PROC (avx512_vbmi, AVX512_VBMI);
+  fails += CHECK_PROC (avx512_vbmi2, AVX512_VBMI2);
+  fails += CHECK_PROC (avx512_vnni, AVX512_VNNI);
+  fails += CHECK_PROC (avx512_vp2intersect, AVX512_VP2INTERSECT);
+  fails += CHECK_PROC (avx512_vpopcntdq, AVX512_VPOPCNTDQ);
+  fails += CHECK_PROC (avx512bw, AVX512BW);
+  fails += CHECK_PROC (avx512cd, AVX512CD);
+  fails += CHECK_PROC (avx512er, AVX512ER);
+  fails += CHECK_PROC (avx512dq, AVX512DQ);
+  fails += CHECK_PROC (avx512f, AVX512F);
+  fails += CHECK_PROC (avx512pf, AVX512PF);
+  fails += CHECK_PROC (avx512vl, AVX512VL);
+  fails += CHECK_PROC (bmi1, BMI1);
+  fails += CHECK_PROC (bmi2, BMI2);
+  fails += CHECK_PROC (cldemote, CLDEMOTE);
+  fails += CHECK_PROC (clflushopt, CLFLUSHOPT);
+  fails += CHECK_PROC (clflush, CLFSH);
+  fails += CHECK_PROC (clwb, CLWB);
+  fails += CHECK_PROC (cmov, CMOV);
+  fails += CHECK_PROC (cx16, CMPXCHG16B);
+  fails += CHECK_PROC (cnxt_id, CNXT_ID);
+  fails += CHECK_PROC (core_capabilities, CORE_CAPABILITIES);
+  fails += CHECK_PROC (cx8, CX8);
+  fails += CHECK_PROC (dca, DCA);
+  fails += CHECK_PROC (de, DE);
+  fails += CHECK_PROC (zero_fcs_fds, DEPR_FPU_CS_DS);
+  fails += CHECK_PROC (ds, DS);
+  fails += CHECK_PROC (ds_cpl, DS_CPL);
+  fails += CHECK_PROC (dtes64, DTES64);
+  fails += CHECK_PROC (est, EIST);
+  fails += CHECK_PROC (enqcmd, ENQCMD);
+  fails += CHECK_PROC (erms, ERMS);
+  fails += CHECK_PROC (f16c, F16C);
+  fails += CHECK_PROC (fma, FMA);
+  fails += CHECK_PROC (fma4, FMA4);
+  fails += CHECK_PROC (fpu, FPU);
+  fails += CHECK_PROC (fsgsbase, FSGSBASE);
+  fails += CHECK_PROC (fsrm, FSRM);
+  fails += CHECK_PROC (fxsr, FXSR);
+  fails += CHECK_PROC (gfni, GFNI);
+  fails += CHECK_PROC (hle, HLE);
+  fails += CHECK_PROC (ht, HTT);
+  fails += CHECK_PROC (hybrid, HYBRID);
+  fails += CHECK_PROC (ibrs, IBRS_IBPB);
+  fails += CHECK_PROC (ibt, IBT);
+  fails += CHECK_PROC (invariant_tsc, INVARIANT_TSC);
+  fails += CHECK_PROC (invpcid, INVPCID);
+  fails += CHECK_PROC (flush_l1d, L1D_FLUSH);
+  fails += CHECK_PROC (lahf_lm, LAHF64_SAHF64);
+  fails += CHECK_PROC (lm, LM);
+  fails += CHECK_PROC (lwp, LWP);
+  fails += CHECK_PROC (abm, LZCNT);
+  fails += CHECK_PROC (mca, MCA);
+  fails += CHECK_PROC (mce, MCE);
+  fails += CHECK_PROC (md_clear, MD_CLEAR);
+  fails += CHECK_PROC (mmx, MMX);
+  fails += CHECK_PROC (monitor, MONITOR);
+  fails += CHECK_PROC (movbe, MOVBE);
+  fails += CHECK_PROC (movdiri, MOVDIRI);
+  fails += CHECK_PROC (movdir64b, MOVDIR64B);
+  fails += CHECK_PROC (mpx, MPX);
+  fails += CHECK_PROC (msr, MSR);
+  fails += CHECK_PROC (mtrr, MTRR);
+  fails += CHECK_PROC (nx, NX);
+  fails += CHECK_PROC (ospke, OSPKE);
+#if 0
+  /* NB: /proc/cpuinfo doesn't report this feature.  */
+  fails += CHECK_PROC (osxsave, OSXSAVE);
+#endif
+  fails += CHECK_PROC (pae, PAE);
+  fails += CHECK_PROC (pdpe1gb, PAGE1GB);
+  fails += CHECK_PROC (pat, PAT);
+  fails += CHECK_PROC (pbe, PBE);
+  fails += CHECK_PROC (pcid, PCID);
+  fails += CHECK_PROC (pclmulqdq, PCLMULQDQ);
+  fails += CHECK_PROC (pconfig, PCONFIG);
+  fails += CHECK_PROC (pdcm, PDCM);
+  fails += CHECK_PROC (pge, PGE);
+  fails += CHECK_PROC (pks, PKS);
+  fails += CHECK_PROC (pku, PKU);
+  fails += CHECK_PROC (popcnt, POPCNT);
+  fails += CHECK_PROC (3dnowprefetch, PREFETCHW);
+  fails += CHECK_PROC (prefetchwt1, PREFETCHWT1);
+  fails += CHECK_PROC (pse, PSE);
+  fails += CHECK_PROC (pse36, PSE_36);
+  fails += CHECK_PROC (psn, PSN);
+  fails += CHECK_PROC (rdpid, RDPID);
+  fails += CHECK_PROC (rdrand, RDRAND);
+  fails += CHECK_PROC (rdseed, RDSEED);
+  fails += CHECK_PROC (rdt_a, RDT_A);
+  fails += CHECK_PROC (cqm, RDT_M);
+  fails += CHECK_PROC (rdtscp, RDTSCP);
+  fails += CHECK_PROC (rtm, RTM);
+  fails += CHECK_PROC (sdbg, SDBG);
+  fails += CHECK_PROC (sep, SEP);
+  fails += CHECK_PROC (serialize, SERIALIZE);
+  fails += CHECK_PROC (sgx, SGX);
+  fails += CHECK_PROC (sgx_lc, SGX_LC);
+  fails += CHECK_PROC (sha_ni, SHA);
+  fails += CHECK_PROC (shstk, SHSTK);
+  fails += CHECK_PROC (smap, SMAP);
+  fails += CHECK_PROC (smep, SMEP);
+  fails += CHECK_PROC (smx, SMX);
+  fails += CHECK_PROC (ss, SS);
+  fails += CHECK_PROC (ssbd, SSBD);
+  fails += CHECK_PROC (sse, SSE);
+  fails += CHECK_PROC (sse2, SSE2);
+  fails += CHECK_PROC (sse3, SSE3);
+  fails += CHECK_PROC (sse4_1, SSE4_1);
+  fails += CHECK_PROC (sse4_2, SSE4_2);
+  fails += CHECK_PROC (sse4a, SSE4A);
+  fails += CHECK_PROC (ssse3, SSSE3);
+  fails += CHECK_PROC (stibp, STIBP);
+  fails += CHECK_PROC (svm, SVM);
+#ifdef __x86_64__
+  /* NB: SYSCALL_SYSRET is 64-bit only.  */
+  fails += CHECK_PROC (syscall, SYSCALL_SYSRET);
+#endif
+  fails += CHECK_PROC (tbm, TBM);
+  fails += CHECK_PROC (tm, TM);
+  fails += CHECK_PROC (tm2, TM2);
+  fails += CHECK_PROC (intel_pt, TRACE);
+  fails += CHECK_PROC (tsc, TSC);
+  fails += CHECK_PROC (tsc_adjust, TSC_ADJUST);
+  fails += CHECK_PROC (tsc_deadline, TSC_DEADLINE);
+  fails += CHECK_PROC (tsxldtrk, TSXLDTRK);
+  fails += CHECK_PROC (umip, UMIP);
+  fails += CHECK_PROC (vaes, VAES);
+  fails += CHECK_PROC (vme, VME);
+  fails += CHECK_PROC (vmx, VMX);
+  fails += CHECK_PROC (vpclmulqdq, VPCLMULQDQ);
+  fails += CHECK_PROC (waitpkg, WAITPKG);
+  fails += CHECK_PROC (wbnoinvd, WBNOINVD);
+  fails += CHECK_PROC (x2apic, X2APIC);
+  fails += CHECK_PROC (xfd, XFD);
+  fails += CHECK_PROC (xgetbv1, XGETBV_ECX_1);
+  fails += CHECK_PROC (xop, XOP);
+  fails += CHECK_PROC (xsave, XSAVE);
+  fails += CHECK_PROC (xsavec, XSAVEC);
+  fails += CHECK_PROC (xsaveopt, XSAVEOPT);
+  fails += CHECK_PROC (xsaves, XSAVES);
+  fails += CHECK_PROC (xtpr, XTPRUPDCTRL);
+
+  printf ("%d differences between /proc/cpuinfo and glibc code.\n", fails);
+
+  return (fails != 0);
+}
+
+#include "../../../test-skeleton.c"