target.h (htm_available): Determine vendor from __get_cpuid_max return.

	* config/x86/target.h (htm_available): Determine vendor from
	__get_cpuid_max return.  Use signature_INTEL_ebx.  Cleanup.

From-SVN: r244644

diff --git a/libitm/ChangeLog b/libitm/ChangeLog
index d50005f..5f44e3f 100644 (file)
--- a/libitm/ChangeLog
+++ b/libitm/ChangeLog
@@ -1,3 +1,8 @@
+2017-01-19  Uros Bizjak  <ubizjak@gmail.com>
+
+       * config/x86/target.h (htm_available): Determine vendor from
+       __get_cpuid_max return.  Use signature_INTEL_ebx.  Cleanup.
+
 2017-01-18  Torvald Riegel  <triegel@redhat.com>
 
        * config/x86/target.h (htm_available): Add check for some processors

diff --git a/libitm/config/x86/target.h b/libitm/config/x86/target.h
index 665c7d6..1b79dc0 100644 (file)
--- a/libitm/config/x86/target.h
+++ b/libitm/config/x86/target.h
@@ -75,31 +75,32 @@ static inline bool
 htm_available ()
 {
   const unsigned cpuid_rtm = bit_RTM;
-  if (__get_cpuid_max (0, NULL) >= 7)
+  unsigned vendor;
+
+  if (__get_cpuid_max (0, &vendor) >= 7)
     {
       unsigned a, b, c, d;
-      /* TSX is broken on some processors.  This can be fixed by microcode,
+      unsigned family;
+
+      __cpuid (1, a, b, c, d);
+      family = (a >> 8) & 0x0f;
+      /* TSX is broken on some processors.  TSX can be disabled by microcode,
         but we cannot reliably detect whether the microcode has been
         updated.  Therefore, do not report availability of TSX on these
         processors.  We use the same approach here as in glibc (see
         https://sourceware.org/ml/libc-alpha/2016-12/msg00470.html).  */
-      __cpuid (0, a, b, c, d);
-      if (b == 0x756e6547 && c == 0x6c65746e && d == 0x49656e69)
+      if (vendor == signature_INTEL_ebx && family == 0x06)
        {
-         __cpuid (1, a, b, c, d);
-         if (((a >> 8) & 0x0f) == 0x06) // Family.
-           {
-             unsigned model = ((a >> 4) & 0x0f) // Model.
-                 + ((a >> 12) & 0xf0); // Extended model.
-             unsigned stepping = a & 0x0f;
-             if ((model == 0x3c)
-                 || (model == 0x45)
-                 || (model == 0x46)
-                 /* Xeon E7 v3 has correct TSX if stepping >= 4.  */
-                 || ((model == 0x3f) && (stepping < 4)))
-               return false;
-           }
+         unsigned model = ((a >> 4) & 0x0f) + ((a >> 12) & 0xf0);
+         unsigned stepping = a & 0x0f;
+         if (model == 0x3c
+             /* Xeon E7 v3 has correct TSX if stepping >= 4.  */
+             || (model == 0x3f && stepping < 4)
+             || model == 0x45
+             || model == 0x46)
+           return false;
        }
+
       __cpuid_count (7, 0, a, b, c, d);
       if (b & cpuid_rtm)
        return true;