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

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

From-SVN: r244644
This commit is contained in:
Uros Bizjak 2017-01-19 18:10:40 +01:00 committed by Uros Bizjak
parent 197d1c095d
commit 16a34ca6ac
2 changed files with 23 additions and 17 deletions
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5
libitm/ChangeLog
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@ -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

35
libitm/config/x86/target.h
View File

@ -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;