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[patch v6 12/12] btrace, x86: disable on some processors
- From: markus dot t dot metzger at intel dot com
- To: jan dot kratochvil at redhat dot com, palves at redhat dot com, tromey at redhat dot com, kettenis at gnu dot org
- Cc: gdb-patches at sourceware dot org, markus dot t dot metzger at gmail dot com, Markus Metzger <markus dot t dot metzger at intel dot com>
- Date: Mon, 17 Dec 2012 17:01:41 +0100
- Subject: [patch v6 12/12] btrace, x86: disable on some processors
- References: <1355760101-26237-1-git-send-email-markus.t.metzger@intel.com>
From: Markus Metzger <markus.t.metzger@intel.com>
LBR, BTM, or BTS records may have incorrect branch "from" information afer an
EIST transition, T-states, C1E, or Adaptive Thermal Throttling (AAJ122).
This results in sporadic test fails. Disable btrace on those processors.
2012-12-17 Markus Metzger <markus.t.metzger@intel.com>
* common/linux-btrace.c (linux_supports_btrace): Add cpuid check.
---
gdb/common/linux-btrace.c | 43 +++++++++++++++++++++++++++++++++++++++++++
1 files changed, 43 insertions(+), 0 deletions(-)
diff --git a/gdb/common/linux-btrace.c b/gdb/common/linux-btrace.c
index 1231ccc..b5a41a5 100644
--- a/gdb/common/linux-btrace.c
+++ b/gdb/common/linux-btrace.c
@@ -247,7 +247,50 @@ perf_event_read_bts (struct btrace_target_info* tinfo, const uint8_t *begin,
int
linux_supports_btrace (void)
{
+#if defined(__i386__) || defined(__x86_64__)
+ {
+ unsigned int cpuid, model, family;
+
+ __asm__ __volatile__ ("movl $1, %%eax;"
+ "cpuid;"
+ : "=a" (cpuid)
+ :: "%ebx", "%ecx", "%edx");
+
+ family = (cpuid >> 8) & 0xf;
+ model = (cpuid >> 4) & 0xf;
+
+ switch (family)
+ {
+ case 6:
+ model += (cpuid >> 12) & 0xf0;
+
+ switch (model)
+ {
+ case 26: /* Nehalem */
+ case 30:
+ case 46:
+ case 37: /* Westmere */
+ case 44:
+ case 47:
+ case 42: /* Sandy Bridge */
+ case 45:
+ case 58: /* Ivy Bridge */
+
+ /* AAJ122: LBR, BTM, or BTS records may have incorrect branch
+ "from" information afer an EIST transition, T-states, C1E, or
+ Adaptive Thermal Throttling. */
+ return 0;
+ }
+ }
+ }
+
return 1;
+
+#else /* defined(__i386__) || defined(__x86_64__) */
+
+ return 0;
+
+#endif /* defined(__i386__) || defined(__x86_64__) */
}
/* See linux-btrace.h. */
--
1.7.6.5