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[PATCH v3 08/15] btrace: identify cpu
- From: Markus Metzger <markus dot t dot metzger at intel dot com>
- To: palves at redhat dot com
- Cc: gdb-patches at sourceware dot org
- Date: Thu, 29 Jan 2015 17:28:12 +0100
- Subject: [PATCH v3 08/15] btrace: identify cpu
- Authentication-results: sourceware.org; auth=none
- References: <1422548899-9789-1-git-send-email-markus dot t dot metzger at intel dot com>
Add a struct for identifying a processor and use it in linux-btrace.c when
identifying the processor we're running on.
We will need this feature for the new btrace format.
2015-01-29 Markus Metzger <markus.t.metzger@intel.com>
gdb/
* common/btrace-common.h (btrace_cpu_vendor, btrace_cpu): New.
* nat/linux-btrace.c: Include x86-cpuid.h.
(btrace_this_cpu): New.
(cpu_supports_bts): Call btrace_this_cpu.
(intel_supports_bts): Add cpu parameter.
---
gdb/common/btrace-common.h | 28 +++++++++++++++++++
gdb/nat/linux-btrace.c | 70 +++++++++++++++++++++++++++++++---------------
2 files changed, 76 insertions(+), 22 deletions(-)
diff --git a/gdb/common/btrace-common.h b/gdb/common/btrace-common.h
index 69e223c..5e67e52 100644
--- a/gdb/common/btrace-common.h
+++ b/gdb/common/btrace-common.h
@@ -61,6 +61,34 @@ enum btrace_format
BTRACE_FORMAT_BTS
};
+/* An enumeration of cpu vendors. */
+
+enum btrace_cpu_vendor
+{
+ /* We do not know this vendor. */
+ CV_UNKNOWN,
+
+ /* Intel. */
+ CV_INTEL
+};
+
+/* A cpu identifier. */
+
+struct btrace_cpu
+{
+ /* The processor vendor. */
+ enum btrace_cpu_vendor vendor;
+
+ /* The cpu family. */
+ unsigned short family;
+
+ /* The cpu model. */
+ unsigned char model;
+
+ /* The cpu stepping. */
+ unsigned char stepping;
+};
+
/* A BTS configuration. */
struct btrace_config_bts
diff --git a/gdb/nat/linux-btrace.c b/gdb/nat/linux-btrace.c
index c7db313..3376a0f 100644
--- a/gdb/nat/linux-btrace.c
+++ b/gdb/nat/linux-btrace.c
@@ -59,6 +59,41 @@ struct perf_event_sample
struct perf_event_bts bts;
};
+/* Identify the cpu we're running on. */
+static struct btrace_cpu
+btrace_this_cpu (void)
+{
+ struct btrace_cpu cpu;
+ unsigned int eax, ebx, ecx, edx;
+ int ok;
+
+ memset (&cpu, 0, sizeof (cpu));
+
+ ok = x86_cpuid (0, &eax, &ebx, &ecx, &edx);
+ if (ok != 0)
+ {
+ if (ebx == signature_INTEL_ebx && ecx == signature_INTEL_ecx
+ && edx == signature_INTEL_edx)
+ {
+ unsigned int cpuid, ignore;
+
+ ok = x86_cpuid (1, &cpuid, &ignore, &ignore, &ignore);
+ if (ok != 0)
+ {
+ cpu.vendor = CV_INTEL;
+
+ cpu.family = (cpuid >> 8) & 0xf;
+ cpu.model = (cpuid >> 4) & 0xf;
+
+ if (cpu.family == 0x6)
+ cpu.model += (cpuid >> 12) & 0xf0;
+ }
+ }
+ }
+
+ return cpu;
+}
+
/* Return non-zero if there is new data in PEVENT; zero otherwise. */
static int
@@ -302,22 +337,12 @@ kernel_supports_bts (void)
/* Check whether an Intel cpu supports BTS. */
static int
-intel_supports_bts (void)
+intel_supports_bts (const struct btrace_cpu *cpu)
{
- unsigned int cpuid, model, family;
-
- if (!x86_cpuid (1, &cpuid, NULL, NULL, NULL))
- return 0;
-
- family = (cpuid >> 8) & 0xf;
- model = (cpuid >> 4) & 0xf;
-
- switch (family)
+ switch (cpu->family)
{
case 0x6:
- model += (cpuid >> 12) & 0xf0;
-
- switch (model)
+ switch (cpu->model)
{
case 0x1a: /* Nehalem */
case 0x1f:
@@ -345,17 +370,18 @@ intel_supports_bts (void)
static int
cpu_supports_bts (void)
{
- unsigned int ebx, ecx, edx;
+ struct btrace_cpu cpu;
- if (!x86_cpuid (0, NULL, &ebx, &ecx, &edx))
- return 0;
-
- if (ebx == signature_INTEL_ebx && ecx == signature_INTEL_ecx
- && edx == signature_INTEL_edx)
- return intel_supports_bts ();
+ cpu = btrace_this_cpu ();
+ switch (cpu.vendor)
+ {
+ default:
+ /* Don't know about others. Let's assume they do. */
+ return 1;
- /* Don't know about others. Let's assume they do. */
- return 1;
+ case CV_INTEL:
+ return intel_supports_bts (&cpu);
+ }
}
/* Check whether the linux target supports BTS. */
--
1.8.3.1