From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 21606 invoked by alias); 8 Mar 2013 09:17:35 -0000 Received: (qmail 21450 invoked by uid 22791); 8 Mar 2013 09:17:26 -0000 X-SWARE-Spam-Status: No, hits=-8.0 required=5.0 tests=AWL,BAYES_00,KHOP_RCVD_UNTRUST,KHOP_SPAMHAUS_DROP,KHOP_THREADED,RCVD_IN_DNSWL_HI,RCVD_IN_HOSTKARMA_W,RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mga03.intel.com (HELO mga03.intel.com) (143.182.124.21) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Fri, 08 Mar 2013 09:16:22 +0000 Received: from azsmga001.ch.intel.com ([10.2.17.19]) by azsmga101.ch.intel.com with ESMTP; 08 Mar 2013 01:16:19 -0800 X-ExtLoop1: 1 Received: from swsutil001.isw.intel.com ([10.237.237.11]) by azsmga001.ch.intel.com with ESMTP; 08 Mar 2013 01:16:17 -0800 Received: from ulslx001.iul.intel.com (ulslx001.iul.intel.com [172.28.207.63]) by swsutil001.isw.intel.com (8.13.6/8.13.6/MailSET/Hub) with ESMTP id r289GDoh022871; Fri, 8 Mar 2013 09:16:13 GMT Received: from ulslx001.iul.intel.com (localhost [127.0.0.1]) by ulslx001.iul.intel.com with ESMTP id r289GCsE002059; Fri, 8 Mar 2013 10:16:12 +0100 Received: (from mmetzger@localhost) by ulslx001.iul.intel.com with id r289GCl4002055; Fri, 8 Mar 2013 10:16:12 +0100 From: Markus Metzger To: jan.kratochvil@redhat.com Cc: gdb-patches@sourceware.org, markus.t.metzger@gmail.com Subject: [patch v10 08/21] btrace, x86: disable on some processors Date: Fri, 08 Mar 2013 09:17:00 -0000 Message-Id: <1362734168-1725-9-git-send-email-markus.t.metzger@intel.com> In-Reply-To: <1362734168-1725-1-git-send-email-markus.t.metzger@intel.com> References: <1362734168-1725-1-git-send-email-markus.t.metzger@intel.com> X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2013-03/txt/msg00334.txt.bz2 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. I added a kernel check before checking cpuid requested by Mark Kettenis. I added the cpuid vendor check requested by HJ. Approved by Jan Kratochvil. Approved by Mark Kettenis. 2013-03-08 Markus Metzger * common/linux-btrace.c: Include sys/ptrace, sys/types, sys/wait.h, and signal.h. (linux_supports_btrace): Add kernel and cpuid check. (kernel_supports_btrace): New function. (cpu_supports_btrace): New function. (intel_supports_btrace): New function. --- gdb/common/linux-btrace.c | 187 ++++++++++++++++++++++++++++++++++++++++++++- 1 files changed, 186 insertions(+), 1 deletions(-) diff --git a/gdb/common/linux-btrace.c b/gdb/common/linux-btrace.c index 2f8c1cf..ed0cb24 100644 --- a/gdb/common/linux-btrace.c +++ b/gdb/common/linux-btrace.c @@ -40,6 +40,10 @@ #include #include #include +#include +#include +#include +#include /* A branch trace record in perf_event. */ struct perf_event_bts @@ -247,12 +251,193 @@ perf_event_read_bts (struct btrace_target_info* tinfo, const uint8_t *begin, return btrace; } +/* Check whether the kernel supports branch tracing. */ + +static int +kernel_supports_btrace (void) +{ + struct perf_event_attr attr; + pid_t child, pid; + int status, file; + + errno = 0; + child = fork (); + switch (child) + { + case -1: + warning (_("test branch tracing: cannot fork: %s."), strerror (errno)); + return 0; + + case 0: + status = ptrace (PTRACE_TRACEME, 0, NULL, NULL); + if (status != 0) + { + warning (_("test branch tracing: cannot PTRACE_TRACEME: %s."), + strerror (errno)); + _exit (1); + } + + status = raise (SIGTRAP); + if (status != 0) + { + warning (_("test branch tracing: cannot raise SIGTRAP: %s."), + strerror (errno)); + _exit (1); + } + + _exit (1); + + default: + pid = waitpid (child, &status, 0); + if (pid != child) + { + warning (_("test branch tracing: bad pid %ld, error: %s."), + (long) pid, strerror (errno)); + return 0; + } + + if (!WIFSTOPPED (status)) + { + warning (_("test branch tracing: expected stop. status: %d."), + status); + return 0; + } + + memset (&attr, 0, sizeof (attr)); + + attr.type = PERF_TYPE_HARDWARE; + attr.config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS; + attr.sample_period = 1; + attr.sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_ADDR; + attr.exclude_kernel = 1; + attr.exclude_hv = 1; + attr.exclude_idle = 1; + + file = syscall (SYS_perf_event_open, &attr, child, -1, -1, 0); + if (file >= 0) + close (file); + + kill (child, SIGKILL); + ptrace (PTRACE_KILL, child, NULL, NULL); + + pid = waitpid (child, &status, 0); + if (pid != child) + { + warning (_("test branch tracing: bad pid %ld, error: %s."), + (long) pid, strerror (errno)); + if (!WIFSIGNALED (status)) + warning (_("test branch tracing: expected killed. status: %d."), + status); + } + + return (file >= 0); + } +} + +/* Check whether an Intel cpu supports branch tracing. */ + +static int +intel_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 0x6: + model += (cpuid >> 12) & 0xf0; + + switch (model) + { + case 0x1a: /* Nehalem */ + case 0x1f: + case 0x1e: + case 0x2e: + case 0x25: /* Westmere */ + case 0x2c: + case 0x2f: + case 0x2a: /* Sandy Bridge */ + case 0x2d: + case 0x3a: /* 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__ */ +} + +/* Check whether the cpu supports branch tracing. */ + +static int +cpu_supports_btrace (void) +{ +#if defined __i386__ || defined __x86_64__ + char vendor[13]; + + __asm__ __volatile__ ("xorl %%ebx, %%ebx;" + "xorl %%ecx, %%ecx;" + "xorl %%edx, %%edx;" + "movl $0, %%eax;" + "cpuid;" + "movl %%ebx, %0;" + "movl %%edx, %1;" + "movl %%ecx, %2;" + : "=m" (vendor[0]), + "=m" (vendor[4]), + "=m" (vendor[8]) + : + : "%eax", "%ebx", "%ecx", "%edx"); + vendor[12] = '\0'; + + if (strcmp (vendor, "GenuineIntel") == 0) + return intel_supports_btrace (); + + /* Don't know about others. Let's assume they do. */ + return 1; + +#else /* !defined __i386__ && !defined __x86_64__ */ + + return 0; + +#endif /* !defined __i386__ && !defined __x86_64__ */ +} + /* See linux-btrace.h. */ int linux_supports_btrace (void) { - return 1; + static int cached; + + if (cached == 0) + { + if (!kernel_supports_btrace ()) + cached = -1; + else if (!cpu_supports_btrace ()) + cached = -1; + else + cached = 1; + } + + return cached > 0; } /* See linux-btrace.h. */ -- 1.7.1