Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758030AbZCMJpb (ORCPT ); Fri, 13 Mar 2009 05:45:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753866AbZCMJpT (ORCPT ); Fri, 13 Mar 2009 05:45:19 -0400 Received: from mga02.intel.com ([134.134.136.20]:3303 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753590AbZCMJpS (ORCPT ); Fri, 13 Mar 2009 05:45:18 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.38,356,1233561600"; d="scan'208";a="394217611" Date: Fri, 13 Mar 2009 10:45:07 +0100 From: Markus Metzger To: linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de, hpa@zytor.com Cc: markus.t.metzger@intel.com, markus.t.metzger@gmail.com, roland@redhat.com, eranian@googlemail.com, oleg@redhat.com, juan.villacis@intel.com, ak@linux.jf.intel.com Subject: [patch 2/5] x86, bts: add selftest for BTS Message-ID: <20090313104507.A30125@sedona.ch.intel.com> Mime-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.2.5i Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9736 Lines: 365 Perform a selftest of branch trace store when a cpu is initialized. WARN and disable branch trace store support if the selftest fails. Signed-off-by: Markus Metzger --- Index: gits/arch/x86/kernel/ds.c =================================================================== --- gits.orig/arch/x86/kernel/ds.c 2009-03-09 12:43:29.000000000 +0100 +++ gits/arch/x86/kernel/ds.c 2009-03-09 12:43:30.000000000 +0100 @@ -29,6 +29,7 @@ #include #include +#include "ds_selftest.h" /* * The configuration for a particular DS hardware implementation. @@ -940,6 +941,26 @@ ds_configure(const struct ds_configurati printk(KERN_INFO "[ds] pebs not available\n"); } + if (ds_cfg.sizeof_rec[ds_bts]) { + int error; + + error = ds_selftest_bts(); + if (error) { + WARN(1, "[ds] selftest failed. disabling bts.\n"); + ds_cfg.sizeof_rec[ds_bts] = 0; + } + } + + if (ds_cfg.sizeof_rec[ds_pebs]) { + int error; + + error = ds_selftest_pebs(); + if (error) { + WARN(1, "[ds] selftest failed. disabling pebs.\n"); + ds_cfg.sizeof_rec[ds_pebs] = 0; + } + } + printk(KERN_INFO "[ds] sizes: address: %u bit, ", 8 * ds_cfg.sizeof_ptr_field); printk("bts/pebs record: %u/%u bytes\n", Index: gits/arch/x86/Kconfig.debug =================================================================== --- gits.orig/arch/x86/Kconfig.debug 2009-03-09 12:43:25.000000000 +0100 +++ gits/arch/x86/Kconfig.debug 2009-03-09 12:43:30.000000000 +0100 @@ -176,6 +176,15 @@ config IOMMU_LEAK Add a simple leak tracer to the IOMMU code. This is useful when you are debugging a buggy device driver that leaks IOMMU mappings. +config X86_DS_SELFTEST + bool "DS selftest" + default y + depends on DEBUG_KERNEL + depends on X86_DS + ---help--- + Perform Debug Store selftests at boot time. + If in doubt, say "N". + config HAVE_MMIOTRACE_SUPPORT def_bool y Index: gits/arch/x86/kernel/ds_selftest.c =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ gits/arch/x86/kernel/ds_selftest.c 2009-03-09 12:43:30.000000000 +0100 @@ -0,0 +1,241 @@ +/* + * Debug Store support - selftest + * + * + * Copyright (C) 2009 Intel Corporation. + * Markus Metzger , 2009 + */ + +#include "ds_selftest.h" + +#include +#include + +#include + + +#define DS_SELFTEST_BUFFER_SIZE 1021 /* Intentionally chose an odd size. */ + + +static int ds_selftest_bts_consistency(const struct bts_trace *trace) +{ + int error = 0; + + if (!trace) { + printk(KERN_CONT "failed to access trace..."); + /* Bail out. Other tests are pointless. */ + return -1; + } + + if (!trace->read) { + printk(KERN_CONT "bts read not available..."); + error = -1; + } + + /* Do some sanity checks on the trace configuration. */ + if (!trace->ds.n) { + printk(KERN_CONT "empty bts buffer..."); + error = -1; + } + if (!trace->ds.size) { + printk(KERN_CONT "bad bts trace setup..."); + error = -1; + } + if (trace->ds.end != + (char *)trace->ds.begin + (trace->ds.n * trace->ds.size)) { + printk(KERN_CONT "bad bts buffer setup..."); + error = -1; + } + if ((trace->ds.top < trace->ds.begin) || + (trace->ds.end <= trace->ds.top)) { + printk(KERN_CONT "bts top out of bounds..."); + error = -1; + } + + return error; +} + +static int ds_selftest_bts_read(struct bts_tracer *tracer, + const struct bts_trace *trace, + const void *from, const void *to) +{ + const unsigned char *at; + + /* + * Check a few things which do not belong to this test. + * They should be covered by other tests. + */ + if (!trace) + return -1; + + if (!trace->read) + return -1; + + if (to < from) + return -1; + + if (from < trace->ds.begin) + return -1; + + if (trace->ds.end < to) + return -1; + + if (!trace->ds.size) + return -1; + + /* Now to the test itself. */ + for (at = from; (void *)at < to; at += trace->ds.size) { + struct bts_struct bts; + size_t index; + int error; + + if (((void *)at - trace->ds.begin) % trace->ds.size) { + printk(KERN_CONT + "read from non-integer index..."); + return -1; + } + index = ((void *)at - trace->ds.begin) / trace->ds.size; + + memset(&bts, 0, sizeof(bts)); + error = trace->read(tracer, at, &bts); + if (error < 0) { + printk(KERN_CONT + "error reading bts trace at [%lu] (0x%p)...", + index, at); + return error; + } + + switch (bts.qualifier) { + case BTS_BRANCH: + break; + default: + printk(KERN_CONT + "unexpected bts entry %llu at [%lu] (0x%p)...", + bts.qualifier, index, at); + return -1; + } + } + + return 0; +} + +int ds_selftest_bts(void) +{ + const struct bts_trace *trace; + struct bts_tracer *tracer; + int error = 0; + void *top; + unsigned char buffer[DS_SELFTEST_BUFFER_SIZE]; + + printk(KERN_INFO "[ds] bts selftest..."); + + tracer = ds_request_bts(NULL, buffer, DS_SELFTEST_BUFFER_SIZE, + NULL, (size_t)-1, BTS_KERNEL); + if (IS_ERR(tracer)) { + error = PTR_ERR(tracer); + tracer = NULL; + + printk(KERN_CONT + "initialization failed (err: %d)...", error); + goto out; + } + + /* The return should already give us enough trace. */ + ds_suspend_bts(tracer); + + /* Let's see if we can access the trace. */ + trace = ds_read_bts(tracer); + + error = ds_selftest_bts_consistency(trace); + if (error < 0) + goto out; + + /* If everything went well, we should have a few trace entries. */ + if (trace->ds.top == trace->ds.begin) { + /* + * It is possible but highly unlikely that we got a + * buffer overflow and end up at exactly the same + * position we started from. + * Let's issue a warning, but continue. + */ + printk(KERN_CONT "no trace/overflow..."); + } + + /* Let's try to read the trace we collected. */ + error = ds_selftest_bts_read(tracer, trace, + trace->ds.begin, trace->ds.top); + if (error < 0) + goto out; + + /* + * Let's read the trace again. + * Since we suspended tracing, we should get the same result. + */ + top = trace->ds.top; + + trace = ds_read_bts(tracer); + error = ds_selftest_bts_consistency(trace); + if (error < 0) + goto out; + + if (top != trace->ds.top) { + printk(KERN_CONT "suspend not working..."); + error = -1; + goto out; + } + + /* Let's collect some more trace - see if resume is working. */ + ds_resume_bts(tracer); + ds_suspend_bts(tracer); + + trace = ds_read_bts(tracer); + + error = ds_selftest_bts_consistency(trace); + if (error < 0) + goto out; + + if (trace->ds.top == top) { + /* + * It is possible but highly unlikely that we got a + * buffer overflow and end up at exactly the same + * position we started from. + * Let's issue a warning and check the full trace. + */ + printk(KERN_CONT + "no resume progress/overflow..."); + + error = ds_selftest_bts_read(tracer, trace, + trace->ds.begin, trace->ds.end); + } else if (trace->ds.top < top) { + /* + * We had a buffer overflow - the entire buffer should + * contain trace records. + */ + error = ds_selftest_bts_read(tracer, trace, + trace->ds.begin, trace->ds.end); + } else { + /* + * It is quite likely that the buffer did not overflow. + * Let's just check the delta trace. + */ + error = ds_selftest_bts_read(tracer, trace, + top, trace->ds.top); + } + if (error < 0) + goto out; + + error = 0; + + /* The final test: release the tracer while tracing is suspended. */ + out: + ds_release_bts(tracer); + + printk(KERN_CONT "%s.\n", (error ? "failed" : "passed")); + + return error; +} + +int ds_selftest_pebs(void) +{ + return 0; +} Index: gits/arch/x86/kernel/ds_selftest.h =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ gits/arch/x86/kernel/ds_selftest.h 2009-03-09 12:43:51.000000000 +0100 @@ -0,0 +1,15 @@ +/* + * Debug Store support - selftest + * + * + * Copyright (C) 2009 Intel Corporation. + * Markus Metzger , 2009 + */ + +#ifdef CONFIG_X86_DS_SELFTEST +extern int ds_selftest_bts(void); +extern int ds_selftest_pebs(void); +#else +static inline int ds_selftest_bts(void) { return 0; } +static inline int ds_selftest_pebs(void) { return 0; } +#endif /* CONFIG_X86_DS_SELFTEST */ Index: gits/arch/x86/kernel/Makefile =================================================================== --- gits.orig/arch/x86/kernel/Makefile 2009-03-09 12:43:25.000000000 +0100 +++ gits/arch/x86/kernel/Makefile 2009-03-09 12:43:30.000000000 +0100 @@ -44,6 +44,7 @@ obj-y += process.o obj-y += i387.o xsave.o obj-y += ptrace.o obj-$(CONFIG_X86_DS) += ds.o +obj-$(CONFIG_X86_DS_SELFTEST) += ds_selftest.o obj-$(CONFIG_X86_32) += tls.o obj-$(CONFIG_IA32_EMULATION) += tls.o obj-y += step.o --------------------------------------------------------------------- Intel GmbH Dornacher Strasse 1 85622 Feldkirchen/Muenchen Germany Sitz der Gesellschaft: Feldkirchen bei Muenchen Geschaeftsfuehrer: Douglas Lusk, Peter Gleissner, Hannes Schwaderer Registergericht: Muenchen HRB 47456 Ust.-IdNr. 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