From 68187872c76a96ed4db7bfb064272591f02e208b Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Thu, 11 Aug 2016 17:45:21 +0200 Subject: uprobes/x86: Fix RIP-relative handling of EVEX-encoded instructions Since instruction decoder now supports EVEX-encoded instructions, two fixes are needed to correctly handle them in uprobes. Extended bits for MODRM.rm field need to be sanitized just like we do it for VEX3, to avoid encoding wrong register for register-relative access. EVEX has _two_ extended bits: b and x. Theoretically, EVEX.x should be ignored by the CPU (since GPRs go only up to 15, not 31), but let's be paranoid here: proper encoding for register-relative access should have EVEX.x = 1. Secondly, we should fetch vex.vvvv for EVEX too. This is now super easy because instruction decoder populates vex_prefix.bytes[2] for all flavors of (e)vex encodings, even for VEX2. Signed-off-by: Denys Vlasenko Acked-by: Masami Hiramatsu Acked-by: Srikar Dronamraju Cc: Alexander Shishkin Cc: Andy Lutomirski Cc: Arnaldo Carvalho de Melo Cc: Borislav Petkov Cc: Brian Gerst Cc: H. Peter Anvin Cc: Jim Keniston Cc: Jiri Olsa Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Masami Hiramatsu Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: linux-kernel@vger.kernel.org Cc: # v4.1+ Fixes: 8a764a875fe3 ("x86/asm/decoder: Create artificial 3rd byte for 2-byte VEX") Link: http://lkml.kernel.org/r/20160811154521.20469-1-dvlasenk@redhat.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/uprobes.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) (limited to 'arch') diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 6c1ff31d99ff..495c776de4b4 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -357,20 +357,22 @@ static void riprel_analyze(struct arch_uprobe *auprobe, struct insn *insn) *cursor &= 0xfe; } /* - * Similar treatment for VEX3 prefix. - * TODO: add XOP/EVEX treatment when insn decoder supports them + * Similar treatment for VEX3/EVEX prefix. + * TODO: add XOP treatment when insn decoder supports them */ - if (insn->vex_prefix.nbytes == 3) { + if (insn->vex_prefix.nbytes >= 3) { /* * vex2: c5 rvvvvLpp (has no b bit) * vex3/xop: c4/8f rxbmmmmm wvvvvLpp * evex: 62 rxbR00mm wvvvv1pp zllBVaaa - * (evex will need setting of both b and x since - * in non-sib encoding evex.x is 4th bit of MODRM.rm) - * Setting VEX3.b (setting because it has inverted meaning): + * Setting VEX3.b (setting because it has inverted meaning). + * Setting EVEX.x since (in non-SIB encoding) EVEX.x + * is the 4th bit of MODRM.rm, and needs the same treatment. + * For VEX3-encoded insns, VEX3.x value has no effect in + * non-SIB encoding, the change is superfluous but harmless. */ cursor = auprobe->insn + insn_offset_vex_prefix(insn) + 1; - *cursor |= 0x20; + *cursor |= 0x60; } /* @@ -415,12 +417,10 @@ static void riprel_analyze(struct arch_uprobe *auprobe, struct insn *insn) reg = MODRM_REG(insn); /* Fetch modrm.reg */ reg2 = 0xff; /* Fetch vex.vvvv */ - if (insn->vex_prefix.nbytes == 2) - reg2 = insn->vex_prefix.bytes[1]; - else if (insn->vex_prefix.nbytes == 3) + if (insn->vex_prefix.nbytes) reg2 = insn->vex_prefix.bytes[2]; /* - * TODO: add XOP, EXEV vvvv reading. + * TODO: add XOP vvvv reading. * * vex.vvvv field is in bits 6-3, bits are inverted. * But in 32-bit mode, high-order bit may be ignored. -- cgit v1.2.3 From 10e9e7bd598f9a66a11a22514c68c13c41fc821b Mon Sep 17 00:00:00 2001 From: Kan Liang Date: Thu, 11 Aug 2016 07:30:20 -0700 Subject: perf/x86/intel/uncore: Fix uncore num_counters Some uncore boxes' num_counters value for Haswell server and Broadwell server are not correct (too large, off by one). This issue was found by comparing the code with the document. Although there is no bug report from users yet, accessing non-existent counters is dangerous and the behavior is undefined: it may cause miscounting or even crashes. This patch makes them consistent with the uncore document. Reported-by: Lukasz Odzioba Signed-off-by: Kan Liang Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: Link: http://lkml.kernel.org/r/1470925820-59847-1-git-send-email-kan.liang@intel.com Signed-off-by: Ingo Molnar --- arch/x86/events/intel/uncore_snbep.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'arch') diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c index 824e54086e07..8aee83bcf71f 100644 --- a/arch/x86/events/intel/uncore_snbep.c +++ b/arch/x86/events/intel/uncore_snbep.c @@ -2626,7 +2626,7 @@ void hswep_uncore_cpu_init(void) static struct intel_uncore_type hswep_uncore_ha = { .name = "ha", - .num_counters = 5, + .num_counters = 4, .num_boxes = 2, .perf_ctr_bits = 48, SNBEP_UNCORE_PCI_COMMON_INIT(), @@ -2645,7 +2645,7 @@ static struct uncore_event_desc hswep_uncore_imc_events[] = { static struct intel_uncore_type hswep_uncore_imc = { .name = "imc", - .num_counters = 5, + .num_counters = 4, .num_boxes = 8, .perf_ctr_bits = 48, .fixed_ctr_bits = 48, @@ -2691,7 +2691,7 @@ static struct intel_uncore_type hswep_uncore_irp = { static struct intel_uncore_type hswep_uncore_qpi = { .name = "qpi", - .num_counters = 5, + .num_counters = 4, .num_boxes = 3, .perf_ctr_bits = 48, .perf_ctr = SNBEP_PCI_PMON_CTR0, @@ -2773,7 +2773,7 @@ static struct event_constraint hswep_uncore_r3qpi_constraints[] = { static struct intel_uncore_type hswep_uncore_r3qpi = { .name = "r3qpi", - .num_counters = 4, + .num_counters = 3, .num_boxes = 3, .perf_ctr_bits = 44, .constraints = hswep_uncore_r3qpi_constraints, @@ -2972,7 +2972,7 @@ static struct intel_uncore_type bdx_uncore_ha = { static struct intel_uncore_type bdx_uncore_imc = { .name = "imc", - .num_counters = 5, + .num_counters = 4, .num_boxes = 8, .perf_ctr_bits = 48, .fixed_ctr_bits = 48, -- cgit v1.2.3 From 95f3be798472f63b495ca4712af005ea5ac7aa47 Mon Sep 17 00:00:00 2001 From: Kan Liang Date: Thu, 11 Aug 2016 07:31:14 -0700 Subject: perf/x86/intel/uncore: Add enable_box for client MSR uncore There are bug reports about miscounting uncore counters on some client machines like Sandybridge, Broadwell and Skylake. It is very likely to be observed on idle systems. This issue is caused by a hardware issue. PERF_GLOBAL_CTL could be cleared after Package C7, and nothing will be count. The related errata (HSD 158) could be found in: www.intel.com/content/dam/www/public/us/en/documents/specification-updates/4th-gen-core-family-desktop-specification-update.pdf This patch tries to work around this issue by re-enabling PERF_GLOBAL_CTL in ->enable_box(). The workaround does not cover all cases. It helps for new events after returning from C7. But it cannot prevent C7, it will still miscount if a counter is already active. There is no drawback in leaving it enabled, so it does not need disable_box() here. Signed-off-by: Kan Liang Cc: Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Link: http://lkml.kernel.org/r/1470925874-59943-1-git-send-email-kan.liang@intel.com Signed-off-by: Ingo Molnar --- arch/x86/events/intel/uncore_snb.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'arch') diff --git a/arch/x86/events/intel/uncore_snb.c b/arch/x86/events/intel/uncore_snb.c index 97a69dbba649..9d35ec0cb8fc 100644 --- a/arch/x86/events/intel/uncore_snb.c +++ b/arch/x86/events/intel/uncore_snb.c @@ -100,6 +100,12 @@ static void snb_uncore_msr_init_box(struct intel_uncore_box *box) } } +static void snb_uncore_msr_enable_box(struct intel_uncore_box *box) +{ + wrmsrl(SNB_UNC_PERF_GLOBAL_CTL, + SNB_UNC_GLOBAL_CTL_EN | SNB_UNC_GLOBAL_CTL_CORE_ALL); +} + static void snb_uncore_msr_exit_box(struct intel_uncore_box *box) { if (box->pmu->pmu_idx == 0) @@ -127,6 +133,7 @@ static struct attribute_group snb_uncore_format_group = { static struct intel_uncore_ops snb_uncore_msr_ops = { .init_box = snb_uncore_msr_init_box, + .enable_box = snb_uncore_msr_enable_box, .exit_box = snb_uncore_msr_exit_box, .disable_event = snb_uncore_msr_disable_event, .enable_event = snb_uncore_msr_enable_event, @@ -192,6 +199,12 @@ static void skl_uncore_msr_init_box(struct intel_uncore_box *box) } } +static void skl_uncore_msr_enable_box(struct intel_uncore_box *box) +{ + wrmsrl(SKL_UNC_PERF_GLOBAL_CTL, + SNB_UNC_GLOBAL_CTL_EN | SKL_UNC_GLOBAL_CTL_CORE_ALL); +} + static void skl_uncore_msr_exit_box(struct intel_uncore_box *box) { if (box->pmu->pmu_idx == 0) @@ -200,6 +213,7 @@ static void skl_uncore_msr_exit_box(struct intel_uncore_box *box) static struct intel_uncore_ops skl_uncore_msr_ops = { .init_box = skl_uncore_msr_init_box, + .enable_box = skl_uncore_msr_enable_box, .exit_box = skl_uncore_msr_exit_box, .disable_event = snb_uncore_msr_disable_event, .enable_event = snb_uncore_msr_enable_event, -- cgit v1.2.3