[tip:perf/core] perf/x86/intel/pt: Add support for address range filtering in PT

tip-bot for Alexander Shishkin
2016-05-05T09:48:27Z

Commit-ID: eadf48cab4b6b0ab8bcd53feb7d52a71e72debd0
Gitweb: http://git.kernel.org/tip/eadf48cab4b6b0ab8bcd53feb7d52a71e72debd0
Author: Alexander Shishkin <alexander.shishkin@linux.intel.com>
AuthorDate: Wed, 27 Apr 2016 18:44:47 +0300
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 5 May 2016 10:13:58 +0200

perf/x86/intel/pt: Add support for address range filtering in PT

Newer versions of Intel PT support address ranges, which can be used to
define IP address range-based filters or TraceSTOP regions. Number of
ranges in enumerated via cpuid.

This patch implements PMU callbacks and related low-level code to allow
filter validation, configuration and programming into the hardware.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: vince@deater.net
Link: http://lkml.kernel.org/r/1461771888-10409-7-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/events/intel/pt.c | 179 ++++++++++++++++++++++++++++++++++++++++++---
arch/x86/events/intel/pt.h | 26 +++++++
2 files changed, 194 insertions(+), 11 deletions(-)

diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c
index e5bfafe..2d1ce2c 100644
--- a/arch/x86/events/intel/pt.c
+++ b/arch/x86/events/intel/pt.c
@@ -265,6 +265,75 @@ static bool pt_event_valid(struct perf_event *event)
* These all are cpu affine and operate on a local PT
*/

+/* Address ranges and their corresponding msr configuration registers */
+static const struct pt_address_range {
+ unsigned long msr_a;
+ unsigned long msr_b;
+ unsigned int reg_off;
+} pt_address_ranges[] = {
+ {
+ .msr_a = MSR_IA32_RTIT_ADDR0_A,
+ .msr_b = MSR_IA32_RTIT_ADDR0_B,
+ .reg_off = RTIT_CTL_ADDR0_OFFSET,
+ },
+ {
+ .msr_a = MSR_IA32_RTIT_ADDR1_A,
+ .msr_b = MSR_IA32_RTIT_ADDR1_B,
+ .reg_off = RTIT_CTL_ADDR1_OFFSET,
+ },
+ {
+ .msr_a = MSR_IA32_RTIT_ADDR2_A,
+ .msr_b = MSR_IA32_RTIT_ADDR2_B,
+ .reg_off = RTIT_CTL_ADDR2_OFFSET,
+ },
+ {
+ .msr_a = MSR_IA32_RTIT_ADDR3_A,
+ .msr_b = MSR_IA32_RTIT_ADDR3_B,
+ .reg_off = RTIT_CTL_ADDR3_OFFSET,
+ }
+};
+
+static u64 pt_config_filters(struct perf_event *event)
+{
+ struct pt_filters *filters = event->hw.addr_filters;
+ struct pt *pt = this_cpu_ptr(&pt_ctx);
+ unsigned int range = 0;
+ u64 rtit_ctl = 0;
+
+ if (!filters)
+ return 0;
+
+ perf_event_addr_filters_sync(event);
+
+ for (range = 0; range < filters->nr_filters; range++) {
+ struct pt_filter *filter = &filters->filter[range];
+
+ /*
+ * Note, if the range has zero start/end addresses due
+ * to its dynamic object not being loaded yet, we just
+ * go ahead and program zeroed range, which will simply
+ * produce no data. Note^2: if executable code at 0x0
+ * is a concern, we can set up an "invalid" configuration
+ * such as msr_b < msr_a.
+ */
+
+ /* avoid redundant msr writes */
+ if (pt->filters.filter[range].msr_a != filter->msr_a) {
+ wrmsrl(pt_address_ranges[range].msr_a, filter->msr_a);
+ pt->filters.filter[range].msr_a = filter->msr_a;
+ }
+
+ if (pt->filters.filter[range].msr_b != filter->msr_b) {
+ wrmsrl(pt_address_ranges[range].msr_b, filter->msr_b);
+ pt->filters.filter[range].msr_b = filter->msr_b;
+ }
+
+ rtit_ctl |= filter->config << pt_address_ranges[range].reg_off;
+ }
+
+ return rtit_ctl;
+}
+
static void pt_config(struct perf_event *event)
{
u64 reg;
@@ -274,7 +343,8 @@ static void pt_config(struct perf_event *event)
wrmsrl(MSR_IA32_RTIT_STATUS, 0);
}

- reg = RTIT_CTL_TOPA | RTIT_CTL_BRANCH_EN | RTIT_CTL_TRACEEN;
+ reg = pt_config_filters(event);
+ reg |= RTIT_CTL_TOPA | RTIT_CTL_BRANCH_EN | RTIT_CTL_TRACEEN;

if (!event->attr.exclude_kernel)
reg |= RTIT_CTL_OS;
@@ -921,6 +991,82 @@ static void pt_buffer_free_aux(void *data)
kfree(buf);
}

+static int pt_addr_filters_init(struct perf_event *event)
+{
+ struct pt_filters *filters;
+ int node = event->cpu == -1 ? -1 : cpu_to_node(event->cpu);
+
+ if (!pt_cap_get(PT_CAP_num_address_ranges))
+ return 0;
+
+ filters = kzalloc_node(sizeof(struct pt_filters), GFP_KERNEL, node);
+ if (!filters)
+ return -ENOMEM;
+
+ if (event->parent)
+ memcpy(filters, event->parent->hw.addr_filters,
+ sizeof(*filters));
+
+ event->hw.addr_filters = filters;
+
+ return 0;
+}
+
+static void pt_addr_filters_fini(struct perf_event *event)
+{
+ kfree(event->hw.addr_filters);
+ event->hw.addr_filters = NULL;
+}
+
+static int pt_event_addr_filters_validate(struct list_head *filters)
+{
+ struct perf_addr_filter *filter;
+ int range = 0;
+
+ list_for_each_entry(filter, filters, entry) {
+ /* PT doesn't support single address triggers */
+ if (!filter->range)
+ return -EOPNOTSUPP;
+
+ if (!filter->inode && !kernel_ip(filter->offset))
+ return -EINVAL;
+
+ if (++range > pt_cap_get(PT_CAP_num_address_ranges))
+ return -EOPNOTSUPP;
+ }
+
+ return 0;
+}
+
+static void pt_event_addr_filters_sync(struct perf_event *event)
+{
+ struct perf_addr_filters_head *head = perf_event_addr_filters(event);
+ unsigned long msr_a, msr_b, *offs = event->addr_filters_offs;
+ struct pt_filters *filters = event->hw.addr_filters;
+ struct perf_addr_filter *filter;
+ int range = 0;
+
+ if (!filters)
+ return;
+
+ list_for_each_entry(filter, &head->list, entry) {
+ if (filter->inode && !offs[range]) {
+ msr_a = msr_b = 0;
+ } else {
+ /* apply the offset */
+ msr_a = filter->offset + offs[range];
+ msr_b = filter->size + msr_a;
+ }
+
+ filters->filter[range].msr_a = msr_a;
+ filters->filter[range].msr_b = msr_b;
+ filters->filter[range].config = filter->filter ? 1 : 2;
+ range++;
+ }
+
+ filters->nr_filters = range;
+}
+
/**
* intel_pt_interrupt() - PT PMI handler
*/
@@ -1128,6 +1274,7 @@ static void pt_event_read(struct perf_event *event)

static void pt_event_destroy(struct perf_event *event)
{
+ pt_addr_filters_fini(event);
x86_del_exclusive(x86_lbr_exclusive_pt);
}

@@ -1142,6 +1289,11 @@ static int pt_event_init(struct perf_event *event)
if (x86_add_exclusive(x86_lbr_exclusive_pt))
return -EBUSY;

+ if (pt_addr_filters_init(event)) {
+ x86_del_exclusive(x86_lbr_exclusive_pt);
+ return -ENOMEM;
+ }
+
event->destroy = pt_event_destroy;

return 0;
@@ -1195,16 +1347,21 @@ static __init int pt_init(void)
PERF_PMU_CAP_AUX_NO_SG | PERF_PMU_CAP_AUX_SW_DOUBLEBUF;

pt_pmu.pmu.capabilities |= PERF_PMU_CAP_EXCLUSIVE | PERF_PMU_CAP_ITRACE;
- pt_pmu.pmu.attr_groups = pt_attr_groups;
- pt_pmu.pmu.task_ctx_nr = perf_sw_context;
- pt_pmu.pmu.event_init = pt_event_init;
- pt_pmu.pmu.add = pt_event_add;
- pt_pmu.pmu.del = pt_event_del;
- pt_pmu.pmu.start = pt_event_start;
- pt_pmu.pmu.stop = pt_event_stop;
- pt_pmu.pmu.read = pt_event_read;
- pt_pmu.pmu.setup_aux = pt_buffer_setup_aux;
- pt_pmu.pmu.free_aux = pt_buffer_free_aux;
+ pt_pmu.pmu.attr_groups = pt_attr_groups;
+ pt_pmu.pmu.task_ctx_nr = perf_sw_context;
+ pt_pmu.pmu.event_init = pt_event_init;
+ pt_pmu.pmu.add = pt_event_add;
+ pt_pmu.pmu.del = pt_event_del;
+ pt_pmu.pmu.start = pt_event_start;
+ pt_pmu.pmu.stop = pt_event_stop;
+ pt_pmu.pmu.read = pt_event_read;
+ pt_pmu.pmu.setup_aux = pt_buffer_setup_aux;
+ pt_pmu.pmu.free_aux = pt_buffer_free_aux;
+ pt_pmu.pmu.addr_filters_sync = pt_event_addr_filters_sync;
+ pt_pmu.pmu.addr_filters_validate = pt_event_addr_filters_validate;
+ pt_pmu.pmu.nr_addr_filters =
+ pt_cap_get(PT_CAP_num_address_ranges);
+
ret = perf_pmu_register(&pt_pmu.pmu, "intel_pt", -1);

return ret;
diff --git a/arch/x86/events/intel/pt.h b/arch/x86/events/intel/pt.h
index 0ed9000..ca64599 100644
--- a/arch/x86/events/intel/pt.h
+++ b/arch/x86/events/intel/pt.h
@@ -140,14 +140,40 @@ struct pt_buffer {
struct topa_entry *topa_index[0];
};

+#define PT_FILTERS_NUM 4
+
+/**
+ * struct pt_filter - IP range filter configuration
+ * @msr_a: range start, goes to RTIT_ADDRn_A
+ * @msr_b: range end, goes to RTIT_ADDRn_B
+ * @config: 4-bit field in RTIT_CTL
+ */
+struct pt_filter {
+ unsigned long msr_a;
+ unsigned long msr_b;
+ unsigned long config;
+};
+
+/**
+ * struct pt_filters - IP range filtering context
+ * @filter: filters defined for this context
+ * @nr_filters: number of defined filters in the @filter array
+ */
+struct pt_filters {
+ struct pt_filter filter[PT_FILTERS_NUM];
+ unsigned int nr_filters;
+};
+
/**
* struct pt - per-cpu pt context
* @handle: perf output handle
+ * @filters: last configured filters
* @handle_nmi: do handle PT PMI on this cpu, there's an active event
* @vmx_on: 1 if VMX is ON on this cpu
*/
struct pt {
struct perf_output_handle handle;
+ struct pt_filters filters;
int handle_nmi;
int vmx_on;
};