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authorLinus Torvalds <torvalds@linux-foundation.org>2010-08-19 09:06:49 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-08-19 09:06:49 -0700
commitb3ea36b7a242773d7a05cec6c071a47b6581c178 (patch)
tree53edfe621b34f30b6f5212f4479d21e2c68dc743 /arch
parent763008c4357b73c8d18396dfd8d79dc58fa3f99d (diff)
parent737480a0d525dae13306296da08029dff545bc72 (diff)
downloadlinux-linaro-android-b3ea36b7a242773d7a05cec6c071a47b6581c178.tar.gz
Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: kprobes/x86: Fix the return address of multiple kretprobes perf tools: Fix build error on read only source. perf, x86: Fix Intel-nhm PMU programming errata workaround
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/cpu/perf_event_intel.c81
-rw-r--r--arch/x86/kernel/kprobes.c25
2 files changed, 85 insertions, 21 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index 214ac860ebe..d8d86d01400 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -491,33 +491,78 @@ static void intel_pmu_enable_all(int added)
* Intel Errata AAP53 (model 30)
* Intel Errata BD53 (model 44)
*
- * These chips need to be 'reset' when adding counters by programming
- * the magic three (non counting) events 0x4300D2, 0x4300B1 and 0x4300B5
- * either in sequence on the same PMC or on different PMCs.
+ * The official story:
+ * These chips need to be 'reset' when adding counters by programming the
+ * magic three (non-counting) events 0x4300B5, 0x4300D2, and 0x4300B1 either
+ * in sequence on the same PMC or on different PMCs.
+ *
+ * In practise it appears some of these events do in fact count, and
+ * we need to programm all 4 events.
*/
-static void intel_pmu_nhm_enable_all(int added)
+static void intel_pmu_nhm_workaround(void)
{
- if (added) {
- struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
- int i;
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ static const unsigned long nhm_magic[4] = {
+ 0x4300B5,
+ 0x4300D2,
+ 0x4300B1,
+ 0x4300B1
+ };
+ struct perf_event *event;
+ int i;
+
+ /*
+ * The Errata requires below steps:
+ * 1) Clear MSR_IA32_PEBS_ENABLE and MSR_CORE_PERF_GLOBAL_CTRL;
+ * 2) Configure 4 PERFEVTSELx with the magic events and clear
+ * the corresponding PMCx;
+ * 3) set bit0~bit3 of MSR_CORE_PERF_GLOBAL_CTRL;
+ * 4) Clear MSR_CORE_PERF_GLOBAL_CTRL;
+ * 5) Clear 4 pairs of ERFEVTSELx and PMCx;
+ */
+
+ /*
+ * The real steps we choose are a little different from above.
+ * A) To reduce MSR operations, we don't run step 1) as they
+ * are already cleared before this function is called;
+ * B) Call x86_perf_event_update to save PMCx before configuring
+ * PERFEVTSELx with magic number;
+ * C) With step 5), we do clear only when the PERFEVTSELx is
+ * not used currently.
+ * D) Call x86_perf_event_set_period to restore PMCx;
+ */
- wrmsrl(MSR_ARCH_PERFMON_EVENTSEL0 + 0, 0x4300D2);
- wrmsrl(MSR_ARCH_PERFMON_EVENTSEL0 + 1, 0x4300B1);
- wrmsrl(MSR_ARCH_PERFMON_EVENTSEL0 + 2, 0x4300B5);
+ /* We always operate 4 pairs of PERF Counters */
+ for (i = 0; i < 4; i++) {
+ event = cpuc->events[i];
+ if (event)
+ x86_perf_event_update(event);
+ }
- wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0x3);
- wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0x0);
+ for (i = 0; i < 4; i++) {
+ wrmsrl(MSR_ARCH_PERFMON_EVENTSEL0 + i, nhm_magic[i]);
+ wrmsrl(MSR_ARCH_PERFMON_PERFCTR0 + i, 0x0);
+ }
- for (i = 0; i < 3; i++) {
- struct perf_event *event = cpuc->events[i];
+ wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0xf);
+ wrmsrl(MSR_CORE_PERF_GLOBAL_CTRL, 0x0);
- if (!event)
- continue;
+ for (i = 0; i < 4; i++) {
+ event = cpuc->events[i];
+ if (event) {
+ x86_perf_event_set_period(event);
__x86_pmu_enable_event(&event->hw,
- ARCH_PERFMON_EVENTSEL_ENABLE);
- }
+ ARCH_PERFMON_EVENTSEL_ENABLE);
+ } else
+ wrmsrl(MSR_ARCH_PERFMON_EVENTSEL0 + i, 0x0);
}
+}
+
+static void intel_pmu_nhm_enable_all(int added)
+{
+ if (added)
+ intel_pmu_nhm_workaround();
intel_pmu_enable_all(added);
}
diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index 1bfb6cf4dd5..770ebfb349e 100644
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -709,6 +709,7 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
struct hlist_node *node, *tmp;
unsigned long flags, orig_ret_address = 0;
unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
+ kprobe_opcode_t *correct_ret_addr = NULL;
INIT_HLIST_HEAD(&empty_rp);
kretprobe_hash_lock(current, &head, &flags);
@@ -740,14 +741,34 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
/* another task is sharing our hash bucket */
continue;
+ orig_ret_address = (unsigned long)ri->ret_addr;
+
+ if (orig_ret_address != trampoline_address)
+ /*
+ * This is the real return address. Any other
+ * instances associated with this task are for
+ * other calls deeper on the call stack
+ */
+ break;
+ }
+
+ kretprobe_assert(ri, orig_ret_address, trampoline_address);
+
+ correct_ret_addr = ri->ret_addr;
+ hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
+ if (ri->task != current)
+ /* another task is sharing our hash bucket */
+ continue;
+
+ orig_ret_address = (unsigned long)ri->ret_addr;
if (ri->rp && ri->rp->handler) {
__get_cpu_var(current_kprobe) = &ri->rp->kp;
get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE;
+ ri->ret_addr = correct_ret_addr;
ri->rp->handler(ri, regs);
__get_cpu_var(current_kprobe) = NULL;
}
- orig_ret_address = (unsigned long)ri->ret_addr;
recycle_rp_inst(ri, &empty_rp);
if (orig_ret_address != trampoline_address)
@@ -759,8 +780,6 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
break;
}
- kretprobe_assert(ri, orig_ret_address, trampoline_address);
-
kretprobe_hash_unlock(current, &flags);
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {