| Message ID | 52DEEDDA.4060302@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Jan 21, 2014 at 09:59:54PM +0000, Stephen Boyd wrote: > On 01/21/14 10:37, Stephen Boyd wrote: > > On 01/21/14 10:07, Will Deacon wrote: > >> Finally, I'd really like to see this get some test coverage, but I don't > >> want to try running mainline on my phone :) Could you give your patches a > >> spin with Vince's perf fuzzer please? > >> > >> https://github.com/deater/perf_event_tests.git > >> > >> (then build the contents of the fuzzer directory and run it for as long as > >> you can). > >> > > Ok. I'll see what I can do. > > Neat. This quickly discovered a problem. Yeah, the fuzzer is good at that! > BUG: using smp_processor_id() in preemptible [00000000] code: perf_fuzzer/70 > caller is krait_pmu_get_event_idx+0x58/0xd8 > CPU: 2 PID: 70 Comm: perf_fuzzer Not tainted 3.13.0-rc7-next-20140108-00041-gb038353c8516-dirty #58 > [<c02165dc>] (unwind_backtrace) from [<c0212ffc>] (show_stack+0x10/0x14) > [<c0212ffc>] (show_stack) from [<c06ad5fc>] (dump_stack+0x6c/0xb8) > [<c06ad5fc>] (dump_stack) from [<c04b0928>] (debug_smp_processor_id+0xc4/0xe8) > [<c04b0928>] (debug_smp_processor_id) from [<c021a19c>] (krait_pmu_get_event_idx+0x58/0xd8) > [<c021a19c>] (krait_pmu_get_event_idx) from [<c021833c>] (validate_event+0x2c/0x54) > [<c021833c>] (validate_event) from [<c02186b4>] (armpmu_event_init+0x264/0x2dc) > [<c02186b4>] (armpmu_event_init) from [<c02b28e4>] (perf_init_event+0x138/0x194) > [<c02b28e4>] (perf_init_event) from [<c02b2c04>] (perf_event_alloc+0x2c4/0x348) > [<c02b2c04>] (perf_event_alloc) from [<c02b37e4>] (SyS_perf_event_open+0x7b8/0x9cc) > [<c02b37e4>] (SyS_perf_event_open) from [<c020ef80>] (ret_fast_syscall+0x0/0x48) > > This is happening because the pmresrn_used mask is per-cpu but > validate_group() is called in preemptible context. It looks like we'll > need to add another unsigned long * field to struct pmu_hw_events just > for Krait purposes? Or we could use the upper 16 bits of the used_mask > bitmap to hold the pmresr_used values? Sounds sort of hacky but it > avoids adding another bitmap for every PMU user and there aren't any > Krait CPUs with more than 5 counters anyway. I'm fine with that approach, but a comment saying what we're doing with those upper bits wouldn't go amiss. > This is the diff for the latter version. I'll let the fuzzer run overnight. Cheers, Will -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/arm/include/asm/pmu.h b/arch/arm/include/asm/pmu.h index 994ac445e792..ae1919be8f98 100644 --- a/arch/arm/include/asm/pmu.h +++ b/arch/arm/include/asm/pmu.h @@ -71,7 +71,8 @@ struct arm_pmu { void (*disable)(struct perf_event *event); int (*get_event_idx)(struct pmu_hw_events *hw_events, struct perf_event *event); - void (*clear_event_idx)(struct perf_event *event); + void (*clear_event_idx)(struct pmu_hw_events *hw_events, + struct perf_event *event); int (*set_event_filter)(struct hw_perf_event *evt, struct perf_event_attr *attr); u32 (*read_counter)(struct perf_event *event); diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c index 70191f68c26d..361a1aaee7c8 100644 --- a/arch/arm/kernel/perf_event.c +++ b/arch/arm/kernel/perf_event.c @@ -208,7 +208,7 @@ armpmu_del(struct perf_event *event, int flags) hw_events->events[idx] = NULL; clear_bit(idx, hw_events->used_mask); if (armpmu->clear_event_idx) - armpmu->clear_event_idx(event); + armpmu->clear_event_idx(hw_events, event); perf_event_update_userpage(event); } diff --git a/arch/arm/kernel/perf_event_v7.c b/arch/arm/kernel/perf_event_v7.c index daa675529c12..1a905395b74c 100644 --- a/arch/arm/kernel/perf_event_v7.c +++ b/arch/arm/kernel/perf_event_v7.c @@ -1483,9 +1483,6 @@ static int armv7_a7_pmu_init(struct arm_pmu *cpu_pmu) #define VENUM_EVENT (2 << 16) #define KRAIT_EVENT_MASK (KRAIT_EVENT | VENUM_EVENT) #define PMRESRn_EN BIT(31) -#define NUM_PMRESR (KRAIT_VPMRESR0_GROUP0 + 4 - KRAIT_PMRESR0_GROUP0) - -static DEFINE_PER_CPU(unsigned long [BITS_TO_LONGS(NUM_PMRESR)], pmresrn_used); static u32 krait_read_pmresrn(int n) { @@ -1542,6 +1539,7 @@ static void krait_pre_vpmresr0(u32 *venum_orig_val, u32 *fp_orig_val) u32 venum_new_val; u32 fp_new_val; + BUG_ON(preemptible()); /* CPACR Enable CP10 and CP11 access */ *venum_orig_val = get_copro_access(); venum_new_val = *venum_orig_val | CPACC_SVC(10) | CPACC_SVC(11); @@ -1555,6 +1553,7 @@ static void krait_pre_vpmresr0(u32 *venum_orig_val, u32 *fp_orig_val) static void krait_post_vpmresr0(u32 venum_orig_val, u32 fp_orig_val) { + BUG_ON(preemptible()); /* Restore FPEXC */ fmxr(FPEXC, fp_orig_val); isb(); @@ -1750,7 +1749,6 @@ static int krait_pmu_get_event_idx(struct pmu_hw_events *cpuc, unsigned int group; bool krait_event; struct hw_perf_event *hwc = &event->hw; - unsigned long *bitmap = this_cpu_ptr(pmresrn_used); region = (hwc->config_base >> 12) & 0xf; code = (hwc->config_base >> 4) & 0xff; @@ -1773,26 +1771,27 @@ static int krait_pmu_get_event_idx(struct pmu_hw_events *cpuc, bit = krait_get_pmresrn_event(region); bit -= krait_get_pmresrn_event(0); bit += group; + bit <<= 16; /* Use the upper 16 bits of the used_mask */ - if (test_and_set_bit(bit, bitmap)) + if (test_and_set_bit(bit, cpuc->used_mask)) return -EAGAIN; } idx = armv7pmu_get_event_idx(cpuc, event); if (idx < 0 && krait_event) - clear_bit(bit, bitmap); + clear_bit(bit, cpuc->used_mask); return idx; } -static void krait_pmu_clear_event_idx(struct perf_event *event) +static void krait_pmu_clear_event_idx(struct pmu_hw_events *cpuc, + struct perf_event *event) { int bit; struct hw_perf_event *hwc = &event->hw; unsigned int region; unsigned int group; bool krait_event; - unsigned long *bitmap = this_cpu_ptr(pmresrn_used); region = (hwc->config_base >> 12) & 0xf; group = (hwc->config_base >> 0) & 0xf; @@ -1805,7 +1804,8 @@ static void krait_pmu_clear_event_idx(struct perf_event *event) bit = krait_get_pmresrn_event(region); bit -= krait_get_pmresrn_event(0); bit += group; - clear_bit(bit, bitmap); + bit <<= 16; + clear_bit(bit, cpuc->used_mask); } }