| Message ID | 20240227170002.188671-3-vadim.shakirov@syntacore.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drivers: perf: fix crash with the legacy riscv driver | expand |
Hi Vadim, On 27/02/2024 18:00, Vadim Shakirov wrote: > With parameters CONFIG_RISCV_PMU_LEGACY=y and CONFIG_RISCV_PMU_SBI=n > linux kernel crashes when you try perf record: > > $ perf record ls > [ 46.749286] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 > [ 46.750199] Oops [#1] > [ 46.750342] Modules linked in: > [ 46.750608] CPU: 0 PID: 107 Comm: perf-exec Not tainted 6.6.0 #2 > [ 46.750906] Hardware name: riscv-virtio,qemu (DT) > [ 46.751184] epc : 0x0 > [ 46.751430] ra : arch_perf_update_userpage+0x54/0x13e > [ 46.751680] epc : 0000000000000000 ra : ffffffff8072ee52 sp : ff2000000022b8f0 > [ 46.751958] gp : ffffffff81505988 tp : ff6000000290d400 t0 : ff2000000022b9c0 > [ 46.752229] t1 : 0000000000000001 t2 : 0000000000000003 s0 : ff2000000022b930 > [ 46.752451] s1 : ff600000028fb000 a0 : 0000000000000000 a1 : ff600000028fb000 > [ 46.752673] a2 : 0000000ae2751268 a3 : 00000000004fb708 a4 : 0000000000000004 > [ 46.752895] a5 : 0000000000000000 a6 : 000000000017ffe3 a7 : 00000000000000d2 > [ 46.753117] s2 : ff600000028fb000 s3 : 0000000ae2751268 s4 : 0000000000000000 > [ 46.753338] s5 : ffffffff8153e290 s6 : ff600000863b9000 s7 : ff60000002961078 > [ 46.753562] s8 : ff60000002961048 s9 : ff60000002961058 s10: 0000000000000001 > [ 46.753783] s11: 0000000000000018 t3 : ffffffffffffffff t4 : ffffffffffffffff > [ 46.754005] t5 : ff6000000292270c t6 : ff2000000022bb30 > [ 46.754179] status: 0000000200000100 badaddr: 0000000000000000 cause: 000000000000000c > [ 46.754653] Code: Unable to access instruction at 0xffffffffffffffec. > [ 46.754939] ---[ end trace 0000000000000000 ]--- > [ 46.755131] note: perf-exec[107] exited with irqs disabled > [ 46.755546] note: perf-exec[107] exited with preempt_count 4 > > This happens because in the legacy case the ctr_get_width function was not > defined, but it is used in arch_perf_update_userpage. > > Also remove extra check in riscv_pmu_ctr_get_width_mask > > Signed-off-by: Vadim Shakirov <vadim.shakirov@syntacore.com> > Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> > Reviewed-by: Atish Patra <atishp@rivosinc.com> > --- > drivers/perf/riscv_pmu.c | 18 +++++------------- > drivers/perf/riscv_pmu_legacy.c | 8 +++++++- > 2 files changed, 12 insertions(+), 14 deletions(-) > > diff --git a/drivers/perf/riscv_pmu.c b/drivers/perf/riscv_pmu.c > index 0dda70e1ef90..c78a6fd6c57f 100644 > --- a/drivers/perf/riscv_pmu.c > +++ b/drivers/perf/riscv_pmu.c > @@ -150,19 +150,11 @@ u64 riscv_pmu_ctr_get_width_mask(struct perf_event *event) > struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu); > struct hw_perf_event *hwc = &event->hw; > > - if (!rvpmu->ctr_get_width) > - /** > - * If the pmu driver doesn't support counter width, set it to default > - * maximum allowed by the specification. > - */ > - cwidth = 63; > - else { > - if (hwc->idx == -1) > - /* Handle init case where idx is not initialized yet */ > - cwidth = rvpmu->ctr_get_width(0); > - else > - cwidth = rvpmu->ctr_get_width(hwc->idx); > - } > + if (hwc->idx == -1) > + /* Handle init case where idx is not initialized yet */ > + cwidth = rvpmu->ctr_get_width(0); > + else > + cwidth = rvpmu->ctr_get_width(hwc->idx); > > return GENMASK_ULL(cwidth, 0); > } > diff --git a/drivers/perf/riscv_pmu_legacy.c b/drivers/perf/riscv_pmu_legacy.c > index a85fc9a15f03..fa0bccf4edf2 100644 > --- a/drivers/perf/riscv_pmu_legacy.c > +++ b/drivers/perf/riscv_pmu_legacy.c > @@ -37,6 +37,12 @@ static int pmu_legacy_event_map(struct perf_event *event, u64 *config) > return pmu_legacy_ctr_get_idx(event); > } > > +/* cycle & instret are always 64 bit, one bit less according to SBI spec */ > +static int pmu_legacy_ctr_get_width(int idx) > +{ > + return 63; > +} > + > static u64 pmu_legacy_read_ctr(struct perf_event *event) > { > struct hw_perf_event *hwc = &event->hw; > @@ -111,7 +117,7 @@ static void pmu_legacy_init(struct riscv_pmu *pmu) > pmu->ctr_stop = NULL; > pmu->event_map = pmu_legacy_event_map; > pmu->ctr_get_idx = pmu_legacy_ctr_get_idx; > - pmu->ctr_get_width = NULL; > + pmu->ctr_get_width = pmu_legacy_ctr_get_width; > pmu->ctr_clear_idx = NULL; > pmu->ctr_read = pmu_legacy_read_ctr; > pmu->event_mapped = pmu_legacy_event_mapped; Thanks for the resend, this one slipped through... Let's add the fixes tag: Fixes: cc4c07c89aad ("drivers: perf: Implement perf event mmap support in the SBI backend") Thanks again, Alex
diff --git a/drivers/perf/riscv_pmu.c b/drivers/perf/riscv_pmu.c index 0dda70e1ef90..c78a6fd6c57f 100644 --- a/drivers/perf/riscv_pmu.c +++ b/drivers/perf/riscv_pmu.c @@ -150,19 +150,11 @@ u64 riscv_pmu_ctr_get_width_mask(struct perf_event *event) struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu); struct hw_perf_event *hwc = &event->hw; - if (!rvpmu->ctr_get_width) - /** - * If the pmu driver doesn't support counter width, set it to default - * maximum allowed by the specification. - */ - cwidth = 63; - else { - if (hwc->idx == -1) - /* Handle init case where idx is not initialized yet */ - cwidth = rvpmu->ctr_get_width(0); - else - cwidth = rvpmu->ctr_get_width(hwc->idx); - } + if (hwc->idx == -1) + /* Handle init case where idx is not initialized yet */ + cwidth = rvpmu->ctr_get_width(0); + else + cwidth = rvpmu->ctr_get_width(hwc->idx); return GENMASK_ULL(cwidth, 0); } diff --git a/drivers/perf/riscv_pmu_legacy.c b/drivers/perf/riscv_pmu_legacy.c index a85fc9a15f03..fa0bccf4edf2 100644 --- a/drivers/perf/riscv_pmu_legacy.c +++ b/drivers/perf/riscv_pmu_legacy.c @@ -37,6 +37,12 @@ static int pmu_legacy_event_map(struct perf_event *event, u64 *config) return pmu_legacy_ctr_get_idx(event); } +/* cycle & instret are always 64 bit, one bit less according to SBI spec */ +static int pmu_legacy_ctr_get_width(int idx) +{ + return 63; +} + static u64 pmu_legacy_read_ctr(struct perf_event *event) { struct hw_perf_event *hwc = &event->hw; @@ -111,7 +117,7 @@ static void pmu_legacy_init(struct riscv_pmu *pmu) pmu->ctr_stop = NULL; pmu->event_map = pmu_legacy_event_map; pmu->ctr_get_idx = pmu_legacy_ctr_get_idx; - pmu->ctr_get_width = NULL; + pmu->ctr_get_width = pmu_legacy_ctr_get_width; pmu->ctr_clear_idx = NULL; pmu->ctr_read = pmu_legacy_read_ctr; pmu->event_mapped = pmu_legacy_event_mapped;