Messages in this thread Patch in this message | | | From | Vadim Shakirov <> | Subject | [PATCH] drivers: perf: ctr_get_width function for legacy is not defined | Date | Mon, 27 Nov 2023 12:54:03 +0300 |
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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.
Fixes: cc4c07c89aad ("drivers: perf: Implement perf event mmap support in the SBI backend") Signed-off-by: Vadim Shakirov <vadim.shakirov@syntacore.com> --- drivers/perf/riscv_pmu_legacy.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/perf/riscv_pmu_legacy.c b/drivers/perf/riscv_pmu_legacy.c index 79fdd667922e..a179ed6ac980 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; -- 2.34.1
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