Re: [RFC PATCH 1/2] perf: arm_spe: Fix consistency of PMSCR register bit CX
From: Leo Yan <hidden>
Date: 2022-02-16 13:23:29
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On Tue, Feb 15, 2022 at 02:29:27PM +0000, German Gomez wrote: [...]
Thanks for the suggestion. I recorded the following stacktrace: perf-323841 [052] d.... 3996.528812: arm_spe_pmu_setup_aux: (arm_spe_pmu_setup_aux+0x60/0x1c0 [arm_spe_pmu]) perf-323841 [052] d.... 3996.528813: <stack trace>
Yeah, this show arm_spe_pmu_setup_aux() is called in perf process.
=> kprobe_dispatcher => kprobe_breakpoint_handler => call_break_hook => brk_handler => do_debug_exception => el1_dbg => el1h_64_sync_handler => el1h_64_sync => arm_spe_pmu_setup_aux => perf_mmap => mmap_region => do_mmap => vm_mmap_pgoff => ksys_mmap_pgoff => __arm64_sys_mmap => invoke_syscall => el0_svc_common.constprop.0 => do_el0_svc => el0_svc => el0t_64_sync_handler => el0t_64_sync So for a v2 I may include something like this:
The change looks good to me, please see below minor comment.
quoted hunk ↗ jump to hunk
diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c index d44bcc29d..aadec5a0e 100644 --- a/drivers/perf/arm_spe_pmu.c +++ b/drivers/perf/arm_spe_pmu.c@@ -45,6 +45,7 @@ struct arm_spe_pmu_buf {int nr_pages; bool snapshot; void *base; + u64 pmscr; }; struct arm_spe_pmu {@@ -748,7 +749,7 @@ static void arm_spe_pmu_start(struct perf_event *event, int flags)write_sysreg_s(reg, SYS_PMSICR_EL1); } - reg = arm_spe_event_to_pmscr(event); + reg = ((struct arm_spe_pmu_buf *) perf_get_aux(handle))->pmscr; isb(); write_sysreg_s(reg, SYS_PMSCR_EL1);
Just nitpick (or it's just my preferring coding style), we can define a local pointer variable 'buf': struct arm_spe_pmu_buf *buf = perf_get_aux(handle); ... isb(); write_sysreg_s(buf->pmscr, SYS_PMSCR_EL1); Thanks, Leo
quoted hunk ↗ jump to hunk
}@@ -855,6 +856,8 @@ static void *arm_spe_pmu_setup_aux(struct perf_event *event, void **pages,if (!pglist) goto out_free_buf; + buf->pmscr = arm_spe_event_to_pmscr(event); + for (i = 0; i < nr_pages; ++i) pglist[i] = virt_to_page(pages[i]);quoted
Thanks, Leo
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