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Date: Mon, 27 May 2019 14:33:09 -0400 From: "Liang, Kan" <kan.liang@...ux.intel.com> To: Ingo Molnar <mingo@...nel.org> Cc: vincent.weaver@...ne.edu, ak@...ux.intel.com, peterz@...radead.org, alexander.shishkin@...ux.intel.com, acme@...hat.com, jolsa@...hat.com, eranian@...gle.com, linux-kernel@...r.kernel.org Subject: Re: [PATCH 1/2] perf/x86: Disable non generic regs for software/probe events On 5/25/2019 4:48 AM, Ingo Molnar wrote: > > * kan.liang@...ux.intel.com <kan.liang@...ux.intel.com> wrote: > >> @@ -57,6 +57,11 @@ static unsigned int pt_regs_offset[PERF_REG_X86_MAX] = { >> #endif >> }; >> >> +u64 non_generic_regs_mask(void) >> +{ >> + return (~((1ULL << PERF_REG_X86_XMM0) - 1)); >> +} >> + >> u64 perf_reg_value(struct pt_regs *regs, int idx) >> { >> struct x86_perf_regs *perf_regs; >> diff --git a/include/linux/perf_regs.h b/include/linux/perf_regs.h >> index 4767474..c1c3454 100644 >> --- a/include/linux/perf_regs.h >> +++ b/include/linux/perf_regs.h >> @@ -9,6 +9,8 @@ struct perf_regs { >> struct pt_regs *regs; >> }; >> >> +u64 non_generic_regs_mask(void); > > This is a *constant* value, why is it in a separate function, not an > inline? > > Or rather, since it's obviously a constant, name it in such a way. > (PERF_REG_X86_NON_GENERIC_MASK or so. > > To the generic code define it as 0 if arch headers haven't overriden it. > I will name it PERF_REG_NON_GENERIC_MASK in generic code. Perf tool also defined a similar macro. I think I will define PERF_REG_NON_GENERIC_MASK in X86 uapi header. So both kernel and user space can use it. I will send out V2 to address all comments. Thanks, Kan >> +u64 __weak non_generic_regs_mask(void) >> +{ >> + return 0; >> +} >> + >> +static inline bool has_non_generic_regs(struct perf_event *event) >> +{ >> + u64 mask = non_generic_regs_mask(); >> + >> + return ((event->attr.sample_regs_user & mask) || >> + (event->attr.sample_regs_intr & mask)); > > 'return' is not a function ... > >> + /* only support generic regs */ >> + if (has_non_generic_regs(event)) >> + return -EOPNOTSUPP; > > In human readable comments please use complete sentences with no > unnecessary abbreviations, i.e. "Only support generic registers". > > Thanks, > > Ingo >
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