On 05/22/2013 05:53 PM, Stephane Eranian wrote: > Hi, > > > > On Wed, May 22, 2013 at 8:43 AM, Anshuman Khandual > <khand...@linux.vnet.ibm.com> wrote: >> On 05/21/2013 07:25 PM, Stephane Eranian wrote: >>> On Thu, May 16, 2013 at 12:15 PM, Michael Neuling <mi...@neuling.org> wrote: >>>> Peter Zijlstra <pet...@infradead.org> wrote: >>>> >>>>> On Wed, May 15, 2013 at 03:37:22PM +0200, Stephane Eranian wrote: >>>>>> On Fri, May 3, 2013 at 2:11 PM, Peter Zijlstra <a.p.zijls...@chello.nl> >>>>>> wrote: >>>>>>> We should always have proper privileges when requesting kernel data. >>>>>>> >>>>>>> Cc: Andi Kleen <a...@linux.intel.com> >>>>>>> Cc: eran...@google.com >>>>>>> Signed-off-by: Peter Zijlstra <a.p.zijls...@chello.nl> >>>>>>> Link: >>>>>>> http://lkml.kernel.org/n/tip-v0x9ky3ahzr6nm3c6ilwr...@git.kernel.org >>>>>>> --- >>>>>>> arch/x86/kernel/cpu/perf_event_intel_lbr.c | 5 ++++- >>>>>>> 1 file changed, 4 insertions(+), 1 deletion(-) >>>>>>> >>>>>>> --- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c >>>>>>> +++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c >>>>>>> @@ -318,8 +318,11 @@ static void intel_pmu_setup_sw_lbr_filte >>>>>>> if (br_type & PERF_SAMPLE_BRANCH_USER) >>>>>>> mask |= X86_BR_USER; >>>>>>> >>>>>>> - if (br_type & PERF_SAMPLE_BRANCH_KERNEL) >>>>>>> + if (br_type & PERF_SAMPLE_BRANCH_KERNEL) { >>>>>>> + if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) >>>>>>> + return -EACCES; >>>>>>> mask |= X86_BR_KERNEL; >>>>>>> + } >>>>>>> >>>>>> This will prevent regular users from capturing kernel -> kernel branches. >>>>>> But it won't prevent users from getting kernel -> user branches. Thus >>>>>> some kernel address will still be captured. I guess they could be >>>>>> eliminated >>>>>> by the sw_filter. >>>>>> >>>>>> When using LBR priv level filtering, the filter applies to the branch >>>>>> target >>>>>> only. >>>>> >>>>> How about something like the below? It also adds the branch flags >>>>> Mikey wanted for PowerPC. >>>> >>>> Peter, >>>> >>>> BTW PowerPC also has the ability to filter on conditional branches. Any >>>> chance we could add something like the follow to perf also? >>>> >>>> Mikey >>>> >>>> diff --git a/include/uapi/linux/perf_event.h >>>> b/include/uapi/linux/perf_event.h >>>> index fb104e5..891c769 100644 >>>> --- a/include/uapi/linux/perf_event.h >>>> +++ b/include/uapi/linux/perf_event.h >>>> @@ -157,8 +157,9 @@ enum perf_branch_sample_type { >>>> PERF_SAMPLE_BRANCH_ANY_CALL = 1U << 4, /* any call branch */ >>>> PERF_SAMPLE_BRANCH_ANY_RETURN = 1U << 5, /* any return branch */ >>>> PERF_SAMPLE_BRANCH_IND_CALL = 1U << 6, /* indirect calls */ >>>> + PERF_SAMPLE_BRANCH_CONDITIONAL = 1U << 7, /* conditional branches >>>> */ >>>> >>> I would use PERF_SAMPLE_BRANCH_COND here. >>> >>>> - PERF_SAMPLE_BRANCH_MAX = 1U << 7, /* non-ABI */ >>>> + PERF_SAMPLE_BRANCH_MAX = 1U << 8, /* non-ABI */ >>>> }; >>>> >>>> #define PERF_SAMPLE_BRANCH_PLM_ALL \ >>>> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c >>>> index cdf58ec..5b0b89d 100644 >>>> --- a/tools/perf/builtin-record.c >>>> +++ b/tools/perf/builtin-record.c >>>> @@ -676,6 +676,7 @@ static const struct branch_mode branch_modes[] = { >>>> BRANCH_OPT("any_call", PERF_SAMPLE_BRANCH_ANY_CALL), >>>> BRANCH_OPT("any_ret", PERF_SAMPLE_BRANCH_ANY_RETURN), >>>> BRANCH_OPT("ind_call", PERF_SAMPLE_BRANCH_IND_CALL), >>>> + BRANCH_OPT("cnd", PERF_SAMPLE_BRANCH_CONDITIONAL), >>> >>> use "cond" >>> >>>> BRANCH_END >>>> }; >>>> >>> >>> And if you do this, you also need to update the x86 >>> perf_event_intel_lbr.c mapping >>> tables to fill out the entries for PERF_SAMPLE_BRANCH_COND: >>> >>> [PERF_SAMPLE_BRANCH_COND] = LBR_JCC, >>> >>> And you also need to update intel_pmu_setup_sw_lbr_filter() >>> to handle the conversion to x86 instructions: >>> >>> if (br_type & PERF_SAMPLE_BRANCH_COND) >>> mask |= X86_BR_JCC; >>> >>> >>> You also need to update the perf-record.txt documentation to list cond >>> as a possible >>> branch filter. >> >> Hey Stephane, >> >> I have incorporated all the review comments into the patch series >> https://lkml.org/lkml/2013/5/22/51. >> > I don't see how you can compile Patch 3/5: > > + BRANCH_OPT("cond", PERF_SAMPLE_BRANCH_CONDITIONAL), > > Needs to be PERF_SAMPLE_BRANCH_COND. >
Ahh, sorry missed it, will fix it. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
