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. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
