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 */
- 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),
BRANCH_END
};
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