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SubjectRe: [PATCH v8 1/3] perf annotate: Show raw form for jump instruction with indirect target
Em Mon, Dec 05, 2016 at 05:21:42PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Mon, Dec 05, 2016 at 09:26:45PM +0530, Ravi Bangoria escreveu:
> > For jump instructions that does not include target address as direct
> > operand, show the original disassembled line for them. This is needed
> > for certain powerpc jump instructions that use target address in a
> > register (such as bctr, btar, ...).
>
> Found it, .__bpf_prog_run, that is present in that perf.data file you
> sent me, has it, will use it in my committer notes for this patch.

So, I've added these committer notes while testing it, will continue
processing your patches later/tomorrow, thanks!

Committer notes:

Testing it using a perf.data file and vmlinux for powerpc64,
cross-annotating it on a x86_64 workstation:

Before:

.__bpf_prog_run vmlinux.powerpc
│ std r10,512(r9) ▒
│ lbz r9,0(r31) ▒
│ rldicr r9,r9,3,60 ▒
│ ldx r9,r30,r9 ▒
│ mtctr r9 ▒
100.00 │ ↓ bctr 3fffffffffe01510 ▒
│ lwa r10,4(r31) ▒
│ lwz r9,0(r31) ▒
<SNIP>
Invalid jump offset: 3fffffffffe01510

After:

.__bpf_prog_run vmlinux.powerpc
│ std r10,512(r9) ▒
│ lbz r9,0(r31) ▒
│ rldicr r9,r9,3,60 ▒
│ ldx r9,r30,r9 ▒
│ mtctr r9 ▒
100.00 │ ↓ bctr ▒
│ lwa r10,4(r31) ▒
│ lwz r9,0(r31) ▒
<SNIP>
Invalid jump offset: 3fffffffffe01510

This, in turn, uncovers another problem with jumps without operands, the
ENTER/-> operation, to jump to the target, still continues using the bogus
target :-)

BTW, this was the file used for the above tests:

[acme@jouet ravi_bangoria]$ perf report --header-only -i perf.data.f22vm.powerdev
# ========
# captured on: Thu Nov 24 12:40:38 2016
# hostname : pdev-f22-qemu
# os release : 4.4.10-200.fc22.ppc64
# perf version : 4.9.rc1.g6298ce
# arch : ppc64
# nrcpus online : 48
# nrcpus avail : 48
# cpudesc : POWER7 (architected), altivec supported
# cpuid : 74,513
# total memory : 4158976 kB
# cmdline : /home/ravi/Workspace/linux/tools/perf/perf record -a
# event : name = cycles:ppp, , size = 112, { sample_period, sample_freq } = 4000, sample_type = IP|TID|TIME|CPU|PERIOD, disabled = 1, inherit = 1, mmap = 1, c
# HEADER_CPU_TOPOLOGY info available, use -I to display
# HEADER_NUMA_TOPOLOGY info available, use -I to display
# pmu mappings: cpu = 4, software = 1, tracepoint = 2, breakpoint = 5
# missing features: HEADER_TRACING_DATA HEADER_BRANCH_STACK HEADER_GROUP_DESC HEADER_AUXTRACE HEADER_STAT HEADER_CACHE
# ========
#
[acme@jouet ravi_bangoria]$

Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>

> - Arnaldo
>
> >
> > Before:
> > ld r12,32088(r12)
> > mtctr r12
> > v bctr ffffffffffffca2c
> > std r2,24(r1)
> > addis r12,r2,-1
> >
> > After:
> > ld r12,32088(r12)
> > mtctr r12
> > v bctr
> > std r2,24(r1)
> > addis r12,r2,-1
> >
> > Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
> > Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
> > ---
> > Changes in v8:
> > - v7: https://lkml.org/lkml/2016/9/21/436
> > - Rebase to acme/perf/core
> > - No logical changes. (Cross arch annotate patches are in. This patch
> > is for hardening annotate for powerpc.)
> >
> > tools/perf/util/annotate.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
> > index 4012b1d..ea7e0de 100644
> > --- a/tools/perf/util/annotate.c
> > +++ b/tools/perf/util/annotate.c
> > @@ -237,6 +237,9 @@ static int jump__parse(struct arch *arch __maybe_unused, struct ins_operands *op
> > static int jump__scnprintf(struct ins *ins, char *bf, size_t size,
> > struct ins_operands *ops)
> > {
> > + if (!ops->target.addr)
> > + return ins__raw_scnprintf(ins, bf, size, ops);
> > +
> > return scnprintf(bf, size, "%-6.6s %" PRIx64, ins->name, ops->target.offset);
> > }
> >
> > --
> > 2.4.11

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