Messages in this thread Patch in this message | | | Date | Wed, 30 Dec 2020 18:00:52 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH v1 03/19] x86/insn: Add an insn_decode() API |
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On Tue, 29 Dec 2020 21:06:54 +0100 Borislav Petkov <bp@alien8.de> wrote:
> On Mon, Dec 28, 2020 at 10:15:10AM +0900, Masami Hiramatsu wrote: > > BTW, insn_decode() can return -EINVAL if !insn_complete(), is that OK? > > It does with this change. Or are you asking whether it returning -EINVAL > in that case is ok? > > I don't see why not - this way callers can differentiate where it failed > - at fetching bytes with -ENODATA or it wasn't decoded completely - > -EINVAL.
Ah, I got it.
> > > I think tools clone code must not use INSN_MODE_KERN because the tools may > > not use kernel Kconfig. > > > > Hmm, this may be better to make a different patch to introduce a NOSYNC tag > > for sync checker in the tools. Something like; > > I'd actually prefer this: > > diff --git a/tools/arch/x86/include/asm/insn.h b/tools/arch/x86/include/asm/insn.h > index f8772b371452..545320c67855 100644 > --- a/tools/arch/x86/include/asm/insn.h > +++ b/tools/arch/x86/include/asm/insn.h > @@ -98,8 +98,6 @@ extern int insn_get_length(struct insn *insn); > enum insn_mode { > INSN_MODE_32, > INSN_MODE_64, > - /* Mode is determined by the current kernel build. */ > - INSN_MODE_KERN, > INSN_NUM_MODES, > };
Agreed. This is much simpler. Maybe I need to replace it with dummy lines but it is possible.
> > > so that when a tool does use INSN_MODE_KERN, it would fail building: > > In file included from util/intel-pt-decoder/intel-pt-insn-decoder.c:15: > util/intel-pt-decoder/../../../arch/x86/lib/insn.c: In function ‘insn_decode’: > util/intel-pt-decoder/../../../arch/x86/lib/insn.c:751:11: error: ‘INSN_MODE_KERN’ undeclared (first use in this function); did you mean ‘INSN_MODE_64’? > 751 | if (m == INSN_MODE_KERN) > | ^~~~~~~~~~~~~~ > | INSN_MODE_64
This part is OK. I can replace it with dummy lines.
> util/intel-pt-decoder/../../../arch/x86/lib/insn.c:751:11: note: each undeclared identifier is reported only once for each function it appears in > LD arch/perf-in.o > util/intel-pt-decoder/intel-pt-insn-decoder.c: In function ‘intel_pt_get_insn’: > util/intel-pt-decoder/intel-pt-insn-decoder.c:163:37: error: ‘INSN_MODE_KERN’ undeclared (first use in this function); did you mean ‘INSN_MODE_64’? > 163 | ret = insn_decode(&insn, buf, len, INSN_MODE_KERN); > | ^~~~~~~~~~~~~~ > | INSN_MODE_64
But in [17/19], your patch seems not using INSN_MODE_KERN there.
--- a/tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.c +++ b/tools/perf/util/intel-pt-decoder/intel-pt-insn-decoder.c @@ -158,11 +158,13 @@ int intel_pt_get_insn(const unsigned char *buf, size_t len, int x86_64, struct intel_pt_insn *intel_pt_insn) { struct insn insn; + int ret; - insn_init(&insn, buf, len, x86_64); - insn_get_length(&insn); - if (!insn_complete(&insn) || insn.length > len) + ret = insn_decode(&insn, buf, len, + x86_64 ? INSN_MODE_64 : INSN_MODE_32); + if (ret < 0 || insn.length > len) return -1; + intel_pt_insn_decoder(&insn, intel_pt_insn); if (insn.length < INTEL_PT_INSN_BUF_SZ) memcpy(intel_pt_insn->buf, buf, insn.length); Thank you,
-- Masami Hiramatsu <mhiramat@kernel.org>
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