linux-kernel - Re: [PATCH] x86: perf: insn: Tweak opcode map for Intel CET instructions

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Message-ID: <20200326135547.GA20397@redhat.com>
Date:   Thu, 26 Mar 2020 10:55:47 -0300
From:   Arnaldo Carvalho de Melo <acme@...hat.com>
To:     Adrian Hunter <adrian.hunter@...el.com>
Cc:     Masami Hiramatsu <mhiramat@...nel.org>,
        Mingbo Zhang <whensungoes@...il.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>, x86@...nel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>, Andi Kleen <ak@...ux.intel.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86: perf: insn: Tweak opcode map for Intel CET
 instructions

Em Thu, Mar 26, 2020 at 07:09:45AM +0200, Adrian Hunter escreveu:
> On 26/03/20 3:31 am, Masami Hiramatsu wrote:
> > Hi,
> > 
> > On Mon,  2 Mar 2020 23:50:30 -0500
> > Mingbo Zhang <whensungoes@...il.com> wrote:
> > 
> >> Intel CET instructions are not described in the Intel SDM. When trying to
> >> get the instruction length, the following instructions get wrong (missing
> >> ModR/M byte).
> >>
> >> RDSSPD r32
> >> RSDDPQ r64
> >> ENDBR32
> >> ENDBR64
> >> WRSSD r/m32, r32
> >> WRSSQ r/m64, r64
> >>
> >> RDSSPD/Q and ENDBR32/64 use the same opcode (f3 0f 1e) slot, which is
> >> described in SDM as Reserved-NOP with no encoding characters, and got an
> >> empty slot in the opcode map. WRSSD/Q (0f 38 f6) also got an empty slot.
> >>
> > 
> > This looks good to me. BTW, wouldn't we need to add decode test cases to perf?
> > 
> > Acked-by: Masami Hiramatsu <mhiramat@...nel.org>
> > 
> > Thank you,
> > 
> 
> We have correct patches that you ack'ed for CET here:
> 
> 	https://lore.kernel.org/lkml/20200204171425.28073-1-yu-cheng.yu@intel.com/
> 
> But they have not yet been applied.
> 
> Sorry for the confusion.

I'll collect them, thanks for pointing this out.

- Arnaldo