Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Fri, 10 Apr 2020 09:47:26 +0900
From:   Masami Hiramatsu <mhiramat@kernel.org>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Christian =?UTF-8?B?S8O2bmln?= <christian.koenig@amd.com>,
        Jann Horn <jannh@google.com>,
        Harry Wentland <harry.wentland@amd.com>,
        Leo Li <sunpeng.li@amd.com>, amd-gfx@lists.freedesktop.org,
        Alex Deucher <alexander.deucher@amd.com>,
        David Zhou <David1.Zhou@amd.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H . Peter Anvin" <hpa@zytor.com>,
        the arch/x86 maintainers <x86@kernel.org>,
        kernel list <linux-kernel@vger.kernel.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Andy Lutomirski <luto@kernel.org>,
        Arnaldo Carvalho de Melo <acme@kernel.org>
Subject: Re: [PATCH v2] x86: insn: Add insn_is_fpu()
Message-Id: <20200410094726.f9885bafa730fe2a8b3b3c3a@kernel.org>
In-Reply-To: <20200409143212.GW20696@hirez.programming.kicks-ass.net>
References: <20200407155449.GF20730@hirez.programming.kicks-ass.net>
        <158636215075.6641.10786116450376715657.stgit@devnote2>
        <20200409143212.GW20696@hirez.programming.kicks-ass.net>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, 9 Apr 2020 16:32:12 +0200
Peter Zijlstra <peterz@infradead.org> wrote:

> On Thu, Apr 09, 2020 at 01:09:11AM +0900, Masami Hiramatsu wrote:
> > Add insn_is_fpu(insn) which tells that the insn is
> > whether touch the FPU/SSE/MMX register or the instruction
> > of FP coprocessor.
> > 
> > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> > ---
> 
> Sadly, it turns out I need "FWAIT" too, which I tried adding like the
> below, but that comes apart most mighty :/

Thanks for pointing it out. Now I understand the FWAIT/WAIT is used
to wait for FPU...

> 
> The trouble is that FWAIT doesn't take a MODRM, so the previous
> assumption that INAT_FPU implied INAT_MODRM needs to be broken, and I
> think that ripples through somewhere.

Oops, I missed it.

> 
> (also, your patch adds some whitespace to convert_operands(), not sure
> that was intended)

Ah, that's my typo.

> 
> --- a/arch/x86/lib/x86-opcode-map.txt
> +++ b/arch/x86/lib/x86-opcode-map.txt
> @@ -206,7 +206,7 @@ Table: one byte opcode
>  98: CBW/CWDE/CDQE
>  99: CWD/CDQ/CQO
>  9a: CALLF Ap (i64)
> -9b: FWAIT/WAIT
> +9b: FWAIT/WAIT {FPU}
>  9c: PUSHF/D/Q Fv (d64)
>  9d: POPF/D/Q Fv (d64)
>  9e: SAHF
> --- a/arch/x86/tools/gen-insn-attr-x86.awk
> +++ b/arch/x86/tools/gen-insn-attr-x86.awk
> @@ -331,9 +331,13 @@ function convert_operands(count,opnd,
>  		if (match(opcode, rex_expr))
>  			flags = add_flags(flags, "INAT_MAKE_PREFIX(INAT_PFX_REX)")
>  
> +		# check coprocessor escape
> +		if (match(ext, "^ESC"))
> +			flags = add_flags(flags, "INAT_MODRM")
> +
>  		# check FPU/MMX/SSE superscripts
>  		if (match(ext, fpu_expr))
> -			flags = add_flags(flags, "INAT_MODRM | INAT_FPU")
> +			flags = add_flags(flags, "INAT_FPU")


OK, I'll include this.

Thank you,

>  
>  		# check VEX codes
>  		if (match(ext, evexonly_expr))


-- 
Masami Hiramatsu <mhiramat@kernel.org>