linux-kernel - Re: [PATCH 8/9] x86/bpf: Convert asm comments to AT&T syntax

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190613191112.hinquqrdzl7u2lrt@treble>
Date:   Thu, 13 Jun 2019 14:11:12 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Song Liu <songliubraving@...com>
Cc:     X86 ML <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Networking <netdev@...r.kernel.org>, bpf <bpf@...r.kernel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Kairui Song <kasong@...hat.com>
Subject: Re: [PATCH 8/9] x86/bpf: Convert asm comments to AT&T syntax

On Thu, Jun 13, 2019 at 06:52:24PM +0000, Song Liu wrote:
> > @@ -403,11 +403,11 @@ static void emit_mov_imm64(u8 **pprog, u32 dst_reg,
> > 		 * For emitting plain u32, where sign bit must not be
> > 		 * propagated LLVM tends to load imm64 over mov32
> > 		 * directly, so save couple of bytes by just doing
> > -		 * 'mov %eax, imm32' instead.
> > +		 * 'mov imm32, %eax' instead.
> > 		 */
> > 		emit_mov_imm32(&prog, false, dst_reg, imm32_lo);
> > 	} else {
> > -		/* movabsq %rax, imm64 */
> > +		/* movabs imm64, %rax */
> 
> 		^^^^^ Should this be moveabsq? 

Not for AT&T syntax:

~ $ cat test.S
movabs $0x1111111111111111, %rax
~ $ as test.S
~ $ objdump -d a.out

a.out:     file format elf64-x86-64


Disassembly of section .text:

0000000000000000 <.text>:
   0:	48 b8 11 11 11 11 11 	movabs $0x1111111111111111,%rax
   7:	11 11 11

-- 
Josh