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Date:   Mon, 8 Aug 2022 23:45:45 +0700
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Subject: Re: [PATCH 1/1] x86: Change mov $0, %reg with xor %reg, %reg
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To:     Joerg Roedel <jroedel@suse.de>
Cc:     David Laight <David.Laight@aculab.com>,
        Borislav Petkov <bp@alien8.de>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        "x86@kernel.org" <x86@kernel.org>,
        Ard Biesheuvel <ardb@kernel.org>,
        Bill Metzenthen <billm@melbpc.org.au>,
        Brijesh Singh <brijesh.singh@amd.com>,
        Josh Poimboeuf <jpoimboe@kernel.org>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Michael Roth <michael.roth@amd.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Sean Christopherson <seanjc@google.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ammar Faizi <ammarfaizi2@gnuweeb.org>,
        GNU/Weeb Mailing List <gwml@vger.gnuweeb.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
References: <20220804152656.8840-1-knscarlet@gnuweeb.org>
 <20220804152656.8840-2-knscarlet@gnuweeb.org> <Yuvrd2yWLnyxOVLU@zn.tnic>
 <20220804180805.9077-1-knscarlet@gnuweeb.org>
 <126271e264204581a42b079b51481740@AcuMS.aculab.com>
 <Yuzl7+qPtK1i2aSj@suse.de>
From:   Kanna Scarlet <knscarlet@gnuweeb.org>
In-Reply-To: <Yuzl7+qPtK1i2aSj@suse.de>
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On 8/5/22 4:42 PM, Joerg Roedel wrote:
> On Fri, Aug 05, 2022 at 09:26:02AM +0000, David Laight wrote:
>> Use "xor %rax,%rax" instead of "xor %eax,%eax" to save
>> the 'reg' prefix.
> 
> Also, some places explicitly use the mov variant to zero a register
> without touching rflags. Please be careful to not change those.

thank you for reminder, i will check again to make myself more sure
the patch doesn't break this %rflags dependency situation

Regards,
-- 
Kanna Scarlet