linux-kernel - [PATCH 0/1] x86 change mov 0, %reg to xor %reg, %reg

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Message-Id: <20220804152656.8840-1-knscarlet@gnuweeb.org>
Date:   Thu,  4 Aug 2022 15:26:54 +0000
From:   Kanna Scarlet <knscarlet@...weeb.org>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org
Cc:     Kanna Scarlet <knscarlet@...weeb.org>,
        Ard Biesheuvel <ardb@...nel.org>,
        Bill Metzenthen <billm@...bpc.org.au>,
        Brijesh Singh <brijesh.singh@....com>,
        Joerg Roedel <jroedel@...e.de>,
        Josh Poimboeuf <jpoimboe@...nel.org>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Mark Rutland <mark.rutland@....com>,
        Michael Roth <michael.roth@....com>,
        Peter Zijlstra <peterz@...radead.org>,
        Sean Christopherson <seanjc@...gle.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ammar Faizi <ammarfaizi2@...weeb.org>,
        GNU/Weeb Mailing List <gwml@...r.gnuweeb.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: [PATCH 0/1] x86 change mov 0, %reg to xor %reg, %reg

Hello Linux x86 maintainers,

I'm an informatic student 19 y.o. I am still studying Linux kernel open
source in GNU/Weeb community. I want to be a linux kerne dev in the
future. This is my first time sending a patch to Linux Kernel, I am
still learning the community. I may make a mistake in this email, please
correct me if i am wrong

I want to improve x86-64 assembly code with this patch. This patch
changes mov $0, %reg with xor %reg, %reg because xor %reg, %reg is
smaller so it is good to save space

asm:
ba 00 00 00 00  mov   $0x0,%edx
31 d2           xor   %edx,%edx


Regards,

Signed-off-by: Kanna Scarlet <knscarlet@...weeb.org>
---

Kanna Scarlet (1):
  x86: Change mov $0, %reg with xor %reg, %reg

 arch/x86/boot/compressed/head_64.S     | 2 +-
 arch/x86/boot/compressed/mem_encrypt.S | 2 +-
 arch/x86/kernel/ftrace_32.S            | 4 ++--
 arch/x86/kernel/head_64.S              | 2 +-
 arch/x86/math-emu/div_Xsig.S           | 2 +-
 arch/x86/math-emu/reg_u_sub.S          | 2 +-
 6 files changed, 7 insertions(+), 7 deletions(-)


base-commit: ff89dd08c0f0a3fd330c9ef9d775e880f82c291e
-- 
Kanna Scarlet