From: Ammar Faizi Date: Sun, 24 Oct 2021 17:43:22 +0000 (+0200) Subject: tools/nolibc: x86-64: Use `mov $60,%eax` instead of `mov $60,%rax` X-Git-Tag: v5.15.92~372 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=487386a49e01a9d7d28d6a52fe6ec095af1ef789;p=platform%2Fkernel%2Flinux-rpi.git tools/nolibc: x86-64: Use `mov $60,%eax` instead of `mov $60,%rax` [ Upstream commit 7bdc0e7a390511cd3df8194003b908f15a6170a5 ] Note that mov to 32-bit register will zero extend to 64-bit register. Thus `mov $60,%eax` has the same effect with `mov $60,%rax`. Use the shorter opcode to achieve the same thing. ``` b8 3c 00 00 00 mov $60,%eax (5 bytes) [1] 48 c7 c0 3c 00 00 00 mov $60,%rax (7 bytes) [2] ``` Currently, we use [2]. Change it to [1] for shorter code. Signed-off-by: Ammar Faizi Signed-off-by: Willy Tarreau Signed-off-by: Paul E. McKenney Stable-dep-of: 184177c3d6e0 ("tools/nolibc: restore mips branch ordering in the _start block") Signed-off-by: Sasha Levin --- diff --git a/tools/include/nolibc/nolibc.h b/tools/include/nolibc/nolibc.h index ece7a70..676fe5d 100644 --- a/tools/include/nolibc/nolibc.h +++ b/tools/include/nolibc/nolibc.h @@ -420,7 +420,7 @@ asm(".section .text\n" "and $-16, %rsp\n" // x86 ABI : esp must be 16-byte aligned before call "call main\n" // main() returns the status code, we'll exit with it. "mov %eax, %edi\n" // retrieve exit code (32 bit) - "mov $60, %rax\n" // NR_exit == 60 + "mov $60, %eax\n" // NR_exit == 60 "syscall\n" // really exit "hlt\n" // ensure it does not return "");