linux-kernel - [PATCH v2 2/4] tools/nolibc: MIPS: drop manual stack pointer alignment

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Message-Id: <20250225-nolibc-mips-n32-v2-2-664b47d87fa0@weissschuh.net>
Date: Tue, 25 Feb 2025 18:02:36 +0100
From: Thomas Weißschuh <linux@...ssschuh.net>
To: Willy Tarreau <w@....eu>, Shuah Khan <shuah@...nel.org>, 
 Thomas Bogendoerfer <tsbogend@...ha.franken.de>, 
 "Maciej W. Rozycki" <macro@...am.me.uk>
Cc: linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org, 
 linux-mips@...r.kernel.org, 
 Thomas Weißschuh <linux@...ssschuh.net>
Subject: [PATCH v2 2/4] tools/nolibc: MIPS: drop manual stack pointer
 alignment

The stack pointer is already aligned by the kernel to a multiple of 16.
All modifications of the register have been removed from the entrypoint,
so the manual realignment is unnecessary.

Drop the manual alignment.

Suggested-by: Maciej W. Rozycki <macro@...am.me.uk>
Link: https://lore.kernel.org/lkml/alpine.DEB.2.21.2502161523290.65342@angie.orcam.me.uk/
Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
---
 tools/include/nolibc/arch-mips.h | 2 --
 1 file changed, 2 deletions(-)

diff --git a/tools/include/nolibc/arch-mips.h b/tools/include/nolibc/arch-mips.h
index 6d023d9f120301b2d6837c923c142ab2cf87ae5a..0776de7574b451aeb34531bc4696c7bd9b694268 100644
--- a/tools/include/nolibc/arch-mips.h
+++ b/tools/include/nolibc/arch-mips.h
@@ -186,8 +186,6 @@ void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector __
 		".set push\n"
 		".set noreorder\n"
 		"move  $a0, $sp\n"       /* save stack pointer to $a0, as arg1 of _start_c */
-		"li    $t0, -8\n"
-		"and   $sp, $sp, $t0\n"  /* $sp must be 8-byte aligned                     */
 		"addiu $sp, $sp, -16\n"  /* the callee expects to save a0..a3 there        */
 		"lui $t9, %hi(_start_c)\n" /* ABI requires current function address in $t9 */
 		"ori $t9, %lo(_start_c)\n"

-- 
2.48.1