github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-06-01 11:03:43 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

tools/nolibc: drop manual stack pointer alignment

Browse Source 
The stack pointer is already aligned by the kernel to a multiple of 16.
See STACK_ROUND() in fs/binfmt_elf.c.

The manual realignment is unnecessary, drop it.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/r/20250316-nolibc-sp-align-v1-1-1e1fb073ca1e@weissschuh.net
This commit is contained in:
Thomas Weißschuh 2025-03-16 20:46:07 +01:00
parent 8e1930296f
commit 60ccc16f53
7 changed files with 0 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
tools/include/nolibc/arch-aarch64.h
View File

@ -146,7 +146,6 @@ void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _s
{
__asm__ volatile (
"mov x0, sp\n" /* save stack pointer to x0, as arg1 of _start_c */
"and sp, x0, -16\n" /* sp must be 16-byte aligned in the callee */
"bl _start_c\n" /* transfer to c runtime */
);
__nolibc_entrypoint_epilogue();

2
tools/include/nolibc/arch-arm.h
View File

@ -189,8 +189,6 @@ void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _s
{
__asm__ volatile (
"mov r0, sp\n" /* save stack pointer to %r0, as arg1 of _start_c */
"and ip, r0, #-8\n" /* sp must be 8-byte aligned in the callee */
"mov sp, ip\n"
"bl _start_c\n" /* transfer to c runtime */
);
__nolibc_entrypoint_epilogue();

2
tools/include/nolibc/arch-i386.h
View File

@ -167,8 +167,6 @@ void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _s
__asm__ volatile (
"xor %ebp, %ebp\n" /* zero the stack frame */
"mov %esp, %eax\n" /* save stack pointer to %eax, as arg1 of _start_c */
"add $12, %esp\n" /* avoid over-estimating after the 'and' & 'sub' below */
"and $-16, %esp\n" /* the %esp must be 16-byte aligned on 'call' */
"sub $12, %esp\n" /* sub 12 to keep it aligned after the push %eax */
"push %eax\n" /* push arg1 on stack to support plain stack modes too */
"call _start_c\n" /* transfer to c runtime */

7
tools/include/nolibc/arch-loongarch.h
View File

@ -142,18 +142,11 @@
_arg1; \
})
#if __loongarch_grlen == 32
#define LONG_BSTRINS "bstrins.w"
#else /* __loongarch_grlen == 64 */
#define LONG_BSTRINS "bstrins.d"
#endif
/* startup code */
void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
{
__asm__ volatile (
"move $a0, $sp\n" /* save stack pointer to $a0, as arg1 of _start_c */
LONG_BSTRINS " $sp, $zero, 3, 0\n" /* $sp must be 16-byte aligned */
"bl _start_c\n" /* transfer to c runtime */
);
__nolibc_entrypoint_epilogue();

2
tools/include/nolibc/arch-powerpc.h
View File

@ -201,7 +201,6 @@ void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _s
__asm__ volatile (
"mr 3, 1\n" /* save stack pointer to r3, as arg1 of _start_c */
"clrrdi 1, 1, 4\n" /* align the stack to 16 bytes */
"li 0, 0\n" /* zero the frame pointer */
"stdu 1, -32(1)\n" /* the initial stack frame */
"bl _start_c\n" /* transfer to c runtime */
@ -209,7 +208,6 @@ void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _s
#else
__asm__ volatile (
"mr 3, 1\n" /* save stack pointer to r3, as arg1 of _start_c */
"clrrwi 1, 1, 4\n" /* align the stack to 16 bytes */
"li 0, 0\n" /* zero the frame pointer */
"stwu 1, -16(1)\n" /* the initial stack frame */
"bl _start_c\n" /* transfer to c runtime */

1
tools/include/nolibc/arch-riscv.h
View File

@ -148,7 +148,6 @@ void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _s
"lla gp, __global_pointer$\n"
".option pop\n"
"mv a0, sp\n" /* save stack pointer to a0, as arg1 of _start_c */
"andi sp, a0, -16\n" /* sp must be 16-byte aligned */
"call _start_c\n" /* transfer to c runtime */
);
__nolibc_entrypoint_epilogue();

1
tools/include/nolibc/arch-x86_64.h
View File

@ -166,7 +166,6 @@ void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _s
__asm__ volatile (
"xor %ebp, %ebp\n" /* zero the stack frame */
"mov %rsp, %rdi\n" /* save stack pointer to %rdi, as arg1 of _start_c */
"and $-16, %rsp\n" /* %rsp must be 16-byte aligned before call */
"call _start_c\n" /* transfer to c runtime */
"hlt\n" /* ensure it does not return */
);