From: Thomas Weißschuh Date: Sun, 16 Mar 2025 19:46:07 +0000 (+0100) Subject: tools/nolibc: drop manual stack pointer alignment X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=60ccc16f530a480abfde399bf80779e5b021b3fe;p=users%2Fdwmw2%2Flinux.git tools/nolibc: drop manual stack pointer alignment 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 Acked-by: Willy Tarreau Link: https://lore.kernel.org/r/20250316-nolibc-sp-align-v1-1-1e1fb073ca1e@weissschuh.net --- diff --git a/tools/include/nolibc/arch-aarch64.h b/tools/include/nolibc/arch-aarch64.h index 06fdef7b291a0..937a348da42e1 100644 --- a/tools/include/nolibc/arch-aarch64.h +++ b/tools/include/nolibc/arch-aarch64.h @@ -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(); diff --git a/tools/include/nolibc/arch-arm.h b/tools/include/nolibc/arch-arm.h index 6180ff99ab43d..1f66e7e5a444b 100644 --- a/tools/include/nolibc/arch-arm.h +++ b/tools/include/nolibc/arch-arm.h @@ -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(); diff --git a/tools/include/nolibc/arch-i386.h b/tools/include/nolibc/arch-i386.h index ff5afc35bbd8b..7c9b38e964183 100644 --- a/tools/include/nolibc/arch-i386.h +++ b/tools/include/nolibc/arch-i386.h @@ -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 */ diff --git a/tools/include/nolibc/arch-loongarch.h b/tools/include/nolibc/arch-loongarch.h index fb519545959ed..5511705303ea9 100644 --- a/tools/include/nolibc/arch-loongarch.h +++ b/tools/include/nolibc/arch-loongarch.h @@ -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" /* $sp must be 16-byte aligned */ "bl _start_c\n" /* transfer to c runtime */ ); __nolibc_entrypoint_epilogue(); diff --git a/tools/include/nolibc/arch-powerpc.h b/tools/include/nolibc/arch-powerpc.h index ee2fdb8d601dc..204564bbcd328 100644 --- a/tools/include/nolibc/arch-powerpc.h +++ b/tools/include/nolibc/arch-powerpc.h @@ -201,7 +201,6 @@ void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _s __asm__ volatile ( "mr 3, 1\n" /* save stack pointer to r3, as arg1 of _start_c */ - "clrrdi 1, 1, 4\n" /* align the stack to 16 bytes */ "li 0, 0\n" /* zero the frame pointer */ "stdu 1, -32(1)\n" /* the initial stack frame */ "bl _start_c\n" /* transfer to c runtime */ @@ -209,7 +208,6 @@ void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _s #else __asm__ volatile ( "mr 3, 1\n" /* save stack pointer to r3, as arg1 of _start_c */ - "clrrwi 1, 1, 4\n" /* align the stack to 16 bytes */ "li 0, 0\n" /* zero the frame pointer */ "stwu 1, -16(1)\n" /* the initial stack frame */ "bl _start_c\n" /* transfer to c runtime */ diff --git a/tools/include/nolibc/arch-riscv.h b/tools/include/nolibc/arch-riscv.h index 8827bf9362124..885383a86c38b 100644 --- a/tools/include/nolibc/arch-riscv.h +++ b/tools/include/nolibc/arch-riscv.h @@ -148,7 +148,6 @@ void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _s "lla gp, __global_pointer$\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(); diff --git a/tools/include/nolibc/arch-x86_64.h b/tools/include/nolibc/arch-x86_64.h index 1e40620a2b33d..67305e24dbefd 100644 --- a/tools/include/nolibc/arch-x86_64.h +++ b/tools/include/nolibc/arch-x86_64.h @@ -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 */ );