public-mirrors/linux
1
0
Fork 0
mirror of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2025-11-01 09:13:37 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

tools/nolibc: riscv: shrink _start with _start_c

Browse source 
move most of the _start operations to _start_c(), include the
stackprotector initialization.

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
This commit is contained in:
Zhangjin Wu 2023-07-16 02:31:12 +08:00 • committed by Willy Tarreau
parent 61bd4621c0
commit eea70cdac6
1 changed files with 5 additions and 39 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

44
tools/include/nolibc/arch-riscv.h
View file

@ -8,18 +8,7 @@
#define _NOLIBC_ARCH_RISCV_H
#include "compiler.h"
#if __riscv_xlen == 64
#define PTRLOG "3"
#define SZREG "8"
#define REG_L "ld"
#define REG_S "sd"
#elif __riscv_xlen == 32
#define PTRLOG "2"
#define SZREG "4"
#define REG_L "lw"
#define REG_S "sw"
#endif
#include "crt.h"
/* Syscalls for RISCV :
* - stack is 16-byte aligned
@ -153,40 +142,17 @@
_arg1; \
})
char **environ __attribute__((weak));
const unsigned long *_auxv __attribute__((weak));
/* startup code */
void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
{
__asm__ volatile (
".option push\n"
".option norelax\n"
"lla gp, __global_pointer$\n"
"lla gp, __global_pointer$\n"
".option pop\n"
#ifdef _NOLIBC_STACKPROTECTOR
"call __stack_chk_init\n" /* initialize stack protector */
#endif
REG_L" a0, 0(sp)\n" /* argc (a0) was in the stack */
"add a1, sp, "SZREG"\n" /* argv (a1) = sp */
"slli a2, a0, "PTRLOG"\n" /* envp (a2) = SZREG*argc ... */
"add a2, a2, "SZREG"\n" /* + SZREG (skip null) */
"add a2,a2,a1\n" /* + argv */
"add a3, a2, zero\n" /* iterate a3 over envp to find auxv (after NULL) */
"0:\n" /* do { */
REG_L" a4, 0(a3)\n" /* a4 = *a3; */
"add a3, a3, "SZREG"\n" /* a3 += sizeof(void*); */
"bne a4, zero, 0b\n" /* } while (a4); */
"lui a4, %hi(_auxv)\n" /* a4 = &_auxv (high bits) */
REG_S" a3, %lo(_auxv)(a4)\n" /* store a3 into _auxv */
"lui a3, %hi(environ)\n" /* a3 = &environ (high bits) */
REG_S" a2,%lo(environ)(a3)\n"/* store envp(a2) into environ */
"andi sp,a1,-16\n" /* sp must be 16-byte aligned */
"call main\n" /* main() returns the status code, we'll exit with it. */
"li a7, 93\n" /* NR_exit == 93 */
"ecall\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 */
);
__builtin_unreachable();
}