Let's move most of the _start operations to _start_c().
Signed-off-by: Zhangjin Wu <falcon@xxxxxxxxxxx>
---
tools/include/nolibc/arch-riscv.h | 42 ++++---------------------------
1 file changed, 5 insertions(+), 37 deletions(-)
diff --git a/tools/include/nolibc/arch-riscv.h b/tools/include/nolibc/arch-riscv.h
index 7f4abcc15206..ec0f9c597d0b 100644
--- a/tools/include/nolibc/arch-riscv.h
+++ b/tools/include/nolibc/arch-riscv.h
@@ -9,18 +9,6 @@
#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
-
/* Syscalls for RISCV :
* - stack is 16-byte aligned
* - syscall number is passed in a7
@@ -153,40 +141,20 @@
_arg1; \
})
-char **environ __attribute__((weak));
-const unsigned long *_auxv __attribute__((weak));
-
/* startup code */
void __attribute__((weak,noreturn,optimize("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 */
+ "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();
}
--
2.25.1
