Commit eea70cda authored by Zhangjin Wu's avatar Zhangjin Wu Committed by Willy Tarreau
Browse files

tools/nolibc: riscv: shrink _start with _start_c 



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

Signed-off-by: default avatarZhangjin Wu <falcon@tinylab.org>
Signed-off-by: default avatarWilly Tarreau <w@1wt.eu>
parent 61bd4621

tools/include/nolibc/arch-riscv.h

+5 −39
Original line number Diff line number Diff line
@@ -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
@@ -153,9 +142,6 @@ 
	_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)

{
@@ -164,29 +150,9 @@ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_ 
		".option norelax\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();

}