tools/nolibc: riscv: add stackprotector support

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/include/nolibc/arch-riscv.h

@@ -177,14 +177,19 @@ struct sys_stat_struct {
 char **environ __attribute__((weak));
 const unsigned long *_auxv __attribute__((weak));
 
+#define __ARCH_SUPPORTS_STACK_PROTECTOR
+
 /* startup code */
-void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) _start(void)
+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"
 		".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 ...                          */

tools/testing/selftests/nolibc/Makefile

@@ -85,6 +85,7 @@ CFLAGS_STKP_x86 = $(CFLAGS_STACKPROTECTOR)
 CFLAGS_STKP_arm64 = $(CFLAGS_STACKPROTECTOR)
 CFLAGS_STKP_arm = $(CFLAGS_STACKPROTECTOR)
 CFLAGS_STKP_mips = $(CFLAGS_STACKPROTECTOR)
+CFLAGS_STKP_riscv = $(CFLAGS_STACKPROTECTOR)
 CFLAGS_STKP_loongarch = $(CFLAGS_STACKPROTECTOR)
 CFLAGS_s390 = -m64
 CFLAGS  ?= -Os -fno-ident -fno-asynchronous-unwind-tables -std=c89 \