[PATCH] tools/nolibc: riscv: add stackprotector support

[Thomas Weißschuh]

Signed-off-by: Thomas Weißschuh <linux at weissschuh.net>
---

This was split out from the general stackprotector series[0] to be
rebased on the nolibc rv32 work from Zhangjin.

This was only tested for rv64 as the nolibc rv32 port is not yet
functional.

Based on the nolibc/20230520-nolibc-rv32+stkp branch.

[0] https://lore.kernel.org/lkml/20230408-nolibc-stackprotector-archs-v1-0-271f5c859c71@weissschuh.net/
---
 tools/include/nolibc/arch-riscv.h       | 7 ++++++-
 tools/testing/selftests/nolibc/Makefile | 1 +
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/include/nolibc/arch-riscv.h b/tools/include/nolibc/arch-riscv.h
index 992a1739dd9c..d0439249c9c9 100644
--- a/tools/include/nolibc/arch-riscv.h
+++ b/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 ...                          */
diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
index 6d660d922240..bd41102ea299 100644
--- a/tools/testing/selftests/nolibc/Makefile
+++ b/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 \

---
base-commit: 6a1f732e0d753a691e9e787615b9a0dd92e1f3f4
change-id: 20230520-nolibc-stackprotector-riscv-160cb957fcd5

Best regards,
-- 
Thomas Weißschuh <linux at weissschuh.net>