[PATCH] firmware: fw_base: make stack guard setup conditional on Zkr

[buenocalvachejoel at gmail.com]

From: Joel Bueno <buenocalvachejoel at gmail.com>

Zkr isn't explicitly selected as a mandatory extension to run OpenSBI
as per: docs/platform_requirements.md

Since this happens very early on the boot flow of OpenSBI where the
dynamic extension checks haven't yet happened, we must guard the Zkr
stack setup behind an ifdef block so that it only gets compiled for
targets that do actually have the extension.

Signed-off-by: Joel Bueno <buenocalvachejoel at gmail.com>
---
 firmware/fw_base.S | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/firmware/fw_base.S b/firmware/fw_base.S
index 63bb4473..9ea93907 100644
--- a/firmware/fw_base.S
+++ b/firmware/fw_base.S
@@ -107,6 +107,7 @@ _bss_zero:
 	add	s4, s4, __SIZEOF_POINTER__
 	blt	s4, s5, _bss_zero
 
+#if defined(__riscv_zkr)
 	/* Trying to initialize the stack guard via the Zkr extension */
 	lla	t0, __stack_chk_guard_done
 	csrw	CSR_MTVEC, t0
@@ -130,6 +131,7 @@ __stack_chk_guard_loop:
 	j	__stack_chk_guard_done
 	.align 3
 __stack_chk_guard_done:
+#endif
 
 	/* Setup temporary trap handler */
 	lla	s4, _start_hang
-- 
2.43.0