[RFC PATCH 05/12] riscv: fix certain indirect jumps for kernel cfi

[Deepak Gupta <debug@rivosinc.com>]

Handwritten `__memset` asm routine performs certain static jumps within
function and uses `a5` to do that. This would require a landing pad
instruction at the target. Since its static jump and no memory load is
involved, use `t2` instead which is exempt from requiring a landing pad.

Signed-off-by: Deepak Gupta <debug@rivosinc.com>
---
 arch/riscv/lib/memset.S | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/lib/memset.S b/arch/riscv/lib/memset.S
index 35f358e70bdb..e129ebf66986 100644
--- a/arch/riscv/lib/memset.S
+++ b/arch/riscv/lib/memset.S
@@ -56,12 +56,12 @@ SYM_FUNC_START(__memset)
 
 	/* Jump into loop body */
 	/* Assumes 32-bit instruction lengths */
-	la a5, 3f
+	la t2, 3f
 #ifdef CONFIG_64BIT
 	srli a4, a4, 1
 #endif
-	add a5, a5, a4
-	jr a5
+	add t2, t2, a4
+	jr t2
 3:
 	REG_S a1,        0(t0)
 	REG_S a1,    SZREG(t0)
-- 
2.43.2


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv