From: Vivian Wang wangruikang@iscas.ac.cn

commit 43169328c7b4623b54b7713ec68479cebda5465f upstream.

In chacha_zvkb, avoid using the s0 register, which is the frame pointer, by reallocating KEY0 to t5. This makes stack traces available if e.g. a crash happens in chacha_zvkb.

No frame pointer maintenance is otherwise required since this is a leaf function.

Signed-off-by: Vivian Wang wangruikang@iscas.ac.cn Fixes: bb54668837a0 ("crypto: riscv - add vector crypto accelerated ChaCha20") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20251202-riscv-chacha_zvkb-fp-v2-1-7bd00098c9dc@is... Signed-off-by: Eric Biggers ebiggers@kernel.org --- arch/riscv/crypto/chacha-riscv64-zvkb.S | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/crypto/chacha-riscv64-zvkb.S b/arch/riscv/crypto/chacha-riscv64-zvkb.S index bf057737ac69..fbef93503571 100644 --- a/arch/riscv/crypto/chacha-riscv64-zvkb.S +++ b/arch/riscv/crypto/chacha-riscv64-zvkb.S @@ -58,11 +58,12 @@ #define CONSTS3 t0 #define TMP t1 #define VL t2 #define STRIDE t3 #define NROUNDS t4 -#define KEY0 s0 +#define KEY0 t5 +// Avoid s0/fp to allow for unwinding #define KEY1 s1 #define KEY2 s2 #define KEY3 s3 #define KEY4 s4 #define KEY5 s5 @@ -139,11 +140,10 @@ // The counter is treated as 32-bit, following the RFC7539 convention. SYM_FUNC_START(chacha20_zvkb) srli LEN, LEN, 6 // Bytes to blocks

addi sp, sp, -96 - sd s0, 0(sp) sd s1, 8(sp) sd s2, 16(sp) sd s3, 24(sp) sd s4, 32(sp) sd s5, 40(sp) @@ -275,11 +275,10 @@ SYM_FUNC_START(chacha20_zvkb) slli TMP, VL, 6 add OUTP, OUTP, TMP add INP, INP, TMP bnez LEN, .Lblock_loop

- ld s0, 0(sp) ld s1, 8(sp) ld s2, 16(sp) ld s3, 24(sp) ld s4, 32(sp) ld s5, 40(sp)

base-commit: 567bd8cbc2fe6b28b78864cbbbc41b0d405eb83c