6.12-stable review patch. If anyone has any objections, please let me know.
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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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/riscv/crypto/chacha-riscv64-zvkb.S | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
--- a/arch/riscv/crypto/chacha-riscv64-zvkb.S +++ b/arch/riscv/crypto/chacha-riscv64-zvkb.S @@ -60,7 +60,8 @@ #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 @@ -141,7 +142,6 @@ 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) @@ -277,7 +277,6 @@ SYM_FUNC_START(chacha20_zvkb) add INP, INP, TMP bnez LEN, .Lblock_loop
- ld s0, 0(sp) ld s1, 8(sp) ld s2, 16(sp) ld s3, 24(sp)