[v2 PATCH] crypto: powerpc/poly1305 - Add poly1305_emit_arch wrapper

Herbert Xu
2025-05-10T05:10:40Z

On Fri, May 09, 2025 at 09:44:50PM -0700, Eric Biggers wrote:
>
> This fixes "-cpu Power10", but older CPUs (e.g. "-cpu POWER9") are still
> failing.

You're right. I'll revert this and apply the following patch
instead.

BTW this thing is still hopelessly broken if it's called from
softirq context because there is no SIMD fallback. Yes I removed
the SIMD check but it was already broken before that as it simply
switched from the 4-block version to the 1-block version if SIMD
is not available rather than actually doing something that is
safe in softirq context.

Perhaps we should just remove this altogether until it's fixed.

---8<---
Add poly1305_emit_arch with fallback instead of calling assembly
directly. This is because the state format differs between p10
and that of the generic implementation.

Reported-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Reported-by: Eric Biggers <ebiggers@google.com>
Fixes: 14d31979145d ("crypto: powerpc/poly1305 - Add block-only interface")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/arch/powerpc/lib/crypto/poly1305-p10-glue.c b/arch/powerpc/lib/crypto/poly1305-p10-glue.c
index 7cea0ebcc6bc..3f1664a724b6 100644
--- a/arch/powerpc/lib/crypto/poly1305-p10-glue.c
+++ b/arch/powerpc/lib/crypto/poly1305-p10-glue.c
@@ -14,10 +14,7 @@

asmlinkage void poly1305_p10le_4blocks(struct poly1305_block_state *state, const u8 *m, u32 mlen);
asmlinkage void poly1305_64s(struct poly1305_block_state *state, const u8 *m, u32 mlen, int highbit);
-asmlinkage void poly1305_emit_arch(const struct poly1305_state *state,
- u8 digest[POLY1305_DIGEST_SIZE],
- const u32 nonce[4]);
-EXPORT_SYMBOL_GPL(poly1305_emit_arch);
+asmlinkage void poly1305_emit_64(const struct poly1305_state *state, const u32 nonce[4], u8 digest[POLY1305_DIGEST_SIZE]);

static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_p10);

@@ -65,6 +62,16 @@ void poly1305_blocks_arch(struct poly1305_block_state *state, const u8 *src,
}
EXPORT_SYMBOL_GPL(poly1305_blocks_arch);

+void poly1305_emit_arch(const struct poly1305_state *state,
+ u8 digest[POLY1305_DIGEST_SIZE],
+ const u32 nonce[4])
+{
+ if (!static_key_enabled(&have_p10))
+ return poly1305_emit_generic(state, digest, nonce);
+ poly1305_emit_64(state, nonce, digest);
+}
+EXPORT_SYMBOL_GPL(poly1305_emit_arch);
+
bool poly1305_is_arch_optimized(void)
{
return static_key_enabled(&have_p10);
diff --git a/arch/powerpc/lib/crypto/poly1305-p10le_64.S b/arch/powerpc/lib/crypto/poly1305-p10le_64.S
index 2ba2911b8038..a3c1987f1ecd 100644
--- a/arch/powerpc/lib/crypto/poly1305-p10le_64.S
+++ b/arch/powerpc/lib/crypto/poly1305-p10le_64.S
@@ -1030,7 +1030,7 @@ SYM_FUNC_END(poly1305_64s)
# Input: r3 = h, r4 = s, r5 = mac
# mac = h + s
#
-SYM_FUNC_START(poly1305_emit_arch)
+SYM_FUNC_START(poly1305_emit_64)
ld 10, 0(3)
ld 11, 8(3)
ld 12, 16(3)
@@ -1060,7 +1060,7 @@ Skip_h64:
std 10, 0(5)
std 11, 8(5)
blr
-SYM_FUNC_END(poly1305_emit_arch)
+SYM_FUNC_END(poly1305_emit_64)

SYM_DATA_START_LOCAL(RMASK)
.align 5