With the SIMD code path removed, we can clean up the CCM auth-only path
a bit further, by passing the 'macp' input buffer pointer by value,
rather than by reference, and taking the output value from the
function's return value.
This way, the compiler is no longer forced to allocate macp on the
stack. This is not expected to make any difference in practice, it just
makes for slightly cleaner code.
Signed-off-by: Ard Biesheuvel <[email protected]>
---
arch/arm64/crypto/aes-ce-ccm-core.S | 23 ++++++++++----------
arch/arm64/crypto/aes-ce-ccm-glue.c | 17 +++++----------
2 files changed, 17 insertions(+), 23 deletions(-)
diff --git a/arch/arm64/crypto/aes-ce-ccm-core.S b/arch/arm64/crypto/aes-ce-ccm-core.S
index 8adff299fcd3..b03f7f71f893 100644
--- a/arch/arm64/crypto/aes-ce-ccm-core.S
+++ b/arch/arm64/crypto/aes-ce-ccm-core.S
@@ -12,22 +12,21 @@
.arch armv8-a+crypto
/*
- * void ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
- * u32 *macp, u8 const rk[], u32 rounds);
+ * u32 ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
+ * u32 macp, u8 const rk[], u32 rounds);
*/
SYM_FUNC_START(ce_aes_ccm_auth_data)
- ldr w8, [x3] /* leftover from prev round? */
ld1 {v0.16b}, [x0] /* load mac */
- cbz w8, 1f
- sub w8, w8, #16
+ cbz w3, 1f
+ sub w3, w3, #16
eor v1.16b, v1.16b, v1.16b
0: ldrb w7, [x1], #1 /* get 1 byte of input */
subs w2, w2, #1
- add w8, w8, #1
+ add w3, w3, #1
ins v1.b[0], w7
ext v1.16b, v1.16b, v1.16b, #1 /* rotate in the input bytes */
beq 8f /* out of input? */
- cbnz w8, 0b
+ cbnz w3, 0b
eor v0.16b, v0.16b, v1.16b
1: ld1 {v3.4s}, [x4] /* load first round key */
prfm pldl1strm, [x1]
@@ -62,7 +61,7 @@ SYM_FUNC_START(ce_aes_ccm_auth_data)
beq 10f
adds w2, w2, #16
beq 10f
- mov w8, w2
+ mov w3, w2
7: ldrb w7, [x1], #1
umov w6, v0.b[0]
eor w6, w6, w7
@@ -71,15 +70,15 @@ SYM_FUNC_START(ce_aes_ccm_auth_data)
beq 10f
ext v0.16b, v0.16b, v0.16b, #1 /* rotate out the mac bytes */
b 7b
-8: cbz w8, 91f
- mov w7, w8
- add w8, w8, #16
+8: cbz w3, 91f
+ mov w7, w3
+ add w3, w3, #16
9: ext v1.16b, v1.16b, v1.16b, #1
adds w7, w7, #1
bne 9b
91: eor v0.16b, v0.16b, v1.16b
st1 {v0.16b}, [x0]
-10: str w8, [x3]
+10: mov w0, w3
ret
SYM_FUNC_END(ce_aes_ccm_auth_data)
diff --git a/arch/arm64/crypto/aes-ce-ccm-glue.c b/arch/arm64/crypto/aes-ce-ccm-glue.c
index 8effd18429ac..d4e87b4e348f 100644
--- a/arch/arm64/crypto/aes-ce-ccm-glue.c
+++ b/arch/arm64/crypto/aes-ce-ccm-glue.c
@@ -29,8 +29,8 @@ static int num_rounds(struct crypto_aes_ctx *ctx)
return 6 + ctx->key_length / 4;
}
-asmlinkage void ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
- u32 *macp, u32 const rk[], u32 rounds);
+asmlinkage u32 ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
+ u32 macp, u32 const rk[], u32 rounds);
asmlinkage void ce_aes_ccm_encrypt(u8 out[], u8 const in[], u32 cbytes,
u32 const rk[], u32 rounds, u8 mac[],
@@ -96,13 +96,6 @@ static int ccm_init_mac(struct aead_request *req, u8 maciv[], u32 msglen)
return 0;
}
-static void ccm_update_mac(struct crypto_aes_ctx *key, u8 mac[], u8 const in[],
- u32 abytes, u32 *macp)
-{
- ce_aes_ccm_auth_data(mac, in, abytes, macp, key->key_enc,
- num_rounds(key));
-}
-
static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[])
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
@@ -122,7 +115,8 @@ static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[])
ltag.len = 6;
}
- ccm_update_mac(ctx, mac, (u8 *)<ag, ltag.len, &macp);
+ macp = ce_aes_ccm_auth_data(mac, (u8 *)<ag, ltag.len, macp,
+ ctx->key_enc, num_rounds(ctx));
scatterwalk_start(&walk, req->src);
do {
@@ -134,7 +128,8 @@ static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[])
n = scatterwalk_clamp(&walk, len);
}
p = scatterwalk_map(&walk);
- ccm_update_mac(ctx, mac, p, n, &macp);
+ macp = ce_aes_ccm_auth_data(mac, p, n, macp, ctx->key_enc,
+ num_rounds(ctx));
len -= n;
scatterwalk_unmap(p);
--
2.20.1
On Fri, May 21, 2021 at 12:20:53PM +0200, Ard Biesheuvel wrote:
> With the SIMD code path removed, we can clean up the CCM auth-only path
> a bit further, by passing the 'macp' input buffer pointer by value,
> rather than by reference, and taking the output value from the
> function's return value.
>
> This way, the compiler is no longer forced to allocate macp on the
> stack. This is not expected to make any difference in practice, it just
> makes for slightly cleaner code.
>
> Signed-off-by: Ard Biesheuvel <[email protected]>
> ---
> arch/arm64/crypto/aes-ce-ccm-core.S | 23 ++++++++++----------
> arch/arm64/crypto/aes-ce-ccm-glue.c | 17 +++++----------
> 2 files changed, 17 insertions(+), 23 deletions(-)
>
> diff --git a/arch/arm64/crypto/aes-ce-ccm-core.S b/arch/arm64/crypto/aes-ce-ccm-core.S
> index 8adff299fcd3..b03f7f71f893 100644
> --- a/arch/arm64/crypto/aes-ce-ccm-core.S
> +++ b/arch/arm64/crypto/aes-ce-ccm-core.S
> @@ -12,22 +12,21 @@
> .arch armv8-a+crypto
>
> /*
> - * void ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
> - * u32 *macp, u8 const rk[], u32 rounds);
> + * u32 ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
> + * u32 macp, u8 const rk[], u32 rounds);
How is this different from 'u8 mac[]' which is already one of the parameters?
- Eric
On Mon, 24 May 2021 at 23:53, Eric Biggers <[email protected]> wrote:
>
> On Fri, May 21, 2021 at 12:20:53PM +0200, Ard Biesheuvel wrote:
> > With the SIMD code path removed, we can clean up the CCM auth-only path
> > a bit further, by passing the 'macp' input buffer pointer by value,
> > rather than by reference, and taking the output value from the
> > function's return value.
> >
> > This way, the compiler is no longer forced to allocate macp on the
> > stack. This is not expected to make any difference in practice, it just
> > makes for slightly cleaner code.
> >
> > Signed-off-by: Ard Biesheuvel <[email protected]>
> > ---
> > arch/arm64/crypto/aes-ce-ccm-core.S | 23 ++++++++++----------
> > arch/arm64/crypto/aes-ce-ccm-glue.c | 17 +++++----------
> > 2 files changed, 17 insertions(+), 23 deletions(-)
> >
> > diff --git a/arch/arm64/crypto/aes-ce-ccm-core.S b/arch/arm64/crypto/aes-ce-ccm-core.S
> > index 8adff299fcd3..b03f7f71f893 100644
> > --- a/arch/arm64/crypto/aes-ce-ccm-core.S
> > +++ b/arch/arm64/crypto/aes-ce-ccm-core.S
> > @@ -12,22 +12,21 @@
> > .arch armv8-a+crypto
> >
> > /*
> > - * void ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
> > - * u32 *macp, u8 const rk[], u32 rounds);
> > + * u32 ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
> > + * u32 macp, u8 const rk[], u32 rounds);
>
> How is this different from 'u8 mac[]' which is already one of the parameters?
>
mac[] is the combined digest/input buffer, and macp is the index into
it that keeps track on how much new input we have accumulated. I.e.,
instead of having a separate buffer of the same size, and accumulating
bytes until we can perform the XOR + AES transformation, the partial
input is accumulated into mac[] using XOR directly.