2020-04-22 20:04:48

by Jason A. Donenfeld

[permalink] [raw]
Subject: [PATCH crypto-stable v2] crypto: arch - limit simd usage to 4k chunks

The initial Zinc patchset, after some mailing list discussion, contained
code to ensure that kernel_fpu_enable would not be kept on for more than
a 4k chunk, since it disables preemption. The choice of 4k isn't totally
scientific, but it's not a bad guess either, and it's what's used in
both the x86 poly1305, blake2s, and nhpoly1305 code already (in the form
of PAGE_SIZE, which this commit corrects to be explicitly 4k).

Ard did some back of the envelope calculations and found that
at 5 cycles/byte (overestimate) on a 1ghz processor (pretty slow), 4k
means we have a maximum preemption disabling of 20us, which Sebastian
confirmed was probably a good limit.

Unfortunately the chunking appears to have been left out of the final
patchset that added the glue code. So, this commit adds it back in.

Fixes: 84e03fa39fbe ("crypto: x86/chacha - expose SIMD ChaCha routine as library function")
Fixes: b3aad5bad26a ("crypto: arm64/chacha - expose arm64 ChaCha routine as library function")
Fixes: a44a3430d71b ("crypto: arm/chacha - expose ARM ChaCha routine as library function")
Fixes: d7d7b8535662 ("crypto: x86/poly1305 - wire up faster implementations for kernel")
Fixes: f569ca164751 ("crypto: arm64/poly1305 - incorporate OpenSSL/CRYPTOGAMS NEON implementation")
Fixes: a6b803b3ddc7 ("crypto: arm/poly1305 - incorporate OpenSSL/CRYPTOGAMS NEON implementation")
Fixes: 0f961f9f670e ("crypto: x86/nhpoly1305 - add AVX2 accelerated NHPoly1305")
Fixes: 012c82388c03 ("crypto: x86/nhpoly1305 - add SSE2 accelerated NHPoly1305")
Fixes: a00fa0c88774 ("crypto: arm64/nhpoly1305 - add NEON-accelerated NHPoly1305")
Fixes: 16aae3595a9d ("crypto: arm/nhpoly1305 - add NEON-accelerated NHPoly1305")
Fixes: ed0356eda153 ("crypto: blake2s - x86_64 SIMD implementation")
Cc: Eric Biggers <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Sebastian Andrzej Siewior <[email protected]>
Cc: [email protected]
Signed-off-by: Jason A. Donenfeld <[email protected]>
---
Changes v1->v2:
- [Ard] Use explicit 4k chunks instead of PAGE_SIZE.
- [Eric] Prefer do-while over for (;;).

arch/arm/crypto/chacha-glue.c | 14 +++++++++++---
arch/arm/crypto/nhpoly1305-neon-glue.c | 2 +-
arch/arm/crypto/poly1305-glue.c | 15 +++++++++++----
arch/arm64/crypto/chacha-neon-glue.c | 14 +++++++++++---
arch/arm64/crypto/nhpoly1305-neon-glue.c | 2 +-
arch/arm64/crypto/poly1305-glue.c | 15 +++++++++++----
arch/x86/crypto/blake2s-glue.c | 10 ++++------
arch/x86/crypto/chacha_glue.c | 14 +++++++++++---
arch/x86/crypto/nhpoly1305-avx2-glue.c | 2 +-
arch/x86/crypto/nhpoly1305-sse2-glue.c | 2 +-
arch/x86/crypto/poly1305_glue.c | 13 ++++++-------
11 files changed, 69 insertions(+), 34 deletions(-)

diff --git a/arch/arm/crypto/chacha-glue.c b/arch/arm/crypto/chacha-glue.c
index 6fdb0ac62b3d..59da6c0b63b6 100644
--- a/arch/arm/crypto/chacha-glue.c
+++ b/arch/arm/crypto/chacha-glue.c
@@ -91,9 +91,17 @@ void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src, unsigned int bytes,
return;
}

- kernel_neon_begin();
- chacha_doneon(state, dst, src, bytes, nrounds);
- kernel_neon_end();
+ do {
+ unsigned int todo = min_t(unsigned int, bytes, SZ_4K);
+
+ kernel_neon_begin();
+ chacha_doneon(state, dst, src, todo, nrounds);
+ kernel_neon_end();
+
+ bytes -= todo;
+ src += todo;
+ dst += todo;
+ } while (bytes);
}
EXPORT_SYMBOL(chacha_crypt_arch);

diff --git a/arch/arm/crypto/nhpoly1305-neon-glue.c b/arch/arm/crypto/nhpoly1305-neon-glue.c
index ae5aefc44a4d..ffa8d73fe722 100644
--- a/arch/arm/crypto/nhpoly1305-neon-glue.c
+++ b/arch/arm/crypto/nhpoly1305-neon-glue.c
@@ -30,7 +30,7 @@ static int nhpoly1305_neon_update(struct shash_desc *desc,
return crypto_nhpoly1305_update(desc, src, srclen);

do {
- unsigned int n = min_t(unsigned int, srclen, PAGE_SIZE);
+ unsigned int n = min_t(unsigned int, srclen, SZ_4K);

kernel_neon_begin();
crypto_nhpoly1305_update_helper(desc, src, n, _nh_neon);
diff --git a/arch/arm/crypto/poly1305-glue.c b/arch/arm/crypto/poly1305-glue.c
index ceec04ec2f40..13cfef4ae22e 100644
--- a/arch/arm/crypto/poly1305-glue.c
+++ b/arch/arm/crypto/poly1305-glue.c
@@ -160,13 +160,20 @@ void poly1305_update_arch(struct poly1305_desc_ctx *dctx, const u8 *src,
unsigned int len = round_down(nbytes, POLY1305_BLOCK_SIZE);

if (static_branch_likely(&have_neon) && do_neon) {
- kernel_neon_begin();
- poly1305_blocks_neon(&dctx->h, src, len, 1);
- kernel_neon_end();
+ do {
+ unsigned int todo = min_t(unsigned int, len, SZ_4K);
+
+ kernel_neon_begin();
+ poly1305_blocks_neon(&dctx->h, src, todo, 1);
+ kernel_neon_end();
+
+ len -= todo;
+ src += todo;
+ } while (len);
} else {
poly1305_blocks_arm(&dctx->h, src, len, 1);
+ src += len;
}
- src += len;
nbytes %= POLY1305_BLOCK_SIZE;
}

diff --git a/arch/arm64/crypto/chacha-neon-glue.c b/arch/arm64/crypto/chacha-neon-glue.c
index 37ca3e889848..af2bbca38e70 100644
--- a/arch/arm64/crypto/chacha-neon-glue.c
+++ b/arch/arm64/crypto/chacha-neon-glue.c
@@ -87,9 +87,17 @@ void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src, unsigned int bytes,
!crypto_simd_usable())
return chacha_crypt_generic(state, dst, src, bytes, nrounds);

- kernel_neon_begin();
- chacha_doneon(state, dst, src, bytes, nrounds);
- kernel_neon_end();
+ do {
+ unsigned int todo = min_t(unsigned int, bytes, SZ_4K);
+
+ kernel_neon_begin();
+ chacha_doneon(state, dst, src, todo, nrounds);
+ kernel_neon_end();
+
+ bytes -= todo;
+ src += todo;
+ dst += todo;
+ } while (bytes);
}
EXPORT_SYMBOL(chacha_crypt_arch);

diff --git a/arch/arm64/crypto/nhpoly1305-neon-glue.c b/arch/arm64/crypto/nhpoly1305-neon-glue.c
index 895d3727c1fb..c5405e6a6db7 100644
--- a/arch/arm64/crypto/nhpoly1305-neon-glue.c
+++ b/arch/arm64/crypto/nhpoly1305-neon-glue.c
@@ -30,7 +30,7 @@ static int nhpoly1305_neon_update(struct shash_desc *desc,
return crypto_nhpoly1305_update(desc, src, srclen);

do {
- unsigned int n = min_t(unsigned int, srclen, PAGE_SIZE);
+ unsigned int n = min_t(unsigned int, srclen, SZ_4K);

kernel_neon_begin();
crypto_nhpoly1305_update_helper(desc, src, n, _nh_neon);
diff --git a/arch/arm64/crypto/poly1305-glue.c b/arch/arm64/crypto/poly1305-glue.c
index e97b092f56b8..f33ada70c4ed 100644
--- a/arch/arm64/crypto/poly1305-glue.c
+++ b/arch/arm64/crypto/poly1305-glue.c
@@ -143,13 +143,20 @@ void poly1305_update_arch(struct poly1305_desc_ctx *dctx, const u8 *src,
unsigned int len = round_down(nbytes, POLY1305_BLOCK_SIZE);

if (static_branch_likely(&have_neon) && crypto_simd_usable()) {
- kernel_neon_begin();
- poly1305_blocks_neon(&dctx->h, src, len, 1);
- kernel_neon_end();
+ do {
+ unsigned int todo = min_t(unsigned int, len, SZ_4K);
+
+ kernel_neon_begin();
+ poly1305_blocks_neon(&dctx->h, src, todo, 1);
+ kernel_neon_end();
+
+ len -= todo;
+ src += todo;
+ } while (len);
} else {
poly1305_blocks(&dctx->h, src, len, 1);
+ src += len;
}
- src += len;
nbytes %= POLY1305_BLOCK_SIZE;
}

diff --git a/arch/x86/crypto/blake2s-glue.c b/arch/x86/crypto/blake2s-glue.c
index 06ef2d4a4701..6737bcea1fa1 100644
--- a/arch/x86/crypto/blake2s-glue.c
+++ b/arch/x86/crypto/blake2s-glue.c
@@ -32,16 +32,16 @@ void blake2s_compress_arch(struct blake2s_state *state,
const u32 inc)
{
/* SIMD disables preemption, so relax after processing each page. */
- BUILD_BUG_ON(PAGE_SIZE / BLAKE2S_BLOCK_SIZE < 8);
+ BUILD_BUG_ON(SZ_4K / BLAKE2S_BLOCK_SIZE < 8);

if (!static_branch_likely(&blake2s_use_ssse3) || !crypto_simd_usable()) {
blake2s_compress_generic(state, block, nblocks, inc);
return;
}

- for (;;) {
+ do {
const size_t blocks = min_t(size_t, nblocks,
- PAGE_SIZE / BLAKE2S_BLOCK_SIZE);
+ SZ_4K / BLAKE2S_BLOCK_SIZE);

kernel_fpu_begin();
if (IS_ENABLED(CONFIG_AS_AVX512) &&
@@ -52,10 +52,8 @@ void blake2s_compress_arch(struct blake2s_state *state,
kernel_fpu_end();

nblocks -= blocks;
- if (!nblocks)
- break;
block += blocks * BLAKE2S_BLOCK_SIZE;
- }
+ } while (nblocks);
}
EXPORT_SYMBOL(blake2s_compress_arch);

diff --git a/arch/x86/crypto/chacha_glue.c b/arch/x86/crypto/chacha_glue.c
index b412c21ee06e..22250091cdbe 100644
--- a/arch/x86/crypto/chacha_glue.c
+++ b/arch/x86/crypto/chacha_glue.c
@@ -153,9 +153,17 @@ void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src, unsigned int bytes,
bytes <= CHACHA_BLOCK_SIZE)
return chacha_crypt_generic(state, dst, src, bytes, nrounds);

- kernel_fpu_begin();
- chacha_dosimd(state, dst, src, bytes, nrounds);
- kernel_fpu_end();
+ do {
+ unsigned int todo = min_t(unsigned int, bytes, SZ_4K);
+
+ kernel_fpu_begin();
+ chacha_dosimd(state, dst, src, todo, nrounds);
+ kernel_fpu_end();
+
+ bytes -= todo;
+ src += todo;
+ dst += todo;
+ } while (bytes);
}
EXPORT_SYMBOL(chacha_crypt_arch);

diff --git a/arch/x86/crypto/nhpoly1305-avx2-glue.c b/arch/x86/crypto/nhpoly1305-avx2-glue.c
index f7567cbd35b6..80fcb85736e1 100644
--- a/arch/x86/crypto/nhpoly1305-avx2-glue.c
+++ b/arch/x86/crypto/nhpoly1305-avx2-glue.c
@@ -29,7 +29,7 @@ static int nhpoly1305_avx2_update(struct shash_desc *desc,
return crypto_nhpoly1305_update(desc, src, srclen);

do {
- unsigned int n = min_t(unsigned int, srclen, PAGE_SIZE);
+ unsigned int n = min_t(unsigned int, srclen, SZ_4K);

kernel_fpu_begin();
crypto_nhpoly1305_update_helper(desc, src, n, _nh_avx2);
diff --git a/arch/x86/crypto/nhpoly1305-sse2-glue.c b/arch/x86/crypto/nhpoly1305-sse2-glue.c
index a661ede3b5cf..cc6b7c1a2705 100644
--- a/arch/x86/crypto/nhpoly1305-sse2-glue.c
+++ b/arch/x86/crypto/nhpoly1305-sse2-glue.c
@@ -29,7 +29,7 @@ static int nhpoly1305_sse2_update(struct shash_desc *desc,
return crypto_nhpoly1305_update(desc, src, srclen);

do {
- unsigned int n = min_t(unsigned int, srclen, PAGE_SIZE);
+ unsigned int n = min_t(unsigned int, srclen, SZ_4K);

kernel_fpu_begin();
crypto_nhpoly1305_update_helper(desc, src, n, _nh_sse2);
diff --git a/arch/x86/crypto/poly1305_glue.c b/arch/x86/crypto/poly1305_glue.c
index 6dfec19f7d57..dfe921efa9b2 100644
--- a/arch/x86/crypto/poly1305_glue.c
+++ b/arch/x86/crypto/poly1305_glue.c
@@ -91,8 +91,8 @@ static void poly1305_simd_blocks(void *ctx, const u8 *inp, size_t len,
struct poly1305_arch_internal *state = ctx;

/* SIMD disables preemption, so relax after processing each page. */
- BUILD_BUG_ON(PAGE_SIZE < POLY1305_BLOCK_SIZE ||
- PAGE_SIZE % POLY1305_BLOCK_SIZE);
+ BUILD_BUG_ON(SZ_4K < POLY1305_BLOCK_SIZE ||
+ SZ_4K % POLY1305_BLOCK_SIZE);

if (!static_branch_likely(&poly1305_use_avx) ||
(len < (POLY1305_BLOCK_SIZE * 18) && !state->is_base2_26) ||
@@ -102,8 +102,8 @@ static void poly1305_simd_blocks(void *ctx, const u8 *inp, size_t len,
return;
}

- for (;;) {
- const size_t bytes = min_t(size_t, len, PAGE_SIZE);
+ do {
+ const size_t bytes = min_t(size_t, len, SZ_4K);

kernel_fpu_begin();
if (IS_ENABLED(CONFIG_AS_AVX512) && static_branch_likely(&poly1305_use_avx512))
@@ -113,11 +113,10 @@ static void poly1305_simd_blocks(void *ctx, const u8 *inp, size_t len,
else
poly1305_blocks_avx(ctx, inp, bytes, padbit);
kernel_fpu_end();
+
len -= bytes;
- if (!len)
- break;
inp += bytes;
- }
+ } while (len);
}

static void poly1305_simd_emit(void *ctx, u8 mac[POLY1305_DIGEST_SIZE],
--
2.26.2


2020-04-22 22:40:43

by Eric Biggers

[permalink] [raw]
Subject: Re: [PATCH crypto-stable v2] crypto: arch - limit simd usage to 4k chunks

On Wed, Apr 22, 2020 at 02:03:44PM -0600, Jason A. Donenfeld wrote:
> The initial Zinc patchset, after some mailing list discussion, contained
> code to ensure that kernel_fpu_enable would not be kept on for more than
> a 4k chunk, since it disables preemption. The choice of 4k isn't totally
> scientific, but it's not a bad guess either, and it's what's used in
> both the x86 poly1305, blake2s, and nhpoly1305 code already (in the form
> of PAGE_SIZE, which this commit corrects to be explicitly 4k).
>
> Ard did some back of the envelope calculations and found that
> at 5 cycles/byte (overestimate) on a 1ghz processor (pretty slow), 4k
> means we have a maximum preemption disabling of 20us, which Sebastian
> confirmed was probably a good limit.
>
> Unfortunately the chunking appears to have been left out of the final
> patchset that added the glue code. So, this commit adds it back in.
>
> Fixes: 84e03fa39fbe ("crypto: x86/chacha - expose SIMD ChaCha routine as library function")
> Fixes: b3aad5bad26a ("crypto: arm64/chacha - expose arm64 ChaCha routine as library function")
> Fixes: a44a3430d71b ("crypto: arm/chacha - expose ARM ChaCha routine as library function")
> Fixes: d7d7b8535662 ("crypto: x86/poly1305 - wire up faster implementations for kernel")
> Fixes: f569ca164751 ("crypto: arm64/poly1305 - incorporate OpenSSL/CRYPTOGAMS NEON implementation")
> Fixes: a6b803b3ddc7 ("crypto: arm/poly1305 - incorporate OpenSSL/CRYPTOGAMS NEON implementation")
> Fixes: 0f961f9f670e ("crypto: x86/nhpoly1305 - add AVX2 accelerated NHPoly1305")
> Fixes: 012c82388c03 ("crypto: x86/nhpoly1305 - add SSE2 accelerated NHPoly1305")
> Fixes: a00fa0c88774 ("crypto: arm64/nhpoly1305 - add NEON-accelerated NHPoly1305")
> Fixes: 16aae3595a9d ("crypto: arm/nhpoly1305 - add NEON-accelerated NHPoly1305")
> Fixes: ed0356eda153 ("crypto: blake2s - x86_64 SIMD implementation")
> Cc: Eric Biggers <[email protected]>
> Cc: Ard Biesheuvel <[email protected]>
> Cc: Sebastian Andrzej Siewior <[email protected]>
> Cc: [email protected]
> Signed-off-by: Jason A. Donenfeld <[email protected]>
> ---
> Changes v1->v2:
> - [Ard] Use explicit 4k chunks instead of PAGE_SIZE.
> - [Eric] Prefer do-while over for (;;).
>
> arch/arm/crypto/chacha-glue.c | 14 +++++++++++---
> arch/arm/crypto/nhpoly1305-neon-glue.c | 2 +-
> arch/arm/crypto/poly1305-glue.c | 15 +++++++++++----
> arch/arm64/crypto/chacha-neon-glue.c | 14 +++++++++++---
> arch/arm64/crypto/nhpoly1305-neon-glue.c | 2 +-
> arch/arm64/crypto/poly1305-glue.c | 15 +++++++++++----
> arch/x86/crypto/blake2s-glue.c | 10 ++++------
> arch/x86/crypto/chacha_glue.c | 14 +++++++++++---
> arch/x86/crypto/nhpoly1305-avx2-glue.c | 2 +-
> arch/x86/crypto/nhpoly1305-sse2-glue.c | 2 +-
> arch/x86/crypto/poly1305_glue.c | 13 ++++++-------
> 11 files changed, 69 insertions(+), 34 deletions(-)

Can you split the nhpoly1305 changes into a separate patch? They're a bit
different from the rest of this patch, which is fixing up the crypto library
interface that's new in v5.5. The nhpoly1305 changes apply to v5.0 and don't
have anything to do with the crypto library interface, and they're also a bit
different since they replace PAGE_SIZE with 4K rather than unlimited with 4K.

- Eric

2020-04-22 23:10:20

by Jason A. Donenfeld

[permalink] [raw]
Subject: Re: [PATCH crypto-stable v2] crypto: arch - limit simd usage to 4k chunks

On Wed, Apr 22, 2020 at 4:39 PM Eric Biggers <[email protected]> wrote:
> Can you split the nhpoly1305 changes into a separate patch? They're a bit
> different from the rest of this patch, which is fixing up the crypto library
> interface that's new in v5.5. The nhpoly1305 changes apply to v5.0 and don't
> have anything to do with the crypto library interface, and they're also a bit
> different since they replace PAGE_SIZE with 4K rather than unlimited with 4K.

Good point about the nhpoly change not being part of the library
interface and thus backportable differently. I'll split that out and
send a v3 shortly.

Jason