[PATCH crypto-stable v3 1/2] crypto: arch/lib - limit simd usage to 4k chunks
From: Jason A. Donenfeld
Date: Wed Apr 22 2020 - 19:19:08 EST
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 for the
former two).
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: ed0356eda153 ("crypto: blake2s - x86_64 SIMD implementation")
Cc: Eric Biggers <ebiggers@xxxxxxxxxx>
Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
---
Changes v2->v3:
- [Eric] Split nhpoly1305 changes into separate commit, since it's not
related to the library interface.
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/poly1305-glue.c | 15 +++++++++++----
arch/arm64/crypto/chacha-neon-glue.c | 14 +++++++++++---
arch/arm64/crypto/poly1305-glue.c | 15 +++++++++++----
arch/x86/crypto/blake2s-glue.c | 10 ++++------
arch/x86/crypto/chacha_glue.c | 14 +++++++++++---
arch/x86/crypto/poly1305_glue.c | 13 ++++++-------
7 files changed, 65 insertions(+), 30 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/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/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/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