[PATCH 6/17] zinc: Add arm accelerated chacha20

Herbert Xu
2019-03-22T06:31:44Z

This patch exposes the crypto API arm neon chacha20 implementation
through zinc.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---

lib/zinc/Kconfig | 2 +
lib/zinc/chacha20/chacha20-arm-glue.c | 68 ++++++++++++++++++++++++++++++++++
lib/zinc/chacha20/chacha20.c | 2 +
3 files changed, 72 insertions(+)

diff --git a/lib/zinc/Kconfig b/lib/zinc/Kconfig
index 010547fa6c9d..2d1750c50919 100644
--- a/lib/zinc/Kconfig
+++ b/lib/zinc/Kconfig
@@ -2,6 +2,8 @@ config ZINC_CHACHA20
tristate
select CRYPTO_CHACHA20
select CRYPTO_CHACHA20_X86_64 if ZINC_ARCH_X86_64
+ select CRYPTO_CHACHA20_NEON if ZINC_ARCH_ARM
+ select CRYPTO_CHACHA20_NEON if ZINC_ARCH_ARM64

config ZINC_SELFTEST
bool "Zinc cryptography library self-tests"
diff --git a/lib/zinc/chacha20/chacha20-arm-glue.c b/lib/zinc/chacha20/chacha20-arm-glue.c
new file mode 100644
index 000000000000..2b6c88cf516b
--- /dev/null
+++ b/lib/zinc/chacha20/chacha20-arm-glue.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+/*
+ * Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#include <asm/hwcap.h>
+#include <asm/neon.h>
+#if defined(CONFIG_ZINC_ARCH_ARM)
+#include <asm/system_info.h>
+#include <asm/cputype.h>
+#endif
+#include <crypto/chacha.h>
+
+static bool chacha20_use_neon __ro_after_init;
+static bool *const chacha20_nobs[] __initconst = { &chacha20_use_neon };
+static void __init chacha20_fpu_init(void)
+{
+#if defined(CONFIG_ZINC_ARCH_ARM64)
+ chacha20_use_neon = elf_hwcap & HWCAP_ASIMD;
+#elif defined(CONFIG_ZINC_ARCH_ARM)
+ switch (read_cpuid_part()) {
+ case ARM_CPU_PART_CORTEX_A7:
+ case ARM_CPU_PART_CORTEX_A5:
+ /* The Cortex-A7 and Cortex-A5 do not perform well with the NEON
+ * implementation but do incredibly with the scalar one and use
+ * less power.
+ */
+ break;
+ default:
+ chacha20_use_neon = elf_hwcap & HWCAP_NEON;
+ }
+#endif
+}
+
+static inline bool chacha20_arch(struct chacha20_ctx *ctx, u8 *dst,
+ const u8 *src, size_t len,
+ simd_context_t *simd_context)
+{
+ /* SIMD disables preemption, so relax after processing each page. */
+ BUILD_BUG_ON(PAGE_SIZE < CHACHA20_BLOCK_SIZE ||
+ PAGE_SIZE % CHACHA20_BLOCK_SIZE);
+
+ if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !chacha20_use_neon ||
+ len < CHACHA20_BLOCK_SIZE * 3 || !simd_use(simd_context)) {
+
+ for (;;) {
+ const size_t bytes = min_t(size_t, len, PAGE_SIZE);
+
+ crypto_chacha_neon(ctx->state, dst, src, bytes, 20);
+
+ len -= bytes;
+ if (!len)
+ break;
+ dst += bytes;
+ src += bytes;
+ simd_relax(simd_context);
+ }
+
+ return true;
+}
+
+static inline bool hchacha20_arch(u32 derived_key[CHACHA20_KEY_WORDS],
+ const u8 nonce[HCHACHA20_NONCE_SIZE],
+ const u8 key[HCHACHA20_KEY_SIZE],
+ simd_context_t *simd_context)
+{
+ return false;
+}
diff --git a/lib/zinc/chacha20/chacha20.c b/lib/zinc/chacha20/chacha20.c
index c84fe504623f..314525f86757 100644
--- a/lib/zinc/chacha20/chacha20.c
+++ b/lib/zinc/chacha20/chacha20.c
@@ -19,6 +19,8 @@

#if defined(CONFIG_ZINC_ARCH_X86_64)
#include "chacha20-x86_64-glue.c"
+#elif defined(CONFIG_ZINC_ARCH_ARM) || defined(CONFIG_ZINC_ARCH_ARM64)
+#include "chacha20-arm-glue.c"
#else
static bool *const chacha20_nobs[] __initconst = { };
static void __init chacha20_fpu_init(void)