On Thu, Jul 09, 2020 at 11:51:10AM +0300, Ard Biesheuvel wrote: > > That looks like a sparse bug to me. Since when is it not allowed to > pass a non-const value as a const parameter? > > I.e., you can pass a u64[] to a function that takes a u64 const *, > giving the caller the guarantee that their u64[] will not be modified > during the call, even if it is passed by reference. > > Here, we are dealing with u64[][2], but the same reasoning holds. A > const u64[][2] formal parameter (or u64 const (*)[2] which comes down > to the same thing) does not require a const argument, it only tells > the caller that the array will be left untouched. This is why the > compiler is perfectly happy with this arrangement. You're right. Luc, here is the patch that triggers the bogus warning with sparse. Thanks, -- Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- diff --git a/arch/arm/crypto/ghash-ce-glue.c b/arch/arm/crypto/ghash-ce-glue.c index a00fd329255f..f13401f3e669 100644 --- a/arch/arm/crypto/ghash-ce-glue.c +++ b/arch/arm/crypto/ghash-ce-glue.c @@ -16,6 +16,7 @@ #include <crypto/gf128mul.h> #include <linux/cpufeature.h> #include <linux/crypto.h> +#include <linux/jump_label.h> #include <linux/module.h> MODULE_DESCRIPTION("GHASH hash function using ARMv8 Crypto Extensions"); @@ -27,12 +28,8 @@ MODULE_ALIAS_CRYPTO("ghash"); #define GHASH_DIGEST_SIZE 16 struct ghash_key { - u64 h[2]; - u64 h2[2]; - u64 h3[2]; - u64 h4[2]; - be128 k; + u64 h[][2]; }; struct ghash_desc_ctx { @@ -46,16 +43,12 @@ struct ghash_async_ctx { }; asmlinkage void pmull_ghash_update_p64(int blocks, u64 dg[], const char *src, - struct ghash_key const *k, - const char *head); + u64 const h[][2], const char *head); asmlinkage void pmull_ghash_update_p8(int blocks, u64 dg[], const char *src, - struct ghash_key const *k, - const char *head); + u64 const h[][2], const char *head); -static void (*pmull_ghash_update)(int blocks, u64 dg[], const char *src, - struct ghash_key const *k, - const char *head); +static __ro_after_init DEFINE_STATIC_KEY_FALSE(use_p64); static int ghash_init(struct shash_desc *desc) { @@ -70,7 +63,10 @@ static void ghash_do_update(int blocks, u64 dg[], const char *src, { if (likely(crypto_simd_usable())) { kernel_neon_begin(); - pmull_ghash_update(blocks, dg, src, key, head); + if (static_branch_likely(&use_p64)) + pmull_ghash_update_p64(blocks, dg, src, key->h, head); + else + pmull_ghash_update_p8(blocks, dg, src, key->h, head); kernel_neon_end(); } else { be128 dst = { cpu_to_be64(dg[1]), cpu_to_be64(dg[0]) }; @@ -161,25 +157,26 @@ static int ghash_setkey(struct crypto_shash *tfm, const u8 *inkey, unsigned int keylen) { struct ghash_key *key = crypto_shash_ctx(tfm); - be128 h; if (keylen != GHASH_BLOCK_SIZE) return -EINVAL; /* needed for the fallback */ memcpy(&key->k, inkey, GHASH_BLOCK_SIZE); - ghash_reflect(key->h, &key->k); + ghash_reflect(key->h[0], &key->k); - h = key->k; - gf128mul_lle(&h, &key->k); - ghash_reflect(key->h2, &h); + if (static_branch_likely(&use_p64)) { + be128 h = key->k; - gf128mul_lle(&h, &key->k); - ghash_reflect(key->h3, &h); + gf128mul_lle(&h, &key->k); + ghash_reflect(key->h[1], &h); - gf128mul_lle(&h, &key->k); - ghash_reflect(key->h4, &h); + gf128mul_lle(&h, &key->k); + ghash_reflect(key->h[2], &h); + gf128mul_lle(&h, &key->k); + ghash_reflect(key->h[3], &h); + } return 0; } @@ -195,7 +192,7 @@ static struct shash_alg ghash_alg = { .base.cra_driver_name = "ghash-ce-sync", .base.cra_priority = 300 - 1, .base.cra_blocksize = GHASH_BLOCK_SIZE, - .base.cra_ctxsize = sizeof(struct ghash_key), + .base.cra_ctxsize = sizeof(struct ghash_key) + sizeof(u64[2]), .base.cra_module = THIS_MODULE, }; @@ -354,10 +351,10 @@ static int __init ghash_ce_mod_init(void) if (!(elf_hwcap & HWCAP_NEON)) return -ENODEV; - if (elf_hwcap2 & HWCAP2_PMULL) - pmull_ghash_update = pmull_ghash_update_p64; - else - pmull_ghash_update = pmull_ghash_update_p8; + if (elf_hwcap2 & HWCAP2_PMULL) { + ghash_alg.base.cra_ctxsize += 3 * sizeof(u64[2]); + static_branch_enable(&use_p64); + } err = crypto_register_shash(&ghash_alg); if (err)
