arm64: HWCAP: add support for AT_HWCAP2

As we will exhaust the first 32 bits of AT_HWCAP let's start
exposing AT_HWCAP2 to userspace to give us up to 64 caps.

Whilst it's possible to use the remaining 32 bits of AT_HWCAP, we
prefer to expand into AT_HWCAP2 in order to provide a consistent
view to userspace between ILP32 and LP64. However internal to the
kernel we prefer to continue to use the full space of elf_hwcap.

To reduce complexity and allow for future expansion, we now
represent hwcaps in the kernel as ordinals and use a
KERNEL_HWCAP_ prefix. This allows us to support automatic feature
based module loading for all our hwcaps.

We introduce cpu_set_feature to set hwcaps which complements the
existing cpu_have_feature helper. These helpers allow us to clean
up existing direct uses of elf_hwcap and reduce any future effort
required to move beyond 64 caps.

For convenience we also introduce cpu_{have,set}_named_feature which
makes use of the cpu_feature macro to allow providing a hwcap name
without a {KERNEL_}HWCAP_ prefix.

Signed-off-by: Andrew Murray <andrew.murray@arm.com>
[will: use const_ilog2() and tweak documentation]
Signed-off-by: Will Deacon <will.deacon@arm.com>

7 files changed, 12 insertions, 12 deletions

diff --git a/arch/arm64/crypto/aes-ce-ccm-glue.c b/arch/arm64/crypto/aes-ce-ccm-glue.c
index 5fc6f51908fd..036ea77f83bc 100644
--- a/arch/arm64/crypto/aes-ce-ccm-glue.c
+++ b/arch/arm64/crypto/aes-ce-ccm-glue.c
@@ -372,7 +372,7 @@ static struct aead_alg ccm_aes_alg = {
 
 static int __init aes_mod_init(void)
 {
-	if (!(elf_hwcap & HWCAP_AES))
+	if (!cpu_have_named_feature(AES))
 		return -ENODEV;
 	return crypto_register_aead(&ccm_aes_alg);
 }
diff --git a/arch/arm64/crypto/aes-neonbs-glue.c b/arch/arm64/crypto/aes-neonbs-glue.c
index e7a95a566462..bf1b321ff4c1 100644
--- a/arch/arm64/crypto/aes-neonbs-glue.c
+++ b/arch/arm64/crypto/aes-neonbs-glue.c
@@ -440,7 +440,7 @@ static int __init aes_init(void)
 	int err;
 	int i;
 
-	if (!(elf_hwcap & HWCAP_ASIMD))
+	if (!cpu_have_named_feature(ASIMD))
 		return -ENODEV;
 
 	err = crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
diff --git a/arch/arm64/crypto/chacha-neon-glue.c b/arch/arm64/crypto/chacha-neon-glue.c
index bece1d85bd81..cb054f51c917 100644
--- a/arch/arm64/crypto/chacha-neon-glue.c
+++ b/arch/arm64/crypto/chacha-neon-glue.c
@@ -173,7 +173,7 @@ static struct skcipher_alg algs[] = {
 
 static int __init chacha_simd_mod_init(void)
 {
-	if (!(elf_hwcap & HWCAP_ASIMD))
+	if (!cpu_have_named_feature(ASIMD))
 		return -ENODEV;
 
 	return crypto_register_skciphers(algs, ARRAY_SIZE(algs));
diff --git a/arch/arm64/crypto/crct10dif-ce-glue.c b/arch/arm64/crypto/crct10dif-ce-glue.c
index dd325829ee44..e81d5bd555c0 100644
--- a/arch/arm64/crypto/crct10dif-ce-glue.c
+++ b/arch/arm64/crypto/crct10dif-ce-glue.c
@@ -101,7 +101,7 @@ static struct shash_alg crc_t10dif_alg[] = {{
 
 static int __init crc_t10dif_mod_init(void)
 {
-	if (elf_hwcap & HWCAP_PMULL)
+	if (cpu_have_named_feature(PMULL))
 		return crypto_register_shashes(crc_t10dif_alg,
 					       ARRAY_SIZE(crc_t10dif_alg));
 	else
@@ -111,7 +111,7 @@ static int __init crc_t10dif_mod_init(void)
 
 static void __exit crc_t10dif_mod_exit(void)
 {
-	if (elf_hwcap & HWCAP_PMULL)
+	if (cpu_have_named_feature(PMULL))
 		crypto_unregister_shashes(crc_t10dif_alg,
 					  ARRAY_SIZE(crc_t10dif_alg));
 	else
diff --git a/arch/arm64/crypto/ghash-ce-glue.c b/arch/arm64/crypto/ghash-ce-glue.c
index 791ad422c427..4e69bb78ea89 100644
--- a/arch/arm64/crypto/ghash-ce-glue.c
+++ b/arch/arm64/crypto/ghash-ce-glue.c
@@ -704,10 +704,10 @@ static int __init ghash_ce_mod_init(void)
 {
 	int ret;
 
-	if (!(elf_hwcap & HWCAP_ASIMD))
+	if (!cpu_have_named_feature(ASIMD))
 		return -ENODEV;
 
-	if (elf_hwcap & HWCAP_PMULL)
+	if (cpu_have_named_feature(PMULL))
 		ret = crypto_register_shashes(ghash_alg,
 					      ARRAY_SIZE(ghash_alg));
 	else
@@ -717,7 +717,7 @@ static int __init ghash_ce_mod_init(void)
 	if (ret)
 		return ret;
 
-	if (elf_hwcap & HWCAP_PMULL) {
+	if (cpu_have_named_feature(PMULL)) {
 		ret = crypto_register_aead(&gcm_aes_alg);
 		if (ret)
 			crypto_unregister_shashes(ghash_alg,
@@ -728,7 +728,7 @@ static int __init ghash_ce_mod_init(void)
 
 static void __exit ghash_ce_mod_exit(void)
 {
-	if (elf_hwcap & HWCAP_PMULL)
+	if (cpu_have_named_feature(PMULL))
 		crypto_unregister_shashes(ghash_alg, ARRAY_SIZE(ghash_alg));
 	else
 		crypto_unregister_shash(ghash_alg);
diff --git a/arch/arm64/crypto/nhpoly1305-neon-glue.c b/arch/arm64/crypto/nhpoly1305-neon-glue.c
index 22cc32ac9448..38a589044b6c 100644
--- a/arch/arm64/crypto/nhpoly1305-neon-glue.c
+++ b/arch/arm64/crypto/nhpoly1305-neon-glue.c
@@ -56,7 +56,7 @@ static struct shash_alg nhpoly1305_alg = {
 
 static int __init nhpoly1305_mod_init(void)
 {
-	if (!(elf_hwcap & HWCAP_ASIMD))
+	if (!cpu_have_named_feature(ASIMD))
 		return -ENODEV;
 
 	return crypto_register_shash(&nhpoly1305_alg);
diff --git a/arch/arm64/crypto/sha256-glue.c b/arch/arm64/crypto/sha256-glue.c
index 4aedeaefd61f..0cccdb9cc2c0 100644
--- a/arch/arm64/crypto/sha256-glue.c
+++ b/arch/arm64/crypto/sha256-glue.c
@@ -173,7 +173,7 @@ static int __init sha256_mod_init(void)
 	if (ret)
 		return ret;
 
-	if (elf_hwcap & HWCAP_ASIMD) {
+	if (cpu_have_named_feature(ASIMD)) {
 		ret = crypto_register_shashes(neon_algs, ARRAY_SIZE(neon_algs));
 		if (ret)
 			crypto_unregister_shashes(algs, ARRAY_SIZE(algs));
@@ -183,7 +183,7 @@ static int __init sha256_mod_init(void)
 
 static void __exit sha256_mod_fini(void)
 {
-	if (elf_hwcap & HWCAP_ASIMD)
+	if (cpu_have_named_feature(ASIMD))
 		crypto_unregister_shashes(neon_algs, ARRAY_SIZE(neon_algs));
 	crypto_unregister_shashes(algs, ARRAY_SIZE(algs));
 }