arm64: Add hwcaps for crypto and CRC32 extensions.

Advertise the optional cryptographic and CRC32 instructions to
user space where present. Several hwcap bits [3-7] are allocated.

Signed-off-by: Steve Capper <steve.capper@linaro.org>
[bit 2 is taken now so use bits 3-7 instead]
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 82d65bb536b2..bb33fff09ba2 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -126,6 +126,7 @@ bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
 static void __init setup_processor(void)
 {
         struct cpu_info *cpu_info;
+        u64 features, block;
 
         cpu_info = lookup_processor_type(read_cpuid_id());
         if (!cpu_info) {
@@ -141,6 +142,37 @@ static void __init setup_processor(void)
 
         sprintf(init_utsname()->machine, ELF_PLATFORM);
         elf_hwcap = 0;
+
+        /*
+         * ID_AA64ISAR0_EL1 contains 4-bit wide signed feature blocks.
+         * The blocks we test below represent incremental functionality
+         * for non-negative values. Negative values are reserved.
+         */
+        features = read_cpuid(ID_AA64ISAR0_EL1);
+        block = (features >> 4) & 0xf;
+        if (!(block & 0x8)) {
+                switch (block) {
+                default:
+                case 2:
+                        elf_hwcap |= HWCAP_PMULL;
+                case 1:
+                        elf_hwcap |= HWCAP_AES;
+                case 0:
+                        break;
+                }
+        }
+
+        block = (features >> 8) & 0xf;
+        if (block && !(block & 0x8))
+                elf_hwcap |= HWCAP_SHA1;
+
+        block = (features >> 12) & 0xf;
+        if (block && !(block & 0x8))
+                elf_hwcap |= HWCAP_SHA2;
+
+        block = (features >> 16) & 0xf;
+        if (block && !(block & 0x8))
+                elf_hwcap |= HWCAP_CRC32;
 }
 
 static void __init setup_machine_fdt(phys_addr_t dt_phys)
@@ -280,6 +312,11 @@ static const char *hwcap_str[] = {
         "fp",
         "asimd",
         "evtstrm",
+        "aes",
+        "pmull",
+        "sha1",
+        "sha2",
+        "crc32",
         NULL
 };