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>

diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h
index 9b12476..73cf0f5 100644 (file)
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -22,6 +22,10 @@
 #define HWCAP_FP               (1 << 0)
 #define HWCAP_ASIMD            (1 << 1)
 #define HWCAP_EVTSTRM          (1 << 2)
-
+#define HWCAP_AES              (1 << 3)
+#define HWCAP_PMULL            (1 << 4)
+#define HWCAP_SHA1             (1 << 5)
+#define HWCAP_SHA2             (1 << 6)
+#define HWCAP_CRC32            (1 << 7)
 
 #endif /* _UAPI__ASM_HWCAP_H */

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 82d65bb..bb33fff 100644 (file)
--- 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
 };