From mboxrd@z Thu Jan 1 00:00:00 1970 From: ard.biesheuvel@linaro.org (Ard Biesheuvel) Date: Fri, 27 Feb 2015 16:36:31 +0000 Subject: [PATCH] ARM: advertise availability of v8 Crypto instructions Message-ID: <1425054991-29951-1-git-send-email-ard.biesheuvel@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org When running the 32-bit ARM kernel on ARMv8 capable bare metal (e.g., 32-bit Android userland and kernel on a Cortex-A53), or as a KVM guest on a 64-bit host, we should advertise the availability of the Crypto instructions, so that userland libraries such as OpenSSL may use them. (Support for the v8 Crypto instructions in the 32-bit build was added to OpenSSL more than six months ago) This adds the ID feature bit detection, and sets elf_hwcap2 accordingly. Signed-off-by: Ard Biesheuvel --- arch/arm/kernel/setup.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index e55408e96559..8d4cb1c1c9ac 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -393,6 +393,22 @@ static void __init cpuid_init_hwcaps(void) vmsa = (read_cpuid_ext(CPUID_EXT_MMFR0) & 0xf) >> 0; if (vmsa >= 5) elf_hwcap |= HWCAP_LPAE; + + /* check for supported v8 Crypto instructions on non v7-M CPUs */ + if (cpu_architecture() == CPU_ARCH_ARMv7) { + unsigned int id = read_cpuid_ext(CPUID_EXT_ISAR5); + + switch ((id >> 4) & 0xf) { + case 2: elf_hwcap2 |= HWCAP2_PMULL; + case 1: elf_hwcap2 |= HWCAP2_AES; + } + if (((id >> 8) & 0xf) == 1) + elf_hwcap2 |= HWCAP2_SHA1; + if (((id >> 12) & 0xf) == 1) + elf_hwcap2 |= HWCAP2_SHA2; + if (((id >> 16) & 0xf) == 1) + elf_hwcap2 |= HWCAP2_CRC32; + } } static void __init elf_hwcap_fixup(void) -- 1.8.3.2