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path: root/arch/arm64/include/asm/archrandom.h
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2021-01-21arm64: Add support for SMCCC TRNG entropy sourceAndre Przywara
The ARM architected TRNG firmware interface, described in ARM spec DEN0098, defines an ARM SMCCC based interface to a true random number generator, provided by firmware. This can be discovered via the SMCCC >=v1.1 interface, and provides up to 192 bits of entropy per call. Hook this SMC call into arm64's arch_get_random_*() implementation, coming to the rescue when the CPU does not implement the ARM v8.5 RNG system registers. For the detection, we piggy back on the PSCI/SMCCC discovery (which gives us the conduit to use (hvc/smc)), then try to call the ARM_SMCCC_TRNG_VERSION function, which returns -1 if this interface is not implemented. Reviewed-by: Mark Brown <broonie@kernel.org> Signed-off-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Will Deacon <will@kernel.org>
2021-01-21firmware: smccc: Introduce SMCCC TRNG frameworkAndre Przywara
The ARM DEN0098 document describe an SMCCC based firmware service to deliver hardware generated random numbers. Its existence is advertised according to the SMCCC v1.1 specification. Add a (dummy) call to probe functions implemented in each architecture (ARM and arm64), to determine the existence of this interface. For now this return false, but this will be overwritten by each architecture's support patch. Signed-off-by: Andre Przywara <andre.przywara@arm.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Will Deacon <will@kernel.org>
2020-10-07arm64: random: Remove no longer needed prototypesAndre Przywara
Commit 9bceb80b3cc4 ("arm64: kaslr: Use standard early random function") removed the direct calls of the __arm64_rndr() and __early_cpu_has_rndr() functions, but left the dummy prototypes in the #else branch of the #ifdef CONFIG_ARCH_RANDOM guard. Remove the redundant prototypes, as they have no users outside of this header file. Signed-off-by: Andre Przywara <andre.przywara@arm.com> Reviewed-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20201006194453.36519-1-andre.przywara@arm.com Signed-off-by: Will Deacon <will@kernel.org>
2020-08-05random: random.h should include archrandom.h, not the other way aroundLinus Torvalds
This is hopefully the final piece of the crazy puzzle with random.h dependencies. And by "hopefully" I obviously mean "Linus is a hopeless optimist". Reported-and-tested-by: Daniel Díaz <daniel.diaz@linaro.org> Acked-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-27arm64: add credited/trusted RNG supportMark Rutland
Currently arm64 doesn't initialize the primary CRNG in a (potentially) trusted manner as we only detect the presence of the RNG once secondary CPUs are up. Now that the core RNG code distinguishes the early initialization of the primary CRNG, we can implement arch_get_random_seed_long_early() to support this. This patch does so. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Mark Brown <broonie@kernel.org> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20200210130015.17664-4-mark.rutland@arm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-01-22arm64: Use v8.5-RNG entropy for KASLR seedMark Brown
When seeding KALSR on a system where we have architecture level random number generation make use of that entropy, mixing it in with the seed passed by the bootloader. Since this is run very early in init before feature detection is complete we open code rather than use archrandom.h. Signed-off-by: Mark Brown <broonie@kernel.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Will Deacon <will@kernel.org>
2020-01-22arm64: Implement archrandom.h for ARMv8.5-RNGRichard Henderson
Expose the ID_AA64ISAR0.RNDR field to userspace, as the RNG system registers are always available at EL0. Implement arch_get_random_seed_long using RNDR. Given that the TRNG is likely to be a shared resource between cores, and VMs, do not explicitly force re-seeding with RNDRRS. In order to avoid code complexity and potential issues with hetrogenous systems only provide values after cpufeature has finalized the system capabilities. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> [Modified to only function after cpufeature has finalized the system capabilities and move all the code into the header -- broonie] Signed-off-by: Mark Brown <broonie@kernel.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> [will: Advertise HWCAP via /proc/cpuinfo] Signed-off-by: Will Deacon <will@kernel.org>