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authorMark Brown <broonie@kernel.org>2020-01-21 15:58:53 +0300
committerWill Deacon <will@kernel.org>2020-01-22 12:54:52 +0300
commit2e8e1ea88cbcb19a77b7acb67f6ffe39cc15740c (patch)
tree24b908d1f3608e4bebf845d9b3202d83e5881beb /arch/arm64/include/asm/archrandom.h
parent1a50ec0b3b2e9a83f1b1245ea37a853aac2f741c (diff)
downloadlinux-2e8e1ea88cbcb19a77b7acb67f6ffe39cc15740c.tar.xz
arm64: Use v8.5-RNG entropy for KASLR seed
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>
Diffstat (limited to 'arch/arm64/include/asm/archrandom.h')
-rw-r--r--arch/arm64/include/asm/archrandom.h8
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/archrandom.h b/arch/arm64/include/asm/archrandom.h
index 5ea5a1ce5a5f..3fe02da70004 100644
--- a/arch/arm64/include/asm/archrandom.h
+++ b/arch/arm64/include/asm/archrandom.h
@@ -59,9 +59,17 @@ static inline bool __must_check arch_get_random_seed_int(unsigned int *v)
return ok;
}
+static inline bool __init __early_cpu_has_rndr(void)
+{
+ /* Open code as we run prior to the first call to cpufeature. */
+ unsigned long ftr = read_sysreg_s(SYS_ID_AA64ISAR0_EL1);
+ return (ftr >> ID_AA64ISAR0_RNDR_SHIFT) & 0xf;
+}
+
#else
static inline bool __arm64_rndr(unsigned long *v) { return false; }
+static inline bool __init __early_cpu_has_rndr(void) { return false; }
#endif /* CONFIG_ARCH_RANDOM */
#endif /* _ASM_ARCHRANDOM_H */