* [PATCH v12 0/2] ARMv8.5-RNG support
@ 2020-01-20 13:46 Mark Brown
2020-01-20 13:46 ` [PATCH v12 1/2] arm64: Implement archrandom.h for ARMv8.5-RNG Mark Brown
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Mark Brown @ 2020-01-20 13:46 UTC (permalink / raw)
To: Will Deacon, Catalin Marinas
Cc: Mark Rutland, Mark Brown, Richard Henderson, linux-arm-kernel,
Ard Biesheuvel
This series is based on Richard Henderson's previous v7, it addresses
review comments from that version by dropping the boot time RNG
support and adds a new change that uses the v8.5-RNG extension to
seed KASLR when ARCH_RANDOM is enabled. The boot time support
will be re-added later, there are awkward potential interactons
with CPU feature enumeration which need a bit more thought.
v12:
- Move definition of __early_cpu_has_rndr() into KASLR patch.
v11:
- Add a hwcap for v8.5-RNG.
- Drop the addition of data to the pool, it's of questionable
value and we need to go back and get the addition of actual
entropy working anyway.
v10:
- Spell out that we're adding data not entropy from setup_arch() in
the commit message for patch 2.
v9:
- Make another static inline helper for early feature checks.
- Add init annotations.
- Use xor to add RNDR output to seed for KASLR.
Mark Brown (1):
arm64: Use v8.5-RNG entropy for KASLR seed
Richard Henderson (1):
arm64: Implement archrandom.h for ARMv8.5-RNG
Documentation/arm64/cpu-feature-registers.rst | 2 +
arch/arm64/Kconfig | 12 +++
arch/arm64/include/asm/archrandom.h | 75 +++++++++++++++++++
arch/arm64/include/asm/cpucaps.h | 3 +-
arch/arm64/include/asm/sysreg.h | 4 +
arch/arm64/kernel/cpufeature.c | 13 ++++
arch/arm64/kernel/kaslr.c | 11 +++
7 files changed, 119 insertions(+), 1 deletion(-)
create mode 100644 arch/arm64/include/asm/archrandom.h
--
2.20.1
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^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH v12 1/2] arm64: Implement archrandom.h for ARMv8.5-RNG 2020-01-20 13:46 [PATCH v12 0/2] ARMv8.5-RNG support Mark Brown @ 2020-01-20 13:46 ` Mark Brown 2020-01-20 13:46 ` [PATCH v12 2/2] arm64: Use v8.5-RNG entropy for KASLR seed Mark Brown 2020-01-21 11:57 ` [PATCH v12 0/2] ARMv8.5-RNG support Will Deacon 2 siblings, 0 replies; 5+ messages in thread From: Mark Brown @ 2020-01-20 13:46 UTC (permalink / raw) To: Will Deacon, Catalin Marinas Cc: Mark Rutland, Mark Brown, Richard Henderson, linux-arm-kernel, Ard Biesheuvel From: Richard Henderson <richard.henderson@linaro.org> 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> --- Documentation/arm64/cpu-feature-registers.rst | 2 + arch/arm64/Kconfig | 12 ++++ arch/arm64/include/asm/archrandom.h | 67 +++++++++++++++++++ arch/arm64/include/asm/cpucaps.h | 3 +- arch/arm64/include/asm/sysreg.h | 4 ++ arch/arm64/kernel/cpufeature.c | 13 ++++ 6 files changed, 100 insertions(+), 1 deletion(-) create mode 100644 arch/arm64/include/asm/archrandom.h diff --git a/Documentation/arm64/cpu-feature-registers.rst b/Documentation/arm64/cpu-feature-registers.rst index b6e44884e3ad..ce320785fb0c 100644 --- a/Documentation/arm64/cpu-feature-registers.rst +++ b/Documentation/arm64/cpu-feature-registers.rst @@ -117,6 +117,8 @@ infrastructure: +------------------------------+---------+---------+ | Name | bits | visible | +------------------------------+---------+---------+ + | RNDR | [63-60] | y | + +------------------------------+---------+---------+ | TS | [55-52] | y | +------------------------------+---------+---------+ | FHM | [51-48] | y | diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index b1b4476ddb83..835f8158220e 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1484,6 +1484,18 @@ config ARM64_PTR_AUTH endmenu +menu "ARMv8.5 architectural features" + +config ARCH_RANDOM + bool "Enable support for random number generation" + default y + help + Random number generation (part of the ARMv8.5 Extensions) + provides a high bandwidth, cryptographically secure + hardware random number generator. + +endmenu + config ARM64_SVE bool "ARM Scalable Vector Extension support" default y diff --git a/arch/arm64/include/asm/archrandom.h b/arch/arm64/include/asm/archrandom.h new file mode 100644 index 000000000000..5ea5a1ce5a5f --- /dev/null +++ b/arch/arm64/include/asm/archrandom.h @@ -0,0 +1,67 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_ARCHRANDOM_H +#define _ASM_ARCHRANDOM_H + +#ifdef CONFIG_ARCH_RANDOM + +#include <linux/random.h> +#include <asm/cpufeature.h> + +static inline bool __arm64_rndr(unsigned long *v) +{ + bool ok; + + /* + * Reads of RNDR set PSTATE.NZCV to 0b0000 on success, + * and set PSTATE.NZCV to 0b0100 otherwise. + */ + asm volatile( + __mrs_s("%0", SYS_RNDR_EL0) "\n" + " cset %w1, ne\n" + : "=r" (*v), "=r" (ok) + : + : "cc"); + + return ok; +} + +static inline bool __must_check arch_get_random_long(unsigned long *v) +{ + return false; +} + +static inline bool __must_check arch_get_random_int(unsigned int *v) +{ + return false; +} + +static inline bool __must_check arch_get_random_seed_long(unsigned long *v) +{ + /* + * Only support the generic interface after we have detected + * the system wide capability, avoiding complexity with the + * cpufeature code and with potential scheduling between CPUs + * with and without the feature. + */ + if (!cpus_have_const_cap(ARM64_HAS_RNG)) + return false; + + return __arm64_rndr(v); +} + + +static inline bool __must_check arch_get_random_seed_int(unsigned int *v) +{ + unsigned long val; + bool ok = arch_get_random_seed_long(&val); + + *v = val; + return ok; +} + +#else + +static inline bool __arm64_rndr(unsigned long *v) { return false; } + +#endif /* CONFIG_ARCH_RANDOM */ +#endif /* _ASM_ARCHRANDOM_H */ diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h index b92683871119..515f4fbcbf91 100644 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -56,7 +56,8 @@ #define ARM64_WORKAROUND_CAVIUM_TX2_219_PRFM 46 #define ARM64_WORKAROUND_1542419 47 #define ARM64_WORKAROUND_1319367 48 +#define ARM64_HAS_RNG 49 -#define ARM64_NCAPS 49 +#define ARM64_NCAPS 50 #endif /* __ASM_CPUCAPS_H */ diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index 6e919fafb43d..5e718f279469 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -365,6 +365,9 @@ #define SYS_CTR_EL0 sys_reg(3, 3, 0, 0, 1) #define SYS_DCZID_EL0 sys_reg(3, 3, 0, 0, 7) +#define SYS_RNDR_EL0 sys_reg(3, 3, 2, 4, 0) +#define SYS_RNDRRS_EL0 sys_reg(3, 3, 2, 4, 1) + #define SYS_PMCR_EL0 sys_reg(3, 3, 9, 12, 0) #define SYS_PMCNTENSET_EL0 sys_reg(3, 3, 9, 12, 1) #define SYS_PMCNTENCLR_EL0 sys_reg(3, 3, 9, 12, 2) @@ -539,6 +542,7 @@ ENDIAN_SET_EL1 | SCTLR_EL1_UCI | SCTLR_EL1_RES1) /* id_aa64isar0 */ +#define ID_AA64ISAR0_RNDR_SHIFT 60 #define ID_AA64ISAR0_TS_SHIFT 52 #define ID_AA64ISAR0_FHM_SHIFT 48 #define ID_AA64ISAR0_DP_SHIFT 44 diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 04cf64e9f0c9..0fea85228956 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -119,6 +119,7 @@ static void cpu_enable_cnp(struct arm64_cpu_capabilities const *cap); * sync with the documentation of the CPU feature register ABI. */ static const struct arm64_ftr_bits ftr_id_aa64isar0[] = { + ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_RNDR_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_TS_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_FHM_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR0_DP_SHIFT, 4, 0), @@ -1566,6 +1567,18 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .sign = FTR_UNSIGNED, .min_field_value = 1, }, +#endif +#ifdef CONFIG_ARCH_RANDOM + { + .desc = "Random Number Generator", + .capability = ARM64_HAS_RNG, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, + .matches = has_cpuid_feature, + .sys_reg = SYS_ID_AA64ISAR0_EL1, + .field_pos = ID_AA64ISAR0_RNDR_SHIFT, + .sign = FTR_UNSIGNED, + .min_field_value = 1, + }, #endif {}, }; -- 2.20.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH v12 2/2] arm64: Use v8.5-RNG entropy for KASLR seed 2020-01-20 13:46 [PATCH v12 0/2] ARMv8.5-RNG support Mark Brown 2020-01-20 13:46 ` [PATCH v12 1/2] arm64: Implement archrandom.h for ARMv8.5-RNG Mark Brown @ 2020-01-20 13:46 ` Mark Brown 2020-01-21 11:57 ` [PATCH v12 0/2] ARMv8.5-RNG support Will Deacon 2 siblings, 0 replies; 5+ messages in thread From: Mark Brown @ 2020-01-20 13:46 UTC (permalink / raw) To: Will Deacon, Catalin Marinas Cc: Mark Rutland, Mark Brown, Richard Henderson, linux-arm-kernel, Ard Biesheuvel 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> --- arch/arm64/include/asm/archrandom.h | 8 ++++++++ arch/arm64/kernel/kaslr.c | 11 +++++++++++ 2 files changed, 19 insertions(+) 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 */ diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c index 2a11a962e571..53b8a4ee64ff 100644 --- a/arch/arm64/kernel/kaslr.c +++ b/arch/arm64/kernel/kaslr.c @@ -120,6 +120,17 @@ u64 __init kaslr_early_init(u64 dt_phys) return 0; } + /* + * Mix in any entropy obtainable architecturally, open coded + * since this runs extremely early. + */ + if (__early_cpu_has_rndr()) { + unsigned long raw; + + if (__arm64_rndr(&raw)) + seed ^= raw; + } + if (!seed) { kaslr_status = KASLR_DISABLED_NO_SEED; return 0; -- 2.20.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v12 0/2] ARMv8.5-RNG support 2020-01-20 13:46 [PATCH v12 0/2] ARMv8.5-RNG support Mark Brown 2020-01-20 13:46 ` [PATCH v12 1/2] arm64: Implement archrandom.h for ARMv8.5-RNG Mark Brown 2020-01-20 13:46 ` [PATCH v12 2/2] arm64: Use v8.5-RNG entropy for KASLR seed Mark Brown @ 2020-01-21 11:57 ` Will Deacon 2020-01-21 12:10 ` Mark Brown 2 siblings, 1 reply; 5+ messages in thread From: Will Deacon @ 2020-01-21 11:57 UTC (permalink / raw) To: Mark Brown Cc: Mark Rutland, Catalin Marinas, Richard Henderson, linux-arm-kernel, Ard Biesheuvel On Mon, Jan 20, 2020 at 01:46:19PM +0000, Mark Brown wrote: > This series is based on Richard Henderson's previous v7, it addresses > review comments from that version by dropping the boot time RNG > support and adds a new change that uses the v8.5-RNG extension to > seed KASLR when ARCH_RANDOM is enabled. The boot time support > will be re-added later, there are awkward potential interactons > with CPU feature enumeration which need a bit more thought. > > v12: > - Move definition of __early_cpu_has_rndr() into KASLR patch. Hmm, the HWCAP also seems to have disappeared in this version :/ Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v12 0/2] ARMv8.5-RNG support 2020-01-21 11:57 ` [PATCH v12 0/2] ARMv8.5-RNG support Will Deacon @ 2020-01-21 12:10 ` Mark Brown 0 siblings, 0 replies; 5+ messages in thread From: Mark Brown @ 2020-01-21 12:10 UTC (permalink / raw) To: Will Deacon Cc: Mark Rutland, Catalin Marinas, Richard Henderson, linux-arm-kernel, Ard Biesheuvel [-- Attachment #1.1: Type: text/plain, Size: 492 bytes --] On Tue, Jan 21, 2020 at 11:57:13AM +0000, Will Deacon wrote: > On Mon, Jan 20, 2020 at 01:46:19PM +0000, Mark Brown wrote: > > This series is based on Richard Henderson's previous v7, it addresses > > review comments from that version by dropping the boot time RNG > Hmm, the HWCAP also seems to have disappeared in this version :/ Oh, sorry :( I was travelling last week and apparently messed up moving this from my laptop back to my desktop before sending this out. Let's try again... [-- Attachment #1.2: signature.asc --] [-- Type: application/pgp-signature, Size: 488 bytes --] [-- Attachment #2: Type: text/plain, Size: 176 bytes --] _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2020-01-21 12:10 UTC | newest] Thread overview: 5+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2020-01-20 13:46 [PATCH v12 0/2] ARMv8.5-RNG support Mark Brown 2020-01-20 13:46 ` [PATCH v12 1/2] arm64: Implement archrandom.h for ARMv8.5-RNG Mark Brown 2020-01-20 13:46 ` [PATCH v12 2/2] arm64: Use v8.5-RNG entropy for KASLR seed Mark Brown 2020-01-21 11:57 ` [PATCH v12 0/2] ARMv8.5-RNG support Will Deacon 2020-01-21 12:10 ` Mark Brown
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