diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 5 | ||||
| -rw-r--r-- | arch/x86/Kconfig | 9 | ||||
| -rw-r--r-- | arch/x86/include/asm/archrandom.h | 75 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/rdrand.c | 73 | ||||
| -rw-r--r-- | drivers/char/random.c | 23 | ||||
| -rw-r--r-- | include/linux/random.h | 13 |
8 files changed, 199 insertions, 2 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 6afd091bc1f8..93413ce96883 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1797,6 +1797,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. noresidual [PPC] Don't use residual data on PReP machines. + nordrand [X86] Disable the direct use of the RDRAND + instruction even if it is supported by the + processor. RDRAND is still available to user + space applications. + noresume [SWSUSP] Disables resume and restores original swap space. diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 16db864c42b7..77f7a384c0b5 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1454,6 +1454,15 @@ config ARCH_USES_PG_UNCACHED def_bool y depends on X86_PAT +config ARCH_RANDOM + def_bool y + prompt "x86 architectural random number generator" if EXPERT + ---help--- + Enable the x86 architectural RDRAND instruction + (Intel Bull Mountain technology) to generate random numbers. + If supported, this is a high bandwidth, cryptographically + secure hardware random number generator. + config EFI bool "EFI runtime service support" depends on ACPI diff --git a/arch/x86/include/asm/archrandom.h b/arch/x86/include/asm/archrandom.h new file mode 100644 index 000000000000..0d9ec770f2f8 --- /dev/null +++ b/arch/x86/include/asm/archrandom.h @@ -0,0 +1,75 @@ +/* + * This file is part of the Linux kernel. + * + * Copyright (c) 2011, Intel Corporation + * Authors: Fenghua Yu <fenghua.yu@intel.com>, + * H. Peter Anvin <hpa@linux.intel.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. + * + */ + +#ifndef ASM_X86_ARCHRANDOM_H +#define ASM_X86_ARCHRANDOM_H + +#include <asm/processor.h> +#include <asm/cpufeature.h> +#include <asm/alternative.h> +#include <asm/nops.h> + +#define RDRAND_RETRY_LOOPS 10 + +#define RDRAND_INT ".byte 0x0f,0xc7,0xf0" +#ifdef CONFIG_X86_64 +# define RDRAND_LONG ".byte 0x48,0x0f,0xc7,0xf0" +#else +# define RDRAND_LONG RDRAND_INT +#endif + +#ifdef CONFIG_ARCH_RANDOM + +#define GET_RANDOM(name, type, rdrand, nop) \ +static inline int name(type *v) \ +{ \ + int ok; \ + alternative_io("movl $0, %0\n\t" \ + nop, \ + "\n1: " rdrand "\n\t" \ + "jc 2f\n\t" \ + "decl %0\n\t" \ + "jnz 1b\n\t" \ + "2:", \ + X86_FEATURE_RDRAND, \ + ASM_OUTPUT2("=r" (ok), "=a" (*v)), \ + "0" (RDRAND_RETRY_LOOPS)); \ + return ok; \ +} + +#ifdef CONFIG_X86_64 + +GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP5); +GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP4); + +#else + +GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP3); +GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP3); + +#endif /* CONFIG_X86_64 */ + +#endif /* CONFIG_ARCH_RANDOM */ + +extern void x86_init_rdrand(struct cpuinfo_x86 *c); + +#endif /* ASM_X86_ARCHRANDOM_H */ diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile index fe6eb197f848..25f24dccdcfa 100644 --- a/arch/x86/kernel/cpu/Makefile +++ b/arch/x86/kernel/cpu/Makefile @@ -15,6 +15,7 @@ CFLAGS_common.o := $(nostackp) obj-y := intel_cacheinfo.o scattered.o topology.o obj-y += proc.o capflags.o powerflags.o common.o obj-y += vmware.o hypervisor.o sched.o mshyperv.o +obj-y += rdrand.o obj-$(CONFIG_X86_32) += bugs.o obj-$(CONFIG_X86_64) += bugs_64.o diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index ec63df54d138..aa003b13a831 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -15,6 +15,7 @@ #include <asm/stackprotector.h> #include <asm/perf_event.h> #include <asm/mmu_context.h> +#include <asm/archrandom.h> #include <asm/hypervisor.h> #include <asm/processor.h> #include <asm/sections.h> @@ -860,6 +861,7 @@ static void __cpuinit identify_cpu(struct cpuinfo_x86 *c) #endif init_hypervisor(c); + x86_init_rdrand(c); /* * Clear/Set all flags overriden by options, need do it diff --git a/arch/x86/kernel/cpu/rdrand.c b/arch/x86/kernel/cpu/rdrand.c new file mode 100644 index 000000000000..feca286c2bb4 --- /dev/null +++ b/arch/x86/kernel/cpu/rdrand.c @@ -0,0 +1,73 @@ +/* + * This file is part of the Linux kernel. + * + * Copyright (c) 2011, Intel Corporation + * Authors: Fenghua Yu <fenghua.yu@intel.com>, + * H. Peter Anvin <hpa@linux.intel.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. + * + */ + +#include <asm/processor.h> +#include <asm/archrandom.h> +#include <asm/sections.h> + +static int __init x86_rdrand_setup(char *s) +{ + setup_clear_cpu_cap(X86_FEATURE_RDRAND); + return 1; +} +__setup("nordrand", x86_rdrand_setup); + +/* We can't use arch_get_random_long() here since alternatives haven't run */ +static inline int rdrand_long(unsigned long *v) +{ + int ok; + asm volatile("1: " RDRAND_LONG "\n\t" + "jc 2f\n\t" + "decl %0\n\t" + "jnz 1b\n\t" + "2:" + : "=r" (ok), "=a" (*v) + : "0" (RDRAND_RETRY_LOOPS)); + return ok; +} + +/* + * Force a reseed cycle; we are architecturally guaranteed a reseed + * after no more than 512 128-bit chunks of random data. This also + * acts as a test of the CPU capability. + */ +#define RESEED_LOOP ((512*128)/sizeof(unsigned long)) + +void __cpuinit x86_init_rdrand(struct cpuinfo_x86 *c) +{ +#ifdef CONFIG_ARCH_RANDOM + unsigned long tmp; + int i, count, ok; + + if (!cpu_has(c, X86_FEATURE_RDRAND)) + return; /* Nothing to do */ + + for (count = i = 0; i < RESEED_LOOP; i++) { + ok = rdrand_long(&tmp); + if (ok) + count++; + } + + if (count != RESEED_LOOP) + clear_cpu_cap(c, X86_FEATURE_RDRAND); +#endif +} diff --git a/drivers/char/random.c b/drivers/char/random.c index c35a785005b0..63e19ba56bbe 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -932,7 +932,21 @@ static ssize_t extract_entropy_user(struct entropy_store *r, void __user *buf, */ void get_random_bytes(void *buf, int nbytes) { - extract_entropy(&nonblocking_pool, buf, nbytes, 0, 0); + char *p = buf; + + while (nbytes) { + unsigned long v; + int chunk = min(nbytes, (int)sizeof(unsigned long)); + + if (!arch_get_random_long(&v)) + break; + + memcpy(buf, &v, chunk); + p += chunk; + nbytes -= chunk; + } + + extract_entropy(&nonblocking_pool, p, nbytes, 0, 0); } EXPORT_SYMBOL(get_random_bytes); @@ -1318,9 +1332,14 @@ late_initcall(random_int_secret_init); DEFINE_PER_CPU(__u32 [MD5_DIGEST_WORDS], get_random_int_hash); unsigned int get_random_int(void) { - __u32 *hash = get_cpu_var(get_random_int_hash); + __u32 *hash; unsigned int ret; + if (arch_get_random_int(&ret)) + return ret; + + hash = get_cpu_var(get_random_int_hash); + hash[0] += current->pid + jiffies + get_cycles(); md5_transform(hash, random_int_secret); ret = hash[0]; diff --git a/include/linux/random.h b/include/linux/random.h index d13059f3ea32..8f74538c96db 100644 --- a/include/linux/random.h +++ b/include/linux/random.h @@ -91,6 +91,19 @@ static inline void prandom32_seed(struct rnd_state *state, u64 seed) state->s3 = __seed(i, 15); } +#ifdef CONFIG_ARCH_RANDOM +# include <asm/archrandom.h> +#else +static inline int arch_get_random_long(unsigned long *v) +{ + return 0; +} +static inline int arch_get_random_int(unsigned int *v) +{ + return 0; +} +#endif + #endif /* __KERNEL___ */ #endif /* _LINUX_RANDOM_H */ |