diff options
| author | Kees Cook <keescook@chromium.org> | 2013-10-10 17:18:15 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2013-10-13 03:12:12 -0700 |
| commit | 5bfce5ef55cbe78ee2ee6e97f2e26a8a582008f3 (patch) | |
| tree | ead4a5281554b6f2e0a334cc7e1d83dccf35e15c /arch/x86/include/asm/archrandom.h | |
| parent | 8ab3820fd5b2896d66da7bb2a906bc382e63e7bc (diff) | |
| download | linux-5bfce5ef55cbe78ee2ee6e97f2e26a8a582008f3.tar.gz | |
x86, kaslr: Provide randomness functions
Adds potential sources of randomness: RDRAND, RDTSC, or the i8254.
This moves the pre-alternatives inline rdrand function into the header so
both pieces of code can use it. Availability of RDRAND is then controlled
by CONFIG_ARCH_RANDOM, if someone wants to disable it even for kASLR.
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/1381450698-28710-4-git-send-email-keescook@chromium.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/include/asm/archrandom.h')
| -rw-r--r-- | arch/x86/include/asm/archrandom.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/x86/include/asm/archrandom.h b/arch/x86/include/asm/archrandom.h index 0d9ec770f2f8..e6a92455740e 100644 --- a/arch/x86/include/asm/archrandom.h +++ b/arch/x86/include/asm/archrandom.h @@ -39,6 +39,20 @@ #ifdef CONFIG_ARCH_RANDOM +/* Instead of arch_get_random_long() when 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; +} + #define GET_RANDOM(name, type, rdrand, nop) \ static inline int name(type *v) \ { \ @@ -68,6 +82,13 @@ GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP3); #endif /* CONFIG_X86_64 */ +#else + +static inline int rdrand_long(unsigned long *v) +{ + return 0; +} + #endif /* CONFIG_ARCH_RANDOM */ extern void x86_init_rdrand(struct cpuinfo_x86 *c); |