diff options
| -rw-r--r-- | arch/x86/boot/compressed/aslr.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86/boot/compressed/aslr.c b/arch/x86/boot/compressed/aslr.c index 8746487fa916..38a07cc4fbac 100644 --- a/arch/x86/boot/compressed/aslr.c +++ b/arch/x86/boot/compressed/aslr.c @@ -64,6 +64,11 @@ static unsigned long get_random_boot(void) static unsigned long get_random_long(void) { +#ifdef CONFIG_X86_64 + const unsigned long mix_const = 0x5d6008cbf3848dd3UL; +#else + const unsigned long mix_const = 0x3f39e593UL; +#endif unsigned long raw, random = get_random_boot(); bool use_i8254 = true; @@ -90,6 +95,12 @@ static unsigned long get_random_long(void) random ^= i8254(); } + /* Circular multiply for better bit diffusion */ + asm("mul %3" + : "=a" (random), "=d" (raw) + : "a" (random), "rm" (mix_const)); + random += raw; + debug_putstr("...\n"); return random; |