Use CC_SET()/CC_OUT() and static_cpu_has(). This produces code good
enough to eliminate ad hoc use of alternatives in ,
greatly simplifying the code.
Signed-off-by: H. Peter Anvin
---
arch/x86/include/asm/archrandom.h | 113 --
1 file changed, 47 insertions(+), 66 deletions(-)
diff --git a/arch/x86/include/asm/archrandom.h
b/arch/x86/include/asm/archrandom.h
index ab6f599..654da36 100644
--- a/arch/x86/include/asm/archrandom.h
+++ b/arch/x86/include/asm/archrandom.h
@@ -40,96 +40,77 @@
# define RDSEED_LONG RDSEED_INT
#endif
-#ifdef CONFIG_ARCH_RANDOM
+/* Unconditional execution of RDRAND and RDSEED */
-/* Instead of arch_get_random_long() when alternatives haven't run. */
static inline bool 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;
+ bool ok;
+ unsigned int retry = RDRAND_RETRY_LOOPS;
+ do {
+ asm volatile(RDRAND_LONG "\n\t"
+CC_SET(c)
+: CC_OUT(c) (ok), "=a" (*v));
+ if (ok)
+ return true;
+ } while (--retry);
+ return false;
+}
+
+static inline bool rdrand_int(unsigned int *v)
+{
+ bool ok;
+ unsigned int retry = RDRAND_RETRY_LOOPS;
+ do {
+ asm volatile(RDRAND_INT "\n\t"
+CC_SET(c)
+: CC_OUT(c) (ok), "=a" (*v));
+ if (ok)
+ return true;
+ } while (--retry);
+ return false;
}
-/* A single attempt at RDSEED */
static inline bool rdseed_long(unsigned long *v)
{
bool ok;
asm volatile(RDSEED_LONG "\n\t"
-"setc %0"
-: "=qm" (ok), "=a" (*v));
+CC_SET(c)
+: CC_OUT(c) (ok), "=a" (*v));
return ok;
}
-#define GET_RANDOM(name, type, rdrand, nop)\
-static inline bool 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;\
-}
-
-#define GET_SEED(name, type, rdseed, nop) \
-static inline bool name(type *v) \
-{ \
- bool ok;\
- alternative_io("movb $0, %0\n\t"\
- nop, \
- rdseed "\n\t"\
- "setc %0", \
- X86_FEATURE_RDSEED, \
- ASM_OUTPUT2("=q" (ok), "=a" (*v))); \
- return ok; \
+static inline bool rdseed_int(unsigned int *v)
+{
+ bool ok;
+ asm volatile(RDSEED_INT "\n\t"
+CC_SET(c)
+: CC_OUT(c) (ok), "=a" (*v));
+ 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);
-
-GET_SEED(arch_get_random_seed_long, unsigned long, RDSEED_LONG, ASM_NOP5);
-GET_SEED(arch_get_random_seed_int, unsigned int, RDSEED_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);
-
-GET_SEED(arch_get_random_seed_long, unsigned long, RDSEED_LONG, ASM_NOP4);
-GET_SEED(arch_get_random_seed_int, unsigned int, RDSEED_INT, ASM_NOP4);
-
-#endif /* CONFIG_X86_64 */
-
+/* Conditional execution based on CPU type */
#define arch_has_random() static_cpu_has(X86_FEATURE_RDRAND)
#define arch_has_random_seed() static_cpu_has(X86_FEATURE_RDSEED)
-#else
+static inline bool arch_get_random_long(unsigned long *v)
+{
+ ret
