From: "H. Peter Anvin" <hpa@linux.intel.com>
To: Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@amacapital.net>,
Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@linux.intel.com>
Subject: [PATCH 09/10] x86, asm: Use CC_SET()/CC_OUT() and static_cpu_has() in archrandom.h
Date: Tue, 7 Jun 2016 16:31:08 -0700 [thread overview]
Message-ID: <1465342269-492350-10-git-send-email-hpa@linux.intel.com> (raw)
In-Reply-To: <1465342269-492350-1-git-send-email-hpa@linux.intel.com>
Use CC_SET()/CC_OUT() and static_cpu_has(). This produces code good
enough to eliminate ad hoc use of alternatives in <asm/archrandom.h>,
greatly simplifying the code.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
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)
+{
+ return arch_has_random() ? rdrand_long(v) : false;
+}
-static inline bool rdrand_long(unsigned long *v)
+static inline bool arch_get_random_int(unsigned int *v)
{
- return 0;
+ return arch_has_random() ? rdrand_int(v) : false;
}
-static inline bool rdseed_long(unsigned long *v)
+static inline bool arch_get_random_seed_long(unsigned long *v)
{
- return 0;
+ return arch_has_random_seed() ? rdseed_long(v) : false;
}
-#endif /* CONFIG_ARCH_RANDOM */
+static inline bool arch_get_random_seed_int(unsigned int *v)
+{
+ return arch_has_random_seed() ? rdseed_int(v) : false;
+}
extern void x86_init_rdrand(struct cpuinfo_x86 *c);
--
2.7.3.0.11.gd79db92
next prev parent reply other threads:[~2016-06-07 23:31 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-07 23:30 [PATCH 00/10] x86: use gcc 6+ asm flag output feature H. Peter Anvin
2016-06-07 23:31 ` [PATCH 01/10] x86, bitops: remove use of "sbb" to return CF H. Peter Anvin
2016-06-07 23:39 ` [tip:x86/asm] " tip-bot for H. Peter Anvin
2016-06-07 23:31 ` [PATCH 02/10] x86, asm: use bool for bitops and other assembly outputs H. Peter Anvin
2016-06-07 23:40 ` [tip:x86/asm] " tip-bot for H. Peter Anvin
2016-06-08 7:49 ` [PATCH 02/10] " Peter Zijlstra
2016-06-08 8:28 ` Ingo Molnar
2016-06-08 8:33 ` Ingo Molnar
2016-06-08 8:55 ` H. Peter Anvin
2016-06-08 9:01 ` Ingo Molnar
2016-06-08 9:12 ` H. Peter Anvin
2016-06-08 9:20 ` Ingo Molnar
2016-06-08 9:31 ` H. Peter Anvin
2016-06-08 9:39 ` Peter Zijlstra
2016-06-08 9:43 ` H. Peter Anvin
2016-06-08 9:40 ` H. Peter Anvin
2016-06-08 8:58 ` H. Peter Anvin
2016-06-08 9:06 ` Ingo Molnar
2016-06-07 23:31 ` [PATCH 03/10] x86, asm: change the GEN_*_RMWcc() macros to not quote the condition H. Peter Anvin
2016-06-07 23:40 ` [tip:x86/asm] " tip-bot for H. Peter Anvin
2016-06-07 23:31 ` [PATCH 04/10] x86, asm: define CC_SET() and CC_OUT() macros H. Peter Anvin
2016-06-07 23:40 ` [tip:x86/asm] " tip-bot for H. Peter Anvin
2016-06-08 5:09 ` [PATCH 04/10] " Andy Lutomirski
2016-06-08 19:29 ` H. Peter Anvin
2016-06-08 19:34 ` H. Peter Anvin
2016-06-08 19:35 ` Borislav Petkov
2016-06-07 23:31 ` [PATCH 05/10] x86, asm: change GEN_*_RMWcc() to use CC_SET()/CC_OUT() H. Peter Anvin
2016-06-07 23:41 ` [tip:x86/asm] " tip-bot for H. Peter Anvin
2016-06-07 23:31 ` [PATCH 06/10] x86, asm: Use CC_SET()/CC_OUT() in <asm/bitops.h> H. Peter Anvin
2016-06-07 23:41 ` [tip:x86/asm] " tip-bot for H. Peter Anvin
2016-06-07 23:31 ` [PATCH 07/10] x86, asm: Use CC_SET()/CC_OUT() in <asm/percpu.h> H. Peter Anvin
2016-06-07 23:42 ` [tip:x86/asm] " tip-bot for H. Peter Anvin
2016-06-07 23:31 ` [PATCH 08/10] x86, asm: Use CC_SET()/CC_OUT() in <asm/rwsem.h> H. Peter Anvin
2016-06-07 23:42 ` [tip:x86/asm] " tip-bot for H. Peter Anvin
2016-06-07 23:31 ` H. Peter Anvin [this message]
2016-06-07 23:42 ` [tip:x86/asm] x86, asm: Use CC_SET()/CC_OUT() and static_cpu_has() in archrandom.h tip-bot for H. Peter Anvin
2016-06-08 5:12 ` [PATCH 09/10] " Andy Lutomirski
2016-06-07 23:31 ` [PATCH 10/10] x86, asm, boot: Use CC_SET()/CC_OUT() in arch/x86/boot/boot.h H. Peter Anvin
2016-06-07 23:43 ` [tip:x86/asm] " tip-bot for H. Peter Anvin
2016-06-08 8:00 ` [PATCH 00/10] x86: use gcc 6+ asm flag output feature Peter Zijlstra
2016-06-08 8:56 ` H. Peter Anvin
2016-06-08 8:26 ` Ingo Molnar
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