Merge branch 'x86-rdrand-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
* 'x86-rdrand-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, random: Verify RDRAND functionality and allow it to be disabled
x86, random: Architectural inlines to get random integers with RDRAND
random: Add support for architectural random hooks
Fix up trivial conflicts in drivers/char/random.c: the architectural
random hooks touched "get_random_int()" that was simplified to use MD5
and not do the keyptr thing any more (see commit 6e5714eaf77d: "net:
Compute protocol sequence numbers and fragment IDs using MD5").
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 6afd091..93413ce 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1797,6 +1797,11 @@
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 16db864..77f7a38 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1454,6 +1454,15 @@
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 0000000..0d9ec77
--- /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 $0, %0\n\t" \
+ nop, \
+ "\n1: " rdrand "\n\t" \
+ "jc 2f\n\t" \
+ "decl %0\n\t" \
+ "jnz 1b\n\t" \
+ "2:", \
+ X86_FEATURE_RDRAND, \
+ ASM_OUTPUT2("=r" (ok), "=a" (*v)), \
+ "0" (RDRAND_RETRY_LOOPS)); \
+ return ok; \
+}
+
+#ifdef CONFIG_X86_64
+
+GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP5);
+GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP4);
+
+#else
+
+GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP3);
+GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP3);
+
+#endif /* CONFIG_X86_64 */
+
+#endif /* CONFIG_ARCH_RANDOM */
+
+extern void x86_init_rdrand(struct cpuinfo_x86 *c);
+
+#endif /* ASM_X86_ARCHRANDOM_H */
diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
index fe6eb19..25f24dc 100644
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -15,6 +15,7 @@
obj-y := intel_cacheinfo.o scattered.o topology.o
obj-y += proc.o capflags.o powerflags.o common.o
obj-y += vmware.o hypervisor.o sched.o mshyperv.o
+obj-y += rdrand.o
obj-$(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 ec63df5..aa003b1 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 @@
#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 0000000..feca286
--- /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 c35a785..63e19ba 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -932,7 +932,21 @@
*/
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 @@
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 d13059f..8f74538 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -91,6 +91,19 @@
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 */