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authorLinus Torvalds <torvalds@linux-foundation.org>2011-10-28 08:29:07 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2011-10-28 08:29:07 -0400
commit8e6d539e0fd0c2124a20a207da70f2af7a9ae52c (patch)
tree73016c1bdb5005125cdb5d60d48f73ab4300be64 /arch
parent8237eb946a1a23c600fb289cf8dd3b399b10604e (diff)
parent49d859d78c5aeb998b6936fcb5f288f78d713489 (diff)
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").
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/Kconfig9
-rw-r--r--arch/x86/include/asm/archrandom.h75
-rw-r--r--arch/x86/kernel/cpu/Makefile1
-rw-r--r--arch/x86/kernel/cpu/common.c2
-rw-r--r--arch/x86/kernel/cpu/rdrand.c73
5 files changed, 160 insertions, 0 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 16db864c42b7..77f7a384c0b5 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1454,6 +1454,15 @@ config ARCH_USES_PG_UNCACHED
1454 def_bool y 1454 def_bool y
1455 depends on X86_PAT 1455 depends on X86_PAT
1456 1456
1457config ARCH_RANDOM
1458 def_bool y
1459 prompt "x86 architectural random number generator" if EXPERT
1460 ---help---
1461 Enable the x86 architectural RDRAND instruction
1462 (Intel Bull Mountain technology) to generate random numbers.
1463 If supported, this is a high bandwidth, cryptographically
1464 secure hardware random number generator.
1465
1457config EFI 1466config EFI
1458 bool "EFI runtime service support" 1467 bool "EFI runtime service support"
1459 depends on ACPI 1468 depends on ACPI
diff --git a/arch/x86/include/asm/archrandom.h b/arch/x86/include/asm/archrandom.h
new file mode 100644
index 000000000000..0d9ec770f2f8
--- /dev/null
+++ b/arch/x86/include/asm/archrandom.h
@@ -0,0 +1,75 @@
1/*
2 * This file is part of the Linux kernel.
3 *
4 * Copyright (c) 2011, Intel Corporation
5 * Authors: Fenghua Yu <fenghua.yu@intel.com>,
6 * H. Peter Anvin <hpa@linux.intel.com>
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms and conditions of the GNU General Public License,
10 * version 2, as published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 * more details.
16 *
17 * You should have received a copy of the GNU General Public License along with
18 * this program; if not, write to the Free Software Foundation, Inc.,
19 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 */
22
23#ifndef ASM_X86_ARCHRANDOM_H
24#define ASM_X86_ARCHRANDOM_H
25
26#include <asm/processor.h>
27#include <asm/cpufeature.h>
28#include <asm/alternative.h>
29#include <asm/nops.h>
30
31#define RDRAND_RETRY_LOOPS 10
32
33#define RDRAND_INT ".byte 0x0f,0xc7,0xf0"
34#ifdef CONFIG_X86_64
35# define RDRAND_LONG ".byte 0x48,0x0f,0xc7,0xf0"
36#else
37# define RDRAND_LONG RDRAND_INT
38#endif
39
40#ifdef CONFIG_ARCH_RANDOM
41
42#define GET_RANDOM(name, type, rdrand, nop) \
43static inline int name(type *v) \
44{ \
45 int ok; \
46 alternative_io("movl $0, %0\n\t" \
47 nop, \
48 "\n1: " rdrand "\n\t" \
49 "jc 2f\n\t" \
50 "decl %0\n\t" \
51 "jnz 1b\n\t" \
52 "2:", \
53 X86_FEATURE_RDRAND, \
54 ASM_OUTPUT2("=r" (ok), "=a" (*v)), \
55 "0" (RDRAND_RETRY_LOOPS)); \
56 return ok; \
57}
58
59#ifdef CONFIG_X86_64
60
61GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP5);
62GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP4);
63
64#else
65
66GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP3);
67GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP3);
68
69#endif /* CONFIG_X86_64 */
70
71#endif /* CONFIG_ARCH_RANDOM */
72
73extern void x86_init_rdrand(struct cpuinfo_x86 *c);
74
75#endif /* ASM_X86_ARCHRANDOM_H */
diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
index fe6eb197f848..25f24dccdcfa 100644
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -15,6 +15,7 @@ CFLAGS_common.o := $(nostackp)
15obj-y := intel_cacheinfo.o scattered.o topology.o 15obj-y := intel_cacheinfo.o scattered.o topology.o
16obj-y += proc.o capflags.o powerflags.o common.o 16obj-y += proc.o capflags.o powerflags.o common.o
17obj-y += vmware.o hypervisor.o sched.o mshyperv.o 17obj-y += vmware.o hypervisor.o sched.o mshyperv.o
18obj-y += rdrand.o
18 19
19obj-$(CONFIG_X86_32) += bugs.o 20obj-$(CONFIG_X86_32) += bugs.o
20obj-$(CONFIG_X86_64) += bugs_64.o 21obj-$(CONFIG_X86_64) += bugs_64.o
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index ec63df54d138..aa003b13a831 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -15,6 +15,7 @@
15#include <asm/stackprotector.h> 15#include <asm/stackprotector.h>
16#include <asm/perf_event.h> 16#include <asm/perf_event.h>
17#include <asm/mmu_context.h> 17#include <asm/mmu_context.h>
18#include <asm/archrandom.h>
18#include <asm/hypervisor.h> 19#include <asm/hypervisor.h>
19#include <asm/processor.h> 20#include <asm/processor.h>
20#include <asm/sections.h> 21#include <asm/sections.h>
@@ -860,6 +861,7 @@ static void __cpuinit identify_cpu(struct cpuinfo_x86 *c)
860#endif 861#endif
861 862
862 init_hypervisor(c); 863 init_hypervisor(c);
864 x86_init_rdrand(c);
863 865
864 /* 866 /*
865 * Clear/Set all flags overriden by options, need do it 867 * 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 000000000000..feca286c2bb4
--- /dev/null
+++ b/arch/x86/kernel/cpu/rdrand.c
@@ -0,0 +1,73 @@
1/*
2 * This file is part of the Linux kernel.
3 *
4 * Copyright (c) 2011, Intel Corporation
5 * Authors: Fenghua Yu <fenghua.yu@intel.com>,
6 * H. Peter Anvin <hpa@linux.intel.com>
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms and conditions of the GNU General Public License,
10 * version 2, as published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 * more details.
16 *
17 * You should have received a copy of the GNU General Public License along with
18 * this program; if not, write to the Free Software Foundation, Inc.,
19 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 */
22
23#include <asm/processor.h>
24#include <asm/archrandom.h>
25#include <asm/sections.h>
26
27static int __init x86_rdrand_setup(char *s)
28{
29 setup_clear_cpu_cap(X86_FEATURE_RDRAND);
30 return 1;
31}
32__setup("nordrand", x86_rdrand_setup);
33
34/* We can't use arch_get_random_long() here since alternatives haven't run */
35static inline int rdrand_long(unsigned long *v)
36{
37 int ok;
38 asm volatile("1: " RDRAND_LONG "\n\t"
39 "jc 2f\n\t"
40 "decl %0\n\t"
41 "jnz 1b\n\t"
42 "2:"
43 : "=r" (ok), "=a" (*v)
44 : "0" (RDRAND_RETRY_LOOPS));
45 return ok;
46}
47
48/*
49 * Force a reseed cycle; we are architecturally guaranteed a reseed
50 * after no more than 512 128-bit chunks of random data. This also
51 * acts as a test of the CPU capability.
52 */
53#define RESEED_LOOP ((512*128)/sizeof(unsigned long))
54
55void __cpuinit x86_init_rdrand(struct cpuinfo_x86 *c)
56{
57#ifdef CONFIG_ARCH_RANDOM
58 unsigned long tmp;
59 int i, count, ok;
60
61 if (!cpu_has(c, X86_FEATURE_RDRAND))
62 return; /* Nothing to do */
63
64 for (count = i = 0; i < RESEED_LOOP; i++) {
65 ok = rdrand_long(&tmp);
66 if (ok)
67 count++;
68 }
69
70 if (count != RESEED_LOOP)
71 clear_cpu_cap(c, X86_FEATURE_RDRAND);
72#endif
73}