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Merge branch 'x86-rdrand-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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* '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 6e5714eaf7: "net:
Compute protocol sequence numbers and fragment IDs using MD5").
This commit is contained in:
Linus Torvalds
2011-10-28 05:29:07 -07:00
parent 8237eb946a 49d859d78c
commit 8e6d539e0f
8 changed files with 199 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
arch/x86/kernel/cpu/Makefile
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@@ -15,6 +15,7 @@ CFLAGS_common.o := $(nostackp)
obj-y := intel_cacheinfo.o scattered.o topology.o
obj-y += proc.o capflags.o powerflags.o common.o
obj-y += vmware.o hypervisor.o sched.o mshyperv.o
obj-y += rdrand.o
obj-$(CONFIG_X86_32) += bugs.o
obj-$(CONFIG_X86_64) += bugs_64.o

2
arch/x86/kernel/cpu/common.c
View File

@@ -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 @@ static void __cpuinit identify_cpu(struct cpuinfo_x86 *c)
#endif
init_hypervisor(c);
x86_init_rdrand(c);
/*
* Clear/Set all flags overriden by options, need do it

73
arch/x86/kernel/cpu/rdrand.c Normal file
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@@ -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
}