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author | Andrew Dodd <atd7@cornell.edu> | 2013-02-16 18:41:04 -0500 |
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committer | Andrew Dodd <atd7@cornell.edu> | 2013-02-27 09:19:08 -0500 |
commit | b08797f2afdfc604c3143f8725d058aeef8ddcb2 (patch) | |
tree | c59e963bd6931d4e9f9526034ab402cc551f18ae /arch/x86/kernel/cpu/rdrand.c | |
parent | cbfae70f1dcaf3cc6e93061179dad80caa1597fe (diff) | |
parent | 54ea5b40f067cf098cac639973c6628c6944cfb2 (diff) | |
download | kernel_samsung_smdk4412-b08797f2afdfc604c3143f8725d058aeef8ddcb2.zip kernel_samsung_smdk4412-b08797f2afdfc604c3143f8725d058aeef8ddcb2.tar.gz kernel_samsung_smdk4412-b08797f2afdfc604c3143f8725d058aeef8ddcb2.tar.bz2 |
Merge remote-tracking branch 'kernelorg/linux-3.0.y' into 3_0_64
Conflicts:
arch/arm/Kconfig
arch/arm/include/asm/hwcap.h
arch/arm/kernel/smp.c
arch/arm/plat-samsung/adc.c
drivers/gpu/drm/i915/i915_reg.h
drivers/gpu/drm/i915/intel_drv.h
drivers/mmc/core/sd.c
drivers/net/tun.c
drivers/net/usb/usbnet.c
drivers/regulator/max8997.c
drivers/usb/core/hub.c
drivers/usb/host/xhci.h
drivers/usb/serial/qcserial.c
fs/jbd2/transaction.c
include/linux/migrate.h
kernel/sys.c
kernel/time/timekeeping.c
lib/genalloc.c
mm/memory-failure.c
mm/memory_hotplug.c
mm/mempolicy.c
mm/page_alloc.c
mm/vmalloc.c
mm/vmscan.c
mm/vmstat.c
scripts/Kbuild.include
Change-Id: I91e2d85c07320c7ccfc04cf98a448e89bed6ade6
Diffstat (limited to 'arch/x86/kernel/cpu/rdrand.c')
-rw-r--r-- | arch/x86/kernel/cpu/rdrand.c | 73 |
1 files changed, 73 insertions, 0 deletions
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 +} |