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linux-pinenote/arch/powerpc/include/asm/archrandom.h

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powerpc: Implement arch_get_random_long/int() for powernv Add the plumbing to implement arch_get_random_long/int(). It didn't seem worth adding an extra ppc_md hook for int, so we reuse the one for long. Add an implementation for powernv based on the hwrng found in power7+ systems. We whiten the output of the hwrng, and the result passes all the dieharder tests. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-11 14:07:57 +11:00
#ifndef _ASM_POWERPC_ARCHRANDOM_H
#define _ASM_POWERPC_ARCHRANDOM_H
#ifdef CONFIG_ARCH_RANDOM
#include <asm/machdep.h>
static inline int arch_get_random_long(unsigned long *v)
{
if (ppc_md.get_random_long)
return ppc_md.get_random_long(v);
return 0;
}
static inline int arch_get_random_int(unsigned int *v)
{
unsigned long val;
int rc;
rc = arch_get_random_long(&val);
if (rc)
*v = val;
return rc;
}
random: Add arch_has_random[_seed]() Add predicate functions for having arch_get_random[_seed]*(). The only current use is to avoid the loop in arch_random_refill() when arch_get_random_seed_long() is unavailable. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-03-17 16:36:30 -07:00
static inline int arch_has_random(void)
{
return !!ppc_md.get_random_long;
}
x86, random: Enable the RDSEED instruction Upcoming Intel silicon adds a new RDSEED instruction, which is similar to RDRAND but provides a stronger guarantee: unlike RDRAND, RDSEED will always reseed the PRNG from the true random number source between each read. Thus, the output of RDSEED is guaranteed to be 100% entropic, unlike RDRAND which is only architecturally guaranteed to be 1/512 entropic (although in practice is much more.) The RDSEED instruction takes the same time to execute as RDRAND, but RDSEED unlike RDRAND can legitimately return failure (CF=0) due to entropy exhaustion if too many threads on too many cores are hammering the RDSEED instruction at the same time. Therefore, we have to be more conservative and only use it in places where we can tolerate failures. This patch introduces the primitives arch_get_random_seed_{int,long}() but does not use it yet. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-03-17 16:36:27 -07:00
static inline int arch_get_random_seed_long(unsigned long *v)
{
return 0;
}
static inline int arch_get_random_seed_int(unsigned int *v)
{
return 0;
}
random: Add arch_has_random[_seed]() Add predicate functions for having arch_get_random[_seed]*(). The only current use is to avoid the loop in arch_random_refill() when arch_get_random_seed_long() is unavailable. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-03-17 16:36:30 -07:00
static inline int arch_has_random_seed(void)
{
return 0;
}
x86, random: Enable the RDSEED instruction Upcoming Intel silicon adds a new RDSEED instruction, which is similar to RDRAND but provides a stronger guarantee: unlike RDRAND, RDSEED will always reseed the PRNG from the true random number source between each read. Thus, the output of RDSEED is guaranteed to be 100% entropic, unlike RDRAND which is only architecturally guaranteed to be 1/512 entropic (although in practice is much more.) The RDSEED instruction takes the same time to execute as RDRAND, but RDSEED unlike RDRAND can legitimately return failure (CF=0) due to entropy exhaustion if too many threads on too many cores are hammering the RDSEED instruction at the same time. Therefore, we have to be more conservative and only use it in places where we can tolerate failures. This patch introduces the primitives arch_get_random_seed_{int,long}() but does not use it yet. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-03-17 16:36:27 -07:00
powerpc: Implement arch_get_random_long/int() for powernv Add the plumbing to implement arch_get_random_long/int(). It didn't seem worth adding an extra ppc_md hook for int, so we reuse the one for long. Add an implementation for powernv based on the hwrng found in power7+ systems. We whiten the output of the hwrng, and the result passes all the dieharder tests. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-11 14:07:57 +11:00
#endif /* CONFIG_ARCH_RANDOM */
KVM: PPC: Book3S HV: Add fast real-mode H_RANDOM implementation. Some PowerNV systems include a hardware random-number generator. This HWRNG is present on POWER7+ and POWER8 chips and is capable of generating one 64-bit random number every microsecond. The random numbers are produced by sampling a set of 64 unstable high-frequency oscillators and are almost completely entropic. PAPR defines an H_RANDOM hypercall which guests can use to obtain one 64-bit random sample from the HWRNG. This adds a real-mode implementation of the H_RANDOM hypercall. This hypercall was implemented in real mode because the latency of reading the HWRNG is generally small compared to the latency of a guest exit and entry for all the threads in the same virtual core. Userspace can detect the presence of the HWRNG and the H_RANDOM implementation by querying the KVM_CAP_PPC_HWRNG capability. The H_RANDOM hypercall implementation will only be invoked when the guest does an H_RANDOM hypercall if userspace first enables the in-kernel H_RANDOM implementation using the KVM_CAP_PPC_ENABLE_HCALL capability. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-20 20:39:41 +11:00
#ifdef CONFIG_PPC_POWERNV
int powernv_hwrng_present(void);
int powernv_get_random_long(unsigned long *v);
int powernv_get_random_real_mode(unsigned long *v);
#else
static inline int powernv_hwrng_present(void) { return 0; }
static inline int powernv_get_random_real_mode(unsigned long *v) { return 0; }
#endif
powerpc: Implement arch_get_random_long/int() for powernv Add the plumbing to implement arch_get_random_long/int(). It didn't seem worth adding an extra ppc_md hook for int, so we reuse the one for long. Add an implementation for powernv based on the hwrng found in power7+ systems. We whiten the output of the hwrng, and the result passes all the dieharder tests. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-11 14:07:57 +11:00
#endif /* _ASM_POWERPC_ARCHRANDOM_H */
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