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powerpc/pseries: Implement arch_get_random_long() based on H_RANDOM

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Add support for the arch_get_random_long() hook based on the H_RANDOM
hypervisor call. We trust the hypervisor to provide us with random data,
ie. we don't whiten it in anyway.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Michael Ellerman 2013-10-11 14:07:59 +11:00 committed by Benjamin Herrenschmidt
parent 66548e4058
commit a489043f46
2 changed files with 45 additions and 1 deletions
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2
arch/powerpc/platforms/pseries/Makefile
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@ -3,7 +3,7 @@ ccflags-$(CONFIG_PPC_PSERIES_DEBUG) += -DDEBUG
obj-y := lpar.o hvCall.o nvram.o reconfig.o \
setup.o iommu.o event_sources.o ras.o \
firmware.o power.o dlpar.o mobility.o
firmware.o power.o dlpar.o mobility.o rng.o
obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_SCANLOG) += scanlog.o
obj-$(CONFIG_EEH) += eeh_pseries.o

44
arch/powerpc/platforms/pseries/rng.c Normal file
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@ -0,0 +1,44 @@
/*
* Copyright 2013, Michael Ellerman, IBM Corporation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#define pr_fmt(fmt) "pseries-rng: " fmt
#include <linux/kernel.h>
#include <linux/of.h>
#include <asm/archrandom.h>
#include <asm/machdep.h>
static int pseries_get_random_long(unsigned long *v)
{
unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
if (plpar_hcall(H_RANDOM, retbuf) == H_SUCCESS) {
*v = retbuf[0];
return 1;
}
return 0;
}
static __init int rng_init(void)
{
struct device_node *dn;
dn = of_find_compatible_node(NULL, NULL, "ibm,random");
if (!dn)
return -ENODEV;
pr_info("Registering arch random hook.\n");
ppc_md.get_random_long = pseries_get_random_long;
return 0;
}
subsys_initcall(rng_init);