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>
This commit is contained in:
parent
f95dabef4c
commit
a4da0d50b2
|
@ -1012,6 +1012,9 @@ config PHYSICAL_START
|
|||
default "0x00000000"
|
||||
endif
|
||||
|
||||
config ARCH_RANDOM
|
||||
def_bool n
|
||||
|
||||
source "net/Kconfig"
|
||||
|
||||
source "drivers/Kconfig"
|
||||
|
|
32
arch/powerpc/include/asm/archrandom.h
Normal file
32
arch/powerpc/include/asm/archrandom.h
Normal file
|
@ -0,0 +1,32 @@
|
|||
#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;
|
||||
}
|
||||
|
||||
int powernv_get_random_long(unsigned long *v);
|
||||
|
||||
#endif /* CONFIG_ARCH_RANDOM */
|
||||
|
||||
#endif /* _ASM_POWERPC_ARCHRANDOM_H */
|
|
@ -263,6 +263,10 @@ struct machdep_calls {
|
|||
ssize_t (*cpu_probe)(const char *, size_t);
|
||||
ssize_t (*cpu_release)(const char *, size_t);
|
||||
#endif
|
||||
|
||||
#ifdef CONFIG_ARCH_RANDOM
|
||||
int (*get_random_long)(unsigned long *v);
|
||||
#endif
|
||||
};
|
||||
|
||||
extern void e500_idle(void);
|
||||
|
|
|
@ -9,6 +9,7 @@ config PPC_POWERNV
|
|||
select EPAPR_BOOT
|
||||
select PPC_INDIRECT_PIO
|
||||
select PPC_UDBG_16550
|
||||
select ARCH_RANDOM
|
||||
default y
|
||||
|
||||
config POWERNV_MSI
|
||||
|
|
|
@ -1,5 +1,5 @@
|
|||
obj-y += setup.o opal-takeover.o opal-wrappers.o opal.o
|
||||
obj-y += opal-rtc.o opal-nvram.o opal-lpc.o
|
||||
obj-y += opal-rtc.o opal-nvram.o opal-lpc.o rng.o
|
||||
|
||||
obj-$(CONFIG_SMP) += smp.o
|
||||
obj-$(CONFIG_PCI) += pci.o pci-p5ioc2.o pci-ioda.o
|
||||
|
|
122
arch/powerpc/platforms/powernv/rng.c
Normal file
122
arch/powerpc/platforms/powernv/rng.c
Normal file
|
@ -0,0 +1,122 @@
|
|||
/*
|
||||
* 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) "powernv-rng: " fmt
|
||||
|
||||
#include <linux/kernel.h>
|
||||
#include <linux/of.h>
|
||||
#include <linux/of_platform.h>
|
||||
#include <linux/slab.h>
|
||||
#include <asm/archrandom.h>
|
||||
#include <asm/io.h>
|
||||
#include <asm/machdep.h>
|
||||
|
||||
|
||||
struct powernv_rng {
|
||||
void __iomem *regs;
|
||||
unsigned long mask;
|
||||
};
|
||||
|
||||
static DEFINE_PER_CPU(struct powernv_rng *, powernv_rng);
|
||||
|
||||
|
||||
static unsigned long rng_whiten(struct powernv_rng *rng, unsigned long val)
|
||||
{
|
||||
unsigned long parity;
|
||||
|
||||
/* Calculate the parity of the value */
|
||||
asm ("popcntd %0,%1" : "=r" (parity) : "r" (val));
|
||||
|
||||
/* xor our value with the previous mask */
|
||||
val ^= rng->mask;
|
||||
|
||||
/* update the mask based on the parity of this value */
|
||||
rng->mask = (rng->mask << 1) | (parity & 1);
|
||||
|
||||
return val;
|
||||
}
|
||||
|
||||
int powernv_get_random_long(unsigned long *v)
|
||||
{
|
||||
struct powernv_rng *rng;
|
||||
|
||||
rng = get_cpu_var(powernv_rng);
|
||||
|
||||
*v = rng_whiten(rng, in_be64(rng->regs));
|
||||
|
||||
put_cpu_var(rng);
|
||||
|
||||
return 1;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(powernv_get_random_long);
|
||||
|
||||
static __init void rng_init_per_cpu(struct powernv_rng *rng,
|
||||
struct device_node *dn)
|
||||
{
|
||||
int chip_id, cpu;
|
||||
|
||||
chip_id = of_get_ibm_chip_id(dn);
|
||||
if (chip_id == -1)
|
||||
pr_warn("No ibm,chip-id found for %s.\n", dn->full_name);
|
||||
|
||||
for_each_possible_cpu(cpu) {
|
||||
if (per_cpu(powernv_rng, cpu) == NULL ||
|
||||
cpu_to_chip_id(cpu) == chip_id) {
|
||||
per_cpu(powernv_rng, cpu) = rng;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
static __init int rng_create(struct device_node *dn)
|
||||
{
|
||||
struct powernv_rng *rng;
|
||||
unsigned long val;
|
||||
|
||||
rng = kzalloc(sizeof(*rng), GFP_KERNEL);
|
||||
if (!rng)
|
||||
return -ENOMEM;
|
||||
|
||||
rng->regs = of_iomap(dn, 0);
|
||||
if (!rng->regs) {
|
||||
kfree(rng);
|
||||
return -ENXIO;
|
||||
}
|
||||
|
||||
val = in_be64(rng->regs);
|
||||
rng->mask = val;
|
||||
|
||||
rng_init_per_cpu(rng, dn);
|
||||
|
||||
pr_info_once("Registering arch random hook.\n");
|
||||
|
||||
ppc_md.get_random_long = powernv_get_random_long;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static __init int rng_init(void)
|
||||
{
|
||||
struct device_node *dn;
|
||||
int rc;
|
||||
|
||||
for_each_compatible_node(dn, NULL, "ibm,power-rng") {
|
||||
rc = rng_create(dn);
|
||||
if (rc) {
|
||||
pr_err("Failed creating rng for %s (%d).\n",
|
||||
dn->full_name, rc);
|
||||
continue;
|
||||
}
|
||||
|
||||
/* Create devices for hwrng driver */
|
||||
of_platform_device_create(dn, NULL, NULL);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
subsys_initcall(rng_init);
|
Loading…
Reference in a new issue