mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-28 11:18:45 +07:00
c0842fbc1b
The addition of percpu.h to the list of includes in random.h revealed
some circular dependencies on arm64 and possibly other platforms. This
include was added solely for the pseudo-random definitions, which have
nothing to do with the rest of the definitions in this file but are
still there for legacy reasons.
This patch moves the pseudo-random parts to linux/prandom.h and the
percpu.h include with it, which is now guarded by _LINUX_PRANDOM_H and
protected against recursive inclusion.
A further cleanup step would be to remove this from <linux/random.h>
entirely, and make people who use the prandom infrastructure include
just the new header file. That's a bit of a churn patch, but grepping
for "prandom_" and "next_pseudo_random32" "struct rnd_state" should
catch most users.
But it turns out that that nice cleanup step is fairly painful, because
a _lot_ of code currently seems to depend on the implicit include of
<linux/random.h>, which can currently come in a lot of ways, including
such fairly core headfers as <linux/net.h>.
So the "nice cleanup" part may or may never happen.
Fixes: 1c9df907da ("random: fix circular include dependency on arm64 after addition of percpu.h")
Tested-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
79 lines
2.0 KiB
C
79 lines
2.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/*
|
|
* include/linux/prandom.h
|
|
*
|
|
* Include file for the fast pseudo-random 32-bit
|
|
* generation.
|
|
*/
|
|
#ifndef _LINUX_PRANDOM_H
|
|
#define _LINUX_PRANDOM_H
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/percpu.h>
|
|
|
|
u32 prandom_u32(void);
|
|
void prandom_bytes(void *buf, size_t nbytes);
|
|
void prandom_seed(u32 seed);
|
|
void prandom_reseed_late(void);
|
|
|
|
struct rnd_state {
|
|
__u32 s1, s2, s3, s4;
|
|
};
|
|
|
|
DECLARE_PER_CPU(struct rnd_state, net_rand_state);
|
|
|
|
u32 prandom_u32_state(struct rnd_state *state);
|
|
void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes);
|
|
void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state);
|
|
|
|
#define prandom_init_once(pcpu_state) \
|
|
DO_ONCE(prandom_seed_full_state, (pcpu_state))
|
|
|
|
/**
|
|
* prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro)
|
|
* @ep_ro: right open interval endpoint
|
|
*
|
|
* Returns a pseudo-random number that is in interval [0, ep_ro). Note
|
|
* that the result depends on PRNG being well distributed in [0, ~0U]
|
|
* u32 space. Here we use maximally equidistributed combined Tausworthe
|
|
* generator, that is, prandom_u32(). This is useful when requesting a
|
|
* random index of an array containing ep_ro elements, for example.
|
|
*
|
|
* Returns: pseudo-random number in interval [0, ep_ro)
|
|
*/
|
|
static inline u32 prandom_u32_max(u32 ep_ro)
|
|
{
|
|
return (u32)(((u64) prandom_u32() * ep_ro) >> 32);
|
|
}
|
|
|
|
/*
|
|
* Handle minimum values for seeds
|
|
*/
|
|
static inline u32 __seed(u32 x, u32 m)
|
|
{
|
|
return (x < m) ? x + m : x;
|
|
}
|
|
|
|
/**
|
|
* prandom_seed_state - set seed for prandom_u32_state().
|
|
* @state: pointer to state structure to receive the seed.
|
|
* @seed: arbitrary 64-bit value to use as a seed.
|
|
*/
|
|
static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
|
|
{
|
|
u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
|
|
|
|
state->s1 = __seed(i, 2U);
|
|
state->s2 = __seed(i, 8U);
|
|
state->s3 = __seed(i, 16U);
|
|
state->s4 = __seed(i, 128U);
|
|
}
|
|
|
|
/* Pseudo random number generator from numerical recipes. */
|
|
static inline u32 next_pseudo_random32(u32 seed)
|
|
{
|
|
return seed * 1664525 + 1013904223;
|
|
}
|
|
|
|
#endif
|