forked from mirrors/linux
d18c13697b
<linux/percpu.h> include was removed from <linux/prandom.h> ind9f29deb7f("prandom: Remove unused include") because this inclusion broke arm64 due to a circular dependency on include files. __percpu tag is defined in include/linux/compiler_types.h, so there is currently no direct need for the inclusion of <linux/percpu.h>. However, in [1] we would like to repurpose __percpu tag as a named address space qualifier, where __percpu macro uses defines from <linux/percpu.h>. The circular dependency was removed in ddd8e37ebaa1 ("random: Do not include <linux/prandom.h> in <linux/random.h>") and it cleared the path for the inclusion of <linux/percpu.h> in <linux/prandom.h>. This patch is basically a revert ofd9f29deb7f("prandom: Remove unused include"). [1] https://lore.kernel.org/lkml/20240812115945.484051-4-ubizjak@gmail.com/ Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
56 lines
1.3 KiB
C
56 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* include/linux/prandom.h
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*
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* Include file for the fast pseudo-random 32-bit
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* generation.
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*/
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#ifndef _LINUX_PRANDOM_H
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#define _LINUX_PRANDOM_H
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#include <linux/types.h>
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#include <linux/once.h>
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#include <linux/percpu.h>
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#include <linux/random.h>
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struct rnd_state {
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__u32 s1, s2, s3, s4;
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};
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u32 prandom_u32_state(struct rnd_state *state);
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void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes);
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void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state);
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#define prandom_init_once(pcpu_state) \
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DO_ONCE(prandom_seed_full_state, (pcpu_state))
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/*
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* Handle minimum values for seeds
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*/
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static inline u32 __seed(u32 x, u32 m)
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{
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return (x < m) ? x + m : x;
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}
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/**
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* prandom_seed_state - set seed for prandom_u32_state().
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* @state: pointer to state structure to receive the seed.
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* @seed: arbitrary 64-bit value to use as a seed.
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*/
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static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
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{
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u32 i = ((seed >> 32) ^ (seed << 10) ^ seed) & 0xffffffffUL;
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state->s1 = __seed(i, 2U);
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state->s2 = __seed(i, 8U);
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state->s3 = __seed(i, 16U);
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state->s4 = __seed(i, 128U);
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}
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/* Pseudo random number generator from numerical recipes. */
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static inline u32 next_pseudo_random32(u32 seed)
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{
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return seed * 1664525 + 1013904223;
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}
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#endif
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