cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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cookie.h (1254B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2#ifndef __LINUX_COOKIE_H
      3#define __LINUX_COOKIE_H
      4
      5#include <linux/atomic.h>
      6#include <linux/percpu.h>
      7#include <asm/local.h>
      8
      9struct pcpu_gen_cookie {
     10	local_t nesting;
     11	u64 last;
     12} __aligned(16);
     13
     14struct gen_cookie {
     15	struct pcpu_gen_cookie __percpu *local;
     16	atomic64_t forward_last ____cacheline_aligned_in_smp;
     17	atomic64_t reverse_last;
     18};
     19
     20#define COOKIE_LOCAL_BATCH	4096
     21
     22#define DEFINE_COOKIE(name)						\
     23	static DEFINE_PER_CPU(struct pcpu_gen_cookie, __##name);	\
     24	static struct gen_cookie name = {				\
     25		.local		= &__##name,				\
     26		.forward_last	= ATOMIC64_INIT(0),			\
     27		.reverse_last	= ATOMIC64_INIT(0),			\
     28	}
     29
     30static __always_inline u64 gen_cookie_next(struct gen_cookie *gc)
     31{
     32	struct pcpu_gen_cookie *local = this_cpu_ptr(gc->local);
     33	u64 val;
     34
     35	if (likely(local_inc_return(&local->nesting) == 1)) {
     36		val = local->last;
     37		if (__is_defined(CONFIG_SMP) &&
     38		    unlikely((val & (COOKIE_LOCAL_BATCH - 1)) == 0)) {
     39			s64 next = atomic64_add_return(COOKIE_LOCAL_BATCH,
     40						       &gc->forward_last);
     41			val = next - COOKIE_LOCAL_BATCH;
     42		}
     43		local->last = ++val;
     44	} else {
     45		val = atomic64_dec_return(&gc->reverse_last);
     46	}
     47	local_dec(&local->nesting);
     48	return val;
     49}
     50
     51#endif /* __LINUX_COOKIE_H */