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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cmpxchg.h (2440B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2/*
      3 * Generic UP xchg and cmpxchg using interrupt disablement.  Does not
      4 * support SMP.
      5 */
      6
      7#ifndef __ASM_GENERIC_CMPXCHG_H
      8#define __ASM_GENERIC_CMPXCHG_H
      9
     10#ifdef CONFIG_SMP
     11#error "Cannot use generic cmpxchg on SMP"
     12#endif
     13
     14#include <linux/types.h>
     15#include <linux/irqflags.h>
     16
     17/*
     18 * This function doesn't exist, so you'll get a linker error if
     19 * something tries to do an invalidly-sized xchg().
     20 */
     21extern void __generic_xchg_called_with_bad_pointer(void);
     22
     23static inline
     24unsigned long __generic_xchg(unsigned long x, volatile void *ptr, int size)
     25{
     26	unsigned long ret, flags;
     27
     28	switch (size) {
     29	case 1:
     30#ifdef __xchg_u8
     31		return __xchg_u8(x, ptr);
     32#else
     33		local_irq_save(flags);
     34		ret = *(volatile u8 *)ptr;
     35		*(volatile u8 *)ptr = x;
     36		local_irq_restore(flags);
     37		return ret;
     38#endif /* __xchg_u8 */
     39
     40	case 2:
     41#ifdef __xchg_u16
     42		return __xchg_u16(x, ptr);
     43#else
     44		local_irq_save(flags);
     45		ret = *(volatile u16 *)ptr;
     46		*(volatile u16 *)ptr = x;
     47		local_irq_restore(flags);
     48		return ret;
     49#endif /* __xchg_u16 */
     50
     51	case 4:
     52#ifdef __xchg_u32
     53		return __xchg_u32(x, ptr);
     54#else
     55		local_irq_save(flags);
     56		ret = *(volatile u32 *)ptr;
     57		*(volatile u32 *)ptr = x;
     58		local_irq_restore(flags);
     59		return ret;
     60#endif /* __xchg_u32 */
     61
     62#ifdef CONFIG_64BIT
     63	case 8:
     64#ifdef __xchg_u64
     65		return __xchg_u64(x, ptr);
     66#else
     67		local_irq_save(flags);
     68		ret = *(volatile u64 *)ptr;
     69		*(volatile u64 *)ptr = x;
     70		local_irq_restore(flags);
     71		return ret;
     72#endif /* __xchg_u64 */
     73#endif /* CONFIG_64BIT */
     74
     75	default:
     76		__generic_xchg_called_with_bad_pointer();
     77		return x;
     78	}
     79}
     80
     81#define generic_xchg(ptr, x) ({							\
     82	((__typeof__(*(ptr)))							\
     83		__generic_xchg((unsigned long)(x), (ptr), sizeof(*(ptr))));	\
     84})
     85
     86/*
     87 * Atomic compare and exchange.
     88 */
     89#include <asm-generic/cmpxchg-local.h>
     90
     91#define generic_cmpxchg_local(ptr, o, n) ({					\
     92	((__typeof__(*(ptr)))__generic_cmpxchg_local((ptr), (unsigned long)(o),	\
     93			(unsigned long)(n), sizeof(*(ptr))));			\
     94})
     95
     96#define generic_cmpxchg64_local(ptr, o, n) \
     97	__generic_cmpxchg64_local((ptr), (o), (n))
     98
     99
    100#ifndef arch_xchg
    101#define arch_xchg		generic_xchg
    102#endif
    103
    104#ifndef arch_cmpxchg_local
    105#define arch_cmpxchg_local	generic_cmpxchg_local
    106#endif
    107
    108#ifndef arch_cmpxchg64_local
    109#define arch_cmpxchg64_local	generic_cmpxchg64_local
    110#endif
    111
    112#define arch_cmpxchg		arch_cmpxchg_local
    113#define arch_cmpxchg64		arch_cmpxchg64_local
    114
    115#endif /* __ASM_GENERIC_CMPXCHG_H */