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 (3783B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2/*
      3 * forked from parisc asm/atomic.h which was:
      4 *	Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
      5 *	Copyright (C) 2006 Kyle McMartin <kyle@parisc-linux.org>
      6 */
      7
      8#ifndef _ASM_PARISC_CMPXCHG_H_
      9#define _ASM_PARISC_CMPXCHG_H_
     10
     11/* This should get optimized out since it's never called.
     12** Or get a link error if xchg is used "wrong".
     13*/
     14extern void __xchg_called_with_bad_pointer(void);
     15
     16/* __xchg32/64 defined in arch/parisc/lib/bitops.c */
     17extern unsigned long __xchg8(char, volatile char *);
     18extern unsigned long __xchg32(int, volatile int *);
     19#ifdef CONFIG_64BIT
     20extern unsigned long __xchg64(unsigned long, volatile unsigned long *);
     21#endif
     22
     23/* optimizer better get rid of switch since size is a constant */
     24static inline unsigned long
     25__xchg(unsigned long x, volatile void *ptr, int size)
     26{
     27	switch (size) {
     28#ifdef CONFIG_64BIT
     29	case 8: return __xchg64(x, (volatile unsigned long *) ptr);
     30#endif
     31	case 4: return __xchg32((int) x, (volatile int *) ptr);
     32	case 1: return __xchg8((char) x, (volatile char *) ptr);
     33	}
     34	__xchg_called_with_bad_pointer();
     35	return x;
     36}
     37
     38/*
     39** REVISIT - Abandoned use of LDCW in xchg() for now:
     40** o need to test sizeof(*ptr) to avoid clearing adjacent bytes
     41** o and while we are at it, could CONFIG_64BIT code use LDCD too?
     42**
     43**	if (__builtin_constant_p(x) && (x == NULL))
     44**		if (((unsigned long)p & 0xf) == 0)
     45**			return __ldcw(p);
     46*/
     47#define arch_xchg(ptr, x)						\
     48({									\
     49	__typeof__(*(ptr)) __ret;					\
     50	__typeof__(*(ptr)) _x_ = (x);					\
     51	__ret = (__typeof__(*(ptr)))					\
     52		__xchg((unsigned long)_x_, (ptr), sizeof(*(ptr)));	\
     53	__ret;								\
     54})
     55
     56/* bug catcher for when unsupported size is used - won't link */
     57extern void __cmpxchg_called_with_bad_pointer(void);
     58
     59/* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */
     60extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old,
     61				   unsigned int new_);
     62extern u64 __cmpxchg_u64(volatile u64 *ptr, u64 old, u64 new_);
     63extern u8 __cmpxchg_u8(volatile u8 *ptr, u8 old, u8 new_);
     64
     65/* don't worry...optimizer will get rid of most of this */
     66static inline unsigned long
     67__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
     68{
     69	switch (size) {
     70#ifdef CONFIG_64BIT
     71	case 8: return __cmpxchg_u64((u64 *)ptr, old, new_);
     72#endif
     73	case 4: return __cmpxchg_u32((unsigned int *)ptr,
     74				     (unsigned int)old, (unsigned int)new_);
     75	case 1: return __cmpxchg_u8((u8 *)ptr, old & 0xff, new_ & 0xff);
     76	}
     77	__cmpxchg_called_with_bad_pointer();
     78	return old;
     79}
     80
     81#define arch_cmpxchg(ptr, o, n)						 \
     82({									 \
     83	__typeof__(*(ptr)) _o_ = (o);					 \
     84	__typeof__(*(ptr)) _n_ = (n);					 \
     85	(__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,	 \
     86				    (unsigned long)_n_, sizeof(*(ptr))); \
     87})
     88
     89#include <asm-generic/cmpxchg-local.h>
     90
     91static inline unsigned long __cmpxchg_local(volatile void *ptr,
     92				      unsigned long old,
     93				      unsigned long new_, int size)
     94{
     95	switch (size) {
     96#ifdef CONFIG_64BIT
     97	case 8:	return __cmpxchg_u64((u64 *)ptr, old, new_);
     98#endif
     99	case 4:	return __cmpxchg_u32(ptr, old, new_);
    100	default:
    101		return __generic_cmpxchg_local(ptr, old, new_, size);
    102	}
    103}
    104
    105/*
    106 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
    107 * them available.
    108 */
    109#define arch_cmpxchg_local(ptr, o, n)					\
    110	((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o),	\
    111			(unsigned long)(n), sizeof(*(ptr))))
    112#ifdef CONFIG_64BIT
    113#define arch_cmpxchg64_local(ptr, o, n)					\
    114({									\
    115	BUILD_BUG_ON(sizeof(*(ptr)) != 8);				\
    116	cmpxchg_local((ptr), (o), (n));					\
    117})
    118#else
    119#define arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n))
    120#endif
    121
    122#define arch_cmpxchg64(ptr, o, n) __cmpxchg_u64(ptr, o, n)
    123
    124#endif /* _ASM_PARISC_CMPXCHG_H_ */