linux-zen-server/arch/s390/include/asm/cmpxchg.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright IBM Corp. 1999, 2011
 *
 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
 */

#ifndef __ASM_CMPXCHG_H
#define __ASM_CMPXCHG_H

#include <linux/mmdebug.h>
#include <linux/types.h>
#include <linux/bug.h>

void __xchg_called_with_bad_pointer(void);

static __always_inline unsigned long __xchg(unsigned long x,
					    unsigned long address, int size)
{
	unsigned long old;
	int shift;

	switch (size) {
	case 1:
		shift = (3 ^ (address & 3)) << 3;
		address ^= address & 3;
		asm volatile(
			"       l       %0,%1\n"
			"0:     lr      0,%0\n"
			"       nr      0,%3\n"
			"       or      0,%2\n"
			"       cs      %0,0,%1\n"
			"       jl      0b\n"
			: "=&d" (old), "+Q" (*(int *) address)
			: "d" ((x & 0xff) << shift), "d" (~(0xff << shift))
			: "memory", "cc", "0");
		return old >> shift;
	case 2:
		shift = (2 ^ (address & 2)) << 3;
		address ^= address & 2;
		asm volatile(
			"       l       %0,%1\n"
			"0:     lr      0,%0\n"
			"       nr      0,%3\n"
			"       or      0,%2\n"
			"       cs      %0,0,%1\n"
			"       jl      0b\n"
			: "=&d" (old), "+Q" (*(int *) address)
			: "d" ((x & 0xffff) << shift), "d" (~(0xffff << shift))
			: "memory", "cc", "0");
		return old >> shift;
	case 4:
		asm volatile(
			"       l       %0,%1\n"
			"0:     cs      %0,%2,%1\n"
			"       jl      0b\n"
			: "=&d" (old), "+Q" (*(int *) address)
			: "d" (x)
			: "memory", "cc");
		return old;
	case 8:
		asm volatile(
			"       lg      %0,%1\n"
			"0:     csg     %0,%2,%1\n"
			"       jl      0b\n"
			: "=&d" (old), "+QS" (*(long *) address)
			: "d" (x)
			: "memory", "cc");
		return old;
	}
	__xchg_called_with_bad_pointer();
	return x;
}

#define arch_xchg(ptr, x)						\
({									\
	__typeof__(*(ptr)) __ret;					\
									\
	__ret = (__typeof__(*(ptr)))					\
		__xchg((unsigned long)(x), (unsigned long)(ptr),	\
		       sizeof(*(ptr)));					\
	__ret;								\
})

void __cmpxchg_called_with_bad_pointer(void);

static __always_inline unsigned long __cmpxchg(unsigned long address,
					       unsigned long old,
					       unsigned long new, int size)
{
	switch (size) {
	case 1: {
		unsigned int prev, shift, mask;

		shift = (3 ^ (address & 3)) << 3;
		address ^= address & 3;
		old = (old & 0xff) << shift;
		new = (new & 0xff) << shift;
		mask = ~(0xff << shift);
		asm volatile(
			"	l	%[prev],%[address]\n"
			"	nr	%[prev],%[mask]\n"
			"	xilf	%[mask],0xffffffff\n"
			"	or	%[new],%[prev]\n"
			"	or	%[prev],%[tmp]\n"
			"0:	lr	%[tmp],%[prev]\n"
			"	cs	%[prev],%[new],%[address]\n"
			"	jnl	1f\n"
			"	xr	%[tmp],%[prev]\n"
			"	xr	%[new],%[tmp]\n"
			"	nr	%[tmp],%[mask]\n"
			"	jz	0b\n"
			"1:"
			: [prev] "=&d" (prev),
			  [address] "+Q" (*(int *)address),
			  [tmp] "+&d" (old),
			  [new] "+&d" (new),
			  [mask] "+&d" (mask)
			:: "memory", "cc");
		return prev >> shift;
	}
	case 2: {
		unsigned int prev, shift, mask;

		shift = (2 ^ (address & 2)) << 3;
		address ^= address & 2;
		old = (old & 0xffff) << shift;
		new = (new & 0xffff) << shift;
		mask = ~(0xffff << shift);
		asm volatile(
			"	l	%[prev],%[address]\n"
			"	nr	%[prev],%[mask]\n"
			"	xilf	%[mask],0xffffffff\n"
			"	or	%[new],%[prev]\n"
			"	or	%[prev],%[tmp]\n"
			"0:	lr	%[tmp],%[prev]\n"
			"	cs	%[prev],%[new],%[address]\n"
			"	jnl	1f\n"
			"	xr	%[tmp],%[prev]\n"
			"	xr	%[new],%[tmp]\n"
			"	nr	%[tmp],%[mask]\n"
			"	jz	0b\n"
			"1:"
			: [prev] "=&d" (prev),
			  [address] "+Q" (*(int *)address),
			  [tmp] "+&d" (old),
			  [new] "+&d" (new),
			  [mask] "+&d" (mask)
			:: "memory", "cc");
		return prev >> shift;
	}
	case 4: {
		unsigned int prev = old;

		asm volatile(
			"	cs	%[prev],%[new],%[address]\n"
			: [prev] "+&d" (prev),
			  [address] "+Q" (*(int *)address)
			: [new] "d" (new)
			: "memory", "cc");
		return prev;
	}
	case 8: {
		unsigned long prev = old;

		asm volatile(
			"	csg	%[prev],%[new],%[address]\n"
			: [prev] "+&d" (prev),
			  [address] "+QS" (*(long *)address)
			: [new] "d" (new)
			: "memory", "cc");
		return prev;
	}
	}
	__cmpxchg_called_with_bad_pointer();
	return old;
}

#define arch_cmpxchg(ptr, o, n)						\
({									\
	__typeof__(*(ptr)) __ret;					\
									\
	__ret = (__typeof__(*(ptr)))					\
		__cmpxchg((unsigned long)(ptr), (unsigned long)(o),	\
			  (unsigned long)(n), sizeof(*(ptr)));		\
	__ret;								\
})

#define arch_cmpxchg64		arch_cmpxchg
#define arch_cmpxchg_local	arch_cmpxchg
#define arch_cmpxchg64_local	arch_cmpxchg

#define system_has_cmpxchg_double()	1

static __always_inline int __cmpxchg_double(unsigned long p1, unsigned long p2,
					    unsigned long o1, unsigned long o2,
					    unsigned long n1, unsigned long n2)
{
	union register_pair old = { .even = o1, .odd = o2, };
	union register_pair new = { .even = n1, .odd = n2, };
	int cc;

	asm volatile(
		"	cdsg	%[old],%[new],%[ptr]\n"
		"	ipm	%[cc]\n"
		"	srl	%[cc],28\n"
		: [cc] "=&d" (cc), [old] "+&d" (old.pair)
		: [new] "d" (new.pair),
		  [ptr] "QS" (*(unsigned long *)p1), "Q" (*(unsigned long *)p2)
		: "memory", "cc");
	return !cc;
}

#define arch_cmpxchg_double(p1, p2, o1, o2, n1, n2)			\
({									\
	typeof(p1) __p1 = (p1);						\
	typeof(p2) __p2 = (p2);						\
									\
	BUILD_BUG_ON(sizeof(*(p1)) != sizeof(long));			\
	BUILD_BUG_ON(sizeof(*(p2)) != sizeof(long));			\
	VM_BUG_ON((unsigned long)((__p1) + 1) != (unsigned long)(__p2));\
	__cmpxchg_double((unsigned long)__p1, (unsigned long)__p2,	\
			 (unsigned long)(o1), (unsigned long)(o2),	\
			 (unsigned long)(n1), (unsigned long)(n2));	\
})

#endif /* __ASM_CMPXCHG_H */