xref: /openbmc/linux/arch/s390/include/asm/cmpxchg.h (revision 1ac731c529cd4d6adbce134754b51ff7d822b145)

/* 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
__arch_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)))					\
		__arch_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_cmpxchg128()		1

static __always_inline u128 arch_cmpxchg128(volatile u128 *ptr, u128 old, u128 new)
{
	asm volatile(
		"	cdsg	%[old],%[new],%[ptr]\n"
		: [old] "+d" (old), [ptr] "+QS" (*ptr)
		: [new] "d" (new)
		: "memory", "cc");
	return old;
}

#define arch_cmpxchg128		arch_cmpxchg128

#endif /* __ASM_CMPXCHG_H */