/* $NetBSD: atomic_cas.S,v 1.16 2025/12/19 03:29:54 thorpej Exp $ */ /*- * Copyright (c) 2007, 2008, 2025 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Jason R. Thorpe and Steve C. Woodford. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include <sys/ras.h> #include "atomic_op_asm.h" .text /* * For kernel builds on systems with a 68010 or __HAVE_M68K_BROKEN_RMC, * then m68k/m68k/lock_stubs.s provides a restartable atomic sequence * implementation of _atomic_cas_32() for the kernel's own use. * * On such systems, _atomic_cas_16() and _atomic_cas_8() are provided * by atomic_cas_by_cas32.c. */ /* =====> restartable atomic sequence implementation (userspace only) <===== */ #if !defined(_KERNEL) ENTRY(_atomic_cas_32_ras) .hidden _C_LABEL(_atomic_cas_32_ras) movl 4(%sp), %a0 /* Fetch ptr */ RAS_START_ASM_HIDDEN(_atomic_cas_32_ras) movl (%a0), %d0 /* d0 = *ptr */ cmpl 8(%sp), %d0 /* Same as old? */ jne 1f /* Nope */ movl 12(%sp), (%a0) /* *ptr = new */ RAS_END_ASM_HIDDEN(_atomic_cas_32_ras) 1: movl %d0, %a0 /* pointers return also in %a0 */ rts END(_atomic_cas_32_ras) ENTRY(_atomic_cas_16_ras) .hidden _C_LABEL(_atomic_cas_16_ras) movl 4(%sp), %a0 /* Fetch ptr */ RAS_START_ASM_HIDDEN(_atomic_cas_16_ras) movw (%a0), %d0 /* d0 = *ptr */ cmpw 8+2(%sp), %d0 /* Same as old? (lower word) */ jne 1f /* Nope */ movw 12+2(%sp), (%a0) /* *ptr = new (lower word) */ RAS_END_ASM_HIDDEN(_atomic_cas_16_ras) 1: rts END(_atomic_cas_16_ras) ENTRY(_atomic_cas_8_ras) .hidden _C_LABEL(_atomic_cas_8_ras) movl 4(%sp), %a0 /* Fetch ptr */ RAS_START_ASM_HIDDEN(_atomic_cas_8_ras) movb (%a0), %d0 /* d0 = *ptr */ cmpb 8+3(%sp), %d0 /* Same as old? (lower byte) */ jne 1f /* Nope */ movb 12+3(%sp), (%a0) /* *ptr = new (lower byte) */ RAS_END_ASM_HIDDEN(_atomic_cas_8_ras) 1: rts END(_atomic_cas_8_ras) #endif /* ! _KERNEL */ /* =====> CASx implementation <===== */ #ifndef __mc68010__ #if !defined(_KERNEL) || !defined(__HAVE_M68K_BROKEN_RMC) ENTRY(_atomic_cas_32_casl) movl 4(%sp), %a0 movl 8(%sp), %d0 movl 12(%sp), %d1 casl %d0, %d1, (%a0) /* %d0 now contains the old value */ movl %d0, %a0 /* pointers return also in %a0 */ rts END(_atomic_cas_32_casl) #ifdef _KERNEL /* Kernel-only aliases; userspace always uses the call stubs. */ STRONG_ALIAS(atomic_cas_ptr,_atomic_cas_32_casl) STRONG_ALIAS(_atomic_cas_ptr,_atomic_cas_32_casl) STRONG_ALIAS(atomic_cas_uint,_atomic_cas_32_casl) STRONG_ALIAS(_atomic_cas_uint,_atomic_cas_32_casl) STRONG_ALIAS(atomic_cas_ulong,_atomic_cas_32_casl) STRONG_ALIAS(_atomic_cas_ulong,_atomic_cas_32_casl) STRONG_ALIAS(atomic_cas_32,_atomic_cas_32_casl) STRONG_ALIAS(_atomic_cas_32,_atomic_cas_32_casl) CRT_ALIAS(__sync_val_compare_and_swap_4,_atomic_cas_32_casl) STRONG_ALIAS(atomic_cas_32_ni,_atomic_cas_32_casl) STRONG_ALIAS(_atomic_cas_32_ni,_atomic_cas_32_casl) STRONG_ALIAS(atomic_cas_ptr_ni,_atomic_cas_32_casl) STRONG_ALIAS(_atomic_cas_ptr_ni,_atomic_cas_32_casl) STRONG_ALIAS(atomic_cas_uint_ni,_atomic_cas_32_casl) STRONG_ALIAS(_atomic_cas_uint_ni,_atomic_cas_32_casl) STRONG_ALIAS(atomic_cas_ulong_ni,_atomic_cas_32_casl) STRONG_ALIAS(_atomic_cas_ulong_ni,_atomic_cas_32_casl) #endif /* _KERNEL */ ENTRY(_atomic_cas_16_casw) movl 4(%sp), %a0 movw 8+2(%sp), %d0 /* lower word */ movw 12+2(%sp), %d1 /* lower word */ casw %d0, %d1, (%a0) /* %d0 now contains the old value */ rts END(_atomic_cas_16_casw) #ifdef _KERNEL ATOMIC_OP_ALIAS(atomic_cas_16,_atomic_cas_16_casw) ATOMIC_OP_ALIAS(_atomic_cas_16,_atomic_cas_16_casw) CRT_ALIAS(__sync_val_compare_and_swap_2,_atomic_cas_16_casw) #endif /* _KERNEL */ ENTRY(_atomic_cas_8_casb) movl 4(%sp), %a0 movb 8+3(%sp), %d0 /* lower byte */ movb 12+3(%sp), %d1 /* lower byte */ casb %d0, %d1, (%a0) /* %d0 now contains the old value */ rts END(_atomic_cas_8_casb) #ifdef _KERNEL ATOMIC_OP_ALIAS(atomic_cas_8,_atomic_cas_8_casb) ATOMIC_OP_ALIAS(_atomic_cas_8,_atomic_cas_8_casb) CRT_ALIAS(__sync_val_compare_and_swap_1,_atomic_cas_8_casb) #endif /* _KERNEL */ #endif /* ! _KERNEL || ! __HAVE_M68K_BROKEN_RMC */ #endif /* ! __mc68010__ */
