diff options
Diffstat (limited to 'arch/csky/kernel/atomic.S')
| -rw-r--r-- | arch/csky/kernel/atomic.S | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/arch/csky/kernel/atomic.S b/arch/csky/kernel/atomic.S new file mode 100644 index 000000000..e73e548f7 --- /dev/null +++ b/arch/csky/kernel/atomic.S @@ -0,0 +1,61 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. + +#include <linux/linkage.h> +#include <abi/entry.h> + +.text + +/* + * int csky_cmpxchg(int oldval, int newval, int *ptr) + * + * If *ptr != oldval && return 1, + * else *ptr = newval return 0. + */ +ENTRY(csky_cmpxchg) + USPTOKSP + + RD_MEH a3 + WR_MEH a3 + + mfcr a3, epc + addi a3, TRAP0_SIZE + + subi sp, 16 + stw a3, (sp, 0) + mfcr a3, epsr + stw a3, (sp, 4) + mfcr a3, usp + stw a3, (sp, 8) + + psrset ee +#ifdef CONFIG_CPU_HAS_LDSTEX +1: + ldex a3, (a2) + cmpne a0, a3 + bt16 2f + mov a3, a1 + stex a3, (a2) + bez a3, 1b +2: + sync.is +#else +GLOBAL(csky_cmpxchg_ldw) + ldw a3, (a2) + cmpne a0, a3 + bt16 3f +GLOBAL(csky_cmpxchg_stw) + stw a1, (a2) +3: +#endif + mvc a0 + ldw a3, (sp, 0) + mtcr a3, epc + ldw a3, (sp, 4) + mtcr a3, epsr + ldw a3, (sp, 8) + mtcr a3, usp + addi sp, 16 + KSPTOUSP + rte +END(csky_cmpxchg) |