csky/kernel/atomic.S

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
0003
0004 #include <linux/linkage.h>
0005 #include <abi/entry.h>
0006
0007 .text
0008
0009 /*
0010  * int csky_cmpxchg(int oldval, int newval, int *ptr)
0011  *
0012  * If *ptr != oldval && return 1,
0013  * else *ptr = newval return 0.
0014  */
0015 ENTRY(csky_cmpxchg)
0016     USPTOKSP
0017
0018     RD_MEH  a3
0019     WR_MEH  a3
0020
0021     mfcr    a3, epc
0022     addi    a3, TRAP0_SIZE
0023
0024     subi    sp, 16
0025     stw     a3, (sp, 0)
0026     mfcr    a3, epsr
0027     stw     a3, (sp, 4)
0028     mfcr    a3, usp
0029     stw     a3, (sp, 8)
0030
0031     psrset  ee
0032 #ifdef CONFIG_CPU_HAS_LDSTEX
0033 1:
0034     ldex    a3, (a2)
0035     cmpne   a0, a3
0036     bt16    2f
0037     mov a3, a1
0038     stex    a3, (a2)
0039     bez a3, 1b
0040 2:
0041     sync.is
0042 #else
0043 GLOBAL(csky_cmpxchg_ldw)
0044     ldw a3, (a2)
0045     cmpne   a0, a3
0046     bt16    3f
0047 GLOBAL(csky_cmpxchg_stw)
0048     stw a1, (a2)
0049 3:
0050 #endif
0051     mvc a0
0052     ldw a3, (sp, 0)
0053     mtcr    a3, epc
0054     ldw     a3, (sp, 4)
0055     mtcr    a3, epsr
0056     ldw     a3, (sp, 8)
0057     mtcr    a3, usp
0058     addi    sp, 16
0059     KSPTOUSP
0060     rte
0061 END(csky_cmpxchg)