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| /* SPDX-License-Identifier: GPL-2.0 */
| /*
| * locks.S: SMP low-level lock primitives on Sparc.
| *
| * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
| * Copyright (C) 1998 Anton Blanchard (anton@progsoc.uts.edu.au)
| * Copyright (C) 1998 Jakub Jelinek (jj@ultra.linux.cz)
| */
|
| #include <asm/ptrace.h>
| #include <asm/psr.h>
| #include <asm/smp.h>
| #include <asm/spinlock.h>
| #include <asm/export.h>
|
| .text
| .align 4
|
| /* Read/writer locks, as usual this is overly clever to make it
| * as fast as possible.
| */
|
| /* caches... */
| ___rw_read_enter_spin_on_wlock:
| orcc %g2, 0x0, %g0
| be,a ___rw_read_enter
| ldstub [%g1 + 3], %g2
| b ___rw_read_enter_spin_on_wlock
| ldub [%g1 + 3], %g2
| ___rw_read_try_spin_on_wlock:
| andcc %g2, 0xff, %g0
| be,a ___rw_read_try
| ldstub [%g1 + 3], %g2
| xnorcc %g2, 0x0, %o0 /* if g2 is ~0, set o0 to 0 and bugger off */
| bne,a ___rw_read_enter_spin_on_wlock
| ld [%g1], %g2
| retl
| mov %g4, %o7
| ___rw_read_exit_spin_on_wlock:
| orcc %g2, 0x0, %g0
| be,a ___rw_read_exit
| ldstub [%g1 + 3], %g2
| b ___rw_read_exit_spin_on_wlock
| ldub [%g1 + 3], %g2
| ___rw_write_enter_spin_on_wlock:
| orcc %g2, 0x0, %g0
| be,a ___rw_write_enter
| ldstub [%g1 + 3], %g2
| b ___rw_write_enter_spin_on_wlock
| ld [%g1], %g2
|
| .globl ___rw_read_enter
| EXPORT_SYMBOL(___rw_read_enter)
| ___rw_read_enter:
| orcc %g2, 0x0, %g0
| bne,a ___rw_read_enter_spin_on_wlock
| ldub [%g1 + 3], %g2
| ld [%g1], %g2
| add %g2, 1, %g2
| st %g2, [%g1]
| retl
| mov %g4, %o7
|
| .globl ___rw_read_exit
| EXPORT_SYMBOL(___rw_read_exit)
| ___rw_read_exit:
| orcc %g2, 0x0, %g0
| bne,a ___rw_read_exit_spin_on_wlock
| ldub [%g1 + 3], %g2
| ld [%g1], %g2
| sub %g2, 0x1ff, %g2
| st %g2, [%g1]
| retl
| mov %g4, %o7
|
| .globl ___rw_read_try
| EXPORT_SYMBOL(___rw_read_try)
| ___rw_read_try:
| orcc %g2, 0x0, %g0
| bne ___rw_read_try_spin_on_wlock
| ld [%g1], %g2
| add %g2, 1, %g2
| st %g2, [%g1]
| set 1, %o1
| retl
| mov %g4, %o7
|
| .globl ___rw_write_enter
| EXPORT_SYMBOL(___rw_write_enter)
| ___rw_write_enter:
| orcc %g2, 0x0, %g0
| bne ___rw_write_enter_spin_on_wlock
| ld [%g1], %g2
| andncc %g2, 0xff, %g0
| bne,a ___rw_write_enter_spin_on_wlock
| stb %g0, [%g1 + 3]
| retl
| mov %g4, %o7
|
|
