/* 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 <linux/export.h> #include <asm/ptrace.h> #include <asm/psr.h> #include <asm/smp.h> #include <asm/spinlock.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