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kernel/linux-imx6_3.14.28/arch/sparc/lib/locks.S 1.91 KB
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  /*
   * 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>
  
  	.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
  ___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
  ___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
  ___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
  ___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