arch/powerpc/kernel/vdso32/getcpu.S

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License as published by
   4  * the Free Software Foundation; either version 2 of the License, or
   5  * (at your option) any later version.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  *
  12  * You should have received a copy of the GNU General Public License
  13  * along with this program; if not, write to the Free Software
  14  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  15  *
  16  * Copyright (C) IBM Corporation, 2012
  17  *
  18  * Author: Anton Blanchard <anton@au.ibm.com>
  19  */
  20 #include <asm/ppc_asm.h>
  21 #include <asm/vdso.h>
  22
  23         .text
  24 /*
  25  * Exact prototype of getcpu
  26  *
  27  * int __kernel_getcpu(unsigned *cpu, unsigned *node);
  28  *
  29  */
  30 V_FUNCTION_BEGIN(__kernel_getcpu)
  31   .cfi_startproc
  32         mfspr   r5,SPRN_SPRG_VDSO_READ
  33         cmpwi   cr0,r3,0
  34         cmpwi   cr1,r4,0
  35         clrlwi  r6,r5,16
  36         rlwinm  r7,r5,16,31-15,31-0
  37         beq     cr0,1f
  38         stw     r6,0(r3)
  39 1:      beq     cr1,2f
  40         stw     r7,0(r4)
  41 2:      crclr   cr0*4+so
  42         li      r3,0                    /* always success */
  43         blr
  44   .cfi_endproc
  45 V_FUNCTION_END(__kernel_getcpu)