arch/arm64/lib/bitops.S

   1 /*
   2  * Based on arch/arm/lib/bitops.h
   3  *
   4  * Copyright (C) 2013 ARM Ltd.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <linux/linkage.h>
  20 #include <asm/assembler.h>
  21 #include <asm/lse.h>
  22
  23 /*
  24  * x0: bits 5:0  bit offset
  25  *     bits 31:6 word offset
  26  * x1: address
  27  */
  28         .macro  bitop, name, llsc, lse
  29 ENTRY(  \name   )
  30         and     w3, w0, #63             // Get bit offset
  31         eor     w0, w0, w3              // Clear low bits
  32         mov     x2, #1
  33         add     x1, x1, x0, lsr #3      // Get word offset
  34 alt_lse "       prfm    pstl1strm, [x1]",       "nop"
  35         lsl     x3, x2, x3              // Create mask
  36
  37 alt_lse "1:     ldxr    x2, [x1]",              "\lse   x3, [x1]"
  38 alt_lse "       \llsc   x2, x2, x3",            "nop"
  39 alt_lse "       stxr    w0, x2, [x1]",          "nop"
  40 alt_lse "       cbnz    w0, 1b",                "nop"
  41
  42         ret
  43 ENDPROC(\name   )
  44         .endm
  45
  46         .macro  testop, name, llsc, lse
  47 ENTRY(  \name   )
  48         and     w3, w0, #63             // Get bit offset
  49         eor     w0, w0, w3              // Clear low bits
  50         mov     x2, #1
  51         add     x1, x1, x0, lsr #3      // Get word offset
  52 alt_lse "       prfm    pstl1strm, [x1]",       "nop"
  53         lsl     x4, x2, x3              // Create mask
  54
  55 alt_lse "1:     ldxr    x2, [x1]",              "\lse   x4, x2, [x1]"
  56         lsr     x0, x2, x3
  57 alt_lse "       \llsc   x2, x2, x4",            "nop"
  58 alt_lse "       stlxr   w5, x2, [x1]",          "nop"
  59 alt_lse "       cbnz    w5, 1b",                "nop"
  60 alt_lse "       dmb     ish",                   "nop"
  61
  62         and     x0, x0, #1
  63         ret
  64 ENDPROC(\name   )
  65         .endm
  66
  67 /*
  68  * Atomic bit operations.
  69  */
  70         bitop   change_bit, eor, steor
  71         bitop   clear_bit, bic, stclr
  72         bitop   set_bit, orr, stset
  73
  74         testop  test_and_change_bit, eor, ldeoral
  75         testop  test_and_clear_bit, bic, ldclral
  76         testop  test_and_set_bit, orr, ldsetal