root/arch/unicore32/lib/strnlen_user.S

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * linux/arch/unicore32/lib/strnlen_user.S
   4  *
   5  * Code specific to PKUnity SoC and UniCore ISA
   6  *
   7  * Copyright (C) 2001-2010 GUAN Xue-tao
   8  */
   9 #include <linux/linkage.h>
  10 #include <asm/assembler.h>
  11 #include <asm/errno.h>
  12 
  13         .text
  14         .align  5
  15 
  16 /* Prototype: unsigned long __strnlen_user(const char *str, long n)
  17  * Purpose  : get length of a string in user memory
  18  * Params   : str - address of string in user memory
  19  * Returns  : length of string *including terminator*
  20  *            or zero on exception, or n + 1 if too long
  21  */
  22 ENTRY(__strnlen_user)
  23         mov     r2, r0
  24 1:
  25         ldrusr  r3, r0, 1
  26         cxor.a  r3, #0
  27         beq     2f
  28         sub.a   r1, r1, #1
  29         bne     1b
  30         add     r0, r0, #1
  31 2:      sub     r0, r0, r2
  32         mov     pc, lr
  33 ENDPROC(__strnlen_user)
  34 
  35         .pushsection .fixup,"ax"
  36         .align  0
  37 9001:   mov     r0, #0
  38         mov     pc, lr
  39         .popsection