331c465914
strnlen_user is supposed to return then length count + 1 if no terminating \0 is found, and it should return 0 on exception. Found by David Howells <dhowells@redhat.com>. Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-By: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
211 lines
4.2 KiB
ArmAsm
211 lines
4.2 KiB
ArmAsm
/*
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* arch/s390/lib/uaccess.S
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* __copy_{from|to}_user functions.
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*
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* s390
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* Copyright (C) 2000,2002 IBM Deutschland Entwicklung GmbH, IBM Corporation
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* Authors(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
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*
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* These functions have standard call interface
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*/
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#include <linux/errno.h>
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#include <asm/lowcore.h>
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#include <asm/asm-offsets.h>
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.text
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.align 4
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.globl __copy_from_user_asm
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# %r2 = to, %r3 = n, %r4 = from
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__copy_from_user_asm:
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slr %r0,%r0
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0: mvcp 0(%r3,%r2),0(%r4),%r0
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jnz 1f
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slr %r2,%r2
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br %r14
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1: la %r2,256(%r2)
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la %r4,256(%r4)
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ahi %r3,-256
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2: mvcp 0(%r3,%r2),0(%r4),%r0
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jnz 1b
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3: slr %r2,%r2
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br %r14
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4: lhi %r0,-4096
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lr %r5,%r4
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slr %r5,%r0
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nr %r5,%r0 # %r5 = (%r4 + 4096) & -4096
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slr %r5,%r4 # %r5 = #bytes to next user page boundary
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clr %r3,%r5 # copy crosses next page boundary ?
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jnh 6f # no, the current page faulted
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# move with the reduced length which is < 256
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5: mvcp 0(%r5,%r2),0(%r4),%r0
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slr %r3,%r5
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6: lr %r2,%r3
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br %r14
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.section __ex_table,"a"
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.long 0b,4b
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.long 2b,4b
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.long 5b,6b
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.previous
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.align 4
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.text
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.globl __copy_to_user_asm
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# %r2 = from, %r3 = n, %r4 = to
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__copy_to_user_asm:
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slr %r0,%r0
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0: mvcs 0(%r3,%r4),0(%r2),%r0
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jnz 1f
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slr %r2,%r2
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br %r14
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1: la %r2,256(%r2)
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la %r4,256(%r4)
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ahi %r3,-256
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2: mvcs 0(%r3,%r4),0(%r2),%r0
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jnz 1b
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3: slr %r2,%r2
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br %r14
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4: lhi %r0,-4096
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lr %r5,%r4
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slr %r5,%r0
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nr %r5,%r0 # %r5 = (%r4 + 4096) & -4096
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slr %r5,%r4 # %r5 = #bytes to next user page boundary
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clr %r3,%r5 # copy crosses next page boundary ?
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jnh 6f # no, the current page faulted
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# move with the reduced length which is < 256
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5: mvcs 0(%r5,%r4),0(%r2),%r0
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slr %r3,%r5
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6: lr %r2,%r3
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br %r14
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.section __ex_table,"a"
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.long 0b,4b
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.long 2b,4b
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.long 5b,6b
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.previous
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.align 4
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.text
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.globl __copy_in_user_asm
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# %r2 = from, %r3 = n, %r4 = to
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__copy_in_user_asm:
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sacf 256
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bras 1,1f
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mvc 0(1,%r4),0(%r2)
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0: mvc 0(256,%r4),0(%r2)
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la %r2,256(%r2)
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la %r4,256(%r4)
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1: ahi %r3,-256
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jnm 0b
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2: ex %r3,0(%r1)
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sacf 0
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slr %r2,%r2
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br 14
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3: mvc 0(1,%r4),0(%r2)
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la %r2,1(%r2)
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la %r4,1(%r4)
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ahi %r3,-1
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jnm 3b
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4: lr %r2,%r3
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sacf 0
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br %r14
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.section __ex_table,"a"
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.long 0b,3b
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.long 2b,3b
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.long 3b,4b
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.previous
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.align 4
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.text
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.globl __clear_user_asm
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# %r2 = to, %r3 = n
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__clear_user_asm:
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bras %r5,0f
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.long empty_zero_page
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0: l %r5,0(%r5)
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slr %r0,%r0
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1: mvcs 0(%r3,%r2),0(%r5),%r0
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jnz 2f
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slr %r2,%r2
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br %r14
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2: la %r2,256(%r2)
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ahi %r3,-256
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3: mvcs 0(%r3,%r2),0(%r5),%r0
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jnz 2b
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4: slr %r2,%r2
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br %r14
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5: lhi %r0,-4096
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lr %r4,%r2
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slr %r4,%r0
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nr %r4,%r0 # %r4 = (%r2 + 4096) & -4096
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slr %r4,%r2 # %r4 = #bytes to next user page boundary
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clr %r3,%r4 # clear crosses next page boundary ?
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jnh 7f # no, the current page faulted
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# clear with the reduced length which is < 256
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6: mvcs 0(%r4,%r2),0(%r5),%r0
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slr %r3,%r4
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7: lr %r2,%r3
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br %r14
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.section __ex_table,"a"
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.long 1b,5b
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.long 3b,5b
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.long 6b,7b
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.previous
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.align 4
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.text
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.globl __strncpy_from_user_asm
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# %r2 = count, %r3 = dst, %r4 = src
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__strncpy_from_user_asm:
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lhi %r0,0
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lr %r1,%r4
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la %r4,0(%r4) # clear high order bit from %r4
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la %r2,0(%r2,%r4) # %r2 points to first byte after string
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sacf 256
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0: srst %r2,%r1
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jo 0b
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sacf 0
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lr %r1,%r2
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jh 1f # \0 found in string ?
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ahi %r1,1 # include \0 in copy
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1: slr %r1,%r4 # %r1 = copy length (without \0)
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slr %r2,%r4 # %r2 = return length (including \0)
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2: mvcp 0(%r1,%r3),0(%r4),%r0
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jnz 3f
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br %r14
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3: la %r3,256(%r3)
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la %r4,256(%r4)
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ahi %r1,-256
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mvcp 0(%r1,%r3),0(%r4),%r0
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jnz 3b
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br %r14
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4: sacf 0
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lhi %r2,-EFAULT
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br %r14
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.section __ex_table,"a"
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.long 0b,4b
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.previous
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.align 4
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.text
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.globl __strnlen_user_asm
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# %r2 = count, %r3 = src
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__strnlen_user_asm:
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lhi %r0,0
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lr %r1,%r3
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la %r3,0(%r3) # clear high order bit from %r4
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la %r2,0(%r2,%r3) # %r2 points to first byte after string
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sacf 256
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0: srst %r2,%r1
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jo 0b
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sacf 0
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ahi %r2,1 # strnlen_user result includes the \0
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# or return count+1 if \0 not found
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slr %r2,%r3
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br %r14
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2: sacf 0
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slr %r2,%r2 # return 0 on exception
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br %r14
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.section __ex_table,"a"
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.long 0b,2b
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.previous
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