/* * arch/s390/lib/uaccess.S * __copy_{from|to}_user functions. * * s390 * Copyright (C) 2000,2002 IBM Deutschland Entwicklung GmbH, IBM Corporation * Authors(s): Martin Schwidefsky (schwidefsky@de.ibm.com) * * These functions have standard call interface */ #include #include #include .text .align 4 .globl __copy_from_user_asm # %r2 = to, %r3 = n, %r4 = from __copy_from_user_asm: slr %r0,%r0 0: mvcp 0(%r3,%r2),0(%r4),%r0 jnz 1f slr %r2,%r2 br %r14 1: la %r2,256(%r2) la %r4,256(%r4) ahi %r3,-256 2: mvcp 0(%r3,%r2),0(%r4),%r0 jnz 1b 3: slr %r2,%r2 br %r14 4: lhi %r0,-4096 lr %r5,%r4 slr %r5,%r0 nr %r5,%r0 # %r5 = (%r4 + 4096) & -4096 slr %r5,%r4 # %r5 = #bytes to next user page boundary clr %r3,%r5 # copy crosses next page boundary ? jnh 6f # no, the current page faulted # move with the reduced length which is < 256 5: mvcp 0(%r5,%r2),0(%r4),%r0 slr %r3,%r5 6: lr %r2,%r3 br %r14 .section __ex_table,"a" .long 0b,4b .long 2b,4b .long 5b,6b .previous .align 4 .text .globl __copy_to_user_asm # %r2 = from, %r3 = n, %r4 = to __copy_to_user_asm: slr %r0,%r0 0: mvcs 0(%r3,%r4),0(%r2),%r0 jnz 1f slr %r2,%r2 br %r14 1: la %r2,256(%r2) la %r4,256(%r4) ahi %r3,-256 2: mvcs 0(%r3,%r4),0(%r2),%r0 jnz 1b 3: slr %r2,%r2 br %r14 4: lhi %r0,-4096 lr %r5,%r4 slr %r5,%r0 nr %r5,%r0 # %r5 = (%r4 + 4096) & -4096 slr %r5,%r4 # %r5 = #bytes to next user page boundary clr %r3,%r5 # copy crosses next page boundary ? jnh 6f # no, the current page faulted # move with the reduced length which is < 256 5: mvcs 0(%r5,%r4),0(%r2),%r0 slr %r3,%r5 6: lr %r2,%r3 br %r14 .section __ex_table,"a" .long 0b,4b .long 2b,4b .long 5b,6b .previous .align 4 .text .globl __copy_in_user_asm # %r2 = from, %r3 = n, %r4 = to __copy_in_user_asm: sacf 256 bras 1,1f mvc 0(1,%r4),0(%r2) 0: mvc 0(256,%r4),0(%r2) la %r2,256(%r2) la %r4,256(%r4) 1: ahi %r3,-256 jnm 0b 2: ex %r3,0(%r1) sacf 0 slr %r2,%r2 br 14 3: mvc 0(1,%r4),0(%r2) la %r2,1(%r2) la %r4,1(%r4) ahi %r3,-1 jnm 3b 4: lr %r2,%r3 sacf 0 br %r14 .section __ex_table,"a" .long 0b,3b .long 2b,3b .long 3b,4b .previous .align 4 .text .globl __clear_user_asm # %r2 = to, %r3 = n __clear_user_asm: bras %r5,0f .long empty_zero_page 0: l %r5,0(%r5) slr %r0,%r0 1: mvcs 0(%r3,%r2),0(%r5),%r0 jnz 2f slr %r2,%r2 br %r14 2: la %r2,256(%r2) ahi %r3,-256 3: mvcs 0(%r3,%r2),0(%r5),%r0 jnz 2b 4: slr %r2,%r2 br %r14 5: lhi %r0,-4096 lr %r4,%r2 slr %r4,%r0 nr %r4,%r0 # %r4 = (%r2 + 4096) & -4096 slr %r4,%r2 # %r4 = #bytes to next user page boundary clr %r3,%r4 # clear crosses next page boundary ? jnh 7f # no, the current page faulted # clear with the reduced length which is < 256 6: mvcs 0(%r4,%r2),0(%r5),%r0 slr %r3,%r4 7: lr %r2,%r3 br %r14 .section __ex_table,"a" .long 1b,5b .long 3b,5b .long 6b,7b .previous .align 4 .text .globl __strncpy_from_user_asm # %r2 = count, %r3 = dst, %r4 = src __strncpy_from_user_asm: lhi %r0,0 lr %r1,%r4 la %r4,0(%r4) # clear high order bit from %r4 la %r2,0(%r2,%r4) # %r2 points to first byte after string sacf 256 0: srst %r2,%r1 jo 0b sacf 0 lr %r1,%r2 jh 1f # \0 found in string ? ahi %r1,1 # include \0 in copy 1: slr %r1,%r4 # %r1 = copy length (without \0) slr %r2,%r4 # %r2 = return length (including \0) 2: mvcp 0(%r1,%r3),0(%r4),%r0 jnz 3f br %r14 3: la %r3,256(%r3) la %r4,256(%r4) ahi %r1,-256 mvcp 0(%r1,%r3),0(%r4),%r0 jnz 3b br %r14 4: sacf 0 lhi %r2,-EFAULT br %r14 .section __ex_table,"a" .long 0b,4b .previous .align 4 .text .globl __strnlen_user_asm # %r2 = count, %r3 = src __strnlen_user_asm: lhi %r0,0 lr %r1,%r3 la %r3,0(%r3) # clear high order bit from %r4 la %r2,0(%r2,%r3) # %r2 points to first byte after string sacf 256 0: srst %r2,%r1 jo 0b sacf 0 ahi %r2,1 # strnlen_user result includes the \0 # or return count+1 if \0 not found slr %r2,%r3 br %r14 2: sacf 0 slr %r2,%r2 # return 0 on exception br %r14 .section __ex_table,"a" .long 0b,2b .previous