| /* |
| * 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 <linux/errno.h> |
| #include <asm/lowcore.h> |
| #include <asm/asm-offsets.h> |
| |
| .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: |
| ahi %r3,-1 |
| jo 6f |
| sacf 256 |
| bras %r1,4f |
| 0: ahi %r3,257 |
| 1: mvc 0(1,%r4),0(%r2) |
| la %r2,1(%r2) |
| la %r4,1(%r4) |
| ahi %r3,-1 |
| jnz 1b |
| 2: lr %r2,%r3 |
| br %r14 |
| 3: mvc 0(256,%r4),0(%r2) |
| la %r2,256(%r2) |
| la %r4,256(%r4) |
| 4: ahi %r3,-256 |
| jnm 3b |
| 5: ex %r3,4(%r1) |
| sacf 0 |
| 6: slr %r2,%r2 |
| br %r14 |
| .section __ex_table,"a" |
| .long 1b,2b |
| .long 3b,0b |
| .long 5b,0b |
| .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 |
