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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/parisc/lib/lusercopy.S
Initial import
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+/*
+ * User Space Access Routines
+ *
+ * Copyright (C) 2000-2002 Hewlett-Packard (John Marvin)
+ * Copyright (C) 2000 Richard Hirst <rhirst with parisc-linux.org>
+ * Copyright (C) 2001 Matthieu Delahaye <delahaym at esiee.fr>
+ * Copyright (C) 2003 Randolph Chung <tausq with parisc-linux.org>
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+/*
+ * These routines still have plenty of room for optimization
+ * (word & doubleword load/store, dual issue, store hints, etc.).
+ */
+
+/*
+ * The following routines assume that space register 3 (sr3) contains
+ * the space id associated with the current users address space.
+ */
+
+
+ .text
+
+#include <asm/assembly.h>
+#include <asm/errno.h>
+#include <linux/linkage.h>
+
+ /*
+ * get_sr gets the appropriate space value into
+ * sr1 for kernel/user space access, depending
+ * on the flag stored in the task structure.
+ */
+
+ .macro get_sr
+ mfctl %cr30,%r1
+ ldw TI_SEGMENT(%r1),%r22
+ mfsp %sr3,%r1
+ or,<> %r22,%r0,%r0
+ copy %r0,%r1
+ mtsp %r1,%sr1
+ .endm
+
+ .macro fixup_branch lbl
+ ldil L%\lbl, %r1
+ ldo R%\lbl(%r1), %r1
+ bv %r0(%r1)
+ .endm
+
+ /*
+ * unsigned long lclear_user(void *to, unsigned long n)
+ *
+ * Returns 0 for success.
+ * otherwise, returns number of bytes not transferred.
+ */
+
+ENTRY(lclear_user)
+ .proc
+ .callinfo NO_CALLS
+ .entry
+ comib,=,n 0,%r25,$lclu_done
+ get_sr
+$lclu_loop:
+ addib,<> -1,%r25,$lclu_loop
+1: stbs,ma %r0,1(%sr1,%r26)
+
+$lclu_done:
+ bv %r0(%r2)
+ copy %r25,%r28
+ .exit
+ENDPROC(lclear_user)
+
+ .section .fixup,"ax"
+2: fixup_branch $lclu_done
+ ldo 1(%r25),%r25
+ .previous
+
+ ASM_EXCEPTIONTABLE_ENTRY(1b,2b)
+
+ .procend
+
+ /*
+ * long lstrnlen_user(char *s, long n)
+ *
+ * Returns 0 if exception before zero byte or reaching N,
+ * N+1 if N would be exceeded,
+ * else strlen + 1 (i.e. includes zero byte).
+ */
+
+ENTRY(lstrnlen_user)
+ .proc
+ .callinfo NO_CALLS
+ .entry
+ comib,= 0,%r25,$lslen_nzero
+ copy %r26,%r24
+ get_sr
+1: ldbs,ma 1(%sr1,%r26),%r1
+$lslen_loop:
+ comib,=,n 0,%r1,$lslen_done
+ addib,<> -1,%r25,$lslen_loop
+2: ldbs,ma 1(%sr1,%r26),%r1
+$lslen_done:
+ bv %r0(%r2)
+ sub %r26,%r24,%r28
+ .exit
+
+$lslen_nzero:
+ b $lslen_done
+ ldo 1(%r26),%r26 /* special case for N == 0 */
+ENDPROC(lstrnlen_user)
+
+ .section .fixup,"ax"
+3: fixup_branch $lslen_done
+ copy %r24,%r26 /* reset r26 so 0 is returned on fault */
+ .previous
+
+ ASM_EXCEPTIONTABLE_ENTRY(1b,3b)
+ ASM_EXCEPTIONTABLE_ENTRY(2b,3b)
+
+ .procend
+
+ .end