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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/avr32/lib/copy_user.S
Initial import
Diffstat (limited to 'arch/avr32/lib/copy_user.S')
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+/*
+ * Copy to/from userspace with optional address space checking.
+ *
+ * Copyright 2004-2006 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <asm/page.h>
+#include <asm/thread_info.h>
+#include <asm/asm.h>
+
+ /*
+ * __kernel_size_t
+ * __copy_user(void *to, const void *from, __kernel_size_t n)
+ *
+ * Returns the number of bytes not copied. Might be off by
+ * max 3 bytes if we get a fault in the main loop.
+ *
+ * The address-space checking functions simply fall through to
+ * the non-checking version.
+ */
+ .text
+ .align 1
+ .global copy_from_user
+ .type copy_from_user, @function
+copy_from_user:
+ branch_if_kernel r8, __copy_user
+ ret_if_privileged r8, r11, r10, r10
+ rjmp __copy_user
+ .size copy_from_user, . - copy_from_user
+
+ .global copy_to_user
+ .type copy_to_user, @function
+copy_to_user:
+ branch_if_kernel r8, __copy_user
+ ret_if_privileged r8, r12, r10, r10
+ .size copy_to_user, . - copy_to_user
+
+ .global __copy_user
+ .type __copy_user, @function
+__copy_user:
+ mov r9, r11
+ andl r9, 3, COH
+ brne 6f
+
+ /* At this point, from is word-aligned */
+1: sub r10, 4
+ brlt 3f
+
+2:
+10: ld.w r8, r11++
+11: st.w r12++, r8
+ sub r10, 4
+ brge 2b
+
+3: sub r10, -4
+ reteq 0
+
+ /*
+ * Handle unaligned count. Need to be careful with r10 here so
+ * that we return the correct value even if we get a fault
+ */
+4:
+20: ld.ub r8, r11++
+21: st.b r12++, r8
+ sub r10, 1
+ reteq 0
+22: ld.ub r8, r11++
+23: st.b r12++, r8
+ sub r10, 1
+ reteq 0
+24: ld.ub r8, r11++
+25: st.b r12++, r8
+ retal 0
+
+ /* Handle unaligned from-pointer */
+6: cp.w r10, 4
+ brlt 4b
+ rsub r9, r9, 4
+
+30: ld.ub r8, r11++
+31: st.b r12++, r8
+ sub r10, 1
+ sub r9, 1
+ breq 1b
+32: ld.ub r8, r11++
+33: st.b r12++, r8
+ sub r10, 1
+ sub r9, 1
+ breq 1b
+34: ld.ub r8, r11++
+35: st.b r12++, r8
+ sub r10, 1
+ rjmp 1b
+ .size __copy_user, . - __copy_user
+
+ .section .fixup,"ax"
+ .align 1
+19: sub r10, -4
+29: retal r10
+
+ .section __ex_table,"a"
+ .align 2
+ .long 10b, 19b
+ .long 11b, 19b
+ .long 20b, 29b
+ .long 21b, 29b
+ .long 22b, 29b
+ .long 23b, 29b
+ .long 24b, 29b
+ .long 25b, 29b
+ .long 30b, 29b
+ .long 31b, 29b
+ .long 32b, 29b
+ .long 33b, 29b
+ .long 34b, 29b
+ .long 35b, 29b