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+/*
+ * Copyright 2011 Tilera Corporation. All Rights Reserved.
+ *
+ * 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, version 2.
+ *
+ * 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, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/linkage.h>
+#include <asm/errno.h>
+#include <asm/cache.h>
+#include <arch/chip.h>
+
+/* Access user memory, but use MMU to avoid propagating kernel exceptions. */
+
+ .pushsection .fixup,"ax"
+
+get_user_fault:
+ { movei r1, -EFAULT; move r0, zero }
+ jrp lr
+ ENDPROC(get_user_fault)
+
+put_user_fault:
+ { movei r0, -EFAULT; jrp lr }
+ ENDPROC(put_user_fault)
+
+ .popsection
+
+/*
+ * __get_user_N functions take a pointer in r0, and return 0 in r1
+ * on success, with the value in r0; or else -EFAULT in r1.
+ */
+#define __get_user_N(bytes, LOAD) \
+ STD_ENTRY(__get_user_##bytes); \
+1: { LOAD r0, r0; move r1, zero }; \
+ jrp lr; \
+ STD_ENDPROC(__get_user_##bytes); \
+ .pushsection __ex_table,"a"; \
+ .quad 1b, get_user_fault; \
+ .popsection
+
+__get_user_N(1, ld1u)
+__get_user_N(2, ld2u)
+__get_user_N(4, ld4u)
+__get_user_N(8, ld)
+
+/*
+ * __put_user_N functions take a value in r0 and a pointer in r1,
+ * and return 0 in r0 on success or -EFAULT on failure.
+ */
+#define __put_user_N(bytes, STORE) \
+ STD_ENTRY(__put_user_##bytes); \
+1: { STORE r1, r0; move r0, zero }; \
+ jrp lr; \
+ STD_ENDPROC(__put_user_##bytes); \
+ .pushsection __ex_table,"a"; \
+ .quad 1b, put_user_fault; \
+ .popsection
+
+__put_user_N(1, st1)
+__put_user_N(2, st2)
+__put_user_N(4, st4)
+__put_user_N(8, st)
+
+/*
+ * strnlen_user_asm takes the pointer in r0, and the length bound in r1.
+ * It returns the length, including the terminating NUL, or zero on exception.
+ * If length is greater than the bound, returns one plus the bound.
+ */
+STD_ENTRY(strnlen_user_asm)
+ { beqz r1, 2f; addi r3, r0, -1 } /* bias down to include NUL */
+1: { ld1u r4, r0; addi r1, r1, -1 }
+ beqz r4, 2f
+ { bnezt r1, 1b; addi r0, r0, 1 }
+2: { sub r0, r0, r3; jrp lr }
+ STD_ENDPROC(strnlen_user_asm)
+ .pushsection .fixup,"ax"
+strnlen_user_fault:
+ { move r0, zero; jrp lr }
+ ENDPROC(strnlen_user_fault)
+ .section __ex_table,"a"
+ .quad 1b, strnlen_user_fault
+ .popsection
+
+/*
+ * strncpy_from_user_asm takes the kernel target pointer in r0,
+ * the userspace source pointer in r1, and the length bound (including
+ * the trailing NUL) in r2. On success, it returns the string length
+ * (not including the trailing NUL), or -EFAULT on failure.
+ */
+STD_ENTRY(strncpy_from_user_asm)
+ { beqz r2, 2f; move r3, r0 }
+1: { ld1u r4, r1; addi r1, r1, 1; addi r2, r2, -1 }
+ { st1 r0, r4; addi r0, r0, 1 }
+ beqz r2, 2f
+ bnezt r4, 1b
+ addi r0, r0, -1 /* don't count the trailing NUL */
+2: { sub r0, r0, r3; jrp lr }
+ STD_ENDPROC(strncpy_from_user_asm)
+ .pushsection .fixup,"ax"
+strncpy_from_user_fault:
+ { movei r0, -EFAULT; jrp lr }
+ ENDPROC(strncpy_from_user_fault)
+ .section __ex_table,"a"
+ .quad 1b, strncpy_from_user_fault
+ .popsection
+
+/*
+ * clear_user_asm takes the user target address in r0 and the
+ * number of bytes to zero in r1.
+ * It returns the number of uncopiable bytes (hopefully zero) in r0.
+ * Note that we don't use a separate .fixup section here since we fall
+ * through into the "fixup" code as the last straight-line bundle anyway.
+ */
+STD_ENTRY(clear_user_asm)
+ { beqz r1, 2f; or r2, r0, r1 }
+ andi r2, r2, 7
+ beqzt r2, .Lclear_aligned_user_asm
+1: { st1 r0, zero; addi r0, r0, 1; addi r1, r1, -1 }
+ bnezt r1, 1b
+2: { move r0, r1; jrp lr }
+ .pushsection __ex_table,"a"
+ .quad 1b, 2b
+ .popsection
+
+.Lclear_aligned_user_asm:
+1: { st r0, zero; addi r0, r0, 8; addi r1, r1, -8 }
+ bnezt r1, 1b
+2: { move r0, r1; jrp lr }
+ STD_ENDPROC(clear_user_asm)
+ .pushsection __ex_table,"a"
+ .quad 1b, 2b
+ .popsection
+
+/*
+ * flush_user_asm takes the user target address in r0 and the
+ * number of bytes to flush in r1.
+ * It returns the number of unflushable bytes (hopefully zero) in r0.
+ */
+STD_ENTRY(flush_user_asm)
+ beqz r1, 2f
+ { movei r2, L2_CACHE_BYTES; add r1, r0, r1 }
+ { sub r2, zero, r2; addi r1, r1, L2_CACHE_BYTES-1 }
+ { and r0, r0, r2; and r1, r1, r2 }
+ { sub r1, r1, r0 }
+1: { flush r0; addi r1, r1, -CHIP_FLUSH_STRIDE() }
+ { addi r0, r0, CHIP_FLUSH_STRIDE(); bnezt r1, 1b }
+2: { move r0, r1; jrp lr }
+ STD_ENDPROC(flush_user_asm)
+ .pushsection __ex_table,"a"
+ .quad 1b, 2b
+ .popsection
+
+/*
+ * inv_user_asm takes the user target address in r0 and the
+ * number of bytes to invalidate in r1.
+ * It returns the number of not inv'able bytes (hopefully zero) in r0.
+ */
+STD_ENTRY(inv_user_asm)
+ beqz r1, 2f
+ { movei r2, L2_CACHE_BYTES; add r1, r0, r1 }
+ { sub r2, zero, r2; addi r1, r1, L2_CACHE_BYTES-1 }
+ { and r0, r0, r2; and r1, r1, r2 }
+ { sub r1, r1, r0 }
+1: { inv r0; addi r1, r1, -CHIP_INV_STRIDE() }
+ { addi r0, r0, CHIP_INV_STRIDE(); bnezt r1, 1b }
+2: { move r0, r1; jrp lr }
+ STD_ENDPROC(inv_user_asm)
+ .pushsection __ex_table,"a"
+ .quad 1b, 2b
+ .popsection
+
+/*
+ * finv_user_asm takes the user target address in r0 and the
+ * number of bytes to flush-invalidate in r1.
+ * It returns the number of not finv'able bytes (hopefully zero) in r0.
+ */
+STD_ENTRY(finv_user_asm)
+ beqz r1, 2f
+ { movei r2, L2_CACHE_BYTES; add r1, r0, r1 }
+ { sub r2, zero, r2; addi r1, r1, L2_CACHE_BYTES-1 }
+ { and r0, r0, r2; and r1, r1, r2 }
+ { sub r1, r1, r0 }
+1: { finv r0; addi r1, r1, -CHIP_FINV_STRIDE() }
+ { addi r0, r0, CHIP_FINV_STRIDE(); bnezt r1, 1b }
+2: { move r0, r1; jrp lr }
+ STD_ENDPROC(finv_user_asm)
+ .pushsection __ex_table,"a"
+ .quad 1b, 2b
+ .popsection
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