Release 4.14 arch/tile/lib/memcpy_user_64.c

/*
 * 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.
 *
 * Do memcpy(), but trap and return "n" when a load or store faults.
 *
 * Note: this idiom only works when memcpy() compiles to a leaf function.
 * Here leaf function not only means it does not have calls, but also
 * requires no stack operations (sp, stack frame pointer) and no
 * use of callee-saved registers, else "jrp lr" will be incorrect since
 * unwinding stack frame is bypassed. Since memcpy() is not complex so
 * these conditions are satisfied here, but we need to be careful when
 * modifying this file. This is not a clean solution but is the best
 * one so far.
 *
 * Also note that we are capturing "n" from the containing scope here.
 */


#define _ST(p, inst, v)						\
	({                                                      \
                asm("1: " #inst " %0, %1;"                      \
                    ".pushsection .coldtext,\"ax\";"    \
                    "2: { move r0, %2; jrp lr };"               \
                    ".section __ex_table,\"a\";"                \
                    ".align 8;"                                 \
                    ".quad 1b, 2b;"                             \
                    ".popsection"                               \
                    : "=m" (*(p)) : "r" (v), "r" (n));          \
        })


#define _LD(p, inst)						\
	({                                                      \
                unsigned long __v;                              \
                asm("1: " #inst " %0, %1;"                      \
                    ".pushsection .coldtext,\"ax\";"    \
                    "2: { move r0, %2; jrp lr };"               \
                    ".section __ex_table,\"a\";"                \
                    ".align 8;"                                 \
                    ".quad 1b, 2b;"                             \
                    ".popsection"                               \
                    : "=r" (__v) : "m" (*(p)), "r" (n));        \
                __v;                                            \
        })


#define USERCOPY_FUNC raw_copy_to_user

#define ST1(p, v) _ST((p), st1, (v))

#define ST2(p, v) _ST((p), st2, (v))

#define ST4(p, v) _ST((p), st4, (v))

#define ST8(p, v) _ST((p), st, (v))

#define LD1 LD

#define LD2 LD

#define LD4 LD

#define LD8 LD
#include "memcpy_64.c"


#define USERCOPY_FUNC raw_copy_from_user

#define ST1 ST

#define ST2 ST

#define ST4 ST

#define ST8 ST

#define LD1(p) _LD((p), ld1u)

#define LD2(p) _LD((p), ld2u)

#define LD4(p) _LD((p), ld4u)

#define LD8(p) _LD((p), ld)
#include "memcpy_64.c"


#define USERCOPY_FUNC raw_copy_in_user

#define ST1(p, v) _ST((p), st1, (v))

#define ST2(p, v) _ST((p), st2, (v))

#define ST4(p, v) _ST((p), st4, (v))

#define ST8(p, v) _ST((p), st, (v))

#define LD1(p) _LD((p), ld1u)

#define LD2(p) _LD((p), ld2u)

#define LD4(p) _LD((p), ld4u)

#define LD8(p) _LD((p), ld)
#include "memcpy_64.c"
Overall Contributors
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Chris Metcalf
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75.00%
Al Viro
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1
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Total
204
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4
100.00%
Directory: arch/tile/lib

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