107 lines
1.9 KiB
ArmAsm
107 lines
1.9 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copy to/from user space, handling exceptions as we go.. This
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* isn't exactly pretty.
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*
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* This is essentially the same as "memcpy()", but with a few twists.
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* Notably, we have to make sure that $0 is always up-to-date and
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* contains the right "bytes left to copy" value (and that it is updated
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* only _after_ a successful copy). There is also some rather minor
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* exception setup stuff..
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*/
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#include <asm/export.h>
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/* Allow an exception for an insn; exit if we get one. */
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#define EXI(x,y...) \
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99: x,##y; \
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.section __ex_table, "a"; \
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.long 99b - .; \
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ldi $31, $exitin-99b($31); \
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.previous
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#define EXO(x,y...) \
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99: x, ##y; \
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.section __ex_table, "a"; \
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.long 99b - .; \
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ldi $31, $exitout-99b($31); \
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.previous
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.set noat
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.align 4
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.globl __copy_user
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.ent __copy_user
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__copy_user:
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.prologue 0
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and $18, $18, $0
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and $16, 7, $3
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beq $0, $35
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beq $3, $36
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subl $3, 8, $3
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.align 4
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$37:
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EXI(ldbu $1, 0($17))
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EXO(stb $1, 0($16))
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addl $3, 1, $3
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subl $0, 1, $0
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addl $16, 1, $16
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addl $17, 1, $17
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beq $0, $41
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bne $3, $37
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$36:
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and $17, 7, $1
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bic $0, 7, $4
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beq $1, $43
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beq $4, $48
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EXI(ldl_u $3, 0($17))
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.align 4
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$50:
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EXI(ldl_u $2, 8($17))
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subl $4, 8, $4
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extll $3, $17, $3
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exthl $2, $17, $1
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bis $3, $1, $1
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EXO(stl $1,0($16))
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addl $17, 8, $17
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subl $0, 8, $0
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addl $16, 8, $16
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bis $2, $2, $3
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bne $4, $50
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$48:
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beq $0, $41
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.align 4
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$57:
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EXI(ldbu $1, 0($17))
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EXO(stb $1, 0($16))
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subl $0, 1, $0
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addl $16, 1, $16
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addl $17, 1, $17
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bne $0, $57
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br $31, $41
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.align 4
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$43:
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beq $4, $65
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.align 4
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$66:
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EXI(ldl $1, 0($17))
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subl $4, 8, $4
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EXO(stl $1,0($16))
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addl $17, 8, $17
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subl $0, 8, $0
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addl $16, 8, $16
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bne $4, $66
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$65:
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beq $0, $41
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EXI(ldbu $1, 0($17))
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EXO(stb $1, 0($16))
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addl $17, 1, $17
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addl $16, 1, $16
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subl $0, 1, $0
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br $31, $65
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$41:
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$35:
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$exitin:
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$exitout:
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ret $31, ($26), 1
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.end __copy_user
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EXPORT_SYMBOL(__copy_user)
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