110 lines
2.0 KiB
ArmAsm
110 lines
2.0 KiB
ArmAsm
/*
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* __get_user functions.
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*
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* (C) Copyright 1998 Linus Torvalds
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* (C) Copyright 2005 Andi Kleen
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*
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* These functions have a non-standard call interface
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* to make them more efficient, especially as they
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* return an error value in addition to the "real"
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* return value.
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*/
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/*
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* __get_user_X
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*
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* Inputs: %rcx contains the address.
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* The register is modified, but all changes are undone
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* before returning because the C code doesn't know about it.
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*
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* Outputs: %rax is error code (0 or -EFAULT)
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* %rdx contains zero-extended value
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*
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* %r8 is destroyed.
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*
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* These functions should not modify any other registers,
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* as they get called from within inline assembly.
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*/
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#include <linux/linkage.h>
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#include <asm/dwarf2.h>
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#include <asm/page.h>
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#include <asm/errno.h>
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#include <asm/asm-offsets.h>
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#include <asm/thread_info.h>
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.text
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ENTRY(__get_user_1)
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CFI_STARTPROC
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GET_THREAD_INFO(%r8)
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cmpq threadinfo_addr_limit(%r8),%rcx
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jae bad_get_user
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1: movzb (%rcx),%edx
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xorl %eax,%eax
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ret
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CFI_ENDPROC
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ENDPROC(__get_user_1)
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ENTRY(__get_user_2)
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CFI_STARTPROC
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GET_THREAD_INFO(%r8)
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addq $1,%rcx
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jc 20f
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cmpq threadinfo_addr_limit(%r8),%rcx
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jae 20f
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decq %rcx
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2: movzwl (%rcx),%edx
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xorl %eax,%eax
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ret
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20: decq %rcx
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jmp bad_get_user
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CFI_ENDPROC
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ENDPROC(__get_user_2)
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ENTRY(__get_user_4)
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CFI_STARTPROC
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GET_THREAD_INFO(%r8)
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addq $3,%rcx
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jc 30f
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cmpq threadinfo_addr_limit(%r8),%rcx
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jae 30f
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subq $3,%rcx
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3: movl (%rcx),%edx
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xorl %eax,%eax
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ret
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30: subq $3,%rcx
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jmp bad_get_user
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CFI_ENDPROC
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ENDPROC(__get_user_4)
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ENTRY(__get_user_8)
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CFI_STARTPROC
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GET_THREAD_INFO(%r8)
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addq $7,%rcx
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jc 40f
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cmpq threadinfo_addr_limit(%r8),%rcx
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jae 40f
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subq $7,%rcx
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4: movq (%rcx),%rdx
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xorl %eax,%eax
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ret
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40: subq $7,%rcx
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jmp bad_get_user
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CFI_ENDPROC
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ENDPROC(__get_user_8)
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bad_get_user:
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CFI_STARTPROC
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xorl %edx,%edx
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movq $(-EFAULT),%rax
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ret
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CFI_ENDPROC
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END(bad_get_user)
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.section __ex_table,"a"
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.quad 1b,bad_get_user
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.quad 2b,bad_get_user
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.quad 3b,bad_get_user
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.quad 4b,bad_get_user
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.previous
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