105 lines
2.1 KiB
ArmAsm
105 lines
2.1 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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* (C) Copyright 2008 Glauber Costa
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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: %[r|e]ax 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: %[r|e]ax is error code (0 or -EFAULT)
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* %[r|e]dx contains zero-extended value
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*
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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_types.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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#include <asm/asm.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(%_ASM_DX)
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cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
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jae bad_get_user
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1: movzb (%_ASM_AX),%edx
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xor %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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add $1,%_ASM_AX
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jc bad_get_user
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GET_THREAD_INFO(%_ASM_DX)
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cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
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jae bad_get_user
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2: movzwl -1(%_ASM_AX),%edx
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xor %eax,%eax
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ret
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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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add $3,%_ASM_AX
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jc bad_get_user
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GET_THREAD_INFO(%_ASM_DX)
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cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
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jae bad_get_user
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3: mov -3(%_ASM_AX),%edx
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xor %eax,%eax
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ret
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CFI_ENDPROC
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ENDPROC(__get_user_4)
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#ifdef CONFIG_X86_64
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ENTRY(__get_user_8)
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CFI_STARTPROC
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add $7,%_ASM_AX
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jc bad_get_user
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GET_THREAD_INFO(%_ASM_DX)
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cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
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jae bad_get_user
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4: movq -7(%_ASM_AX),%_ASM_DX
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xor %eax,%eax
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ret
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CFI_ENDPROC
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ENDPROC(__get_user_8)
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#endif
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bad_get_user:
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CFI_STARTPROC
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xor %edx,%edx
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mov $(-EFAULT),%_ASM_AX
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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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_ASM_PTR 1b,bad_get_user
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_ASM_PTR 2b,bad_get_user
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_ASM_PTR 3b,bad_get_user
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#ifdef CONFIG_X86_64
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_ASM_PTR 4b,bad_get_user
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#endif
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