Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
		
			
				
	
	
		
			109 lines
		
	
	
	
		
			2 KiB
			
		
	
	
	
		
			ArmAsm
		
	
	
	
	
	
			
		
		
	
	
			109 lines
		
	
	
	
		
			2 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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