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kernel/linux-imx6_3.14.28/arch/x86/lib/putuser.S 1.87 KB
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  /*
   * __put_user functions.
   *
   * (C) Copyright 2005 Linus Torvalds
   * (C) Copyright 2005 Andi Kleen
   * (C) Copyright 2008 Glauber Costa
   *
   * These functions have a non-standard call interface
   * to make them more efficient, especially as they
   * return an error value in addition to the "real"
   * return value.
   */
  #include <linux/linkage.h>
  #include <asm/dwarf2.h>
  #include <asm/thread_info.h>
  #include <asm/errno.h>
  #include <asm/asm.h>
  #include <asm/smap.h>
  
  
  /*
   * __put_user_X
   *
   * Inputs:	%eax[:%edx] contains the data
   *		%ecx contains the address
   *
   * Outputs:	%eax is error code (0 or -EFAULT)
   *
   * These functions should not modify any other registers,
   * as they get called from within inline assembly.
   */
  
  #define ENTER	CFI_STARTPROC ; \
  		GET_THREAD_INFO(%_ASM_BX)
  #define EXIT	ASM_CLAC ;	\
  		ret ;		\
  		CFI_ENDPROC
  
  .text
  ENTRY(__put_user_1)
  	ENTER
  	cmp TI_addr_limit(%_ASM_BX),%_ASM_CX
  	jae bad_put_user
  	ASM_STAC
  1:	movb %al,(%_ASM_CX)
  	xor %eax,%eax
  	EXIT
  ENDPROC(__put_user_1)
  
  ENTRY(__put_user_2)
  	ENTER
  	mov TI_addr_limit(%_ASM_BX),%_ASM_BX
  	sub $1,%_ASM_BX
  	cmp %_ASM_BX,%_ASM_CX
  	jae bad_put_user
  	ASM_STAC
  2:	movw %ax,(%_ASM_CX)
  	xor %eax,%eax
  	EXIT
  ENDPROC(__put_user_2)
  
  ENTRY(__put_user_4)
  	ENTER
  	mov TI_addr_limit(%_ASM_BX),%_ASM_BX
  	sub $3,%_ASM_BX
  	cmp %_ASM_BX,%_ASM_CX
  	jae bad_put_user
  	ASM_STAC
  3:	movl %eax,(%_ASM_CX)
  	xor %eax,%eax
  	EXIT
  ENDPROC(__put_user_4)
  
  ENTRY(__put_user_8)
  	ENTER
  	mov TI_addr_limit(%_ASM_BX),%_ASM_BX
  	sub $7,%_ASM_BX
  	cmp %_ASM_BX,%_ASM_CX
  	jae bad_put_user
  	ASM_STAC
  4:	mov %_ASM_AX,(%_ASM_CX)
  #ifdef CONFIG_X86_32
  5:	movl %edx,4(%_ASM_CX)
  #endif
  	xor %eax,%eax
  	EXIT
  ENDPROC(__put_user_8)
  
  bad_put_user:
  	CFI_STARTPROC
  	movl $-EFAULT,%eax
  	EXIT
  END(bad_put_user)
  
  	_ASM_EXTABLE(1b,bad_put_user)
  	_ASM_EXTABLE(2b,bad_put_user)
  	_ASM_EXTABLE(3b,bad_put_user)
  	_ASM_EXTABLE(4b,bad_put_user)
  #ifdef CONFIG_X86_32
  	_ASM_EXTABLE(5b,bad_put_user)
  #endif