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kernel/linux-imx6_3.14.28/arch/arm/lib/uaccess.S 13.5 KB
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  /*
   *  linux/arch/arm/lib/uaccess.S
   *
   *  Copyright (C) 1995, 1996,1997,1998 Russell King
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   *  Routines to block copy data to/from user memory
   *   These are highly optimised both for the 4k page size
   *   and for various alignments.
   */
  #include <linux/linkage.h>
  #include <asm/assembler.h>
  #include <asm/errno.h>
  #include <asm/domain.h>
  
  		.text
  
  #define PAGE_SHIFT 12
  
  /* Prototype: int __copy_to_user(void *to, const char *from, size_t n)
   * Purpose  : copy a block to user memory from kernel memory
   * Params   : to   - user memory
   *          : from - kernel memory
   *          : n    - number of bytes to copy
   * Returns  : Number of bytes NOT copied.
   */
  
  .Lc2u_dest_not_aligned:
  		rsb	ip, ip, #4
  		cmp	ip, #2
  		ldrb	r3, [r1], #1
  USER(	TUSER(	strb)	r3, [r0], #1)			@ May fault
  		ldrgeb	r3, [r1], #1
  USER(	TUSER(	strgeb) r3, [r0], #1)			@ May fault
  		ldrgtb	r3, [r1], #1
  USER(	TUSER(	strgtb) r3, [r0], #1)			@ May fault
  		sub	r2, r2, ip
  		b	.Lc2u_dest_aligned
  
  ENTRY(__copy_to_user)
  		stmfd	sp!, {r2, r4 - r7, lr}
  		cmp	r2, #4
  		blt	.Lc2u_not_enough
  		ands	ip, r0, #3
  		bne	.Lc2u_dest_not_aligned
  .Lc2u_dest_aligned:
  
  		ands	ip, r1, #3
  		bne	.Lc2u_src_not_aligned
  /*
   * Seeing as there has to be at least 8 bytes to copy, we can
   * copy one word, and force a user-mode page fault...
   */
  
  .Lc2u_0fupi:	subs	r2, r2, #4
  		addmi	ip, r2, #4
  		bmi	.Lc2u_0nowords
  		ldr	r3, [r1], #4
  USER(	TUSER(	str)	r3, [r0], #4)			@ May fault
  		mov	ip, r0, lsl #32 - PAGE_SHIFT	@ On each page, use a ld/st??t instruction
  		rsb	ip, ip, #0
  		movs	ip, ip, lsr #32 - PAGE_SHIFT
  		beq	.Lc2u_0fupi
  /*
   * ip = max no. of bytes to copy before needing another "strt" insn
   */
  		cmp	r2, ip
  		movlt	ip, r2
  		sub	r2, r2, ip
  		subs	ip, ip, #32
  		blt	.Lc2u_0rem8lp
  
  .Lc2u_0cpy8lp:	ldmia	r1!, {r3 - r6}
  		stmia	r0!, {r3 - r6}			@ Shouldnt fault
  		ldmia	r1!, {r3 - r6}
  		subs	ip, ip, #32
  		stmia	r0!, {r3 - r6}			@ Shouldnt fault
  		bpl	.Lc2u_0cpy8lp
  
  .Lc2u_0rem8lp:	cmn	ip, #16
  		ldmgeia	r1!, {r3 - r6}
  		stmgeia	r0!, {r3 - r6}			@ Shouldnt fault
  		tst	ip, #8
  		ldmneia	r1!, {r3 - r4}
  		stmneia	r0!, {r3 - r4}			@ Shouldnt fault
  		tst	ip, #4
  		ldrne	r3, [r1], #4
  	TUSER(	strne) r3, [r0], #4			@ Shouldnt fault
  		ands	ip, ip, #3
  		beq	.Lc2u_0fupi
  .Lc2u_0nowords:	teq	ip, #0
  		beq	.Lc2u_finished
  .Lc2u_nowords:	cmp	ip, #2
  		ldrb	r3, [r1], #1
  USER(	TUSER(	strb)	r3, [r0], #1)			@ May fault
  		ldrgeb	r3, [r1], #1
  USER(	TUSER(	strgeb) r3, [r0], #1)			@ May fault
  		ldrgtb	r3, [r1], #1
  USER(	TUSER(	strgtb) r3, [r0], #1)			@ May fault
  		b	.Lc2u_finished
  
  .Lc2u_not_enough:
  		movs	ip, r2
  		bne	.Lc2u_nowords
  .Lc2u_finished:	mov	r0, #0
  		ldmfd	sp!, {r2, r4 - r7, pc}
  
  .Lc2u_src_not_aligned:
  		bic	r1, r1, #3
  		ldr	r7, [r1], #4
  		cmp	ip, #2
  		bgt	.Lc2u_3fupi
  		beq	.Lc2u_2fupi
  .Lc2u_1fupi:	subs	r2, r2, #4
  		addmi	ip, r2, #4
  		bmi	.Lc2u_1nowords
  		mov	r3, r7, pull #8
  		ldr	r7, [r1], #4
  		orr	r3, r3, r7, push #24
  USER(	TUSER(	str)	r3, [r0], #4)			@ May fault
  		mov	ip, r0, lsl #32 - PAGE_SHIFT
  		rsb	ip, ip, #0
  		movs	ip, ip, lsr #32 - PAGE_SHIFT
  		beq	.Lc2u_1fupi
  		cmp	r2, ip
  		movlt	ip, r2
  		sub	r2, r2, ip
  		subs	ip, ip, #16
  		blt	.Lc2u_1rem8lp
  
  .Lc2u_1cpy8lp:	mov	r3, r7, pull #8
  		ldmia	r1!, {r4 - r7}
  		subs	ip, ip, #16
  		orr	r3, r3, r4, push #24
  		mov	r4, r4, pull #8
  		orr	r4, r4, r5, push #24
  		mov	r5, r5, pull #8
  		orr	r5, r5, r6, push #24
  		mov	r6, r6, pull #8
  		orr	r6, r6, r7, push #24
  		stmia	r0!, {r3 - r6}			@ Shouldnt fault
  		bpl	.Lc2u_1cpy8lp
  
  .Lc2u_1rem8lp:	tst	ip, #8
  		movne	r3, r7, pull #8
  		ldmneia	r1!, {r4, r7}
  		orrne	r3, r3, r4, push #24
  		movne	r4, r4, pull #8
  		orrne	r4, r4, r7, push #24
  		stmneia	r0!, {r3 - r4}			@ Shouldnt fault
  		tst	ip, #4
  		movne	r3, r7, pull #8
  		ldrne	r7, [r1], #4
  		orrne	r3, r3, r7, push #24
  	TUSER(	strne) r3, [r0], #4			@ Shouldnt fault
  		ands	ip, ip, #3
  		beq	.Lc2u_1fupi
  .Lc2u_1nowords:	mov	r3, r7, get_byte_1
  		teq	ip, #0
  		beq	.Lc2u_finished
  		cmp	ip, #2
  USER(	TUSER(	strb)	r3, [r0], #1)			@ May fault
  		movge	r3, r7, get_byte_2
  USER(	TUSER(	strgeb) r3, [r0], #1)			@ May fault
  		movgt	r3, r7, get_byte_3
  USER(	TUSER(	strgtb) r3, [r0], #1)			@ May fault
  		b	.Lc2u_finished
  
  .Lc2u_2fupi:	subs	r2, r2, #4
  		addmi	ip, r2, #4
  		bmi	.Lc2u_2nowords
  		mov	r3, r7, pull #16
  		ldr	r7, [r1], #4
  		orr	r3, r3, r7, push #16
  USER(	TUSER(	str)	r3, [r0], #4)			@ May fault
  		mov	ip, r0, lsl #32 - PAGE_SHIFT
  		rsb	ip, ip, #0
  		movs	ip, ip, lsr #32 - PAGE_SHIFT
  		beq	.Lc2u_2fupi
  		cmp	r2, ip
  		movlt	ip, r2
  		sub	r2, r2, ip
  		subs	ip, ip, #16
  		blt	.Lc2u_2rem8lp
  
  .Lc2u_2cpy8lp:	mov	r3, r7, pull #16
  		ldmia	r1!, {r4 - r7}
  		subs	ip, ip, #16
  		orr	r3, r3, r4, push #16
  		mov	r4, r4, pull #16
  		orr	r4, r4, r5, push #16
  		mov	r5, r5, pull #16
  		orr	r5, r5, r6, push #16
  		mov	r6, r6, pull #16
  		orr	r6, r6, r7, push #16
  		stmia	r0!, {r3 - r6}			@ Shouldnt fault
  		bpl	.Lc2u_2cpy8lp
  
  .Lc2u_2rem8lp:	tst	ip, #8
  		movne	r3, r7, pull #16
  		ldmneia	r1!, {r4, r7}
  		orrne	r3, r3, r4, push #16
  		movne	r4, r4, pull #16
  		orrne	r4, r4, r7, push #16
  		stmneia	r0!, {r3 - r4}			@ Shouldnt fault
  		tst	ip, #4
  		movne	r3, r7, pull #16
  		ldrne	r7, [r1], #4
  		orrne	r3, r3, r7, push #16
  	TUSER(	strne) r3, [r0], #4			@ Shouldnt fault
  		ands	ip, ip, #3
  		beq	.Lc2u_2fupi
  .Lc2u_2nowords:	mov	r3, r7, get_byte_2
  		teq	ip, #0
  		beq	.Lc2u_finished
  		cmp	ip, #2
  USER(	TUSER(	strb)	r3, [r0], #1)			@ May fault
  		movge	r3, r7, get_byte_3
  USER(	TUSER(	strgeb) r3, [r0], #1)			@ May fault
  		ldrgtb	r3, [r1], #0
  USER(	TUSER(	strgtb) r3, [r0], #1)			@ May fault
  		b	.Lc2u_finished
  
  .Lc2u_3fupi:	subs	r2, r2, #4
  		addmi	ip, r2, #4
  		bmi	.Lc2u_3nowords
  		mov	r3, r7, pull #24
  		ldr	r7, [r1], #4
  		orr	r3, r3, r7, push #8
  USER(	TUSER(	str)	r3, [r0], #4)			@ May fault
  		mov	ip, r0, lsl #32 - PAGE_SHIFT
  		rsb	ip, ip, #0
  		movs	ip, ip, lsr #32 - PAGE_SHIFT
  		beq	.Lc2u_3fupi
  		cmp	r2, ip
  		movlt	ip, r2
  		sub	r2, r2, ip
  		subs	ip, ip, #16
  		blt	.Lc2u_3rem8lp
  
  .Lc2u_3cpy8lp:	mov	r3, r7, pull #24
  		ldmia	r1!, {r4 - r7}
  		subs	ip, ip, #16
  		orr	r3, r3, r4, push #8
  		mov	r4, r4, pull #24
  		orr	r4, r4, r5, push #8
  		mov	r5, r5, pull #24
  		orr	r5, r5, r6, push #8
  		mov	r6, r6, pull #24
  		orr	r6, r6, r7, push #8
  		stmia	r0!, {r3 - r6}			@ Shouldnt fault
  		bpl	.Lc2u_3cpy8lp
  
  .Lc2u_3rem8lp:	tst	ip, #8
  		movne	r3, r7, pull #24
  		ldmneia	r1!, {r4, r7}
  		orrne	r3, r3, r4, push #8
  		movne	r4, r4, pull #24
  		orrne	r4, r4, r7, push #8
  		stmneia	r0!, {r3 - r4}			@ Shouldnt fault
  		tst	ip, #4
  		movne	r3, r7, pull #24
  		ldrne	r7, [r1], #4
  		orrne	r3, r3, r7, push #8
  	TUSER(	strne) r3, [r0], #4			@ Shouldnt fault
  		ands	ip, ip, #3
  		beq	.Lc2u_3fupi
  .Lc2u_3nowords:	mov	r3, r7, get_byte_3
  		teq	ip, #0
  		beq	.Lc2u_finished
  		cmp	ip, #2
  USER(	TUSER(	strb)	r3, [r0], #1)			@ May fault
  		ldrgeb	r3, [r1], #1
  USER(	TUSER(	strgeb) r3, [r0], #1)			@ May fault
  		ldrgtb	r3, [r1], #0
  USER(	TUSER(	strgtb) r3, [r0], #1)			@ May fault
  		b	.Lc2u_finished
  ENDPROC(__copy_to_user)
  
  		.pushsection .fixup,"ax"
  		.align	0
  9001:		ldmfd	sp!, {r0, r4 - r7, pc}
  		.popsection
  
  /* Prototype: unsigned long __copy_from_user(void *to,const void *from,unsigned long n);
   * Purpose  : copy a block from user memory to kernel memory
   * Params   : to   - kernel memory
   *          : from - user memory
   *          : n    - number of bytes to copy
   * Returns  : Number of bytes NOT copied.
   */
  .Lcfu_dest_not_aligned:
  		rsb	ip, ip, #4
  		cmp	ip, #2
  USER(	TUSER(	ldrb)	r3, [r1], #1)			@ May fault
  		strb	r3, [r0], #1
  USER(	TUSER(	ldrgeb) r3, [r1], #1)			@ May fault
  		strgeb	r3, [r0], #1
  USER(	TUSER(	ldrgtb) r3, [r1], #1)			@ May fault
  		strgtb	r3, [r0], #1
  		sub	r2, r2, ip
  		b	.Lcfu_dest_aligned
  
  ENTRY(__copy_from_user)
  		stmfd	sp!, {r0, r2, r4 - r7, lr}
  		cmp	r2, #4
  		blt	.Lcfu_not_enough
  		ands	ip, r0, #3
  		bne	.Lcfu_dest_not_aligned
  .Lcfu_dest_aligned:
  		ands	ip, r1, #3
  		bne	.Lcfu_src_not_aligned
  
  /*
   * Seeing as there has to be at least 8 bytes to copy, we can
   * copy one word, and force a user-mode page fault...
   */
  
  .Lcfu_0fupi:	subs	r2, r2, #4
  		addmi	ip, r2, #4
  		bmi	.Lcfu_0nowords
  USER(	TUSER(	ldr)	r3, [r1], #4)
  		str	r3, [r0], #4
  		mov	ip, r1, lsl #32 - PAGE_SHIFT	@ On each page, use a ld/st??t instruction
  		rsb	ip, ip, #0
  		movs	ip, ip, lsr #32 - PAGE_SHIFT
  		beq	.Lcfu_0fupi
  /*
   * ip = max no. of bytes to copy before needing another "strt" insn
   */
  		cmp	r2, ip
  		movlt	ip, r2
  		sub	r2, r2, ip
  		subs	ip, ip, #32
  		blt	.Lcfu_0rem8lp
  
  .Lcfu_0cpy8lp:	ldmia	r1!, {r3 - r6}			@ Shouldnt fault
  		stmia	r0!, {r3 - r6}
  		ldmia	r1!, {r3 - r6}			@ Shouldnt fault
  		subs	ip, ip, #32
  		stmia	r0!, {r3 - r6}
  		bpl	.Lcfu_0cpy8lp
  
  .Lcfu_0rem8lp:	cmn	ip, #16
  		ldmgeia	r1!, {r3 - r6}			@ Shouldnt fault
  		stmgeia	r0!, {r3 - r6}
  		tst	ip, #8
  		ldmneia	r1!, {r3 - r4}			@ Shouldnt fault
  		stmneia	r0!, {r3 - r4}
  		tst	ip, #4
  	TUSER(	ldrne) r3, [r1], #4			@ Shouldnt fault
  		strne	r3, [r0], #4
  		ands	ip, ip, #3
  		beq	.Lcfu_0fupi
  .Lcfu_0nowords:	teq	ip, #0
  		beq	.Lcfu_finished
  .Lcfu_nowords:	cmp	ip, #2
  USER(	TUSER(	ldrb)	r3, [r1], #1)			@ May fault
  		strb	r3, [r0], #1
  USER(	TUSER(	ldrgeb) r3, [r1], #1)			@ May fault
  		strgeb	r3, [r0], #1
  USER(	TUSER(	ldrgtb) r3, [r1], #1)			@ May fault
  		strgtb	r3, [r0], #1
  		b	.Lcfu_finished
  
  .Lcfu_not_enough:
  		movs	ip, r2
  		bne	.Lcfu_nowords
  .Lcfu_finished:	mov	r0, #0
  		add	sp, sp, #8
  		ldmfd	sp!, {r4 - r7, pc}
  
  .Lcfu_src_not_aligned:
  		bic	r1, r1, #3
  USER(	TUSER(	ldr)	r7, [r1], #4)			@ May fault
  		cmp	ip, #2
  		bgt	.Lcfu_3fupi
  		beq	.Lcfu_2fupi
  .Lcfu_1fupi:	subs	r2, r2, #4
  		addmi	ip, r2, #4
  		bmi	.Lcfu_1nowords
  		mov	r3, r7, pull #8
  USER(	TUSER(	ldr)	r7, [r1], #4)			@ May fault
  		orr	r3, r3, r7, push #24
  		str	r3, [r0], #4
  		mov	ip, r1, lsl #32 - PAGE_SHIFT
  		rsb	ip, ip, #0
  		movs	ip, ip, lsr #32 - PAGE_SHIFT
  		beq	.Lcfu_1fupi
  		cmp	r2, ip
  		movlt	ip, r2
  		sub	r2, r2, ip
  		subs	ip, ip, #16
  		blt	.Lcfu_1rem8lp
  
  .Lcfu_1cpy8lp:	mov	r3, r7, pull #8
  		ldmia	r1!, {r4 - r7}			@ Shouldnt fault
  		subs	ip, ip, #16
  		orr	r3, r3, r4, push #24
  		mov	r4, r4, pull #8
  		orr	r4, r4, r5, push #24
  		mov	r5, r5, pull #8
  		orr	r5, r5, r6, push #24
  		mov	r6, r6, pull #8
  		orr	r6, r6, r7, push #24
  		stmia	r0!, {r3 - r6}
  		bpl	.Lcfu_1cpy8lp
  
  .Lcfu_1rem8lp:	tst	ip, #8
  		movne	r3, r7, pull #8
  		ldmneia	r1!, {r4, r7}			@ Shouldnt fault
  		orrne	r3, r3, r4, push #24
  		movne	r4, r4, pull #8
  		orrne	r4, r4, r7, push #24
  		stmneia	r0!, {r3 - r4}
  		tst	ip, #4
  		movne	r3, r7, pull #8
  USER(	TUSER(	ldrne) r7, [r1], #4)			@ May fault
  		orrne	r3, r3, r7, push #24
  		strne	r3, [r0], #4
  		ands	ip, ip, #3
  		beq	.Lcfu_1fupi
  .Lcfu_1nowords:	mov	r3, r7, get_byte_1
  		teq	ip, #0
  		beq	.Lcfu_finished
  		cmp	ip, #2
  		strb	r3, [r0], #1
  		movge	r3, r7, get_byte_2
  		strgeb	r3, [r0], #1
  		movgt	r3, r7, get_byte_3
  		strgtb	r3, [r0], #1
  		b	.Lcfu_finished
  
  .Lcfu_2fupi:	subs	r2, r2, #4
  		addmi	ip, r2, #4
  		bmi	.Lcfu_2nowords
  		mov	r3, r7, pull #16
  USER(	TUSER(	ldr)	r7, [r1], #4)			@ May fault
  		orr	r3, r3, r7, push #16
  		str	r3, [r0], #4
  		mov	ip, r1, lsl #32 - PAGE_SHIFT
  		rsb	ip, ip, #0
  		movs	ip, ip, lsr #32 - PAGE_SHIFT
  		beq	.Lcfu_2fupi
  		cmp	r2, ip
  		movlt	ip, r2
  		sub	r2, r2, ip
  		subs	ip, ip, #16
  		blt	.Lcfu_2rem8lp
  
  
  .Lcfu_2cpy8lp:	mov	r3, r7, pull #16
  		ldmia	r1!, {r4 - r7}			@ Shouldnt fault
  		subs	ip, ip, #16
  		orr	r3, r3, r4, push #16
  		mov	r4, r4, pull #16
  		orr	r4, r4, r5, push #16
  		mov	r5, r5, pull #16
  		orr	r5, r5, r6, push #16
  		mov	r6, r6, pull #16
  		orr	r6, r6, r7, push #16
  		stmia	r0!, {r3 - r6}
  		bpl	.Lcfu_2cpy8lp
  
  .Lcfu_2rem8lp:	tst	ip, #8
  		movne	r3, r7, pull #16
  		ldmneia	r1!, {r4, r7}			@ Shouldnt fault
  		orrne	r3, r3, r4, push #16
  		movne	r4, r4, pull #16
  		orrne	r4, r4, r7, push #16
  		stmneia	r0!, {r3 - r4}
  		tst	ip, #4
  		movne	r3, r7, pull #16
  USER(	TUSER(	ldrne) r7, [r1], #4)			@ May fault
  		orrne	r3, r3, r7, push #16
  		strne	r3, [r0], #4
  		ands	ip, ip, #3
  		beq	.Lcfu_2fupi
  .Lcfu_2nowords:	mov	r3, r7, get_byte_2
  		teq	ip, #0
  		beq	.Lcfu_finished
  		cmp	ip, #2
  		strb	r3, [r0], #1
  		movge	r3, r7, get_byte_3
  		strgeb	r3, [r0], #1
  USER(	TUSER(	ldrgtb) r3, [r1], #0)			@ May fault
  		strgtb	r3, [r0], #1
  		b	.Lcfu_finished
  
  .Lcfu_3fupi:	subs	r2, r2, #4
  		addmi	ip, r2, #4
  		bmi	.Lcfu_3nowords
  		mov	r3, r7, pull #24
  USER(	TUSER(	ldr)	r7, [r1], #4)			@ May fault
  		orr	r3, r3, r7, push #8
  		str	r3, [r0], #4
  		mov	ip, r1, lsl #32 - PAGE_SHIFT
  		rsb	ip, ip, #0
  		movs	ip, ip, lsr #32 - PAGE_SHIFT
  		beq	.Lcfu_3fupi
  		cmp	r2, ip
  		movlt	ip, r2
  		sub	r2, r2, ip
  		subs	ip, ip, #16
  		blt	.Lcfu_3rem8lp
  
  .Lcfu_3cpy8lp:	mov	r3, r7, pull #24
  		ldmia	r1!, {r4 - r7}			@ Shouldnt fault
  		orr	r3, r3, r4, push #8
  		mov	r4, r4, pull #24
  		orr	r4, r4, r5, push #8
  		mov	r5, r5, pull #24
  		orr	r5, r5, r6, push #8
  		mov	r6, r6, pull #24
  		orr	r6, r6, r7, push #8
  		stmia	r0!, {r3 - r6}
  		subs	ip, ip, #16
  		bpl	.Lcfu_3cpy8lp
  
  .Lcfu_3rem8lp:	tst	ip, #8
  		movne	r3, r7, pull #24
  		ldmneia	r1!, {r4, r7}			@ Shouldnt fault
  		orrne	r3, r3, r4, push #8
  		movne	r4, r4, pull #24
  		orrne	r4, r4, r7, push #8
  		stmneia	r0!, {r3 - r4}
  		tst	ip, #4
  		movne	r3, r7, pull #24
  USER(	TUSER(	ldrne) r7, [r1], #4)			@ May fault
  		orrne	r3, r3, r7, push #8
  		strne	r3, [r0], #4
  		ands	ip, ip, #3
  		beq	.Lcfu_3fupi
  .Lcfu_3nowords:	mov	r3, r7, get_byte_3
  		teq	ip, #0
  		beq	.Lcfu_finished
  		cmp	ip, #2
  		strb	r3, [r0], #1
  USER(	TUSER(	ldrgeb) r3, [r1], #1)			@ May fault
  		strgeb	r3, [r0], #1
  USER(	TUSER(	ldrgtb) r3, [r1], #1)			@ May fault
  		strgtb	r3, [r0], #1
  		b	.Lcfu_finished
  ENDPROC(__copy_from_user)
  
  		.pushsection .fixup,"ax"
  		.align	0
  		/*
  		 * We took an exception.  r0 contains a pointer to
  		 * the byte not copied.
  		 */
  9001:		ldr	r2, [sp], #4			@ void *to
  		sub	r2, r0, r2			@ bytes copied
  		ldr	r1, [sp], #4			@ unsigned long count
  		subs	r4, r1, r2			@ bytes left to copy
  		movne	r1, r4
  		blne	__memzero
  		mov	r0, r4
  		ldmfd	sp!, {r4 - r7, pc}
  		.popsection