arch/arm/lib/copy_from_user.S

Source file repositories/reference/linux-study-clean/arch/arm/lib/copy_from_user.S

File Facts

System
Linux kernel
Corpus path
arch/arm/lib/copy_from_user.S
Extension
.S
Size
2409 bytes
Lines
126
Domain
Architecture Layer
Bucket
arch/arm
Inferred role
Architecture Layer: arch/arm
Status
atlas-only

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/unwind.h>

/*
 * Prototype:
 *
 *	size_t arm_copy_from_user(void *to, const void *from, size_t n)
 *
 * Purpose:
 *
 *	copy a block to kernel memory from user memory
 *
 * Params:
 *
 *	to = kernel memory
 *	from = user memory
 *	n = number of bytes to copy
 *
 * Return value:
 *
 *	Number of bytes NOT copied.
 */

#ifdef CONFIG_CPU_USE_DOMAINS

#ifndef CONFIG_THUMB2_KERNEL
#define LDR1W_SHIFT	0
#else
#define LDR1W_SHIFT	1
#endif

	.macro ldr1w ptr reg abort
	ldrusr	\reg, \ptr, 4, abort=\abort
	.endm

	.macro ldr4w ptr reg1 reg2 reg3 reg4 abort
	ldr1w \ptr, \reg1, \abort
	ldr1w \ptr, \reg2, \abort
	ldr1w \ptr, \reg3, \abort
	ldr1w \ptr, \reg4, \abort
	.endm

	.macro ldr8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
	ldr4w \ptr, \reg1, \reg2, \reg3, \reg4, \abort
	ldr4w \ptr, \reg5, \reg6, \reg7, \reg8, \abort
	.endm

#else

#define LDR1W_SHIFT	0

	.macro ldr1w ptr reg abort
	USERL(\abort, W(ldr) \reg, [\ptr], #4)
	.endm

	.macro ldr4w ptr reg1 reg2 reg3 reg4 abort
	USERL(\abort, ldmia \ptr!, {\reg1, \reg2, \reg3, \reg4})
	.endm

	.macro ldr8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
	USERL(\abort, ldmia \ptr!, {\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8})
	.endm

#endif /* CONFIG_CPU_USE_DOMAINS */

	.macro ldr1b ptr reg cond=al abort
	ldrusr	\reg, \ptr, 1, \cond, abort=\abort
	.endm

Annotation

Implementation Notes