arch/arm/lib/copy_page.S

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

File Facts

System
Linux kernel
Corpus path
arch/arm/lib/copy_page.S
Extension
.S
Size
1141 bytes
Lines
45
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/asm-offsets.h>
#include <asm/cache.h>

#define COPY_COUNT (PAGE_SZ / (2 * L1_CACHE_BYTES) PLD( -1 ))

		.text
		.align	5
/*
 * StrongARM optimised copy_page routine
 * now 1.78bytes/cycle, was 1.60 bytes/cycle (50MHz bus -> 89MB/s)
 * Note that we probably achieve closer to the 100MB/s target with
 * the core clock switching.
 */
ENTRY(copy_page)
		stmfd	sp!, {r4, lr}			@	2
	PLD(	pld	[r1, #0]		)
	PLD(	pld	[r1, #L1_CACHE_BYTES]		)
		mov	r2, #COPY_COUNT			@	1
		ldmia	r1!, {r3, r4, ip, lr}		@	4+1
1:	PLD(	pld	[r1, #2 * L1_CACHE_BYTES])
	PLD(	pld	[r1, #3 * L1_CACHE_BYTES])
2:
	.rept	(2 * L1_CACHE_BYTES / 16 - 1)
		stmia	r0!, {r3, r4, ip, lr}		@	4
		ldmia	r1!, {r3, r4, ip, lr}		@	4
	.endr
		subs	r2, r2, #1			@	1
		stmia	r0!, {r3, r4, ip, lr}		@	4
		ldmiagt	r1!, {r3, r4, ip, lr}		@	4
		bgt	1b				@	1
	PLD(	ldmiaeq r1!, {r3, r4, ip, lr}	)
	PLD(	beq	2b			)
		ldmfd	sp!, {r4, pc}			@	3
ENDPROC(copy_page)

Annotation

Implementation Notes