arch/arm/kernel/fiqasm.S

Source file repositories/reference/linux-study-clean/arch/arm/kernel/fiqasm.S

File Facts

System
Linux kernel
Corpus path
arch/arm/kernel/fiqasm.S
Extension
.S
Size
1250 bytes
Lines
50
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>

/*
 * Taking an interrupt in FIQ mode is death, so both these functions
 * disable irqs for the duration.
 */

ENTRY(__set_fiq_regs)
	mov	r2, #PSR_I_BIT | PSR_F_BIT | FIQ_MODE
	mrs	r1, cpsr
	msr	cpsr_c, r2	@ select FIQ mode
	mov	r0, r0		@ avoid hazard prior to ARMv4
	ldmia	r0!, {r8 - r12}
	ldr	sp, [r0], #4
	ldr	lr, [r0]
	msr	cpsr_c, r1	@ return to SVC mode
	mov	r0, r0		@ avoid hazard prior to ARMv4
	ret	lr
ENDPROC(__set_fiq_regs)

ENTRY(__get_fiq_regs)
	mov	r2, #PSR_I_BIT | PSR_F_BIT | FIQ_MODE
	mrs	r1, cpsr
	msr	cpsr_c, r2	@ select FIQ mode
	mov	r0, r0		@ avoid hazard prior to ARMv4
	stmia	r0!, {r8 - r12}
	str	sp, [r0], #4
	str	lr, [r0]
	msr	cpsr_c, r1	@ return to SVC mode
	mov	r0, r0		@ avoid hazard prior to ARMv4
	ret	lr
ENDPROC(__get_fiq_regs)

Annotation

Implementation Notes