1. 内核版本
4.19
2. 在arch/arm/kernel/sleep.S中实现如下:
/*
* Save CPU state for a suspend. This saves the CPU general purpose
* registers, and allocates space on the kernel stack to save the CPU
* specific registers and some other data for resume.
* r0 = suspend function arg0
* r1 = suspend function
* r2 = MPIDR value the resuming CPU will use
*/
ENTRY(__cpu_suspend)
stmfd sp!, {r4 - r11, lr}
#ifdef MULTI_CPU
ldr r10, =processor
ldr r4, [r10, #CPU_SLEEP_SIZE] @ size of CPU sleep state
#else
ldr r4, =cpu_suspend_size
#endif
mov r5, sp @ current virtual SP
add r4, r4, #12 @ Space for pgd, virt sp, phys resume fn
sub sp, sp, r4 @ allocate CPU state on stack
ldr r3, =sleep_save_sp
stmfd sp!, {r0, r1} @ save suspend func arg and pointer
ldr r3, [r3, #SLEEP_SAVE_SP_VIRT]
ALT_SMP(ldr r0, =mpidr_hash)
ALT_UP_B(1f)
/* This ldmia relies on the memory layout of the mpidr_hash struct */
ldmia r0, {r1, r6-r8} @ r1 = mpidr mask (r6,r7,r8) = l[0,1,2] shifts
compute_mpidr_hash r0, r6, r7, r8, r2, r1
add r3, r3, r0, lsl #2
1: mov r2, r5 @ virtual SP
mov r1, r4 @ size of save block
add r0, sp, #8 @ pointer to save block
bl __cpu_suspend_save
badr lr, cpu_suspend_abort
ldmfd sp!, {r0, pc} @ call suspend fn
ENDPROC(__cpu_suspend)