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#include <linux/percpu.h>
#include <linux/slab.h>
#include <asm/cacheflush.h>
#include <asm/cpu_ops.h>
#include <asm/debug-monitors.h>
#include <asm/pgtable.h>
#include <asm/memory.h>
#include <asm/mmu_context.h>
#include <asm/smp_plat.h>
#include <asm/suspend.h>
#include <asm/tlbflush.h>
extern int __cpu_suspend_enter(unsigned long arg, int (*fn)(unsigned long));
/*
* This is called by __cpu_suspend_enter() to save the state, and do whatever
* flushing is required to ensure that when the CPU goes to sleep we have
* the necessary data available when the caches are not searched.
*
* ptr: CPU context virtual address
* save_ptr: address of the location where the context physical address
* must be saved
*/
void notrace __cpu_suspend_save(struct cpu_suspend_ctx *ptr,
phys_addr_t *save_ptr)
{
*save_ptr = virt_to_phys(ptr);
cpu_do_suspend(ptr);
/*
* Only flush the context that must be retrieved with the MMU
* off. VA primitives ensure the flush is applied to all
* cache levels so context is pushed to DRAM.
*/
__flush_dcache_area(ptr, sizeof(*ptr));
__flush_dcache_area(save_ptr, sizeof(*save_ptr));
}
/*
* This hook is provided so that cpu_suspend code can restore HW
* breakpoints as early as possible in the resume path, before reenabling
* debug exceptions. Code cannot be run from a CPU PM notifier since by the
* time the notifier runs debug exceptions might have been enabled already,
* with HW breakpoints registers content still in an unknown state.
*/
void (*hw_breakpoint_restore)(void *);
void __init cpu_suspend_set_dbg_restorer(void (*hw_bp_restore)(void *))
{
/* Prevent multiple restore hook initializations */
if (WARN_ON(hw_breakpoint_restore))
return;
hw_breakpoint_restore = hw_bp_restore;
}
/**
* cpu_suspend() - function to enter a low-power state
* @arg: argument to pass to CPU suspend operations
*
* Return: 0 on success, -EOPNOTSUPP if CPU suspend hook not initialized, CPU
* operations back-end error code otherwise.
*/
int cpu_suspend(unsigned long arg)
{
int cpu = smp_processor_id();
/*
* If cpu_ops have not been registered or suspend
* has not been initialized, cpu_suspend call fails early.
*/
if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_suspend)
return -EOPNOTSUPP;
return cpu_ops[cpu]->cpu_suspend(arg);
}
/*
* __cpu_suspend
*
* arg: argument to pass to the finisher function
* fn: finisher function pointer
*
*/
int __cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
{
struct mm_struct *mm = current->active_mm;
int ret;
unsigned long flags;
/*
* From this point debug exceptions are disabled to prevent
* updates to mdscr register (saved and restored along with
* general purpose registers) from kernel debuggers.
*/
local_dbg_save(flags);
/*
* mm context saved on the stack, it will be restored when
* the cpu comes out of reset through the identity mapped
* page tables, so that the thread address space is properly
* set-up on function return.
*/
ret = __cpu_suspend_enter(arg, fn);
if (ret == 0) {
/*
* We are resuming from reset with TTBR0_EL1 set to the
* idmap to enable the MMU; restore the active_mm mappings in
* TTBR0_EL1 unless the active_mm == &init_mm, in which case
* the thread entered __cpu_suspend with TTBR0_EL1 set to
* reserved TTBR0 page tables and should be restored as such.
*/
if (mm == &init_mm)
cpu_set_reserved_ttbr0();
else
cpu_switch_mm(mm->pgd, mm);
flush_tlb_all();
/*
* Restore per-cpu offset before any kernel
* subsystem relying on it has a chance to run.
*/
set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
/*
* Restore HW breakpoint registers to sane values
* before debug exceptions are possibly reenabled
* through local_dbg_restore.
*/
if (hw_breakpoint_restore)
hw_breakpoint_restore(NULL);
}
/*
* Restore pstate flags. OS lock and mdscr have been already
* restored, so from this point onwards, debugging is fully
* renabled if it was enabled when core started shutdown.
*/
local_dbg_restore(flags);
return ret;
}
struct sleep_save_sp sleep_save_sp;
phys_addr_t sleep_idmap_phys;
static int __init cpu_suspend_init(void)
{
void *ctx_ptr;
/* ctx_ptr is an array of physical addresses */
ctx_ptr = kcalloc(mpidr_hash_size(), sizeof(phys_addr_t), GFP_KERNEL);
if (WARN_ON(!ctx_ptr))
return -ENOMEM;
sleep_save_sp.save_ptr_stash = ctx_ptr;
sleep_save_sp.save_ptr_stash_phys = virt_to_phys(ctx_ptr);
sleep_idmap_phys = virt_to_phys(idmap_pg_dir);
__flush_dcache_area(&sleep_save_sp, sizeof(struct sleep_save_sp));
__flush_dcache_area(&sleep_idmap_phys, sizeof(sleep_idmap_phys));
return 0;
}
early_initcall(cpu_suspend_init);
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