blob: 357418137db7c533efc078095e0260d4752815d9 [file] [log] [blame]
#include <linux/ftrace.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <asm/cacheflush.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);
* 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))
hw_breakpoint_restore = hw_bp_restore;
* 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.
* Function graph tracer state gets incosistent when the kernel
* calls functions that never return (aka suspend finishers) hence
* disable graph tracing during their execution.
* 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; set the TTBR0 to the reserved
* page tables to prevent speculative TLB allocations, flush
* the local tlb and set the default tcr_el1.t0sz so that
* the TTBR0 address space set-up is properly restored.
* If the current active_mm != &init_mm we entered cpu_suspend
* with mappings in TTBR0 that must be restored, so we switch
* them back to complete the address space configuration
* restoration before returning.
if (mm != &init_mm)
cpu_switch_mm(mm->pgd, mm);
* Restore per-cpu offset before any kernel
* subsystem relying on it has a chance to run.
* Restore HW breakpoint registers to sane values
* before debug exceptions are possibly reenabled
* through local_dbg_restore.
if (hw_breakpoint_restore)
* 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.
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;