| #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(unsigned long); |
| /* |
| * This is called by __cpu_suspend() 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. |
| * |
| * @arg: Argument to pass to suspend operations |
| * @ptr: CPU context virtual address |
| * @save_ptr: address of the location where the context physical address |
| * must be saved |
| */ |
| int __cpu_suspend_finisher(unsigned long arg, struct cpu_suspend_ctx *ptr, |
| phys_addr_t *save_ptr) |
| { |
| int cpu = smp_processor_id(); |
| |
| *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)); |
| |
| return cpu_ops[cpu]->cpu_suspend(arg); |
| } |
| |
| /* |
| * 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 |
| * |
| * @arg: argument to pass to the finisher function |
| */ |
| int cpu_suspend(unsigned long arg) |
| { |
| struct mm_struct *mm = current->active_mm; |
| int ret, cpu = smp_processor_id(); |
| unsigned long flags; |
| |
| /* |
| * 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; |
| |
| /* |
| * 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(arg); |
| 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(cpu)); |
| |
| /* |
| * 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; |
| } |
| |
| extern struct sleep_save_sp sleep_save_sp; |
| extern phys_addr_t sleep_idmap_phys; |
| |
| static int 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); |