/*
* cpu_suspend
*
* arg: argument to pass to the finisher function
* fn: finisher function pointer
*
*/
int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
{
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);
/*
* Function graph tracer state gets incosistent when the kernel
* calls functions that never return (aka suspend finishers) hence
* disable graph tracing during their execution.
*/
pause_graph_tracing();
/*
* 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 the idmap active in TTBR0_EL1.
* We must uninstall the idmap and restore the expected MMU
* state before we can possibly return to userspace.
*/
cpu_uninstall_idmap();
/*
* 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);
}
unpause_graph_tracing();
/*
* 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;
}
/*
* __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);
/*
* Function graph tracer state gets incosistent when the kernel
* calls functions that never return (aka suspend finishers) hence
* disable graph tracing during their execution.
*/
pause_graph_tracing();
/*
* 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);
}
unpause_graph_tracing();
/*
* 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;
}
