cabe1c81ea
By enabling the MMU early in cpu_resume(), the sleep_save_sp and stack can
be accessed by VA, which avoids the need to convert-addresses and clean to
PoC on the suspend path.
MMU setup is shared with the boot path, meaning the swapper_pg_dir is
restored directly: ttbr1_el1 is no longer saved/restored.
struct sleep_save_sp is removed, replacing it with a single array of
pointers.
cpu_do_{suspend,resume} could be further reduced to not restore: cpacr_el1,
mdscr_el1, tcr_el1, vbar_el1 and sctlr_el1, all of which are set by
__cpu_setup(). However these values all contain res0 bits that may be used
to enable future features.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
127 lines
3.3 KiB
C
127 lines
3.3 KiB
C
#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>
|
|
|
|
/*
|
|
* This is allocated by cpu_suspend_init(), and used to store a pointer to
|
|
* the 'struct sleep_stack_data' the contains a particular CPUs state.
|
|
*/
|
|
unsigned long *sleep_save_stash;
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
static 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;
|
|
}
|
|
|
|
void notrace __cpu_suspend_exit(void)
|
|
{
|
|
/*
|
|
* 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);
|
|
}
|
|
|
|
/*
|
|
* 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 = 0;
|
|
unsigned long flags;
|
|
struct sleep_stack_data state;
|
|
|
|
/*
|
|
* 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();
|
|
|
|
if (__cpu_suspend_enter(&state)) {
|
|
/* Call the suspend finisher */
|
|
ret = fn(arg);
|
|
|
|
/*
|
|
* Never gets here, unless the suspend finisher fails.
|
|
* Successful cpu_suspend() should return from cpu_resume(),
|
|
* returning through this code path is considered an error
|
|
* If the return value is set to 0 force ret = -EOPNOTSUPP
|
|
* to make sure a proper error condition is propagated
|
|
*/
|
|
if (!ret)
|
|
ret = -EOPNOTSUPP;
|
|
} else {
|
|
__cpu_suspend_exit();
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
static int __init cpu_suspend_init(void)
|
|
{
|
|
/* ctx_ptr is an array of physical addresses */
|
|
sleep_save_stash = kcalloc(mpidr_hash_size(), sizeof(*sleep_save_stash),
|
|
GFP_KERNEL);
|
|
|
|
if (WARN_ON(!sleep_save_stash))
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
early_initcall(cpu_suspend_init);
|