Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 | #include <linux/ftrace.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <asm/alternative.h>
#include <asm/cacheflush.h>
#include <asm/cpufeature.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.
*/
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;
}
/*
* 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; 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.
*/
cpu_set_reserved_ttbr0();
local_flush_tlb_all();
cpu_set_default_tcr_t0sz();
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.
*/
set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
/*
* PSTATE was not saved over suspend/resume, re-enable any
* detected features that might not have been set correctly.
*/
asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN,
CONFIG_ARM64_PAN));
/*
* 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;
}
struct sleep_save_sp sleep_save_sp;
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);
__flush_dcache_area(&sleep_save_sp, sizeof(struct sleep_save_sp));
return 0;
}
early_initcall(cpu_suspend_init);
|