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Diffstat (limited to 'arch/arm64/kernel/suspend.c')
-rw-r--r--arch/arm64/kernel/suspend.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/arch/arm64/kernel/suspend.c b/arch/arm64/kernel/suspend.c
index e074b1c32723..430344e2c989 100644
--- a/arch/arm64/kernel/suspend.c
+++ b/arch/arm64/kernel/suspend.c
@@ -38,6 +38,22 @@ int __cpu_suspend_finisher(unsigned long arg, struct cpu_suspend_ctx *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
*
@@ -73,6 +89,13 @@ int cpu_suspend(unsigned long arg)
if (ret == 0) {
cpu_switch_mm(mm->pgd, mm);
flush_tlb_all();
+ /*
+ * 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);
}
/*