pm: acpi hibernation: utilize hardware signature
ACPI defines a hardware signature. BIOS calculates the signature according to
hardware configure and if hardware changes while hibernated, the signature
will change. In that case, S4 resume should fail.
Still, there may be systems on which this mechanism does not work correctly,
so it is better to provide a workaround for them. For this reason, add a new
switch to the acpi_sleep= command line argument allowing one to disable
hardware signature checking.
[shaohua.li@intel.com: build fix]
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Len Brown <lenb@kernel.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: <Valdis.Kletnieks@vt.edu>
Cc: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/acpi/sleep/main.c b/drivers/acpi/sleep/main.c
index 0489a7d..313507a 100644
--- a/drivers/acpi/sleep/main.c
+++ b/drivers/acpi/sleep/main.c
@@ -283,6 +283,15 @@
#endif /* CONFIG_SUSPEND */
#ifdef CONFIG_HIBERNATION
+static unsigned long s4_hardware_signature;
+static struct acpi_table_facs *facs;
+static bool nosigcheck;
+
+void __init acpi_no_s4_hw_signature(void)
+{
+ nosigcheck = true;
+}
+
static int acpi_hibernation_begin(void)
{
acpi_target_sleep_state = ACPI_STATE_S4;
@@ -316,6 +325,12 @@
acpi_enable();
/* Reprogram control registers and execute _BFS */
acpi_leave_sleep_state_prep(ACPI_STATE_S4);
+ /* Check the hardware signature */
+ if (facs && s4_hardware_signature != facs->hardware_signature) {
+ printk(KERN_EMERG "ACPI: Hardware changed while hibernated, "
+ "cannot resume!\n");
+ panic("ACPI S4 hardware signature mismatch");
+ }
}
static void acpi_pm_enable_gpes(void)
@@ -544,6 +559,13 @@
&acpi_hibernation_ops_old : &acpi_hibernation_ops);
sleep_states[ACPI_STATE_S4] = 1;
printk(" S4");
+ if (!nosigcheck) {
+ acpi_get_table_by_index(ACPI_TABLE_INDEX_FACS,
+ (struct acpi_table_header **)&facs);
+ if (facs)
+ s4_hardware_signature =
+ facs->hardware_signature;
+ }
}
#endif
status = acpi_get_sleep_type_data(ACPI_STATE_S5, &type_a, &type_b);