arm64: acpi: Honour firmware_signature field of FACS, if it exists

If the firmware_signature changes then OSPM should not attempt to resume
from hibernate, but should instead perform a clean reboot. Set the global
swsusp_hardware_signature to allow the generic code to include the value
in the swsusp header on disk, and perform the appropriate check on resume.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20240412073530.2222496-3-dwmw2@infradead.org
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index dba8fcec7f33d6581848bbfd61b9e65f3413bcaa..e0e7b93c16cc430f5e60be3ebc23f58818c89d48 100644 (file)
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -26,6 +26,7 @@
 #include <linux/libfdt.h>
 #include <linux/smp.h>
 #include <linux/serial_core.h>
+#include <linux/suspend.h>
 #include <linux/pgtable.h>
 
 #include <acpi/ghes.h>
@@ -227,6 +228,15 @@ done:
                if (earlycon_acpi_spcr_enable)
                        early_init_dt_scan_chosen_stdout();
        } else {
+#ifdef CONFIG_HIBERNATION
+               struct acpi_table_header *facs = NULL;
+               acpi_get_table(ACPI_SIG_FACS, 1, &facs);
+               if (facs) {
+                       swsusp_hardware_signature =
+                               ((struct acpi_table_facs *)facs)->hardware_signature;
+                       acpi_put_table(facs);
+               }
+#endif
                acpi_parse_spcr(earlycon_acpi_spcr_enable, true);
                if (IS_ENABLED(CONFIG_ACPI_BGRT))
                        acpi_table_parse(ACPI_SIG_BGRT, acpi_parse_bgrt);