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-rw-r--r--src/shared/boot-timestamps.c46
1 files changed, 46 insertions, 0 deletions
diff --git a/src/shared/boot-timestamps.c b/src/shared/boot-timestamps.c
new file mode 100644
index 0000000..bcbb86d
--- /dev/null
+++ b/src/shared/boot-timestamps.c
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include "acpi-fpdt.h"
+#include "boot-timestamps.h"
+#include "efivars.h"
+#include "macro.h"
+#include "time-util.h"
+
+int boot_timestamps(const dual_timestamp *n, dual_timestamp *firmware, dual_timestamp *loader) {
+ usec_t x = 0, y = 0, a;
+ int r;
+ dual_timestamp _n;
+
+ assert(firmware);
+ assert(loader);
+
+ if (!n) {
+ dual_timestamp_get(&_n);
+ n = &_n;
+ }
+
+ r = acpi_get_boot_usec(&x, &y);
+ if (r < 0) {
+ r = efi_loader_get_boot_usec(&x, &y);
+ if (r < 0)
+ return r;
+ }
+
+ /* Let's convert this to timestamps where the firmware
+ * began/loader began working. To make this more confusing:
+ * since usec_t is unsigned and the kernel's monotonic clock
+ * begins at kernel initialization we'll actually initialize
+ * the monotonic timestamps here as negative of the actual
+ * value. */
+
+ firmware->monotonic = y;
+ loader->monotonic = y - x;
+
+ a = n->monotonic + firmware->monotonic;
+ firmware->realtime = n->realtime > a ? n->realtime - a : 0;
+
+ a = n->monotonic + loader->monotonic;
+ loader->realtime = n->realtime > a ? n->realtime - a : 0;
+
+ return 0;
+}