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..e49bd8f
--- /dev/null
+++ b/src/shared/boot-timestamps.c
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "acpi-fpdt.h"
+#include "boot-timestamps.h"
+#include "efi-loader.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_now(&_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;
+}