1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
2 
3 #include "acpi-fpdt.h"
4 #include "boot-timestamps.h"
5 #include "efi-loader.h"
6 #include "macro.h"
7 #include "time-util.h"
8 
boot_timestamps(const dual_timestamp * n,dual_timestamp * firmware,dual_timestamp * loader)9 int boot_timestamps(const dual_timestamp *n, dual_timestamp *firmware, dual_timestamp *loader) {
10         usec_t x = 0, y = 0, a;
11         int r;
12         dual_timestamp _n;
13 
14         assert(firmware);
15         assert(loader);
16 
17         if (!n) {
18                 dual_timestamp_get(&_n);
19                 n = &_n;
20         }
21 
22         r = acpi_get_boot_usec(&x, &y);
23         if (r < 0) {
24                 r = efi_loader_get_boot_usec(&x, &y);
25                 if (r < 0)
26                         return r;
27         }
28 
29         /* Let's convert this to timestamps where the firmware
30          * began/loader began working. To make this more confusing:
31          * since usec_t is unsigned and the kernel's monotonic clock
32          * begins at kernel initialization we'll actually initialize
33          * the monotonic timestamps here as negative of the actual
34          * value. */
35 
36         firmware->monotonic = y;
37         loader->monotonic = y - x;
38 
39         a = n->monotonic + firmware->monotonic;
40         firmware->realtime = n->realtime > a ? n->realtime - a : 0;
41 
42         a = n->monotonic + loader->monotonic;
43         loader->realtime = n->realtime > a ? n->realtime - a : 0;
44 
45         return 0;
46 }
47