1 files changed, 147 insertions, 0 deletions
diff --git a/src/shared/acpi-fpdt.c b/src/shared/acpi-fpdt.c
new file mode 100644
index 0000000..cccea2f
--- /dev/null
+++ b/src/shared/acpi-fpdt.c
@@ -0,0 +1,147 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "acpi-fpdt.h"
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "time-util.h"
+
+struct acpi_table_header {
+        char signature[4];
+        uint32_t length;
+        uint8_t revision;
+        uint8_t checksum;
+        char oem_id[6];
+        char oem_table_id[8];
+        uint32_t oem_revision;
+        char asl_compiler_id[4];
+        uint32_t asl_compiler_revision;
+} _packed_;
+
+enum {
+        ACPI_FPDT_TYPE_BOOT =   0,
+        ACPI_FPDT_TYPE_S3PERF = 1,
+};
+
+struct acpi_fpdt_header {
+        uint16_t type;
+        uint8_t length;
+        uint8_t revision;
+        uint8_t reserved[4];
+        uint64_t ptr;
+} _packed_;
+
+struct acpi_fpdt_boot_header {
+        char signature[4];
+        uint32_t length;
+} _packed_;
+
+enum {
+        ACPI_FPDT_S3PERF_RESUME_REC =   0,
+        ACPI_FPDT_S3PERF_SUSPEND_REC =  1,
+        ACPI_FPDT_BOOT_REC =            2,
+};
+
+struct acpi_fpdt_boot {
+        uint16_t type;
+        uint8_t length;
+        uint8_t revision;
+        uint8_t reserved[4];
+        uint64_t reset_end;
+        uint64_t load_start;
+        uint64_t startup_start;
+        uint64_t exit_services_entry;
+        uint64_t exit_services_exit;
+} _packed;
+
+int acpi_get_boot_usec(usec_t *loader_start, usec_t *loader_exit) {
+        _cleanup_free_ char *buf = NULL;
+        struct acpi_table_header *tbl;
+        size_t l = 0;
+        struct acpi_fpdt_header *rec;
+        int r;
+        uint64_t ptr = 0;
+        _cleanup_close_ int fd = -1;
+        struct acpi_fpdt_boot_header hbrec;
+        struct acpi_fpdt_boot brec;
+
+        r = read_full_virtual_file("/sys/firmware/acpi/tables/FPDT", &buf, &l);
+        if (r < 0)
+                return r;
+
+        if (l < sizeof(struct acpi_table_header) + sizeof(struct acpi_fpdt_header))
+                return -EINVAL;
+
+        tbl = (struct acpi_table_header *)buf;
+        if (l != tbl->length)
+                return -EINVAL;
+
+        if (memcmp(tbl->signature, "FPDT", 4) != 0)
+                return -EINVAL;
+
+        /* find Firmware Basic Boot Performance Pointer Record */
+        for (rec = (struct acpi_fpdt_header *)(buf + sizeof(struct acpi_table_header));
+             (char *)rec < buf + l;
+             rec = (struct acpi_fpdt_header *)((char *)rec + rec->length)) {
+                if (rec->length <= 0)
+                        break;
+                if (rec->type != ACPI_FPDT_TYPE_BOOT)
+                        continue;
+                if (rec->length != sizeof(struct acpi_fpdt_header))
+                        continue;
+
+                ptr = rec->ptr;
+                break;
+        }
+
+        if (ptr == 0)
+                return -ENODATA;
+
+        /* read Firmware Basic Boot Performance Data Record */
+        fd = open("/dev/mem", O_CLOEXEC|O_RDONLY);
+        if (fd < 0)
+                return -errno;
+
+        l = pread(fd, &hbrec, sizeof(struct acpi_fpdt_boot_header), ptr);
+        if (l != sizeof(struct acpi_fpdt_boot_header))
+                return -EINVAL;
+
+        if (memcmp(hbrec.signature, "FBPT", 4) != 0)
+                return -EINVAL;
+
+        if (hbrec.length < sizeof(struct acpi_fpdt_boot_header) + sizeof(struct acpi_fpdt_boot))
+                return -EINVAL;
+
+        l = pread(fd, &brec, sizeof(struct acpi_fpdt_boot), ptr + sizeof(struct acpi_fpdt_boot_header));
+        if (l != sizeof(struct acpi_fpdt_boot))
+                return -EINVAL;
+
+        if (brec.length != sizeof(struct acpi_fpdt_boot))
+                return -EINVAL;
+
+        if (brec.type != ACPI_FPDT_BOOT_REC)
+                return -EINVAL;
+
+        if (brec.exit_services_exit == 0)
+                /* Non-UEFI compatible boot. */
+                return -ENODATA;
+
+        if (brec.startup_start == 0 || brec.exit_services_exit < brec.startup_start)
+                return -EINVAL;
+        if (brec.exit_services_exit > NSEC_PER_HOUR)
+                return -EINVAL;
+
+        if (loader_start)
+                *loader_start = brec.startup_start / 1000;
+        if (loader_exit)
+                *loader_exit = brec.exit_services_exit / 1000;
+
+        return 0;
+}