efi_loader: Add runtime services
After booting has finished, EFI allows firmware to still interact with the OS
using the "runtime services". These callbacks live in a separate address space,
since they are available long after U-Boot has been overwritten by the OS.
This patch adds enough framework for arbitrary code inside of U-Boot to become
a runtime service with the right section attributes set. For now, we don't make
use of it yet though.
We could maybe in the future map U-boot environment variables to EFI variables
here.
Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
diff --git a/lib/efi_loader/efi_runtime.c b/lib/efi_loader/efi_runtime.c
new file mode 100644
index 0000000..22bcd08
--- /dev/null
+++ b/lib/efi_loader/efi_runtime.c
@@ -0,0 +1,290 @@
+/*
+ * EFI application runtime services
+ *
+ * Copyright (c) 2016 Alexander Graf
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <command.h>
+#include <dm.h>
+#include <efi_loader.h>
+#include <rtc.h>
+#include <asm/global_data.h>
+
+/* For manual relocation support */
+DECLARE_GLOBAL_DATA_PTR;
+
+static efi_status_t EFI_RUNTIME_TEXT EFIAPI efi_unimplemented(void);
+static efi_status_t EFI_RUNTIME_TEXT EFIAPI efi_device_error(void);
+static efi_status_t EFI_RUNTIME_TEXT EFIAPI efi_invalid_parameter(void);
+
+#if defined(CONFIG_ARM64)
+#define R_RELATIVE 1027
+#define R_MASK 0xffffffffULL
+#define IS_RELA 1
+#elif defined(CONFIG_ARM)
+#define R_RELATIVE 23
+#define R_MASK 0xffULL
+#else
+#error Need to add relocation awareness
+#endif
+
+struct elf_rel {
+ ulong *offset;
+ ulong info;
+};
+
+struct elf_rela {
+ ulong *offset;
+ ulong info;
+ long addend;
+};
+
+/*
+ * EFI Runtime code lives in 2 stages. In the first stage, U-Boot and an EFI
+ * payload are running concurrently at the same time. In this mode, we can
+ * handle a good number of runtime callbacks
+ */
+
+static void EFIAPI efi_reset_system(enum efi_reset_type reset_type,
+ efi_status_t reset_status,
+ unsigned long data_size, void *reset_data)
+{
+ EFI_ENTRY("%d %lx %lx %p", reset_type, reset_status, data_size,
+ reset_data);
+
+ switch (reset_type) {
+ case EFI_RESET_COLD:
+ case EFI_RESET_WARM:
+ do_reset(NULL, 0, 0, NULL);
+ break;
+ case EFI_RESET_SHUTDOWN:
+ /* We don't have anything to map this to */
+ break;
+ }
+
+ EFI_EXIT(EFI_SUCCESS);
+}
+
+static efi_status_t EFIAPI efi_get_time(struct efi_time *time,
+ struct efi_time_cap *capabilities)
+{
+#if defined(CONFIG_CMD_DATE) && defined(CONFIG_DM_RTC)
+ struct rtc_time tm;
+ int r;
+ struct udevice *dev;
+
+ EFI_ENTRY("%p %p", time, capabilities);
+
+ r = uclass_get_device(UCLASS_RTC, 0, &dev);
+ if (r)
+ return EFI_EXIT(EFI_DEVICE_ERROR);
+
+ r = dm_rtc_get(dev, &tm);
+ if (r)
+ return EFI_EXIT(EFI_DEVICE_ERROR);
+
+ memset(time, 0, sizeof(*time));
+ time->year = tm.tm_year;
+ time->month = tm.tm_mon;
+ time->day = tm.tm_mday;
+ time->hour = tm.tm_hour;
+ time->minute = tm.tm_min;
+ time->daylight = tm.tm_isdst;
+
+ return EFI_EXIT(EFI_SUCCESS);
+#else
+ return EFI_DEVICE_ERROR;
+#endif
+}
+
+struct efi_runtime_detach_list_struct {
+ void *ptr;
+ void *patchto;
+};
+
+static const struct efi_runtime_detach_list_struct efi_runtime_detach_list[] = {
+ {
+ /* do_reset is gone */
+ .ptr = &efi_runtime_services.reset_system,
+ .patchto = NULL,
+ }, {
+ /* invalidate_*cache_all are gone */
+ .ptr = &efi_runtime_services.set_virtual_address_map,
+ .patchto = &efi_invalid_parameter,
+ }, {
+ /* RTC accessors are gone */
+ .ptr = &efi_runtime_services.get_time,
+ .patchto = &efi_device_error,
+ },
+};
+
+static bool efi_runtime_tobedetached(void *p)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(efi_runtime_detach_list); i++)
+ if (efi_runtime_detach_list[i].ptr == p)
+ return true;
+
+ return false;
+}
+
+static void efi_runtime_detach(ulong offset)
+{
+ int i;
+ ulong patchoff = offset - (ulong)gd->relocaddr;
+
+ for (i = 0; i < ARRAY_SIZE(efi_runtime_detach_list); i++) {
+ ulong patchto = (ulong)efi_runtime_detach_list[i].patchto;
+ ulong *p = efi_runtime_detach_list[i].ptr;
+ ulong newaddr = patchto ? (patchto + patchoff) : 0;
+
+#ifdef DEBUG_EFI
+ printf("%s: Setting %p to %lx\n", __func__, p, newaddr);
+#endif
+ *p = newaddr;
+ }
+}
+
+/* Relocate EFI runtime to uboot_reloc_base = offset */
+void efi_runtime_relocate(ulong offset, struct efi_mem_desc *map)
+{
+#ifdef IS_RELA
+ struct elf_rela *rel = (void*)&__efi_runtime_rel_start;
+#else
+ struct elf_rel *rel = (void*)&__efi_runtime_rel_start;
+ static ulong lastoff = CONFIG_SYS_TEXT_BASE;
+#endif
+
+#ifdef DEBUG_EFI
+ printf("%s: Relocating to offset=%lx\n", __func__, offset);
+#endif
+
+ for (; (ulong)rel < (ulong)&__efi_runtime_rel_stop; rel++) {
+ ulong base = CONFIG_SYS_TEXT_BASE;
+ ulong *p;
+ ulong newaddr;
+
+ p = (void*)((ulong)rel->offset - base) + gd->relocaddr;
+
+ if ((rel->info & R_MASK) != R_RELATIVE) {
+ continue;
+ }
+
+#ifdef IS_RELA
+ newaddr = rel->addend + offset - CONFIG_SYS_TEXT_BASE;
+#else
+ newaddr = *p - lastoff + offset;
+#endif
+
+ /* Check if the relocation is inside bounds */
+ if (map && ((newaddr < map->virtual_start) ||
+ newaddr > (map->virtual_start + (map->num_pages << 12)))) {
+ if (!efi_runtime_tobedetached(p))
+ printf("U-Boot EFI: Relocation at %p is out of "
+ "range (%lx)\n", p, newaddr);
+ continue;
+ }
+
+#ifdef DEBUG_EFI
+ printf("%s: Setting %p to %lx\n", __func__, p, newaddr);
+#endif
+
+ *p = newaddr;
+ flush_dcache_range((ulong)p, (ulong)&p[1]);
+ }
+
+#ifndef IS_RELA
+ lastoff = offset;
+#endif
+
+ invalidate_icache_all();
+}
+
+static efi_status_t EFIAPI efi_set_virtual_address_map(
+ unsigned long memory_map_size,
+ unsigned long descriptor_size,
+ uint32_t descriptor_version,
+ struct efi_mem_desc *virtmap)
+{
+ ulong runtime_start = (ulong)&__efi_runtime_start & ~0xfffULL;
+ int n = memory_map_size / descriptor_size;
+ int i;
+
+ EFI_ENTRY("%lx %lx %x %p", memory_map_size, descriptor_size,
+ descriptor_version, virtmap);
+
+ for (i = 0; i < n; i++) {
+ struct efi_mem_desc *map;
+
+ map = (void*)virtmap + (descriptor_size * i);
+ if (map->type == EFI_RUNTIME_SERVICES_CODE) {
+ ulong new_offset = map->virtual_start - (runtime_start - gd->relocaddr);
+
+ efi_runtime_relocate(new_offset, map);
+ /* Once we're virtual, we can no longer handle
+ complex callbacks */
+ efi_runtime_detach(new_offset);
+ return EFI_EXIT(EFI_SUCCESS);
+ }
+ }
+
+ return EFI_EXIT(EFI_INVALID_PARAMETER);
+}
+
+/*
+ * In the second stage, U-Boot has disappeared. To isolate our runtime code
+ * that at this point still exists from the rest, we put it into a special
+ * section.
+ *
+ * !!WARNING!!
+ *
+ * This means that we can not rely on any code outside of this file in any
+ * function or variable below this line.
+ *
+ * Please keep everything fully self-contained and annotated with
+ * EFI_RUNTIME_TEXT and EFI_RUNTIME_DATA markers.
+ */
+
+/*
+ * Relocate the EFI runtime stub to a different place. We need to call this
+ * the first time we expose the runtime interface to a user and on set virtual
+ * address map calls.
+ */
+
+static efi_status_t EFI_RUNTIME_TEXT EFIAPI efi_unimplemented(void)
+{
+ return EFI_UNSUPPORTED;
+}
+
+static efi_status_t EFI_RUNTIME_TEXT EFIAPI efi_device_error(void)
+{
+ return EFI_DEVICE_ERROR;
+}
+
+static efi_status_t EFI_RUNTIME_TEXT EFIAPI efi_invalid_parameter(void)
+{
+ return EFI_INVALID_PARAMETER;
+}
+
+struct efi_runtime_services EFI_RUNTIME_DATA efi_runtime_services = {
+ .hdr = {
+ .signature = EFI_RUNTIME_SERVICES_SIGNATURE,
+ .revision = EFI_RUNTIME_SERVICES_REVISION,
+ .headersize = sizeof(struct efi_table_hdr),
+ },
+ .get_time = &efi_get_time,
+ .set_time = (void *)&efi_device_error,
+ .get_wakeup_time = (void *)&efi_unimplemented,
+ .set_wakeup_time = (void *)&efi_unimplemented,
+ .set_virtual_address_map = &efi_set_virtual_address_map,
+ .convert_pointer = (void *)&efi_invalid_parameter,
+ .get_variable = (void *)&efi_device_error,
+ .get_next_variable = (void *)&efi_device_error,
+ .set_variable = (void *)&efi_device_error,
+ .get_next_high_mono_count = (void *)&efi_device_error,
+ .reset_system = &efi_reset_system,
+};