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