[U-Boot] [PATCH 04/16] efi_loader: Add boot time services
Alexander Graf
agraf at suse.de
Fri Feb 26 02:00:44 CET 2016
On 02.02.16 15:47, Leif Lindholm wrote:
> On Tue, Feb 02, 2016 at 03:45:02AM +0100, Alexander Graf wrote:
>> When an EFI application runs, it has access to a few descriptor and callback
>> tables to instruct the EFI compliant firmware to do things for it. The bulk
>> of those interfaces are "boot time services". They handle all object management,
>> and memory allocation.
>>
>> This patch adds support for the boot time services and also exposes a system
>> table, which is the point of entry descriptor table for EFI payloads.
>>
>> Signed-off-by: Alexander Graf <agraf at suse.de>
>> Reviewed-by: Simon Glass <sjg at chromium.org>
>>
>> ---
>>
>> v1 -> v2:
>>
>> - Fix typo s/does now/does not/
>> - Add #ifdefs around header to allow inclusion when efi_loader is disabled
>> - Add stub efi_restore_gd() function when efi_loader is disabled
>> - Disable debug
>> - Mark runtime region as such
>> - Fix up memory map
>> - Allow efi_restore_gd to be called before first efi entry
>> - Add 32bit arm cache workaround
>> - Move memory map to separate patch
>> - Change BTS version to 2.5
>> - Fix return values for a few callbacks to more EFI compliant ones
>> - Change vendor to "Das U-Boot"
>> - Add warning when truncating timer trigger
>> - Move to GPLv2+
>>
>> v2 -> v3:
>>
>> - Use external efi_memory helpers
>> - Add EFIAPI to function prototypes
>> - Initialize event timer to -1ULL to prevent early firing
>> - Document header
>> - Move obj list to lib
>> - Remove implicit guid table
>> - Add guid compare function
>> - Fix return values
>> - Implement efi_wait_for_event
>> - Implement efi_install_configuration_table
>> ---
>> include/efi_loader.h | 84 +++++
>> lib/efi_loader/efi_boottime.c | 781 ++++++++++++++++++++++++++++++++++++++++++
>> 2 files changed, 865 insertions(+)
>> create mode 100644 lib/efi_loader/efi_boottime.c
>>
>> diff --git a/include/efi_loader.h b/include/efi_loader.h
>> index 5618185..a7f033e 100644
>> --- a/include/efi_loader.h
>> +++ b/include/efi_loader.h
>> @@ -6,15 +6,99 @@
>> * SPDX-License-Identifier: GPL-2.0+
>> */
>>
>> +#include <common.h>
>> #include <part_efi.h>
>> #include <efi_api.h>
>> +
>> +#ifdef CONFIG_EFI_LOADER
>> +
>> #include <linux/list.h>
>>
>> +/* #define DEBUG_EFI */
>> +
>> +#ifdef DEBUG_EFI
>> +#define EFI_ENTRY(format, ...) do { \
>> + efi_restore_gd(); \
>> + printf("EFI: Entry %s(" format ")\n", __func__, ##__VA_ARGS__); \
>> + } while(0)
>> +#else
>> +#define EFI_ENTRY(format, ...) do { \
>> + efi_restore_gd(); \
>> + } while(0)
>> +#endif
>> +
>> +#define EFI_EXIT(ret) efi_exit_func(ret);
>> +
>> +extern struct efi_system_table systab;
>> +
>> extern const efi_guid_t efi_guid_device_path;
>> extern const efi_guid_t efi_guid_loaded_image;
>>
>> +/*
>> + * While UEFI objects can have callbacks, you can also call functions on
>> + * protocols (classes) themselves. This struct maps a protocol GUID to its
>> + * interface (usually a struct with callback functions).
>> + */
>> +struct efi_class_map {
>> + const efi_guid_t *guid;
>> + const void *interface;
>> +};
>> +
>> +/*
>> + * When the UEFI payload wants to open a protocol on an object to get its
>> + * interface (usually a struct with callback functions), this struct maps the
>> + * protocol GUID to the respective protocol handler open function for that
>> + * object protocol combination.
>> + */
>> +struct efi_handler {
>> + const efi_guid_t *guid;
>> + efi_status_t (EFIAPI *open)(void *handle,
>> + efi_guid_t *protocol, void **protocol_interface,
>> + void *agent_handle, void *controller_handle,
>> + uint32_t attributes);
>> +};
>> +
>> +/*
>> + * UEFI has a poor man's OO model where one "object" can be polimorphic and have
>
> Polymorphic.
> Also, somewhat long lines in this comment block?
Exactly 80 characters long :).
>
>> + * multiple different protocols (classes) attached to it.
>> + *
>> + * This struct is the parent struct for all of our actual implementation objects
>> + * that can include it to make themselves an EFI object
>> + */
>> +struct efi_object {
>> + /* Every UEFI object is part of a global object list */
>> + struct list_head link;
>> + /* We support up to 4 "protocols" an object can be accessed through */
>> + struct efi_handler protocols[4];
>> + /* The object spawner can either use this for data or as identifier */
>> + void *handle;
>> +};
>> +
>> +/* This list contains all UEFI objects we know of */
>> +extern struct list_head efi_obj_list;
>> +
>> +/*
>> + * Stub implementation for a protocol opener that just returns the handle as
>> + * interface
>> + */
>> efi_status_t efi_return_handle(void *handle,
>> efi_guid_t *protocol, void **protocol_interface,
>> void *agent_handle, void *controller_handle,
>> uint32_t attributes);
>> +/* Called from places to check whether a timer expired */
>> +void efi_timer_check(void);
>> +/* PE loader implementation */
>> void *efi_load_pe(void *efi, struct efi_loaded_image *loaded_image_info);
>> +/* Called once to store the pristine gd pointer */
>> +void efi_save_gd(void);
>> +/* Called from EFI_ENTRY on callback entry to put gd into the gd register */
>> +void efi_restore_gd(void);
>> +/* Called from EFI_EXIT on callback exit to restore the gd register */
>> +efi_status_t efi_exit_func(efi_status_t ret);
>> +
>> +#else /* defined(EFI_LOADER) */
>> +
>> +/* No loader configured, stub out EFI_ENTRY */
>> +static inline void efi_restore_gd(void) { }
>> +
>> +#endif
>> diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
>> new file mode 100644
>> index 0000000..e60fae9
>> --- /dev/null
>> +++ b/lib/efi_loader/efi_boottime.c
>> @@ -0,0 +1,781 @@
>> +/*
>> + * EFI application boot time services
>> + *
>> + * Copyright (c) 2016 Alexander Graf
>> + *
>> + * SPDX-License-Identifier: GPL-2.0+
>> + */
>> +
>> +/* #define DEBUG_EFI */
>> +
>> +#include <common.h>
>> +#include <efi_loader.h>
>> +#include <malloc.h>
>> +#include <asm/global_data.h>
>> +#include <libfdt_env.h>
>> +#include <u-boot/crc.h>
>> +#include <bootm.h>
>> +#include <inttypes.h>
>> +#include <watchdog.h>
>> +
>> +DECLARE_GLOBAL_DATA_PTR;
>> +
>> +/* This list contains all the EFI objects our payload has access to */
>> +LIST_HEAD(efi_obj_list);
>> +
>> +/*
>> + * If we're running on nasty systems (32bit ARM booting into non-EFI Linux)
>> + * we need to do trickery with caches. Since we don't want to break the EFI
>> + * aware boot path, only apply hacks when loading exiting directly (breaking
>> + * direct Linux EFI booting along the way - oh well).
>> + */
>> +static bool efi_is_direct_boot = true;
>
> Is this a case worth supporting?
Which one? :)
Without this hack we can't run current Linux kernels. Without the check
we break the grub2 -> Linux case with EFI enabled Linux.
Both are IMHO the two most important use cases. I want to have grub2 be
able to boot today's kernels and tomorrows just as well.
>
>
>> +
>> +/*
>> + * EFI can pass arbitrary additional "tables" containing vendor specific
>> + * information to the payload. One such table is the FDT table which contains
>> + * a pointer to a flattened device tree blob.
>> + *
>> + * In most cases we want to pass an FDT to the payload, so reserve one slot of
>> + * config table space for it. The pointer gets populated by do_bootefi_exec().
>> + */
>> +static struct efi_configuration_table efi_conf_table[1];
>> +
>> +/*
>> + * The "gd" pointer lives in a register on ARM and AArch64 that we declare
>> + * fixed when compiling U-Boot. However, the payload does not know about that
>> + * restriction so we need to manually swap its and our view of that register on
>> + * EFI callback entry/exit.
>> + */
>> +static volatile void *efi_gd, *app_gd;
>> +
>> +/* Called from do_bootefi_exec() */
>> +void efi_save_gd(void)
>> +{
>> + efi_gd = gd;
>> +}
>> +
>> +/* Called on every callback entry */
>> +void efi_restore_gd(void)
>> +{
>> + /* Only restore if we're already in EFI context */
>> + if (!efi_gd)
>> + return;
>> +
>> + if (gd != efi_gd)
>> + app_gd = gd;
>> + gd = efi_gd;
>> +}
>> +
>> +/* Called on every callback exit */
>> +efi_status_t efi_exit_func(efi_status_t ret)
>> +{
>> + gd = app_gd;
>> + return ret;
>> +}
>> +
>> +static efi_status_t efi_unsupported(const char *funcname)
>> +{
>> +#ifdef DEBUG_EFI
>> + printf("EFI: App called into unimplemented function %s\n", funcname);
>> +#endif
>> + return EFI_EXIT(EFI_UNSUPPORTED);
>> +}
>> +
>> +static int guidcmp(const efi_guid_t *g1, const efi_guid_t *g2)
>> +{
>> + return memcmp(g1, g2, sizeof(efi_guid_t));
>> +}
>
> Not necessary for this set, but this could be useful as a generic
> function. (at least part_efi.c could be another consumer)
>
>> +
>> +static unsigned long EFIAPI efi_raise_tpl(unsigned long new_tpl)
>> +{
>> + EFI_ENTRY("0x%lx", new_tpl);
>> + return EFI_EXIT(0);
>> +}
>> +
>> +static void EFIAPI efi_restore_tpl(unsigned long old_tpl)
>> +{
>> + EFI_ENTRY("0x%lx", old_tpl);
>> + EFI_EXIT(efi_unsupported(__func__));
>> +}
>> +
>> +efi_status_t EFIAPI efi_allocate_pages_ext(int type, int memory_type,
>> + unsigned long pages,
>> + uint64_t *memory)
>> +{
>> + efi_status_t r;
>> +
>> + EFI_ENTRY("%d, %d, 0x%lx, %p", type, memory_type, pages, memory);
>> + r = efi_allocate_pages(type, memory_type, pages, memory);
>> + return EFI_EXIT(r);
>> +}
>> +
>> +efi_status_t EFIAPI efi_free_pages_ext(uint64_t memory, unsigned long pages)
>> +{
>> + efi_status_t r;
>> +
>> + EFI_ENTRY("%"PRIx64", 0x%lx", memory, pages);
>> + r = efi_free_pages(memory, pages);
>> + return EFI_EXIT(r);
>> +}
>> +
>> +efi_status_t EFIAPI efi_get_memory_map_ext(unsigned long *memory_map_size,
>> + struct efi_mem_desc *memory_map,
>> + unsigned long *map_key,
>> + unsigned long *descriptor_size,
>> + uint32_t *descriptor_version)
>> +{
>> + efi_status_t r;
>> +
>> + EFI_ENTRY("%p, %p, %p, %p, %p", memory_map_size, memory_map,
>> + map_key, descriptor_size, descriptor_version);
>> + r = efi_get_memory_map(memory_map_size, memory_map, map_key,
>> + descriptor_size, descriptor_version);
>> + return EFI_EXIT(r);
>> +}
>> +
>> +static efi_status_t EFIAPI efi_allocate_pool(int pool_type, unsigned long size,
>> + void **buffer)
>> +{
>> + return efi_allocate_pages(0, pool_type, (size + 0xfff) >> 12, (void*)buffer);
>> +}
>> +
>> +static efi_status_t EFIAPI efi_free_pool(void *buffer)
>> +{
>> + return efi_free_pages((ulong)buffer, 0);
>> +}
>> +
>> +/*
>> + * Our event capabilities are very limited. Only support a single
>> + * event to exist, so we don't need to maintain lists.
>> + */
>> +static struct {
>> + enum efi_event_type type;
>> + u32 trigger_type;
>> + u32 trigger_time;
>> + u64 trigger_next;
>> + unsigned long notify_tpl;
>> + void (*notify_function) (void *event, void *context);
>> + void *notify_context;
>> +} efi_event = {
>> + /* Disable timers on bootup */
>> + .trigger_next = -1ULL,
>> +};
>> +
>> +static efi_status_t EFIAPI efi_create_event(
>> + enum efi_event_type type, ulong notify_tpl,
>> + void (*notify_function) (void *event, void *context),
>> + void *notify_context, void **event)
>> +{
>> + EFI_ENTRY("%d, 0x%lx, %p, %p", type, notify_tpl, notify_function,
>> + notify_context);
>> + if (efi_event.notify_function) {
>> + /* We only support one event at a time */
>> + return EFI_EXIT(EFI_OUT_OF_RESOURCES);
>> + }
>> +
>> + efi_event.type = type;
>> + efi_event.notify_tpl = notify_tpl;
>> + efi_event.notify_function = notify_function;
>> + efi_event.notify_context = notify_context;
>> + *event = &efi_event;
>> +
>> + return EFI_EXIT(EFI_SUCCESS);
>> +}
>> +
>> +/*
>> + * Our timers have to work without interrupts, so we check whenever keyboard
>> + * input or disk accesses happen if enough time elapsed for it to fire.
>> + */
>> +void efi_timer_check(void)
>> +{
>> + u64 now = timer_get_us();
>> +
>> + if (now >= efi_event.trigger_next) {
>> + /* Triggering! */
>> + if (efi_event.trigger_type == EFI_TIMER_PERIODIC)
>> + efi_event.trigger_next += efi_event.trigger_time / 10;
>> + efi_event.notify_function(&efi_event, efi_event.notify_context);
>> + }
>> +
>> + WATCHDOG_RESET();
>> +}
>> +
>> +static efi_status_t EFIAPI efi_set_timer(void *event, int type,
>> + uint64_t trigger_time)
>> +{
>> + /* We don't have 64bit division available everywhere, so limit timer
>> + * distances to 32bit bits. */
>> + u32 trigger32 = trigger_time;
>> +
>> + EFI_ENTRY("%p, %d, %"PRIx64, event, type, trigger_time);
>> +
>> + if (trigger32 < trigger_time) {
>> + printf("WARNING: Truncating timer from %"PRIx64" to %x\n",
>> + trigger_time, trigger32);
>> + }
>> +
>> + if (event != &efi_event) {
>> + /* We only support one event at a time */
>> + return EFI_EXIT(EFI_INVALID_PARAMETER);
>> + }
>> +
>> + switch (type) {
>> + case EFI_TIMER_STOP:
>> + efi_event.trigger_next = -1ULL;
>> + break;
>> + case EFI_TIMER_PERIODIC:
>> + case EFI_TIMER_RELATIVE:
>> + efi_event.trigger_next = timer_get_us() + (trigger32 / 10);
>> + break;
>> + default:
>> + return EFI_EXIT(EFI_INVALID_PARAMETER);
>> + }
>> + efi_event.trigger_type = type;
>> + efi_event.trigger_time = trigger_time;
>> +
>> + return EFI_EXIT(EFI_SUCCESS);
>> +}
>> +
>> +static efi_status_t EFIAPI efi_wait_for_event(unsigned long num_events,
>> + void *event, unsigned long *index)
>> +{
>> + u64 now;
>> +
>> + EFI_ENTRY("%ld, %p, %p", num_events, event, index);
>> +
>> + now = timer_get_us();
>> + while (now < efi_event.trigger_next) { }
>> + efi_timer_check();
>> +
>> + return EFI_EXIT(EFI_SUCCESS);
>> +}
>> +
>> +static efi_status_t EFIAPI efi_signal_event(void *event)
>> +{
>> + EFI_ENTRY("%p", event);
>> + return EFI_EXIT(EFI_SUCCESS);
>> +}
>> +
>> +static efi_status_t EFIAPI efi_close_event(void *event)
>> +{
>> + EFI_ENTRY("%p", event);
>> + efi_event.trigger_next = -1ULL;
>> + return EFI_EXIT(EFI_SUCCESS);
>> +}
>> +
>> +static efi_status_t EFIAPI efi_check_event(void *event)
>> +{
>> + EFI_ENTRY("%p", event);
>> + return EFI_EXIT(EFI_NOT_READY);
>> +}
>> +
>> +static efi_status_t EFIAPI efi_install_protocol_interface(void **handle,
>> + efi_guid_t *protocol, int protocol_interface_type,
>> + void *protocol_interface)
>> +{
>> + EFI_ENTRY("%p, %p, %d, %p", handle, protocol, protocol_interface_type,
>> + protocol_interface);
>> + return EFI_EXIT(EFI_OUT_OF_RESOURCES);
>> +}
>> +static efi_status_t EFIAPI efi_reinstall_protocol_interface(void *handle,
>> + efi_guid_t *protocol, void *old_interface,
>> + void *new_interface)
>> +{
>> + EFI_ENTRY("%p, %p, %p, %p", handle, protocol, old_interface,
>> + new_interface);
>> + return EFI_EXIT(EFI_ACCESS_DENIED);
>> +}
>> +
>> +static efi_status_t EFIAPI efi_uninstall_protocol_interface(void *handle,
>> + efi_guid_t *protocol, void *protocol_interface)
>> +{
>> + EFI_ENTRY("%p, %p, %p", handle, protocol, protocol_interface);
>> + return EFI_EXIT(EFI_NOT_FOUND);
>> +}
>> +
>> +static efi_status_t EFIAPI efi_register_protocol_notify(efi_guid_t *protocol,
>> + void *event,
>> + void **registration)
>> +{
>> + EFI_ENTRY("%p, %p, %p", protocol, event, registration);
>> + return EFI_EXIT(EFI_OUT_OF_RESOURCES);
>> +}
>> +
>> +static int efi_search(enum efi_locate_search_type search_type,
>> + efi_guid_t *protocol, void *search_key,
>> + struct efi_object *efiobj)
>> +{
>> + int i;
>> +
>> + switch (search_type) {
>> + case all_handles:
>> + return 0;
>> + case by_register_notify:
>> + return -1;
>> + case by_protocol:
>> + for (i = 0; i < ARRAY_SIZE(efiobj->protocols); i++) {
>> + const efi_guid_t *guid = efiobj->protocols[i].guid;
>> + if (guid && !guidcmp(guid, protocol))
>> + return 0;
>> + }
>> + return -1;
>> + }
>> +
>> + return -1;
>> +}
>> +
>> +static efi_status_t EFIAPI efi_locate_handle(
>> + enum efi_locate_search_type search_type,
>> + efi_guid_t *protocol, void *search_key,
>> + unsigned long *buffer_size, efi_handle_t *buffer)
>> +{
>> + struct list_head *lhandle;
>> + unsigned long size = 0;
>> +
>> + EFI_ENTRY("%d, %p, %p, %p, %p", search_type, protocol, search_key,
>> + buffer_size, buffer);
>> +
>> + /* Count how much space we need */
>> + list_for_each(lhandle, &efi_obj_list) {
>> + struct efi_object *efiobj;
>> + efiobj = list_entry(lhandle, struct efi_object, link);
>> + if (!efi_search(search_type, protocol, search_key, efiobj)) {
>> + size += sizeof(void*);
>> + }
>> + }
>> +
>> + if (*buffer_size < size) {
>> + *buffer_size = size;
>> + return EFI_EXIT(EFI_BUFFER_TOO_SMALL);
>> + }
>> +
>> + /* Then fill the array */
>> + list_for_each(lhandle, &efi_obj_list) {
>> + struct efi_object *efiobj;
>> + efiobj = list_entry(lhandle, struct efi_object, link);
>> + if (!efi_search(search_type, protocol, search_key, efiobj)) {
>> + *(buffer++) = efiobj->handle;
>> + }
>> + }
>> +
>> + *buffer_size = size;
>> + return EFI_EXIT(EFI_SUCCESS);
>> +}
>> +
>> +static efi_status_t EFIAPI efi_locate_device_path(efi_guid_t *protocol,
>> + struct efi_device_path **device_path,
>> + efi_handle_t *device)
>> +{
>> + EFI_ENTRY("%p, %p, %p", protocol, device_path, device);
>> + return EFI_EXIT(EFI_NOT_FOUND);
>> +}
>> +
>> +static efi_status_t EFIAPI efi_install_configuration_table(efi_guid_t *guid,
>> + void *table)
>> +{
>> + int i;
>> +
>> + EFI_ENTRY("%p, %p", guid, table);
>> +
>> + /* Check for guid override */
>> + for (i = 0; i < systab.nr_tables; i++) {
>> + if (!guidcmp(guid, &efi_conf_table[i].guid)) {
>> + efi_conf_table[i].table = table;
>> + return EFI_EXIT(EFI_SUCCESS);
>> + }
>> + }
>> +
>> + /* No override, check for overflow */
>> + if (i >= ARRAY_SIZE(efi_conf_table))
>> + return EFI_EXIT(EFI_OUT_OF_RESOURCES);
>> +
>> + /* Add a new entry */
>> + memcpy(&efi_conf_table[i].guid, guid, sizeof(*guid));
>> + efi_conf_table[i].table = table;
>> + systab.nr_tables = i;
>> +
>> + return EFI_EXIT(EFI_SUCCESS);
>> +}
>> +
>> +static efi_status_t EFIAPI efi_load_image(bool boot_policy,
>> + efi_handle_t parent_image,
>> + struct efi_device_path *file_path,
>> + void *source_buffer,
>> + unsigned long source_size,
>> + efi_handle_t *image_handle)
>> +{
>> + static struct efi_object loaded_image_info_obj = {
>> + .protocols = {
>> + {
>> + .guid = &efi_guid_loaded_image,
>> + .open = &efi_return_handle,
>> + },
>> + },
>> + };
>> + struct efi_loaded_image *info;
>> + struct efi_object *obj;
>> +
>> + EFI_ENTRY("%d, %p, %p, %p, %ld, %p", boot_policy, parent_image,
>> + file_path, source_buffer, source_size, image_handle);
>> + info = malloc(sizeof(*info));
>> + obj = malloc(sizeof(loaded_image_info_obj));
>> + memset(info, 0, sizeof(*info));
>> + memcpy(obj, &loaded_image_info_obj, sizeof(loaded_image_info_obj));
>> + obj->handle = info;
>> + info->file_path = file_path;
>> + info->reserved = efi_load_pe(source_buffer, info);
>> + if (!info->reserved) {
>> + free(info);
>> + free(obj);
>> + return EFI_EXIT(EFI_UNSUPPORTED);
>> + }
>> +
>> + *image_handle = info;
>> + list_add_tail(&obj->link, &efi_obj_list);
>> +
>> + return EFI_EXIT(EFI_SUCCESS);
>> +}
>> +
>> +static efi_status_t EFIAPI efi_start_image(efi_handle_t image_handle,
>> + unsigned long *exit_data_size,
>> + s16 **exit_data)
>> +{
>> + ulong (*entry)(void *image_handle, struct efi_system_table *st);
>> + struct efi_loaded_image *info = image_handle;
>> +
>> + EFI_ENTRY("%p, %p, %p", image_handle, exit_data_size, exit_data);
>> + entry = info->reserved;
>> +
>> + efi_is_direct_boot = false;
>> +
>> + /* call the image! */
>> + entry(image_handle, &systab);
>> +
>> + /* Should usually never get here */
>> + return EFI_EXIT(EFI_SUCCESS);
>> +}
>> +
>> +static efi_status_t EFIAPI efi_exit(void *image_handle, long exit_status,
>> + unsigned long exit_data_size,
>> + uint16_t *exit_data)
>> +{
>> + EFI_ENTRY("%p, %ld, %ld, %p", image_handle, exit_status,
>> + exit_data_size, exit_data);
>> + return EFI_EXIT(efi_unsupported(__func__));
>> +}
>> +
>> +static struct efi_object *efi_search_obj(void *handle)
>> +{
>> + struct list_head *lhandle;
>> +
>> + list_for_each(lhandle, &efi_obj_list) {
>> + struct efi_object *efiobj;
>> + efiobj = list_entry(lhandle, struct efi_object, link);
>> + if (efiobj->handle == handle)
>> + return efiobj;
>> + }
>> +
>> + return NULL;
>> +}
>> +
>> +static efi_status_t EFIAPI efi_unload_image(void *image_handle)
>> +{
>> + struct efi_object *efiobj;
>> +
>> + EFI_ENTRY("%p", image_handle);
>> + efiobj = efi_search_obj(image_handle);
>> + if (efiobj)
>> + list_del(&efiobj->link);
>> +
>> + return EFI_EXIT(EFI_SUCCESS);
>> +}
>> +
>> +static void efi_exit_caches(void)
>> +{
>> +#if defined(CONFIG_ARM) && !defined(CONFIG_ARM64)
>> + /*
>> + * Grub on 32bit ARM needs to have caches disabled before jumping into
>> + * a zImage, but does not know of all cache layers. Give it a hand.
>> + */
>
> Should we even be doing this hack?
> EFI stub support for 32-bit ARM is now (finally) upstream.
See above :). We can talk about removing the hack a few years down the
road, when all kernels out in the wild have an efi stub.
Alex
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