[U-Boot] [PATCH v5 17/30] efi_loader: Add runtime services

Alexander Graf
2016-03-04T00:10:01Z

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>

---

v1 -> v2:

- Fix runtime service sections
- Add runtime detach
- Enable runtime relocations
- Add get_time
- Fix relocation
- Fix 32bit
- Add am335x support
- Move section definition to header
- Add systab to runtime section
- Add self-relocation hook table
- Fix self-relocation
- Relocate efi_runtime section early during bootup
- Fix return values for a number of callbacks to be more UEFI compliant
- Move to GPLv2+

v2 -> v3:

- Patch reset to NULL
- Add EFIAPI to function prototypes
- Document header
- Add dm.h include
- Remove non-dm rtc support
- Return DEVICE_ERROR in rtc path
---
arch/arm/config.mk | 4 +
arch/arm/cpu/armv8/u-boot.lds | 16 +++
arch/arm/cpu/u-boot.lds | 30 +++++
arch/arm/lib/sections.c | 4 +
board/ti/am335x/u-boot.lds | 30 +++++
common/board_r.c | 4 +
include/efi_loader.h | 17 +++
lib/efi_loader/efi_boottime.c | 6 +-
lib/efi_loader/efi_runtime.c | 290 ++++++++++++++++++++++++++++++++++++++++++
9 files changed, 398 insertions(+), 3 deletions(-)
create mode 100644 lib/efi_loader/efi_runtime.c

diff --git a/arch/arm/config.mk b/arch/arm/config.mk
index 8fa57ec..9af6c37 100644
--- a/arch/arm/config.mk
+++ b/arch/arm/config.mk
@@ -122,6 +122,10 @@ ifdef CONFIG_OF_EMBED
OBJCOPYFLAGS += -j .dtb.init.rodata
endif

+ifdef CONFIG_EFI_LOADER
+OBJCOPYFLAGS += -j .efi_runtime -j .efi_runtime_rel
+endif
+
ifneq ($(CONFIG_IMX_CONFIG),)
ifdef CONFIG_SPL
ifndef CONFIG_SPL_BUILD
diff --git a/arch/arm/cpu/armv8/u-boot.lds b/arch/arm/cpu/armv8/u-boot.lds
index 4c12222..fd15ad5 100644
--- a/arch/arm/cpu/armv8/u-boot.lds
+++ b/arch/arm/cpu/armv8/u-boot.lds
@@ -42,6 +42,22 @@ SECTIONS

. = ALIGN(8);

+ .efi_runtime : {
+ __efi_runtime_start = .;
+ *(efi_runtime_text)
+ *(efi_runtime_data)
+ __efi_runtime_stop = .;
+ }
+
+ .efi_runtime_rel : {
+ __efi_runtime_rel_start = .;
+ *(.relaefi_runtime_text)
+ *(.relaefi_runtime_data)
+ __efi_runtime_rel_stop = .;
+ }
+
+ . = ALIGN(8);
+
.image_copy_end :
{
*(.__image_copy_end)
diff --git a/arch/arm/cpu/u-boot.lds b/arch/arm/cpu/u-boot.lds
index e148ab7..13aa4fa 100644
--- a/arch/arm/cpu/u-boot.lds
+++ b/arch/arm/cpu/u-boot.lds
@@ -90,6 +90,36 @@ SECTIONS

. = ALIGN(4);

+ .__efi_runtime_start : {
+ *(.__efi_runtime_start)
+ }
+
+ .efi_runtime : {
+ *(efi_runtime_text)
+ *(efi_runtime_data)
+ }
+
+ .__efi_runtime_stop : {
+ *(.__efi_runtime_stop)
+ }
+
+ .efi_runtime_rel_start :
+ {
+ *(.__efi_runtime_rel_start)
+ }
+
+ .efi_runtime_rel : {
+ *(.relefi_runtime_text)
+ *(.relefi_runtime_data)
+ }
+
+ .efi_runtime_rel_stop :
+ {
+ *(.__efi_runtime_rel_stop)
+ }
+
+ . = ALIGN(4);
+
.image_copy_end :
{
*(.__image_copy_end)
diff --git a/arch/arm/lib/sections.c b/arch/arm/lib/sections.c
index a1205c3..6a94522 100644
--- a/arch/arm/lib/sections.c
+++ b/arch/arm/lib/sections.c
@@ -27,4 +27,8 @@ char __rel_dyn_start[0] __attribute__((section(".__rel_dyn_start")));
char __rel_dyn_end[0] __attribute__((section(".__rel_dyn_end")));
char __secure_start[0] __attribute__((section(".__secure_start")));
char __secure_end[0] __attribute__((section(".__secure_end")));
+char __efi_runtime_start[0] __attribute__((section(".__efi_runtime_start")));
+char __efi_runtime_stop[0] __attribute__((section(".__efi_runtime_stop")));
+char __efi_runtime_rel_start[0] __attribute__((section(".__efi_runtime_rel_start")));
+char __efi_runtime_rel_stop[0] __attribute__((section(".__efi_runtime_rel_stop")));
char _end[0] __attribute__((section(".__end")));
diff --git a/board/ti/am335x/u-boot.lds b/board/ti/am335x/u-boot.lds
index 78f294a..a56cc82 100644
--- a/board/ti/am335x/u-boot.lds
+++ b/board/ti/am335x/u-boot.lds
@@ -59,6 +59,36 @@ SECTIONS

. = ALIGN(4);

+ .__efi_runtime_start : {
+ *(.__efi_runtime_start)
+ }
+
+ .efi_runtime : {
+ *(efi_runtime_text)
+ *(efi_runtime_data)
+ }
+
+ .__efi_runtime_stop : {
+ *(.__efi_runtime_stop)
+ }
+
+ .efi_runtime_rel_start :
+ {
+ *(.__efi_runtime_rel_start)
+ }
+
+ .efi_runtime_rel : {
+ *(.relefi_runtime_text)
+ *(.relefi_runtime_data)
+ }
+
+ .efi_runtime_rel_stop :
+ {
+ *(.__efi_runtime_rel_stop)
+ }
+
+ . = ALIGN(4);
+
.image_copy_end :
{
*(.__image_copy_end)
diff --git a/common/board_r.c b/common/board_r.c
index 52a9b26..6432d23 100644
--- a/common/board_r.c
+++ b/common/board_r.c
@@ -65,6 +65,7 @@
#ifdef CONFIG_AVR32
#include <asm/arch/mmu.h>
#endif
+#include <efi_loader.h>

DECLARE_GLOBAL_DATA_PTR;

@@ -177,6 +178,9 @@ static int initr_reloc_global_data(void)
*/
gd->fdt_blob += gd->reloc_off;
#endif
+#ifdef CONFIG_EFI_LOADER
+ efi_runtime_relocate(gd->relocaddr, NULL);
+#endif

return 0;
}
diff --git a/include/efi_loader.h b/include/efi_loader.h
index b4e82ac..3a71a77 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -29,6 +29,7 @@

#define EFI_EXIT(ret) efi_exit_func(ret);

+extern struct efi_runtime_services efi_runtime_services;
extern struct efi_system_table systab;

extern const struct efi_simple_text_output_protocol efi_con_out;
@@ -39,6 +40,9 @@ extern const efi_guid_t efi_guid_console_control;
extern const efi_guid_t efi_guid_device_path;
extern const efi_guid_t efi_guid_loaded_image;

+extern unsigned int __efi_runtime_start, __efi_runtime_stop;
+extern unsigned int __efi_runtime_rel_start, __efi_runtime_rel_stop;
+
/*
* While UEFI objects can have callbacks, you can also call functions on
* protocols (classes) themselves. This struct maps a protocol GUID to its
@@ -100,9 +104,22 @@ void efi_save_gd(void);
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);
+/* Call this to relocate the runtime section to an address space */
+void efi_runtime_relocate(ulong offset, struct efi_mem_desc *map);
+
+/*
+ * Use these to indicate that your code / data should go into the EFI runtime
+ * section and thus still be available when the OS is running
+ */
+#define EFI_RUNTIME_DATA __attribute__ ((section ("efi_runtime_data")))
+#define EFI_RUNTIME_TEXT __attribute__ ((section ("efi_runtime_text")))

#else /* defined(EFI_LOADER) */

+/* Without CONFIG_EFI_LOADER we don't have a runtime section, stub it out */
+#define EFI_RUNTIME_DATA
+#define EFI_RUNTIME_TEXT
+
/* No loader configured, stub out EFI_ENTRY */
static inline void efi_restore_gd(void) { }

diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index e60fae9..87400de 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -39,7 +39,7 @@ static bool efi_is_direct_boot = true;
* 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];
+static struct efi_configuration_table EFI_RUNTIME_DATA efi_conf_table[1];

/*
* The "gd" pointer lives in a register on ARM and AArch64 that we declare
@@ -761,10 +761,10 @@ static const struct efi_boot_services efi_boot_services = {
};

-static uint16_t firmware_vendor[] =
+static uint16_t EFI_RUNTIME_DATA firmware_vendor[] =
{ 'D','a','s',' ','U','-','b','o','o','t',0 };

-struct efi_system_table systab = {
+struct efi_system_table EFI_RUNTIME_DATA systab = {
.hdr = {
.signature = EFI_SYSTEM_TABLE_SIGNATURE,
.revision = 0x20005, /* 2.5 */
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@%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,
+};
--
1.8.5.6