Re: [PATCH RFC 02/14] efi: stub: support running U-Boot as an EFI payload on ARM64

Hi Caleb,

On Sun, 24 Nov 2024 at 22:27, Caleb Connolly caleb.connolly@linaro.org wrote:

Implement support for launching U-Boot via an EFI stub app on ARM64.

This is more or less a straight port of the x86 implementation, but due to the highly x86/qemu specific nature of that implementation I decided to just split it out to its own file.

Unlike the x86 implementation, there is no debug UART here since ARM platforms don't have a standard UART interface. However it is usually possible to port over the debug uart implementation for you platform for bringup purposes.

Currently this implementation doesn't provide a DTB to U-Boot and expects U-Boot to use a built-in one, however this ought to be a fairly trivial addition in the future.

The other significant difference to the x86 version is that rather than copying U-Boot to CONFIG_TEXT_OFFSET, we require that U-Boot is built position independent and copy it to EFI allocated memory.

This isn't bad, but there's lots of duplication from x86. For an RFC that's fine but for a v1, please create an efi_stub_common.c and move code in there

Cheers /Ilias

Signed-off-by: Caleb Connolly caleb.connolly@linaro.org

Makefile | 15 ++- arch/arm/cpu/armv8/config.mk | 11 ++ arch/arm/include/asm/global_data.h | 3 + arch/arm/lib/Makefile | 2 + include/efi.h | 2 +- lib/efi/Kconfig | 9 +- lib/efi/Makefile | 28 ++-- lib/efi/efi_info.c | 4 +- lib/efi/efi_stub_arm64.c | 236 +++++++++++++++++++++++++++++++++ lib/efi/{efi_stub.c => efi_stub_x86.c} | 0 10 files changed, 294 insertions(+), 16 deletions(-)

diff --git a/Makefile b/Makefile index da742ceae76e..8d0340622d7c 100644 --- a/Makefile +++ b/Makefile @@ -1681,21 +1681,32 @@ u-boot.bin.o: u-boot.bin FORCE

u-boot-payload.lds: $(LDSCRIPT_EFI) FORCE $(call if_changed_dep,cpp_lds)

+# Determine the file suffix for the efi stub implementation +EFI_STUB_ARCH := $(if $(CONFIG_ARM64),arm64,$(if $(CONFIG_X86_64),x86,$(ARCH)))

# Rule to link the EFI payload which contains a stub and a U-Boot binary quiet_cmd_u-boot_payload ?= LD $@ cmd_u-boot_payload ?= $(LD) $(LDFLAGS_EFI_PAYLOAD) -o $@ \

•  -T u-boot-payload.lds arch/x86/cpu/call32.o \
  

•  lib/efi/efi.o lib/efi/efi_stub.o u-boot.bin.o \
  

•  -T u-boot-payload.lds $(if $(CONFIG_X86),arch/x86/cpu/call32.o,) \
  

•  lib/efi/efi.o lib/efi/efi_stub_$(EFI_STUB_ARCH).o u-boot.bin.o \
   $(addprefix arch/$(ARCH)/lib/,$(EFISTUB))
  
  

+quiet_cmd_u-boot_payload_arm64.efi ?= OBJCOPY $@

•  cmd_u-boot_payload_arm64.efi ?= $(OBJCOPY) -O binary u-boot-payload $@
  

u-boot-payload: u-boot.bin.o u-boot-payload.lds FORCE $(call if_changed,u-boot_payload)

OBJCOPYFLAGS_u-boot-payload.efi := $(OBJCOPYFLAGS_EFI) +ifeq ($(CONFIG_X86),y) u-boot-payload.efi: u-boot-payload FORCE $(call if_changed,zobjcopy) +else +u-boot-payload.efi: u-boot-payload FORCE

•   $(call if_changed,u-boot_payload_$(EFI_STUB_ARCH).efi)
  

+endif

u-boot-img.bin: spl/u-boot-spl.bin u-boot.img FORCE $(call if_changed,cat)

diff --git a/arch/arm/cpu/armv8/config.mk b/arch/arm/cpu/armv8/config.mk index 4d74b2a533e0..1ee316801064 100644 --- a/arch/arm/cpu/armv8/config.mk +++ b/arch/arm/cpu/armv8/config.mk @@ -9,4 +9,15 @@ PLATFORM_CPPFLAGS += $(PF_NO_UNALIGNED)

EFI_LDS := elf_aarch64_efi.lds EFI_CRT0 := crt0_aarch64_efi.o EFI_RELOC := reloc_aarch64_efi.o

+LDSCRIPT_EFI := $(srctree)/arch/arm/lib/elf_aarch64_efi.lds +EFISTUB := crt0_aarch64_efi.o reloc_aarch64_efi.o +OBJCOPYFLAGS_EFI += --target=pei-aarch64-little +EFIPAYLOAD_BFDTARGET := pei-aarch64-little +EFIPAYLOAD_BFDARCH := aarch64 +LDFLAGS_EFI_PAYLOAD := -Bsymbolic -Bsymbolic-functions -shared --no-undefined \

•                  -s -zexecstack
  

+CPPFLAGS_REMOVE_crt0-efi-aarch64.o += $(CFLAGS_NON_EFI) +CPPFLAGS_crt0-efi-aarch64.o += $(CFLAGS_EFI) diff --git a/arch/arm/include/asm/global_data.h b/arch/arm/include/asm/global_data.h index 45401d5e3c8a..6e4471662a38 100644 --- a/arch/arm/include/asm/global_data.h +++ b/arch/arm/include/asm/global_data.h @@ -107,8 +107,11 @@ struct arch_global_data { #endif #ifdef CONFIG_SMBIOS ulong smbios_start; /* Start address of SMBIOS table */ #endif +#ifdef CONFIG_EFI_STUB

•   ulong table;
  

+#endif };

#include <asm-generic/global_data.h>

diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile index 1c95dd6fed21..14e3990925a7 100644 --- a/arch/arm/lib/Makefile +++ b/arch/arm/lib/Makefile @@ -130,4 +130,6 @@ CFLAGS_$(EFI_CRT0) := $(CFLAGS_EFI) CFLAGS_REMOVE_$(EFI_CRT0) := $(CFLAGS_NON_EFI)

CFLAGS_$(EFI_RELOC) := $(CFLAGS_EFI) CFLAGS_REMOVE_$(EFI_RELOC) := $(CFLAGS_NON_EFI)

+extra-$(CONFIG_EFI_STUB) += $(EFI_CRT0) $(EFI_RELOC) diff --git a/include/efi.h b/include/efi.h index c559fda3004c..a6eff13a6bbb 100644 --- a/include/efi.h +++ b/include/efi.h @@ -496,9 +496,9 @@ struct efi_media_plat { /* Base address of the EFI image */ extern char image_base[];

/* Start and end of U-Boot image (for payload) */ -extern char _binary_u_boot_bin_start[], _binary_u_boot_bin_end[]; +extern char _binary_u_boot_bin_start[], _binary_u_boot_bin_end[], _binary_u_boot_bin_size[];

/*

• Variable Attributes

*/ diff --git a/lib/efi/Kconfig b/lib/efi/Kconfig index 81ed3e66b34d..18f69bdcfbec 100644 --- a/lib/efi/Kconfig +++ b/lib/efi/Kconfig @@ -1,10 +1,10 @@ menu "U-Boot as UEFI application"

•   depends on X86
  

•   depends on X86 || ARM
  
  

config EFI bool "Support running U-Boot from EFI"

•   depends on X86
  

•   depends on X86 || ARM
    imply X86_TSC_READ_BASE
    help
      U-Boot can be started from EFI on certain platforms. This allows
      EFI to perform most of the system init and then jump to U-Boot for
  

@@ -12,12 +12,13 @@ config EFI application, with U-Boot using EFI's drivers instead of its own.

choice prompt "Select EFI mode to use"

•   depends on X86 && EFI
  

•   depends on EFI
  
  

config EFI_APP bool "Support running as an EFI application"

•   depends on !ARM
    select CHARSET
    help
      Build U-Boot as an application which can be started from EFI. This
      is useful for examining a platform in the early stages of porting
  

@@ -25,8 +26,9 @@ config EFI_APP command prompt and memory and I/O functions. Use 'reset' to return to EFI.

config EFI_STUB

•   select POSITION_INDEPENDENT if ARM
    bool "Support running as an EFI payload"
  
  

endchoice

@@ -58,8 +60,9 @@ choice 32-bit EFI, select 32-bit here, else select 64-bit. Failure to do this may produce no error message - it just won't start!

config EFI_STUB_32BIT

•   depends on !ARM
    bool "Produce a stub for running with 32-bit EFI"
  
  

config EFI_STUB_64BIT bool "Produce a stub for running with 64-bit EFI" diff --git a/lib/efi/Makefile b/lib/efi/Makefile index 232fa684360e..bf65bacf47e7 100644 --- a/lib/efi/Makefile +++ b/lib/efi/Makefile @@ -4,14 +4,24 @@

obj-$(CONFIG_EFI_APP) += efi_app.o efi.o efi_app_init.o obj-$(CONFIG_EFI_STUB) += efi_info.o

-CFLAGS_REMOVE_efi_stub.o := -mregparm=3 \

•   $(if $(CONFIG_EFI_STUB_64BIT),-march=i386 -m32)
  

-CFLAGS_efi_stub.o := -fpic -fshort-wchar \

•   $(if $(CONFIG_EFI_STUB_64BIT),-m64)
  

-CFLAGS_REMOVE_efi.o := -mregparm=3 \

•   $(if $(CONFIG_EFI_STUB_64BIT),-march=i386 -m32)
  

-CFLAGS_efi.o := -fpic -fshort-wchar \

•   $(if $(CONFIG_EFI_STUB_64BIT),-m64)
  

+ifeq ($(CONFIG_ARM64),y) +efi_stub.o := efi_stub_arm64.o +else +efi_stub.o := efi_stub_x86.o

-extra-$(CONFIG_EFI_STUB) += efi_stub.o efi.o +ifeq ($(CONFIG_EFI_STUB_64BIT),y) # && !CONFIG_ARM64 +CFLAGS_REMOVE_$(efi_stub.o) := -march=i386 -m32 +CFLAGS_$(efi_stub.o) := -m64 +CFLAGS_REMOVE_efi.o := -march=i386 -m32 +CFLAGS_efi.o := -fpic -m64 +endif +endif

+CFLAGS_REMOVE_$(efi_stub.o) += -mregparm=3 +CFLAGS_$(efi_stub.o) += -fpic -fshort-wchar +CFLAGS_REMOVE_efi.o += -mregparm=3 +CFLAGS_efi.o += -fpic -fshort-wchar

+$(info removing flags $(CFLAGS_REMOVE_$(efi_stub.o))) +extra-$(CONFIG_EFI_STUB) += $(efi_stub.o) efi.o diff --git a/lib/efi/efi_info.c b/lib/efi/efi_info.c index 5b564c5651d5..5fa4baeec635 100644 --- a/lib/efi/efi_info.c +++ b/lib/efi/efi_info.c @@ -9,8 +9,10 @@ #include <errno.h> #include <mapmem.h> #include <asm/global_data.h>

+DECLARE_GLOBAL_DATA_PTR;

int efi_info_get(enum efi_entry_t type, void **datap, int *sizep) { struct efi_entry_hdr *entry; struct efi_info_hdr *info; @@ -41,6 +43,6 @@ int efi_info_get(enum efi_entry_t type, void **datap, int *sizep) ret = -ENOENT; err: unmap_sysmem(info);

•   return ret;
  

•   return -ENOSYS;
  

} diff --git a/lib/efi/efi_stub_arm64.c b/lib/efi/efi_stub_arm64.c new file mode 100644 index 000000000000..54bee6c55d7e --- /dev/null +++ b/lib/efi/efi_stub_arm64.c @@ -0,0 +1,236 @@ +// SPDX-License-Identifier: GPL-2.0+ +/*

• • Copyright (c) 2015 Google, Inc
• • Copyright (c) 2024 Linaro, Ltd.
• • EFI information obtained here:
• • http://wiki.phoenix.com/wiki/index.php/EFI_BOOT_SERVICES
• • Call ExitBootServices() and launch U-Boot from an EFI environment.
• */

+#include <debug_uart.h> +#include <efi.h> +#include <efi_api.h> +#include <malloc.h> +#include <asm/io.h> +#include <linux/err.h> +#include <linux/types.h>

+static bool ebs_called;

+void _debug_uart_putc(int ch) +{

•   struct efi_priv *priv = efi_get_priv();
  

•   if (ch == '\n')
  

•           _debug_uart_putc('\r');
  

•   /*
  

•    * After calling EBS we can't log anywhere.
  

•    * NOTE: for development it is possible to re-implement
  

•    * your boards debug uart here like in efi_stub.c for x86.
  

•    */
  

•   if (!ebs_called)
  

•           efi_putc(priv, ch);
  

+}

+void _debug_uart_init(void) {}

+DEBUG_UART_FUNCS;

+void putc(const char ch) +{

•   _debug_uart_putc(ch);
  

+}

+void puts(const char *str) +{

•   while (*str)
  

•           putc(*str++);
  

+}

+void *memcpy(void *dest, const void *src, size_t size) +{

•   unsigned char *dptr = dest;
  

•   const unsigned char *ptr = src;
  

•   const unsigned char *end = src + size;
  

•   while (ptr < end)
  

•           *dptr++ = *ptr++;
  

•   return dest;
  

+}

+void *memset(void *inptr, int ch, size_t size) +{

•   char *ptr = inptr;
  

•   char *end = ptr + size;
  

•   while (ptr < end)
  

•           *ptr++ = ch;
  

•   return ptr;
  

+}

+/**

• • setup_info_table() - sets up a table containing information from EFI
• • We must call exit_boot_services() before jumping out of the stub into U-Boot
• • proper, so that U-Boot has full control of peripherals, memory, etc.
• • Once we do this, we cannot call any boot-services functions so we must find
• • out everything we need to before doing that.
• • Set up a struct efi_info_hdr table which can hold various records (e.g.
• • struct efi_entry_memmap) with information obtained from EFI.
• • @priv: Pointer to our private information which contains the list
• • @size: Size of the table to allocate
• • Return: 0 if OK, non-zero on error
• */

+static int setup_info_table(struct efi_priv *priv, int size) +{

•   struct efi_info_hdr *info;
  

•   efi_status_t ret;
  

•   /* Get some memory for our info table */
  

•   priv->info_size = size;
  

•   info = efi_malloc(priv, priv->info_size, &ret);
  

•   if (ret) {
  

•           printhex2(ret);
  

•           puts(" No memory for info table: ");
  

•           return ret;
  

•   }
  

•   memset(info, '\0', sizeof(*info));
  

•   info->version = EFI_TABLE_VERSION;
  

•   info->hdr_size = sizeof(*info);
  

•   priv->info = info;
  

•   priv->next_hdr = (char *)info + info->hdr_size;
  

•   return 0;
  

+}

+/**

• • add_entry_addr() - Add a new entry to the efi_info list
• • This adds an entry, consisting of a tag and two lots of data. This avoids the
• • caller having to coalesce the data first
• • @priv: Pointer to our private information which contains the list
• • @type: Type of the entry to add
• • @ptr1: Pointer to first data block to add
• • @size1: Size of first data block in bytes (can be 0)
• • @ptr2: Pointer to second data block to add
• • @size2: Size of second data block in bytes (can be 0)
• */

+static void add_entry_addr(struct efi_priv *priv, enum efi_entry_t type,

•                      void *ptr1, int size1, void *ptr2, int size2)
  

+{

•   struct efi_entry_hdr *hdr = priv->next_hdr;
  

•   hdr->type = type;
  

•   hdr->size = size1 + size2;
  

•   hdr->addr = 0;
  

•   hdr->link = ALIGN(sizeof(*hdr) + hdr->size, 16);
  

•   priv->next_hdr += hdr->link;
  

•   memcpy(hdr + 1, ptr1, size1);
  

•   memcpy((void *)(hdr + 1) + size1, ptr2, size2);
  

•   priv->info->total_size = (ulong)priv->next_hdr - (ulong)priv->info;
  

+}

+/**

• • efi_main() - Start an EFI image
• • This function is called by our EFI start-up code. It handles running
• • U-Boot. If it returns, EFI will continue.
• */

+efi_status_t EFIAPI efi_main(efi_handle_t image,

•                        struct efi_system_table *sys_table)
  

+{

•   struct efi_priv local_priv, *priv = &local_priv;
  

•   struct efi_boot_services *boot = sys_table->boottime;
  

•   struct efi_entry_memmap map;
  

•   struct efi_gop *gop;
  

•   struct efi_entry_gopmode mode;
  

•   struct efi_entry_systable table;
  

•   efi_guid_t efi_gop_guid = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
  

•   efi_status_t ret;
  

•   ebs_called = false;
  

•   ret = efi_init(priv, "Payload", image, sys_table);
  

•   if (ret) {
  

•           printhex2(ret);
  

•           puts(" efi_init() failed\n");
  

•           return ret;
  

•   }
  

•   efi_set_priv(priv);
  

•   phys_addr_t reloc_addr = ULONG_MAX;
  

•   ret = boot->allocate_pages(EFI_ALLOCATE_MAX_ADDRESS, EFI_LOADER_CODE,
  

•                              (phys_addr_t)_binary_u_boot_bin_size / EFI_PAGE_SIZE,
  

•                              &reloc_addr);
  

•   if (ret != EFI_SUCCESS) {
  

•           puts("Failed to allocate memory for U-Boot: ");
  

•           printhex2(ret);
  

•           putc('\n');
  

•           return ret;
  

•   }
  

•   ret = efi_store_memory_map(priv);
  

•   if (ret)
  

•           return ret;
  

•   ret = setup_info_table(priv, priv->memmap_size + 128);
  

•   if (ret)
  

•           return ret;
  

•   ret = boot->locate_protocol(&efi_gop_guid, NULL, (void **)&gop);
  

•   if (ret) {
  

•           puts(" GOP unavailable\n");
  

•   } else {
  

•           mode.fb_base = gop->mode->fb_base;
  

•           mode.fb_size = gop->mode->fb_size;
  

•           mode.info_size = gop->mode->info_size;
  

•           add_entry_addr(priv, EFIET_GOP_MODE, &mode, sizeof(mode),
  

•                          gop->mode->info,
  

•                          sizeof(struct efi_gop_mode_info));
  

•   }
  

•   table.sys_table = (ulong)sys_table;
  

•   add_entry_addr(priv, EFIET_SYS_TABLE, &table, sizeof(table), NULL, 0);
  

•   ret = efi_call_exit_boot_services();
  

•   if (ret)
  

•           return ret;
  

•   /* The EFI console won't work now :( */
  

•   ebs_called = true;
  

•   map.version = priv->memmap_version;
  

•   map.desc_size = priv->memmap_desc_size;
  

•   add_entry_addr(priv, EFIET_MEMORY_MAP, &map, sizeof(map),
  

•                  priv->memmap_desc, priv->memmap_size);
  

•   add_entry_addr(priv, EFIET_END, NULL, 0, 0, 0);
  

•   memcpy((void *)reloc_addr, _binary_u_boot_bin_start,
  

•          (ulong)_binary_u_boot_bin_end -
  

•          (ulong)_binary_u_boot_bin_start);
  

+/* This will only work if you patched your own debug uart into this file. */ +#ifdef DEBUG

•   puts("EFI table at ");
  

•   printhex8((ulong)priv->info);
  

•   puts(" size ");
  

•   printhex8(priv->info->total_size);
  

•   putc('\n');
  

+#endif

•   typedef void (*func_t)(u64 x0, u64 x1, u64 x2, u64 x3);
  

•   puts("Jumping to U-Boot\n");
  

•   ((func_t)reloc_addr)((phys_addr_t)priv->info, 0, 0, 0);
  

•   return EFI_LOAD_ERROR;
  

+} diff --git a/lib/efi/efi_stub.c b/lib/efi/efi_stub_x86.c similarity index 100% rename from lib/efi/efi_stub.c rename to lib/efi/efi_stub_x86.c

-- 2.47.0