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[PATCH v3 7/8] efi: implement LoadFile2 initrd loading protocol for Linu
From: |
Ard Biesheuvel |
Subject: |
[PATCH v3 7/8] efi: implement LoadFile2 initrd loading protocol for Linux |
Date: |
Thu, 18 Aug 2022 16:51:34 +0200 |
Recent Linux kernels will invoke the LoadFile2 protocol installed on
a well-known vendor media path to load the initrd if it is exposed by
the firmware. Using this method is preferred for two reasons:
- the Linux kernel is in charge of allocating the memory, and so it can
implement any placement policy it wants (given that these tend to
change between kernel versions),
- it is no longer necessary to modify the device tree provided by the
firmware.
So let's install this protocol when handling the 'initrd' command if
such a recent kernel was detected (based on the PE/COFF image version),
and defer loading the initrd contents until the point where the kernel
invokes the LoadFile2 protocol.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
grub-core/commands/efi/lsefi.c | 1 +
grub-core/loader/arm64/linux.c | 123 +++++++++++++++++++-
include/grub/efi/api.h | 40 +++++++
3 files changed, 163 insertions(+), 1 deletion(-)
diff --git a/grub-core/commands/efi/lsefi.c b/grub-core/commands/efi/lsefi.c
index f46ba3b49384..c304d25ccdd6 100644
--- a/grub-core/commands/efi/lsefi.c
+++ b/grub-core/commands/efi/lsefi.c
@@ -55,6 +55,7 @@ struct known_protocol
{ GRUB_EFI_ABSOLUTE_POINTER_PROTOCOL_GUID, "absolute pointer" },
{ GRUB_EFI_DRIVER_BINDING_PROTOCOL_GUID, "EFI driver binding" },
{ GRUB_EFI_LOAD_FILE_PROTOCOL_GUID, "load file" },
+ { GRUB_EFI_LOAD_FILE2_PROTOCOL_GUID, "load file2" },
{ GRUB_EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID, "simple FS" },
{ GRUB_EFI_TAPE_IO_PROTOCOL_GUID, "tape I/O" },
{ GRUB_EFI_UNICODE_COLLATION_PROTOCOL_GUID, "unicode collation" },
diff --git a/grub-core/loader/arm64/linux.c b/grub-core/loader/arm64/linux.c
index 56ba8d0a6ea3..8b7fbb35fb72 100644
--- a/grub-core/loader/arm64/linux.c
+++ b/grub-core/loader/arm64/linux.c
@@ -48,6 +48,39 @@ static grub_uint32_t cmdline_size;
static grub_addr_t initrd_start;
static grub_addr_t initrd_end;
+static struct grub_linux_initrd_context initrd_ctx = { 0, 0, 0 };
+static grub_efi_handle_t initrd_lf2_handle = NULL;
+static int initrd_use_loadfile2 = 0;
+
+static grub_efi_guid_t load_file2_guid = GRUB_EFI_LOAD_FILE2_PROTOCOL_GUID;
+static grub_efi_guid_t device_path_guid = GRUB_EFI_DEVICE_PATH_GUID;
+
+static initrd_media_device_path_t initrd_lf2_device_path = {
+ {
+ {
+ GRUB_EFI_MEDIA_DEVICE_PATH_TYPE,
+ GRUB_EFI_VENDOR_MEDIA_DEVICE_PATH_SUBTYPE,
+ sizeof(grub_efi_vendor_media_device_path_t),
+ },
+ LINUX_EFI_INITRD_MEDIA_GUID
+ }, {
+ GRUB_EFI_END_DEVICE_PATH_TYPE,
+ GRUB_EFI_END_ENTIRE_DEVICE_PATH_SUBTYPE,
+ sizeof(grub_efi_device_path_t)
+ }
+};
+
+static grub_efi_status_t __grub_efi_api
+grub_efi_initrd_load_file2(grub_efi_load_file2_t *this,
+ grub_efi_device_path_t *device_path,
+ grub_efi_boolean_t boot_policy,
+ grub_efi_uintn_t *buffer_size,
+ void *buffer);
+
+static grub_efi_load_file2_t initrd_lf2 = {
+ grub_efi_initrd_load_file2
+};
+
grub_err_t
grub_arch_efi_linux_load_image_header (grub_file_t file,
struct linux_arch_kernel_header * lh)
@@ -78,6 +111,18 @@ grub_arch_efi_linux_load_image_header (grub_file_t file,
return grub_error(GRUB_ERR_FILE_READ_ERROR, "failed to read COFF image
header");
}
+ /*
+ * Linux kernels built for any architecture are guaranteed to support the
+ * LoadFile2 based initrd loading protocol if the image version is >= 1.
+ */
+ if (lh->coff_image_header.optional_header.major_image_version >= 1)
+ initrd_use_loadfile2 = 1;
+ else
+ initrd_use_loadfile2 = 0;
+
+ grub_dprintf ("linux", "LoadFile2 initrd loading %sabled\n",
+ initrd_use_loadfile2 ? "en" : "dis");
+
return GRUB_ERR_NONE;
}
@@ -197,6 +242,8 @@ grub_linux_boot (void)
static grub_err_t
grub_linux_unload (void)
{
+ grub_efi_boot_services_t *b = grub_efi_system_table->boot_services;
+
grub_dl_unref (my_mod);
loaded = 0;
if (initrd_start)
@@ -208,6 +255,18 @@ grub_linux_unload (void)
grub_efi_free_pages ((grub_addr_t) kernel_addr,
GRUB_EFI_BYTES_TO_PAGES (kernel_size));
grub_fdt_unload ();
+
+ if (initrd_lf2_handle)
+ {
+ b->uninstall_multiple_protocol_interfaces (initrd_lf2_handle,
+ &load_file2_guid,
+ &initrd_lf2,
+ &device_path_guid,
+ &initrd_lf2_device_path,
+ NULL);
+ initrd_lf2_handle = NULL;
+ initrd_use_loadfile2 = 0;
+ }
return GRUB_ERR_NONE;
}
@@ -247,13 +306,50 @@ allocate_initrd_mem (int initrd_pages)
GRUB_EFI_LOADER_DATA);
}
+static grub_efi_status_t __grub_efi_api
+grub_efi_initrd_load_file2(grub_efi_load_file2_t *this,
+ grub_efi_device_path_t *device_path,
+ grub_efi_boolean_t boot_policy,
+ grub_efi_uintn_t *buffer_size,
+ void *buffer)
+{
+ grub_efi_status_t status = GRUB_EFI_SUCCESS;
+ grub_efi_uintn_t initrd_size;
+
+ if (this != &initrd_lf2 || buffer_size == NULL)
+ return GRUB_EFI_INVALID_PARAMETER;
+
+ if (device_path->type != GRUB_EFI_END_DEVICE_PATH_TYPE ||
+ device_path->subtype != GRUB_EFI_END_ENTIRE_DEVICE_PATH_SUBTYPE)
+ return GRUB_EFI_NOT_FOUND;
+
+ if (boot_policy)
+ return GRUB_EFI_UNSUPPORTED;
+
+ initrd_size = grub_get_initrd_size (&initrd_ctx);
+ if (buffer == NULL || *buffer_size < initrd_size)
+ {
+ *buffer_size = initrd_size;
+ return GRUB_EFI_BUFFER_TOO_SMALL;
+ }
+
+ grub_dprintf ("linux", "Providing initrd via EFI_LOAD_FILE2_PROTOCOL\n");
+
+ if (grub_initrd_load (&initrd_ctx, buffer))
+ status = GRUB_EFI_DEVICE_ERROR;
+
+ grub_initrd_close (&initrd_ctx);
+ return status;
+}
+
static grub_err_t
grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
int argc, char *argv[])
{
- struct grub_linux_initrd_context initrd_ctx = { 0, 0, 0 };
int initrd_size, initrd_pages;
void *initrd_mem = NULL;
+ grub_efi_boot_services_t *b = grub_efi_system_table->boot_services;
+ grub_efi_status_t status;
if (argc == 0)
{
@@ -271,6 +367,31 @@ grub_cmd_initrd (grub_command_t cmd __attribute__
((unused)),
if (grub_initrd_init (argc, argv, &initrd_ctx))
goto fail;
+ if (initrd_use_loadfile2)
+ {
+ if (!initrd_lf2_handle)
+ {
+ status = b->install_multiple_protocol_interfaces (&initrd_lf2_handle,
+ &load_file2_guid,
+ &initrd_lf2,
+ &device_path_guid,
+
&initrd_lf2_device_path,
+ NULL);
+ if (status == GRUB_EFI_OUT_OF_RESOURCES)
+ {
+ grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory"));
+ goto fail;
+ }
+ else if (status != GRUB_EFI_SUCCESS)
+ {
+ grub_error (GRUB_ERR_BAD_ARGUMENT, N_("failed to install
protocols"));
+ goto fail;
+ }
+ }
+ grub_dprintf ("linux", "Using LoadFile2 initrd loading protocol\n");
+ return GRUB_ERR_NONE;
+ }
+
initrd_size = grub_get_initrd_size (&initrd_ctx);
grub_dprintf ("linux", "Loading initrd\n");
diff --git a/include/grub/efi/api.h b/include/grub/efi/api.h
index 1ef4046225cb..58b13b8c66b5 100644
--- a/include/grub/efi/api.h
+++ b/include/grub/efi/api.h
@@ -149,6 +149,11 @@
{ 0x8E, 0x3F, 0x00, 0xA0, 0xC9, 0x69, 0x72, 0x3B } \
}
+#define GRUB_EFI_LOAD_FILE2_PROTOCOL_GUID \
+ { 0x4006c0c1, 0xfcb3, 0x403e, \
+ { 0x99, 0x6d, 0x4a, 0x6c, 0x87, 0x24, 0xe0, 0x6d } \
+ }
+
#define GRUB_EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID \
{ 0x0964e5b22, 0x6459, 0x11d2, \
{ 0x8e, 0x39, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b } \
@@ -359,6 +364,11 @@
{ 0x86, 0x2e, 0xc0, 0x1c, 0xdc, 0x29, 0x1f, 0x44 } \
}
+#define LINUX_EFI_INITRD_MEDIA_GUID \
+ { 0x5568e427, 0x68fc, 0x4f3d, \
+ { 0xac, 0x74, 0xca, 0x55, 0x52, 0x31, 0xcc, 0x68 } \
+ }
+
struct grub_efi_sal_system_table
{
grub_uint32_t signature;
@@ -559,6 +569,20 @@ typedef grub_uint16_t grub_efi_char16_t;
typedef grub_efi_uintn_t grub_efi_status_t;
+/*
+ * On x86, the EFI calling convention may deviate from the local one, so
+ * callback functions exposed to the firmware must carry the follow attribute
+ * annotation. (This includes protocols implemented by GRUB that are installed
+ * into the EFI protocol database.)
+ */
+#if defined(__i386__)
+#define __grub_efi_api __attribute__((regparm(0)))
+#elif defined(__x86_64__)
+#define __grub_efi_api __attribute__((ms_abi))
+#else
+#define __grub_efi_api
+#endif
+
#define GRUB_EFI_ERROR_CODE(value) \
((((grub_efi_status_t) 1) << (sizeof (grub_efi_status_t) * 8 - 1)) | (value))
@@ -1749,6 +1773,22 @@ struct grub_efi_rng_protocol
};
typedef struct grub_efi_rng_protocol grub_efi_rng_protocol_t;
+struct grub_efi_load_file2
+{
+ grub_efi_status_t (__grub_efi_api *load_file)(struct grub_efi_load_file2
*this,
+ grub_efi_device_path_t
*file_path,
+ grub_efi_boolean_t boot_policy,
+ grub_efi_uintn_t *buffer_size,
+ void *buffer);
+};
+typedef struct grub_efi_load_file2 grub_efi_load_file2_t;
+
+struct initrd_media_device_path {
+ grub_efi_vendor_media_device_path_t vendor;
+ grub_efi_device_path_t end;
+} GRUB_PACKED;
+typedef struct initrd_media_device_path initrd_media_device_path_t;
+
#if (GRUB_TARGET_SIZEOF_VOID_P == 4) || defined (__ia64__) \
|| defined (__aarch64__) || defined (__MINGW64__) || defined (__CYGWIN__) \
|| defined(__riscv)
--
2.35.1
- [PATCH v3 0/8] linux: implement LoadFile2 initrd loading, Ard Biesheuvel, 2022/08/18
- [PATCH v3 1/8] loader: drop argv[] argument in grub_initrd_load(), Ard Biesheuvel, 2022/08/18
- [PATCH v3 2/8] efi: move MS-DOS stub out of generic PE header definition, Ard Biesheuvel, 2022/08/18
- [PATCH v3 3/8] arm64/linux: Remove magic number header field check, Ard Biesheuvel, 2022/08/18
- [PATCH v3 6/8] efi/efinet: Don't close connections at fini_hw() time, Ard Biesheuvel, 2022/08/18
- [PATCH v3 4/8] linux/arm: unify ARM/arm64 vs Xen PE/COFF header handling, Ard Biesheuvel, 2022/08/18
- [PATCH v3 5/8] linux/arm: account for COFF headers appearing at unexpected offsets, Ard Biesheuvel, 2022/08/18
- [PATCH v3 7/8] efi: implement LoadFile2 initrd loading protocol for Linux,
Ard Biesheuvel <=
- [PATCH v3 8/8] linux: ignore FDT unless we need to modify it, Ard Biesheuvel, 2022/08/18