From: Heinrich Schuchardt Date: Fri, 29 Jan 2021 07:36:42 +0100 Subject: efi: EFI Device Tree Fixup Protocol Device-trees are used to convey information about hardware to the operating system. Some of the properties are only known at boot time. (One example of such a property is the number of the boot hart on RISC-V systems.) Therefore the firmware applies fix-ups to the original device-tree. Some nodes and properties are added or altered. When using GRUB's device-tree command the same fix-ups have to be applied. The EFI Device Tree Fixup Protocol allows to pass the loaded device tree to the firmware for this purpose. The protocol can * add nodes and update properties * reserve memory according to the /reserved-memory node and the memory reservation block * install the device-tree as configuration table With the patch GRUB checks if the protocol is installed and invokes it if available. (LP: #1965796) Link: https://lists.gnu.org/archive/html/grub-devel/2021-02/msg00013.html Signed-off-by: Heinrich Schuchardt Signed-off-by: Julian Andres Klode --- grub-core/loader/efi/fdt.c | 37 +++++++++++++++++++++++++++++++++++++ include/grub/efi/api.h | 22 ++++++++++++++++++++++ 2 files changed, 59 insertions(+) diff --git a/grub-core/loader/efi/fdt.c b/grub-core/loader/efi/fdt.c index b4a0447..948ef7e 100644 --- a/grub-core/loader/efi/fdt.c +++ b/grub-core/loader/efi/fdt.c @@ -32,6 +32,7 @@ static void *loaded_fdt; static void *fdt; +static grub_guid_t dt_fixup_guid = GRUB_EFI_DT_FIXUP_PROTOCOL_GUID; #define FDT_ADDR_CELLS_STRING "#address-cells" #define FDT_SIZE_CELLS_STRING "#size-cells" @@ -46,6 +47,41 @@ static const struct grub_arg_option options_fdtdump[] = { {0, 0, 0, 0, 0, 0} }; +static void * +grub_fdt_fixup (void *blob) +{ + grub_efi_dt_fixup_t *dt_fixup_prot; + grub_efi_uintn_t size = 0; + grub_efi_status_t status; + void *fixup_fdt; + + dt_fixup_prot = grub_efi_locate_protocol (&dt_fixup_guid, 0); + if (!dt_fixup_prot) + return blob; + + grub_dprintf ("linux", "EFI_DT_FIXUP_PROTOCOL available\n"); + + status = dt_fixup_prot->fixup (dt_fixup_prot, blob, &size, + GRUB_EFI_DT_APPLY_FIXUPS + | GRUB_EFI_DT_RESERVE_MEMORY); + if (status != GRUB_EFI_BUFFER_TOO_SMALL) + return blob; + + fixup_fdt = grub_realloc (blob, size); + if (!fixup_fdt) + return blob; + blob = fixup_fdt; + + status = dt_fixup_prot->fixup (dt_fixup_prot, blob, &size, + GRUB_EFI_DT_APPLY_FIXUPS + | GRUB_EFI_DT_RESERVE_MEMORY); + + if (status == GRUB_EFI_SUCCESS) + grub_dprintf ("linux", "Device tree fixed up via EFI_DT_FIXUP_PROTOCOL\n"); + + return blob; +} + void * grub_fdt_load (grub_size_t additional_size) { @@ -170,6 +206,7 @@ out: if (blob) { grub_dprintf ("fdt", "Device-tree %s loaded\n", argv[0]); + blob = grub_fdt_fixup (blob); if (grub_errno == GRUB_ERR_NONE) loaded_fdt = blob; else diff --git a/include/grub/efi/api.h b/include/grub/efi/api.h index 5c2be0f..c9980af 100644 --- a/include/grub/efi/api.h +++ b/include/grub/efi/api.h @@ -354,6 +354,11 @@ { 0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0 } \ } +#define GRUB_EFI_DT_FIXUP_PROTOCOL_GUID \ + { 0xe617d64c, 0xfe08, 0x46da, \ + { 0xf4, 0xdc, 0xbb, 0xd5, 0x87, 0x0c, 0x73, 0x00 } \ + } + #define GRUB_EFI_VENDOR_APPLE_GUID \ { 0x2B0585EB, 0xD8B8, 0x49A9, \ { 0x8B, 0x8C, 0xE2, 0x1B, 0x01, 0xAE, 0xF2, 0xB7 } \ @@ -1924,6 +1929,13 @@ enum GRUB_EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS_MULTICAST = 0x10, }; +enum + { + GRUB_EFI_DT_APPLY_FIXUPS = 0x01, + GRUB_EFI_DT_RESERVE_MEMORY = 0x02, + GRUB_EFI_EFI_DT_INSTALL_TABLE = 0x04, + }; + struct grub_efi_simple_network { grub_uint64_t revision; @@ -2006,6 +2018,16 @@ struct grub_efi_block_io }; typedef struct grub_efi_block_io grub_efi_block_io_t; +struct grub_efi_dt_fixup +{ + grub_efi_uint64_t revision; + grub_efi_status_t (__grub_efi_api *fixup) (struct grub_efi_dt_fixup *this, + void *fdt, + grub_efi_uintn_t *buffer_size, + grub_uint32_t flags); +}; +typedef struct grub_efi_dt_fixup grub_efi_dt_fixup_t; + struct grub_efi_shim_lock_protocol { /*