diff options
Diffstat (limited to 'src/boot/efi/devicetree.c')
| -rw-r--r-- | src/boot/efi/devicetree.c | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/src/boot/efi/devicetree.c b/src/boot/efi/devicetree.c new file mode 100644 index 0000000..0312670 --- /dev/null +++ b/src/boot/efi/devicetree.c @@ -0,0 +1,154 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include <efi.h> + +#include "devicetree.h" +#include "missing_efi.h" +#include "util.h" + +#define FDT_V1_SIZE (7*4) + +static void *get_dtb_table(void) { + for (UINTN i = 0; i < ST->NumberOfTableEntries; i++) + if (memcmp(&EfiDtbTableGuid, &ST->ConfigurationTable[i].VendorGuid, sizeof(EfiDtbTableGuid)) == 0) + return ST->ConfigurationTable[i].VendorTable; + return NULL; +} + +static EFI_STATUS devicetree_allocate(struct devicetree_state *state, UINTN size) { + UINTN pages = DIV_ROUND_UP(size, EFI_PAGE_SIZE); + EFI_STATUS err; + + assert(state); + + err = BS->AllocatePages(AllocateAnyPages, EfiACPIReclaimMemory, pages, &state->addr); + if (err != EFI_SUCCESS) + return err; + + state->pages = pages; + return err; +} + +static UINTN devicetree_allocated(const struct devicetree_state *state) { + assert(state); + return state->pages * EFI_PAGE_SIZE; +} + +static EFI_STATUS devicetree_fixup(struct devicetree_state *state, UINTN len) { + EFI_DT_FIXUP_PROTOCOL *fixup; + UINTN size; + EFI_STATUS err; + + assert(state); + + err = BS->LocateProtocol(&EfiDtFixupProtocol, NULL, (void **) &fixup); + if (err != EFI_SUCCESS) + return log_error_status_stall(EFI_SUCCESS, + L"Could not locate device tree fixup protocol, skipping."); + + size = devicetree_allocated(state); + err = fixup->Fixup(fixup, PHYSICAL_ADDRESS_TO_POINTER(state->addr), &size, + EFI_DT_APPLY_FIXUPS | EFI_DT_RESERVE_MEMORY); + if (err == EFI_BUFFER_TOO_SMALL) { + EFI_PHYSICAL_ADDRESS oldaddr = state->addr; + UINTN oldpages = state->pages; + void *oldptr = PHYSICAL_ADDRESS_TO_POINTER(state->addr); + + err = devicetree_allocate(state, size); + if (err != EFI_SUCCESS) + return err; + + memcpy(PHYSICAL_ADDRESS_TO_POINTER(state->addr), oldptr, len); + err = BS->FreePages(oldaddr, oldpages); + if (err != EFI_SUCCESS) + return err; + + size = devicetree_allocated(state); + err = fixup->Fixup(fixup, PHYSICAL_ADDRESS_TO_POINTER(state->addr), &size, + EFI_DT_APPLY_FIXUPS | EFI_DT_RESERVE_MEMORY); + } + + return err; +} + +EFI_STATUS devicetree_install(struct devicetree_state *state, EFI_FILE *root_dir, char16_t *name) { + _cleanup_(file_closep) EFI_FILE *handle = NULL; + _cleanup_free_ EFI_FILE_INFO *info = NULL; + UINTN len; + EFI_STATUS err; + + assert(state); + assert(root_dir); + assert(name); + + state->orig = get_dtb_table(); + if (!state->orig) + return EFI_UNSUPPORTED; + + err = root_dir->Open(root_dir, &handle, name, EFI_FILE_MODE_READ, EFI_FILE_READ_ONLY); + if (err != EFI_SUCCESS) + return err; + + err = get_file_info_harder(handle, &info, NULL); + if (err != EFI_SUCCESS) + return err; + if (info->FileSize < FDT_V1_SIZE || info->FileSize > 32 * 1024 * 1024) + /* 32MB device tree blob doesn't seem right */ + return EFI_INVALID_PARAMETER; + + len = info->FileSize; + + err = devicetree_allocate(state, len); + if (err != EFI_SUCCESS) + return err; + + err = handle->Read(handle, &len, PHYSICAL_ADDRESS_TO_POINTER(state->addr)); + if (err != EFI_SUCCESS) + return err; + + err = devicetree_fixup(state, len); + if (err != EFI_SUCCESS) + return err; + + return BS->InstallConfigurationTable(&EfiDtbTableGuid, PHYSICAL_ADDRESS_TO_POINTER(state->addr)); +} + +EFI_STATUS devicetree_install_from_memory(struct devicetree_state *state, + const void *dtb_buffer, UINTN dtb_length) { + + EFI_STATUS err; + + assert(state); + assert(dtb_buffer && dtb_length > 0); + + state->orig = get_dtb_table(); + if (!state->orig) + return EFI_UNSUPPORTED; + + err = devicetree_allocate(state, dtb_length); + if (err != EFI_SUCCESS) + return err; + + memcpy(PHYSICAL_ADDRESS_TO_POINTER(state->addr), dtb_buffer, dtb_length); + + err = devicetree_fixup(state, dtb_length); + if (err != EFI_SUCCESS) + return err; + + return BS->InstallConfigurationTable(&EfiDtbTableGuid, PHYSICAL_ADDRESS_TO_POINTER(state->addr)); +} + +void devicetree_cleanup(struct devicetree_state *state) { + EFI_STATUS err; + + if (!state->pages) + return; + + err = BS->InstallConfigurationTable(&EfiDtbTableGuid, state->orig); + /* don't free the current device tree if we can't reinstate the old one */ + if (err != EFI_SUCCESS) + return; + + BS->FreePages(state->addr, state->pages); + state->pages = 0; +} |