diff options
Diffstat (limited to 'src/boot/efi/devicetree.c')
| -rw-r--r-- | src/boot/efi/devicetree.c | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/src/boot/efi/devicetree.c b/src/boot/efi/devicetree.c new file mode 100644 index 0000000..61a43cd --- /dev/null +++ b/src/boot/efi/devicetree.c @@ -0,0 +1,149 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include "devicetree.h" +#include "proto/dt-fixup.h" +#include "util.h" + +#define FDT_V1_SIZE (7*4) + +static EFI_STATUS devicetree_allocate(struct devicetree_state *state, size_t size) { + size_t 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 size_t devicetree_allocated(const struct devicetree_state *state) { + assert(state); + return state->pages * EFI_PAGE_SIZE; +} + +static EFI_STATUS devicetree_fixup(struct devicetree_state *state, size_t len) { + EFI_DT_FIXUP_PROTOCOL *fixup; + size_t size; + EFI_STATUS err; + + assert(state); + + err = BS->LocateProtocol(MAKE_GUID_PTR(EFI_DT_FIXUP_PROTOCOL), NULL, (void **) &fixup); + /* Skip fixup if we cannot locate device tree fixup protocol */ + if (err != EFI_SUCCESS) + return EFI_SUCCESS; + + 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; + size_t 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; + size_t len; + EFI_STATUS err; + + assert(state); + assert(root_dir); + assert(name); + + /* Capture the original value for the devicetree table. NULL is not an error in this case so we don't + * need to check the return value. NULL simply means the system fw had no devicetree initially (and + * is the correct value to use to return to the initial state if needed). */ + state->orig = find_configuration_table(MAKE_GUID_PTR(EFI_DTB_TABLE)); + + 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(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( + MAKE_GUID_PTR(EFI_DTB_TABLE), PHYSICAL_ADDRESS_TO_POINTER(state->addr)); +} + +EFI_STATUS devicetree_install_from_memory( + struct devicetree_state *state, const void *dtb_buffer, size_t dtb_length) { + + EFI_STATUS err; + + assert(state); + assert(dtb_buffer && dtb_length > 0); + + /* Capture the original value for the devicetree table. NULL is not an error in this case so we don't + * need to check the return value. NULL simply means the system fw had no devicetree initially (and + * is the correct value to use to return to the initial state if needed). */ + state->orig = find_configuration_table(MAKE_GUID_PTR(EFI_DTB_TABLE)); + + 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( + MAKE_GUID_PTR(EFI_DTB_TABLE), PHYSICAL_ADDRESS_TO_POINTER(state->addr)); +} + +void devicetree_cleanup(struct devicetree_state *state) { + EFI_STATUS err; + + if (!state->pages) + return; + + err = BS->InstallConfigurationTable(MAKE_GUID_PTR(EFI_DTB_TABLE), 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; +} |