diff options
| -rw-r--r-- | Userland/Libraries/CMakeLists.txt | 1 | ||||
| -rw-r--r-- | Userland/Libraries/LibDeviceTree/CMakeLists.txt | 7 | ||||
| -rw-r--r-- | Userland/Libraries/LibDeviceTree/FlattenedDeviceTree.h | 41 | ||||
| -rw-r--r-- | Userland/Libraries/LibDeviceTree/Validation.cpp | 143 | ||||
| -rw-r--r-- | Userland/Libraries/LibDeviceTree/Validation.h | 22 |
5 files changed, 214 insertions, 0 deletions
diff --git a/Userland/Libraries/CMakeLists.txt b/Userland/Libraries/CMakeLists.txt index 140ae6e3ee..f51f4d1390 100644 --- a/Userland/Libraries/CMakeLists.txt +++ b/Userland/Libraries/CMakeLists.txt @@ -12,6 +12,7 @@ add_subdirectory(LibCrypt) add_subdirectory(LibCrypto) add_subdirectory(LibDebug) add_subdirectory(LibDesktop) +add_subdirectory(LibDeviceTree) add_subdirectory(LibDiff) add_subdirectory(LibDl) add_subdirectory(LibDSP) diff --git a/Userland/Libraries/LibDeviceTree/CMakeLists.txt b/Userland/Libraries/LibDeviceTree/CMakeLists.txt new file mode 100644 index 0000000000..f81192fc3c --- /dev/null +++ b/Userland/Libraries/LibDeviceTree/CMakeLists.txt @@ -0,0 +1,7 @@ + +set(SOURCES + Validation.cpp +) + +serenity_lib(LibDeviceTree DeviceTree) +target_link_libraries(LibDeviceTree LibC LibCore) diff --git a/Userland/Libraries/LibDeviceTree/FlattenedDeviceTree.h b/Userland/Libraries/LibDeviceTree/FlattenedDeviceTree.h new file mode 100644 index 0000000000..75b23c6964 --- /dev/null +++ b/Userland/Libraries/LibDeviceTree/FlattenedDeviceTree.h @@ -0,0 +1,41 @@ +/* + * Copyright (c) 2021, Andrew Kaster <akaster@serenityos.org> + * + * SPDX-License-Identifier: BSD-2-Clause + */ + +#pragma once + +#include <AK/Endian.h> +#include <AK/Types.h> + +namespace DeviceTree { + +// https://devicetree-specification.readthedocs.io/en/v0.3/flattened-format.html +struct FlattenedDeviceTreeHeader { + BigEndian<u32> magic; // 0xDOODFEED (BE) + BigEndian<u32> totalsize; // Total size of entire blob including padding b/w and after fields + BigEndian<u32> off_dt_struct; // Offset of StructureBlock from beginning of header + // https://devicetree-specification.readthedocs.io/en/v0.3/flattened-format.html#sect-fdt-structure-block + BigEndian<u32> off_dt_strings; // Offset of StringsBlock from beginning of header + // https://devicetree-specification.readthedocs.io/en/v0.3/flattened-format.html#sect-fdt-strings-block + BigEndian<u32> off_mem_rsvmap; // Offset of MemoryReservationBlock from beginning of header + BigEndian<u32> version; // 0.3 spec defines version 17 + BigEndian<u32> last_comp_version; // 0.3 spec back-compatible with version 16, mandated to be 16 + BigEndian<u32> boot_cpuid_phys; // Physical ID given in `reg` property of CPU node of boot cpu + BigEndian<u32> size_dt_strings; // Length in bytes of StringsBlock + BigEndian<u32> size_dt_struct; // Length in bytes of StructureBlock +}; +static_assert(sizeof(FlattenedDeviceTreeHeader) == 40, "FDT Header size must match specification"); + +// https://devicetree-specification.readthedocs.io/en/v0.3/flattened-format.html#format +struct FlattenedDeviceTreeReserveEntry { + BigEndian<u64> address; + BigEndian<u64> size; + + bool operator==(FlattenedDeviceTreeReserveEntry const& other) const { return other.address == address && other.size == size; } + bool operator!=(FlattenedDeviceTreeReserveEntry const& other) const { return !(operator==(other)); } +}; +static_assert(sizeof(FlattenedDeviceTreeReserveEntry) == 16, "FDT Memory Reservation entry size must match specification"); + +} // namespace DeviceTree diff --git a/Userland/Libraries/LibDeviceTree/Validation.cpp b/Userland/Libraries/LibDeviceTree/Validation.cpp new file mode 100644 index 0000000000..1a733f9085 --- /dev/null +++ b/Userland/Libraries/LibDeviceTree/Validation.cpp @@ -0,0 +1,143 @@ +/* + * Copyright (c) 2021, Andrew Kaster <akaster@serenityos.org> + * + * SPDX-License-Identifier: BSD-2-Clause + */ + +#include <AK/Endian.h> +#include <AK/Format.h> +#include <AK/String.h> +#include <LibDeviceTree/Validation.h> + +namespace DeviceTree { + +bool validate_flattened_device_tree(FlattenedDeviceTreeHeader const& header, u8 const* blob_start, size_t blob_size, Verbose verbose) +{ + if (header.magic != 0xD00DFEEDU) { + if (verbose == Verbose::Yes) + warnln("FDT Header has invalid magic value 0x{:08x}. Are you sure it's a flattened device tree?", header.magic); + return false; + } + + if ((header.off_mem_rsvmap & ~0x7) != header.off_mem_rsvmap) { + if (verbose == Verbose::Yes) + warnln("FDT Header's MemoryReservationBlock is not 8 byte aligned! Offset: 0x{:08x}", header.off_mem_rsvmap); + return false; + } + + if ((header.off_dt_struct & ~0x3) != header.off_dt_struct) { + if (verbose == Verbose::Yes) + warnln("FDT Header's StructureBlock is not 4 byte aligned! Offset: 0x{:08x}", header.off_dt_struct); + return false; + } + + if (header.totalsize != blob_size) { + if (verbose == Verbose::Yes) + warnln("FDT Header total size mismatch: {}, expected {}!", header.totalsize, blob_size); + return false; + } + + if (header.off_dt_struct > blob_size) { + if (verbose == Verbose::Yes) + warnln("FDT Header reports larger StructureBlock offset than possible: {} but total size is {}!", header.off_dt_struct, blob_size); + return false; + } + + if (header.off_dt_strings > blob_size) { + if (verbose == Verbose::Yes) + warnln("FDT Header reports larger StringsBlock offset than possible: {} but total size is {}!", header.off_dt_strings, blob_size); + return false; + } + + if (header.off_mem_rsvmap > blob_size) { + if (verbose == Verbose::Yes) + warnln("FDT Header reports larger MemoryReservationBlock offset than possible: {} but total size is {}!", header.off_mem_rsvmap, blob_size); + return false; + } + + // Verify format is correct. Header --> MemoryReservation --> Structures --> Strings + if (header.off_dt_strings <= header.off_dt_struct) { + if (verbose == Verbose::Yes) + warnln("FDT Header has invalid StringsBlock offset {}, must be after v (@ {})", header.off_dt_strings, header.off_dt_struct); + return false; + } + + if (header.off_dt_struct <= header.off_mem_rsvmap) { + if (verbose == Verbose::Yes) + warnln("FDT Header has invalid StructureBlock offset {}, must be after MemoryReservationBlock (@ {})", header.off_dt_struct, header.off_mem_rsvmap); + return false; + } + + if (header.version != 17) { + if (verbose == Verbose::Yes) + warnln("Expected FDT header version 17, got {}", header.version); + return false; + } + + if (header.last_comp_version != 16) { + if (verbose == Verbose::Yes) + warnln("Expected FDT header last compatible version 16, got {}", header.last_comp_version); + return false; + } + + auto* mem_reserve_block = reinterpret_cast<FlattenedDeviceTreeReserveEntry const*>(&blob_start[header.off_mem_rsvmap]); + u64 next_block_offset = header.off_mem_rsvmap + sizeof(FlattenedDeviceTreeReserveEntry); + while ((next_block_offset < header.off_dt_struct) && (*mem_reserve_block != FlattenedDeviceTreeReserveEntry {})) { + ++mem_reserve_block; + next_block_offset += sizeof(FlattenedDeviceTreeReserveEntry); + } + + if (next_block_offset >= header.off_dt_strings) { + if (verbose == Verbose::Yes) + warnln("FDT malformed, MemoryReservationBlock spill into StructureBlock section!"); + return false; + } + + // check for overlap. Overflow not possible b/c the fields are u32 + u64 structure_block_size = header.off_dt_struct + header.size_dt_struct; + if ((structure_block_size > header.off_dt_strings) || (structure_block_size > blob_size)) { + if (verbose == Verbose::Yes) + warnln("FDT Header reports invalid StructureBlock block size: {} is too large given StringsBlock offset {} and total size {}", structure_block_size, header.off_dt_strings, blob_size); + return false; + } + + u64 strings_block_size = header.off_dt_strings + header.size_dt_strings; + if (strings_block_size > blob_size) { + if (verbose == Verbose::Yes) + warnln("FDT Header reports invalid StringsBlock size: {} is too large given total size {}", structure_block_size, blob_size); + return false; + } + + return true; +} + +bool dump(FlattenedDeviceTreeHeader const& header, u8 const* blob_start, size_t blob_size) +{ + outln("/dts-v1/;"); + outln("// magic: 0x{:08x}", header.magic); + outln("// totalsize: 0x{:08x} ({})", header.totalsize, header.totalsize); + outln("// off_dt_struct: 0x{:08x}", header.off_dt_struct); + outln("// off_dt_strings: 0x{:08x}", header.off_dt_strings); + outln("// off_mem_rsvmap: 0x{:08x}", header.off_mem_rsvmap); + outln("// version: 0x{:08x}", header.version); + outln("// last_comp_version: 0x{:08x}", header.last_comp_version); + outln("// boot_cpuid_phys: 0x{:08x}", header.boot_cpuid_phys); + outln("// size_dt_strings: 0x{:08x}", header.size_dt_strings); + outln("// size_dt_struct: 0x{:08x}", header.size_dt_struct); + + if (!validate_flattened_device_tree(header, blob_start, blob_size, Verbose::Yes)) + return false; + + // Now that we know the device tree is valid, print out the rest of the information + auto* mem_reserve_block = reinterpret_cast<FlattenedDeviceTreeReserveEntry const*>(&blob_start[header.off_mem_rsvmap]); + u64 next_block_offset = header.off_mem_rsvmap + sizeof(FlattenedDeviceTreeReserveEntry); + while ((next_block_offset < header.off_dt_struct) && (*mem_reserve_block != FlattenedDeviceTreeReserveEntry {})) { + outln("/memreserve/ 0x{:08x} 0x{:08x};", mem_reserve_block->address, mem_reserve_block->size); + ++mem_reserve_block; + next_block_offset += sizeof(FlattenedDeviceTreeReserveEntry); + } + + return true; +} + +} // namespace DeviceTree diff --git a/Userland/Libraries/LibDeviceTree/Validation.h b/Userland/Libraries/LibDeviceTree/Validation.h new file mode 100644 index 0000000000..069ca6a818 --- /dev/null +++ b/Userland/Libraries/LibDeviceTree/Validation.h @@ -0,0 +1,22 @@ +/* + * Copyright (c) 2021, Andrew Kaster <akaster@serenityos.org> + * + * SPDX-License-Identifier: BSD-2-Clause + */ + +#pragma once + +#include <LibDeviceTree/FlattenedDeviceTree.h> + +namespace DeviceTree { + +enum class Verbose { + No, + Yes +}; + +bool validate_flattened_device_tree(FlattenedDeviceTreeHeader const& header, u8 const* blob_start, size_t blob_size, Verbose = Verbose::No); + +bool dump(FlattenedDeviceTreeHeader const& header, u8 const* blob_start, size_t blob_size); + +} |