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Bootloader: Add .data section

This commit is contained in:
Bananymous 2024-01-12 19:25:07 +02:00
parent 7adc7e55a5
commit 7e36a0be75
13 changed files with 40 additions and 26 deletions
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2
bootloader/bios/a20_line.S
View File

@ -156,6 +156,8 @@ enable_a20:
popw %ax
ret
.section .data
a20_line_disabled_msg:
.asciz "A20 line disabled. Trying to enable it"

2
bootloader/bios/boot.S
View File

@ -143,6 +143,8 @@ enter_unreal_mode:
ret
.section .data
hello_msg:
.asciz "This is banan-os bootloader"

2
bootloader/bios/command_line.S
View File

@ -74,6 +74,8 @@ read_user_command_line:
ret
.section .data
command_line_enter_msg:
.asciz "cmdline: "

1
bootloader/bios/disk.S
View File

@ -470,6 +470,7 @@ print_root_partition_info:
popw %ax
ret
.section .data
# These will be patched during bootloader installation
root_disk_guid:

1
bootloader/bios/elf.S
View File

@ -196,6 +196,7 @@ elf_read_kernel_to_memory:
movw $elf_read_kernel_to_memory_not_loadable_header_msg, %si
jmp print_and_halt
.section .data
elf_validate_file_header_invalid_magic_msg:
.asciz "ELF: file has invalid ELF magic"

2
bootloader/bios/ext2.S
View File

@ -692,6 +692,7 @@ ext2_find_kernel:
movw $ext2_kernel_not_reg_msg, %si
jmp print_and_halt
.section .data
kernel_path:
.short kernel_path1
@ -704,7 +705,6 @@ kernel_path2:
.short 15
.asciz "banan-os.kernel"
root_partition_does_not_fit_ext2_filesystem_msg:
.asciz "Root partition is too small to contain ext2 filesystem"
root_partition_has_invalid_ext2_magic_msg:

1
bootloader/bios/framebuffer.S
View File

@ -185,6 +185,7 @@ vesa_set_video_mode:
popw %ax
ret
.section .data
vesa_error_msg:
.asciz "VESA error"

2
bootloader/bios/linker.ld
View File

@ -8,6 +8,8 @@ SECTIONS
. = ALIGN(512);
stage2_start = .;
.stage2 : { *(.stage2) }
. = ALIGN(512);
.data : { *(.data) }
stage2_end = .;
. = ALIGN(512);

1
bootloader/bios/memory_map.S
View File

@ -114,6 +114,7 @@ print_memory_map:
ret
.section .data
memory_map_msg:
.asciz "memmap:"

38
bootloader/installer/GPT.cpp
View File

@ -99,33 +99,33 @@ bool GPTFile::install_stage1(std::span<const uint8_t> stage1)
return true;
}
bool GPTFile::install_stage2(std::span<const uint8_t> stage2, const GUID& root_partition_guid)
bool GPTFile::install_stage2(std::span<const uint8_t> stage2, std::span<const uint8_t> data, const GUID& root_partition_guid)
{
if (stage2.size() < 16)
if (data.size() < 16)
{
std::cerr << m_path << ": contains invalid .stage2 section, too small for patches" << std::endl;
std::cerr << m_path << ": contains invalid .data section, too small for patches" << std::endl;
return false;
}
// find GUID patch offsets
std::size_t disk_guid_offset(-1);
std::size_t part_guid_offset(-1);
for (std::size_t i = 0; i < stage2.size() - 16; i++)
for (std::size_t i = 0; i < data.size() - 16; i++)
{
if (memcmp(stage2.data() + i, "root disk guid ", 16) == 0)
if (memcmp(data.data() + i, "root disk guid ", 16) == 0)
{
if (disk_guid_offset != std::size_t(-1))
{
std::cerr << m_path << ": contains invalid .stage2 section, multiple patchable disk guids" << std::endl;
std::cerr << m_path << ": contains invalid .data section, multiple patchable disk guids" << std::endl;
return false;
}
disk_guid_offset = i;
}
if (memcmp(stage2.data() + i, "root part guid ", 16) == 0)
if (memcmp(data.data() + i, "root part guid ", 16) == 0)
{
if (part_guid_offset != std::size_t(-1))
{
std::cerr << m_path << ": contains invalid .stage2 section, multiple patchable partition guids" << std::endl;
std::cerr << m_path << ": contains invalid .data section, multiple patchable partition guids" << std::endl;
return false;
}
part_guid_offset = i;
@ -133,16 +133,15 @@ bool GPTFile::install_stage2(std::span<const uint8_t> stage2, const GUID& root_p
}
if (disk_guid_offset == std::size_t(-1))
{
std::cerr << m_path << ": contains invalid .stage2 section, no patchable disk guid" << std::endl;
std::cerr << m_path << ": contains invalid .data section, no patchable disk guid" << std::endl;
return false;
}
if (part_guid_offset == std::size_t(-1))
{
std::cerr << m_path << ": contains invalid .stage2 section, no patchable partition guid" << std::endl;
std::cerr << m_path << ": contains invalid .data section, no patchable partition guid" << std::endl;
return false;
}
auto partition = find_partition_with_type(bios_boot_guid);
if (!partition.has_value())
{
@ -152,23 +151,28 @@ bool GPTFile::install_stage2(std::span<const uint8_t> stage2, const GUID& root_p
const std::size_t partition_size = (partition->ending_lba - partition->starting_lba + 1) * SECTOR_SIZE;
if (stage2.size() > partition_size)
std::size_t data_offset = stage2.size();
if (std::size_t rem = data_offset % 512)
data_offset += 512 - rem;
if (data_offset + data.size() > partition_size)
{
std::cerr << m_path << ": can't fit " << stage2.size() << " bytes of data to partition of size " << partition_size << std::endl;
std::cerr << m_path << ": can't fit " << stage2.size() + data.size() << " bytes of data to partition of size " << partition_size << std::endl;
return false;
}
uint8_t* partition_start = m_mmap + partition->starting_lba * SECTOR_SIZE;
memcpy(partition_start, stage2.data(), stage2.size());
memcpy(partition_start + data_offset, data.data(), data.size());
// patch GUIDs
*reinterpret_cast<GUID*>(partition_start + disk_guid_offset) = gpt_header().disk_guid;
*reinterpret_cast<GUID*>(partition_start + part_guid_offset) = root_partition_guid;
*reinterpret_cast<GUID*>(partition_start + data_offset + disk_guid_offset) = gpt_header().disk_guid;
*reinterpret_cast<GUID*>(partition_start + data_offset + part_guid_offset) = root_partition_guid;
return true;
}
bool GPTFile::install_bootloader(std::span<const uint8_t> stage1, std::span<const uint8_t> stage2, const GUID& root_partition_guid)
bool GPTFile::install_bootloader(std::span<const uint8_t> stage1, std::span<const uint8_t> stage2, std::span<const uint8_t> data, const GUID& root_partition_guid)
{
if (!find_partition_with_guid(root_partition_guid).has_value())
{
@ -177,7 +181,7 @@ bool GPTFile::install_bootloader(std::span<const uint8_t> stage1, std::span<cons
}
if (!install_stage1(stage1))
return false;
if (!install_stage2(stage2, root_partition_guid))
if (!install_stage2(stage2, data, root_partition_guid))
return false;
return true;
}

4
bootloader/installer/GPT.h
View File

@ -65,7 +65,7 @@ public:
GPTFile(std::string_view path);
~GPTFile();
bool install_bootloader(std::span<const uint8_t> stage1, std::span<const uint8_t> stage2, const GUID& root_partition_guid);
bool install_bootloader(std::span<const uint8_t> stage1, std::span<const uint8_t> stage2, std::span<const uint8_t> data, const GUID& root_partition_guid);
const GPTHeader& gpt_header() const;
@ -80,7 +80,7 @@ private:
std::optional<GPTPartitionEntry> find_partition_with_type(const GUID& type_guid) const;
bool install_stage1(std::span<const uint8_t> stage1);
bool install_stage2(std::span<const uint8_t> stage2, const GUID& root_partition_guid);
bool install_stage2(std::span<const uint8_t> stage2, std::span<const uint8_t> data, const GUID& root_partition_guid);
private:
const std::string m_path;

3
bootloader/installer/build.sh
View File

@ -1,3 +0,0 @@
#!/bin/sh
g++ -O2 -std=c++20 main.cpp crc32.cpp ELF.cpp GPT.cpp GUID.cpp -o install-bootloader

7
bootloader/installer/main.cpp
View File

@ -26,9 +26,10 @@ int main(int argc, char** argv)
auto stage1 = bootloader.find_section(".stage1"sv);
auto stage2 = bootloader.find_section(".stage2"sv);
if (!stage1.has_value() || !stage2.has_value())
auto data = bootloader.find_section(".data"sv);
if (!stage1.has_value() || !stage2.has_value() || !data.has_value())
{
std::cerr << bootloader.path() << " doesn't contain .stage1 and .stage2 sections" << std::endl;
std::cerr << bootloader.path() << " doesn't contain .stage1, .stage2 and .data sections" << std::endl;
return 1;
}
@ -36,7 +37,7 @@ int main(int argc, char** argv)
if (!disk_image.success())
return 1;
if (!disk_image.install_bootloader(*stage1, *stage2, *root_partition_guid))
if (!disk_image.install_bootloader(*stage1, *stage2, *data, *root_partition_guid))
return 1;
std::cout << "bootloader installed" << std::endl;