diff options
| -rw-r--r-- | kernel/entry_efi.c | 2 | ||||
| -rw-r--r-- | kernel/kernel.ld | 9 | ||||
| -rw-r--r-- | loader/loader_efi.c | 199 |
3 files changed, 189 insertions, 21 deletions
diff --git a/kernel/entry_efi.c b/kernel/entry_efi.c index 1acd399..40e674f 100644 --- a/kernel/entry_efi.c +++ b/kernel/entry_efi.c @@ -3,8 +3,6 @@ #include <boot/entry/entry_efi.h> -static const char kernel_entry_data[4096]; - noreturn void kernel_entry(struct efi_boot_data *data) { (void)data; diff --git a/kernel/kernel.ld b/kernel/kernel.ld index 9538056..17cb8b4 100644 --- a/kernel/kernel.ld +++ b/kernel/kernel.ld @@ -1,15 +1,16 @@ ENTRY(kernel_entry) +k_virt_base = 0xffffffff80000000; + SECTIONS { - . = SIZEOF_HEADERS; - - .text 0 : + .text k_virt_base : AT(ADDR(.text) - k_virt_base) { *(.text) + . = ALIGN(4K); } =0x90 - .data : ALIGN(4K) + .data ALIGN(4K) : AT(ADDR(.data) - k_virt_base) { *(.rodata) *(.data) diff --git a/loader/loader_efi.c b/loader/loader_efi.c index de9ed39..f73b9ac 100644 --- a/loader/loader_efi.c +++ b/loader/loader_efi.c @@ -20,6 +20,7 @@ struct system_image EFI_FILE_PROTOCOL *file; Elf64_Ehdr ehdr; Elf64_Phdr *phdrs; + uint64_t *maps; }; static struct system_image *open_system_image(CHAR16 *path); @@ -28,29 +29,155 @@ static struct efi_memory_map_data *get_memory_map_data(void); static struct efi_framebuffer_data *get_framebuffer_data(void); static void *get_acpi_rsdp(void); -void loader_main(void) +enum page_type { - struct efi_boot_data data; + INVALID_PAGE_TYPE = 0x0, + CODE_PAGE_TYPE = 0x1, + RODATA_PAGE_TYPE = 0x1, + DATA_PAGE_TYPE = 0x3 +}; - struct system_image *kernel_image = open_system_image(kernel_path); +#define PAGE_MAP_LEVELS 4 +#define PAGE_MAP_BITS 9 +#define PAGE_OFFSET_BITS 12 - Print(L"loading %s\r\n", kernel_path); +#define PAGE_TABLE_INDEX_MASK ((1 << PAGE_MAP_BITS) - 1) +#define PAGE_TABLE_ADDRESS_MASK ~((1 << PAGE_OFFSET_BITS) - 1) - if (load_system_image(kernel_image)) +#define page_table_index(v, l) ((v >> ((PAGE_OFFSET_BITS + (l - 1) * PAGE_MAP_BITS))) & PAGE_TABLE_INDEX_MASK) + +static uint64_t new_page_table(void) +{ + EFI_STATUS status; + uint64_t table_address; + + status = e_bs->AllocatePages(AllocateAnyPages, + SystemMemoryType, + 1, + &table_address); + + if (EFI_ERROR(status)) { - Print(L"loaded kernel image at base %16.0x size %d bytes\r\n", - kernel_image->buffer.base, - kernel_image->buffer.size); + Print(L"fatal: failed allocating page table: %r", status); + efi_exit(status); + } + + e_bs->SetMem((void *)table_address, EFI_PAGE_SIZE, 0); + + return table_address; +} + +static void map_page(void *map, + uint64_t virt, + uint64_t phys, + enum page_type type) +{ + uint64_t *this_map = (uint64_t *)map; + uint64_t next_map; + + if (!this_map[page_table_index(virt, 4)]) + { + next_map = new_page_table(); + this_map[page_table_index(virt, 4)] = next_map | 1; + this_map = (uint64_t *)next_map; } else { - Print(L"failed loading kernel image\r\n"); - efi_exit(EFI_ABORTED); + next_map = this_map[page_table_index(virt, 4)]; + next_map &= PAGE_TABLE_ADDRESS_MASK; + this_map = (uint64_t *)next_map; + } + + if (!this_map[page_table_index(virt, 3)]) + { + next_map = new_page_table(); + this_map[page_table_index(virt, 3)] = next_map | 1; + this_map = (uint64_t *)next_map; + } + else + { + next_map = this_map[page_table_index(virt, 3)]; + next_map &= PAGE_TABLE_ADDRESS_MASK; + this_map = (uint64_t *)next_map; + } + + if (!this_map[page_table_index(virt, 2)]) + { + next_map = new_page_table(); + this_map[page_table_index(virt, 2)] = next_map | 1; + this_map = (uint64_t *)next_map; + } + else + { + next_map = this_map[page_table_index(virt, 2)]; + next_map &= PAGE_TABLE_ADDRESS_MASK; + this_map = (uint64_t *)next_map; + } + + this_map[page_table_index(virt, 1)] = phys | type; +} + +enum page_type get_page_type(Elf64_Phdr *phdr) +{ + switch (phdr->p_flags) + { + case (PF_R|PF_X): + return CODE_PAGE_TYPE; + case (PF_R): + return RODATA_PAGE_TYPE; + case (PF_R|PF_W): + return DATA_PAGE_TYPE; + } + + return INVALID_PAGE_TYPE; +} + +static void map_pages(void *map, + uint64_t virt, + uint64_t phys, + enum page_type type, + size_t size) +{ + for (size_t offset = 0; offset < size; offset += EFI_PAGE_SIZE) + { + map_page(map, virt + offset, phys + offset, type); } +} + +static void create_kernel_maps(struct system_image *image) +{ + Elf64_Ehdr *ehdr = &image->ehdr; + Elf64_Phdr *phdrs = image->phdrs; + for (int i = 0; i < ehdr->e_phnum; i++) + { + if (phdrs[i].p_type != PT_LOAD) + { + continue; + } + else + { + uint64_t virt_begin = phdrs[i].p_vaddr; + uint64_t phys_begin = image->buffer.base + phdrs[i].p_paddr; + size_t size = phdrs[i].p_memsz; + Print(L"mapping segment %16.0lx to %16.0lx %d bytes\r\n", + virt_begin, + phys_begin, + size); + map_pages(image->maps, + virt_begin, + phys_begin, + get_page_type(&phdrs[i]), + size); + } + } +} + +static void enter_kernel(struct system_image *kernel_image) +{ + struct efi_boot_data data; kernel_entry_func kernel_entry; - kernel_entry = (kernel_entry_func)(kernel_image->buffer.base + - kernel_image->ehdr.e_entry); + kernel_entry = (kernel_entry_func)(kernel_image->ehdr.e_entry); data.system_table = e_st; data.framebuffer = get_framebuffer_data(); @@ -66,9 +193,50 @@ void loader_main(void) efi_exit(status); } + uint64_t *efi_maps; + uint64_t efi_maps_raw; + + __asm__ ("mov %%cr3, %0" : "=r"(efi_maps_raw)); + efi_maps_raw &= PAGE_TABLE_ADDRESS_MASK; + efi_maps = (uint64_t *)efi_maps_raw; + + ((uint64_t *)kernel_image->maps)[0] = efi_maps[0]; + + __asm__ ( + "cli\n\t" + "mov %0, %%cr3" :: "r"(kernel_image->maps) + ); + kernel_entry(&data); } +void loader_main(void) +{ + + struct system_image *kernel_image = open_system_image(kernel_path); + + Print(L"loading %s\r\n", kernel_path); + + if (load_system_image(kernel_image)) + { + Print(L"loaded kernel image at base %16.0lx size %d bytes\r\n", + kernel_image->buffer.base, + kernel_image->buffer.size); + } + else + { + Print(L"failed loading kernel image\r\n"); + efi_exit(EFI_ABORTED); + } + + kernel_image->maps = (void *)new_page_table(); + create_kernel_maps(kernel_image); + Print(L"kernel maps created. entering kernel\r\n"); + enter_kernel(kernel_image); + + efi_exit(EFI_ABORTED); +} + static bool validate_image(Elf64_Ehdr *ehdr) { if (ehdr->e_ident[EI_MAG0] != ELFMAG0 || @@ -180,7 +348,7 @@ static struct system_buffer get_system_buffer(UINTN size) buffer.size = 0; } - Print(L"allocated system buffer at %16.0x of %d bytes\r\n", + Print(L"allocated system buffer at %16.0lx of %d bytes\r\n", buffer.base, buffer.size); @@ -233,7 +401,8 @@ static bool load_system_image(struct system_image *image) switch (phdrs[i].p_type) { case PT_LOAD: - Print(L"loadable segment at offset %x of %d bytes\r\n", + Print(L"loadable segment %16.0lx at offset %x of %d bytes\r\n", + phdrs[i].p_vaddr, phdrs[i].p_offset, phdrs[i].p_memsz); @@ -345,7 +514,7 @@ static void *get_acpi_rsdp(void) { if (!CompareGuid(&acpi_20_guid, &e_st->ConfigurationTable[i].VendorGuid)) { - Print(L"acpi rsdp: 0x%16.0x\r\n", + Print(L"acpi rsdp: 0x%16.0lx\r\n", e_st->ConfigurationTable[i].VendorTable); return e_st->ConfigurationTable[i].VendorTable; |