static uint32_t contract(uint32_t new_size, heap_t *heap) {
// Sanity check.
ASSERT(new_size < heap->end_address-heap->start_address);
// Get the nearest following page boundary.
if(new_size & 0x1000) {
new_size &= 0x1000;
new_size += 0x1000;
}
// Don't contract too far!
if(new_size < HEAP_MIN_SIZE) {
new_size = HEAP_MIN_SIZE;
}
uint32_t old_size = heap->end_address-heap->start_address;
uint32_t i = old_size - 0x1000;
while(new_size < i) {
free_frame(paging_get_page(heap->start_address+i, 0, kernel_directory));
i -= 0x1000;
pages_wired--;
}
heap->end_address = heap->start_address + new_size;
return new_size;
}
static void expand(uint32_t new_size, heap_t *heap, int size) {
// Sanity check.
ASSERT(new_size > heap->end_address - heap->start_address);
// Get the nearest following page boundary.
if((new_size & 0xFFFFF000) != 0) {
new_size &= 0xFFFFF000;
new_size += 0x1000;
}
// Make sure we are not overreaching ourselves.
ASSERT(heap->start_address+new_size <= heap->max_address);
// This should always be on a page boundary.
uint32_t old_size = heap->end_address-heap->start_address;
// Expand until there is enough pages mapped
uint32_t i = old_size;
// new_size += 0x1000;
while(i < new_size) {
alloc_frame(paging_get_page(heap->start_address+i, true, kernel_directory), (heap->supervisor) ? true : false, true);
i += 0x1000;
pages_wired++;
}
// kprintf("Expanding heap from 0x%X until 0x%X\n", heap->end_address, heap->start_address + new_size);
heap->end_address = heap->start_address+new_size;
}
uint32_t kmalloc_int(uint32_t sz, bool align, uint32_t *phys) {
if(kheap != 0) { // if we have a kernel heap, use that
void *addr = alloc(sz, align, kheap);
if(phys != 0) {
page_t *page = paging_get_page((uint32_t) addr, false, kernel_directory);
uint32_t physAddr = ((page->frame * 0x1000) + ((uint32_t) addr & 0xFFF));
*phys = physAddr;
}
return (uint32_t) addr;
} else { // otherwise, use the 'dumb' allocation
if(align == 1 && (kheap_placement_address & 0xFFFFF000)) {
// Align the placement address;
kheap_placement_address &= 0xFFFFF000;
kheap_placement_address += 0x1000;
} if(phys) {
*phys = kheap_placement_address;
}
uint32_t tmp = kheap_placement_address;
kheap_placement_address += sz;
return tmp;
}
}
/*
* Initialises paging and sets up page tables.
*/
void paging_init() {
kheap = NULL;
unsigned int i = 0;
// Hopefully the bootloader got the correct himem size
uint32_t mem_end_page = sys_multiboot_info->mem_upper * 1024;
nframes = mem_end_page / 0x1000;
pages_total = nframes;
frames = (uint32_t *) kmalloc(INDEX_FROM_BIT(nframes));
memclr(frames, INDEX_FROM_BIT(nframes));
// Allocate mem for a page directory.
kernel_directory = (page_directory_t *) kmalloc_a(sizeof(page_directory_t));
ASSERT(kernel_directory != NULL);
memclr(kernel_directory, sizeof(page_directory_t));
current_directory = kernel_directory;
// Map some pages in the kernel heap area.
// Here we call get_page but not alloc_frame. This causes page_table_t's
// to be created where necessary. We can't allocate frames yet because they
// they need to be identity mapped first below, and yet we can't increase
// placement_address between identity mapping and enabling the heap
for(i = KHEAP_START; i < KHEAP_START+KHEAP_INITIAL_SIZE; i += 0x1000) {
page_t* page = paging_get_page(i, true, kernel_directory);
memclr(page, sizeof(page_t));
page->rw = 1;
page->user = 0;
}
// This step serves to map the kernel itself
// We don't allocate frames here, as that's done below.
for(i = 0xC0000000; i < 0xC7FFF000; i += 0x1000) {
page_t* page = paging_get_page(i, true, kernel_directory);
memclr(page, sizeof(page_t));
page->present = 1;
page->rw = 1;
page->user = 0;
page->frame = ((i & 0x0FFFF000) >> 12);
}
// Allocate enough memory past the kernel heap so we can use the 'smart' allocator.
// Note that this actually performs identity mapping.
i = 0x00000000;
while(i < (kheap_placement_address & 0x0FFFFFFF) + 0x1000) {
alloc_frame(paging_get_page(i, true, kernel_directory), true, true);
if(i < (uint32_t) &__kern_size) {
pages_wired++;
}
i += 0x1000;
}
// Allocate kernel heap pages.
for(i = KHEAP_START; i < KHEAP_START+KHEAP_INITIAL_SIZE; i += 0x1000) {
alloc_frame(paging_get_page(i, false, kernel_directory), true, true);
}
// Set page fault handler
// sys_set_idt_gate(14, (uint32_t) isr14, 0x08, 0x8E);
// Convert kernel directory address to physical and save it
kern_dir_phys = (uint32_t) &kernel_directory->tablesPhysical;
kern_dir_phys -= 0xC0000000;
kernel_directory->physicalAddr = kern_dir_phys;
// Enable paging
paging_switch_directory(kernel_directory);
// Initialise a kernel heap
kheap = create_heap(KHEAP_START, KHEAP_START+KHEAP_INITIAL_SIZE, 0xCFFFF000, true, true);
}
/*
* Links the module into the kernel.
*/
void module_load(void *elf, char *moduleName) {
elf_header_t *header = (elf_header_t *) elf;
elf_section_entry_t *sections = elf + header->sh_offset;
// Verify header
if(ELF_CHECK_MAGIC(header->ident.magic)) {
KERROR("Module '%s' has invalid ELF magic of 0x%X%X%X%X\n", moduleName, header->ident.magic[0], header->ident.magic[1], header->ident.magic[2], header->ident.magic[3]);
goto nextModule;
}
// Variables used for mapping of sections
unsigned int progbits_start = 0, progbits_size = 0, progbits_offset = 0, progbits_size_raw = 0;
unsigned int nobits_start = 0, nobits_size = 0;
// Symbol table
elf_symbol_entry_t *symtab = NULL;
unsigned int symtab_entries = 0;
// String and section string tables
char *strtab = NULL;
char *shstrtab = NULL;
elf_section_entry_t *shstrtab_sec = §ions[header->sh_str_index];
shstrtab = elf + shstrtab_sec->sh_offset;
// Relocation table(s)
unsigned int currentRtab = 0;
struct {
elf_program_relocation_t *rtab;
unsigned int rtab_entries;
} rtabs[16];
// Read the section table
for(unsigned int s = 0; s < header->sh_entry_count; s++) {
elf_section_entry_t *section = §ions[s];
char *section_name = shstrtab + section->sh_name;
// Does this section have physical memory associated with it?
if(section->sh_type == SHT_PROGBITS) {
// Ignore .eh_frame section
if(strcmp(".eh_frame", section_name)) {
progbits_size += section->sh_size;
if(!progbits_offset) {
progbits_offset = section->sh_offset;
}
}
} else if(section->sh_type == SHT_NOBITS) { // NOBITS?
nobits_size += section->sh_size;
// Ensure consecutive NOBITS sections are properly handled
if(!nobits_start) {
nobits_start = section->sh_addr;
}
} else if(section->sh_type == SHT_REL) { // relocation
// Ignore .eh_frame section
if(strcmp(".rel.eh_frame", section_name)) {
rtabs[currentRtab].rtab = elf + section->sh_offset;
rtabs[currentRtab++].rtab_entries = section->sh_size / sizeof(elf_program_relocation_t);
}
} else if(section->sh_type == SHT_SYMTAB) { // symbol table
symtab = elf + section->sh_offset;
symtab_entries = section->sh_size / sizeof(elf_symbol_entry_t);
} else if(section->sh_type == SHT_STRTAB) { // string table
if((elf + section->sh_offset) != shstrtab) {
strtab = elf + section->sh_offset;
}
}
}
// Sane-ify section addresses and sizes
progbits_size_raw = progbits_size;
progbits_size += 0x1000;
progbits_size &= 0xFFFFF000;
progbits_start = module_placement_addr;
// Traverse symbol table to find "module_entry" and "compiler"
unsigned int init_addr = 0;
char *compilerInfo = NULL, *supportedKernel = NULL;
bool entry_found = false;
for(unsigned int s = 0; s < symtab_entries; s++) {
elf_symbol_entry_t *symbol = &symtab[s];
// Look for some symbols
if(symbol->st_info & STT_OBJECT) {
char *name = strtab + symbol->st_name;
// Note how sh_offset is used, as we read out of the loaded elf
if(!strcmp(name, "compiler")) {
elf_section_entry_t *section = §ions[symbol->st_shndx];
compilerInfo = elf + section->sh_offset + symbol->st_address;
} else if(!strcmp(name, "supported_kernel")) {
elf_section_entry_t *section = §ions[symbol->st_shndx];
supportedKernel = elf + section->sh_offset + symbol->st_address;
}
}
}
// Check if we're using compatible compiler versions
if(strcmp(compilerInfo, KERNEL_COMPILER)) {
if(!hal_config_get_bool("module_ignore_compiler")) {
KERROR("'%s' has incompatible compiler of '%s', expected '%s'", moduleName, compilerInfo, KERNEL_COMPILER);
goto nextModule;
} else {
KWARNING("'%s' has incompatible compiler of '%s', but loading anyways", moduleName, compilerInfo);
}
}
// Check if the module is for this kernel version
if(strcmp(supportedKernel, KERNEL_VERSION)) {
if(!hal_config_get_bool("module_ignore_version")) {
KERROR("'%s' requires TSOS version '%s', but kernel is '%s'", moduleName, supportedKernel, KERNEL_VERSION);
goto nextModule;
} else {
KERROR("'%s' requires TSOS version '%s', but kernel is '%s', loading anyways", moduleName, supportedKernel, KERNEL_VERSION);
}
}
/*
* To determine the entry function to initialise this module, we
* depend on the ELF file's entry header field to have the correct
* value. This means that the module's entry point MUST be extern C,
* and be named "start".
*/
unsigned int init_function_addr = progbits_start + header->entry;
/*
* In order for the module to be able to properly call into kernel
* functions, relocation needs to be performed so it has the proper
* addresses for kernel functions.
*
* To do this, the relocation table is searched for entries whose
* type is R_386_PC32, and who are marked as "undefined" in the
* symbol table.
*
* If all of the above conditions are met for a symbol, it's looked
* up in the kernel symbol table. If this lookup fails, module
* loading is aborted, as the module may crash later in hard to
* debug ways if a function is simply left unrelocated.
*/
for(unsigned int u = 0; u < currentRtab; u++) {
elf_program_relocation_t *rtab = rtabs[u].rtab;
unsigned int rtab_entries = rtabs[u].rtab_entries;
// Perform relocation for this rtab.
for(unsigned int r = 0; r < rtab_entries; r++) {
elf_program_relocation_t *ent = &rtab[r];
unsigned int symtab_index = ELF32_R_SYM(ent->r_info);
// Function call relocations?
if(ELF32_R_TYPE(ent->r_info) == R_386_PC32) {
/*
* The ELF spec says that R_386_PC32 relocation entries must
* add the value at the offset to the symbol address, and
* subtract the section base address added to the offset.
*/
// Look up only non-NULL relocations
if(symtab_index != STN_UNDEF) {
// Get symbol in question
elf_symbol_entry_t *symbol = &symtab[symtab_index];
char *name = strtab + symbol->st_name;
unsigned int *ptr = elf + progbits_offset + ent->r_offset;
unsigned int kern_symbol_loc = 0;
// Search the module first
for(unsigned int i = 0; i < symtab_entries; i++) {
elf_symbol_entry_t *entry = &symtab[i];
char *symbol_name = strtab + entry->st_name;
// Symbol found in module?
if(unlikely(!strcmp(name, symbol_name)) && likely(entry->st_shndx != STN_UNDEF)) {
kern_symbol_loc = (entry->st_address + module_placement_addr);
*ptr = kern_symbol_loc + *ptr - (module_placement_addr + ent->r_offset);
#if DEBUG_MOBULE_RELOC
KDEBUG("0x%08X -> 0x%08X (%s, module)", (unsigned int) ent->r_offset, *ptr, name);
#endif
goto linkNext;
}
}
// We drop down here if the symbol isn't in the module
kern_symbol_loc = find_symbol_in_kernel(name);
if(kern_symbol_loc) {
// Perform the relocation.
*ptr = kern_symbol_loc + *ptr - (module_placement_addr + ent->r_offset);
#if DEBUG_MOBULE_RELOC
KDEBUG("0x%08X -> 0x%08X (%s, kernel)", (unsigned int) ent->r_offset, *ptr, name);
#endif
} else {
KERROR("Module %s references '%s', but symbol does not exist", moduleName, name);
goto nextModule;
}
} else {
KERROR("Module %s has undefined linkage", moduleName);
goto nextModule;
}
} else if(ELF32_R_TYPE(ent->r_info) == R_386_32) {
/*
* The ELF spec says that R_386_32 relocation entries must
* add the value at the offset to the symbol address.
*/
elf_symbol_entry_t *symbol = &symtab[symtab_index];
// If name = 0, relocating section
if(symbol->st_name == 0) {
// Get the section requested
unsigned int sectionIndex = symbol->st_shndx;
elf_section_entry_t *section = §ions[sectionIndex];
char *name = shstrtab + section->sh_name;
// Get virtual address of the section
unsigned int addr = section->sh_addr + module_placement_addr;
// Perform relocation
unsigned int *ptr = elf + progbits_offset + ent->r_offset;
*ptr = addr + *ptr;
#if DEBUG_MOBULE_RELOC
KDEBUG("0x%08X -> 0x%08X (section: %s+0x%X)", (unsigned int) ent->r_offset, *ptr, name, *ptr - addr);
#endif
} else {
// Get symbol name and a placeholder address
char *name = strtab + symbol->st_name;
unsigned int addr = 0;
#if DEBUG_MOBULE_RELOC
bool inKernel = false;
#endif
// Search through the module's symbols first
for(unsigned int i = 0; i < symtab_entries; i++) {
elf_symbol_entry_t *entry = &symtab[i];
char *symbol_name = strtab + entry->st_name;
// Symbol found in module?
if(unlikely(!strcmp(name, symbol_name)) && likely(entry->st_shndx != STN_UNDEF)) {
addr = entry->st_address + module_placement_addr;
// Take into account the section's address
elf_section_entry_t *section = §ions[symbol->st_shndx];
addr += section->sh_addr;
// Go to the relocation code
#if DEBUG_MOBULE_RELOC
inKernel = false;
#endif
goto R_386_32_reloc_good;
}
}
// See if the kernel has the symbol
if(unlikely(!(addr = find_symbol_in_kernel(name)))) {
KERROR("Module %s references '%s', but symbol does not exist", moduleName, name);
goto nextModule;
}
#if DEBUG_MOBULE_RELOC
inKernel = true;
#endif
// Perform relocation
R_386_32_reloc_good: ;
unsigned int *ptr = elf + progbits_offset + ent->r_offset;
*ptr = addr + *ptr;
#if DEBUG_MOBULE_RELOC
KDEBUG("0x%08X -> 0x%08X (%s, %s)", (unsigned int) ent->r_offset, addr, name, inKernel ? "kernel" : "module");
#endif
}
}
// Drop down here to link the next symbol
linkNext: ;
}
}
// Move PROGBITS from the file forward however many bytes the offset is
memmove(elf, elf+progbits_offset, progbits_size_raw);
// Perform mapping for the PROGBITS section
#if DEBUG_MODULE_MAPPING
KDEBUG("Mapping PROGBITS from 0x%08X to 0x%08X", module_placement_addr, module_placement_addr+progbits_size);
#endif
unsigned int progbits_end = module_placement_addr + progbits_size;
for(unsigned int a = module_placement_addr; a < progbits_end; a += 0x1000) {
unsigned int progbits_offset = a - module_placement_addr;
unsigned int progbits_virt_addr = ((unsigned int) elf) + progbits_offset;
// Get the page whose physical address we want
page_t *elf_page = paging_get_page(progbits_virt_addr, false, kernel_directory);
// Create a page in the proper virtual space, and assign physical address of above
page_t *new_page = paging_get_page(a, true, kernel_directory);
new_page->rw = 1;
new_page->present = 1;
new_page->frame = elf_page->frame;
// KDEBUG("0x%08X -> 0x%08X (0x%08X)", a, progbits_offset, progbits_virt_addr);
}
module_placement_addr += progbits_size;
// Perform mapping for NOBITS section, if needed
if(nobits_size) {
nobits_size += 0x1000;
nobits_size &= 0xFFFFF000;
unsigned int nobits_end = module_placement_addr+nobits_size;
#if DEBUG_MODULE_MAPPING
KDEBUG("Mapping NOBITS from 0x%08X to 0x%08X", module_placement_addr, nobits_end);
#endif
// Map the pages, and allocate memory to them
for(unsigned a = module_placement_addr; a < nobits_end; a += 0x1000) {
page_t *page = paging_get_page(a, true, kernel_directory);
alloc_frame(page, true, true);
// Zero the memory
memclr((void *) a, 4096);
}
nobits_start = module_placement_addr;
module_placement_addr += nobits_size;
} else {
#if DEBUG_MODULE_MAPPING
KDEBUG("NOBITS section not required");
#endif
}
// Initialise driver
module_t *driver = ((module_t* (*)(void)) init_function_addr)();
// Save locations
driver->progbits_start = progbits_start;
driver->map_end = module_placement_addr-1;
// If there's no BSS, leave the nobits_start empty
if(nobits_size) {
driver->nobits_start = nobits_start;
} else {
driver->nobits_start = 0;
}
// Register them
list_add(loaded_module_names, (char *) driver->name);
hashmap_insert(loaded_module_map, (char *) driver->name, driver);
// Drop down here when the module is all happy
nextModule: ;
}