diff options
Diffstat (limited to 'arch/x86_64/usermode.c')
| -rw-r--r-- | arch/x86_64/usermode.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/arch/x86_64/usermode.c b/arch/x86_64/usermode.c new file mode 100644 index 0000000..9ce5ed3 --- /dev/null +++ b/arch/x86_64/usermode.c @@ -0,0 +1,184 @@ +#include "arch/x86_64/object.h" +#include "object.h" +#include "memory.h" +#include "bootargs.h" +#include "device/initrd.h" +#include "object.h" +#include "panic.h" +#include "string.h" +#include "print.h" +#include "device/processor.h" +#include "arch/x86_64/page.h" + +static tcb_t s_init_tcb; + +//Dynamic allocation hell!!! +static uintptr_t +s_new_mapping(objdir_t *untyped_dir) +{ + objdir_entry_t *untyped_entry = NULL; + for(int i = 1; i < OBJECT_DIRECTORY_MAX_ENTRIES; i++) { + untyped_entry = &untyped_dir->entries[i]; + if(untyped_entry->type != KO_MEMORY_UNTYPED) continue; + uintptr_t mapping = 0; + int err = untyped_retype_page(untyped_entry, (void**)&mapping); + if(err != 0) continue; + return mapping; + } + return 0; +} + +static uintptr_t +s_new_kstack(objdir_t *untyped_dir, objdir_entry_t *dest_entry) +{ + objdir_entry_t *untyped_entry = NULL; + for(int i = 1; i < OBJECT_DIRECTORY_MAX_ENTRIES; i++) { + untyped_entry = &untyped_dir->entries[i]; + if(untyped_entry->type != KO_MEMORY_UNTYPED) continue; + + int err = untyped_retype_kernel_stack(untyped_entry, dest_entry); + if(err != 0) continue; + + uintptr_t ptr = dest_entry->data; + return (uintptr_t)vmem_phys_tovirt(ptr); + } + return 0; +} + +static pmle_t* +s_ensure_mapping_layer(pmle_t *pml, objdir_t *untyped_dir, uintptr_t addr, uint8_t layer) +{ + pmli_t pmli = PML_I_FOR_LAYER(addr, layer); + if(pml[pmli].p) + return pmle_get_page(pml[pmli]); + + uintptr_t table_phys = s_new_mapping(untyped_dir); + pmle_t *table = vmem_phys_tovirt(table_phys); + memset(table, 0, 0x1000); + + pml[pmli] = (pmle_t) { + .p = 1, + .rw = 1, + .us = 1, + .paddr = table_phys >> 12 + }; + __asm__ volatile("invlpg (%0)":: "r"(table_phys)); + return vmem_phys_tovirt(table_phys); +} + +static void +s_map_page(pmle_t *pml4, objdir_t *untyped_dir, uintptr_t addr) +{ + pmle_t *pml3 = s_ensure_mapping_layer(pml4, untyped_dir, addr, 4); + pmle_t *pml2 = s_ensure_mapping_layer(pml3, untyped_dir, addr, 3); + pmle_t *pml1 = s_ensure_mapping_layer(pml2, untyped_dir, addr, 2); + + pmli_t pml1i = PML_I_FOR_LAYER(addr, 1); + pmle_t *pmle = &pml1[pml1i]; + + uintptr_t pptr = s_new_mapping(untyped_dir); + + *pmle = (pmle_t) { + .p = 1, + .rw = 1, + .us = 1, + .paddr = pptr >> 12 + }; + __asm__ volatile("invlpg (%0)":: "r"(addr)); +} + +__attribute__((noreturn)) +static void +s_enter_usermode(void *ip, void *sp) +{ + __asm__ volatile("mov %0, %%rsp; \ + movq %1, %%rcx; \ + movq $0x202, %%r11; \ + cli; \ + swapgs; \ + sysretq":: + "r"(sp), "r"(ip): "memory"); + for(;;); +} + +void +init_load(void) +{ + const char *init_filename = bootargs_getarg("init"); + if(init_filename == NULL) { + kpanic("Missing boot argument \"init\""); + } + tar_header_t *init_header = initrd_find_file(init_filename); + if(init_header == NULL) { + kpanic("Init file not found in initrd. (expected \"%s\")", init_filename); + } + + size_t tcb_diri = _initDirectory.self.data++; + size_t kstack_diri = _initDirectory.self.data++; + size_t message_diri = _initDirectory.self.data++; + + _initData.tcb_object = tcb_diri; + _initData.kernel_stack_object = kstack_diri; + _initData.message_object = message_diri; + + _initDirectory.entries[tcb_diri] = (objdir_entry_t) { + .type = KO_TCB, + .data = (uintptr_t)&s_init_tcb + }; + + size_t untyped_diri = _initData.untyped_data_dir; + objdir_t *untyped_dir = (objdir_t*)_initDirectory.entries[untyped_diri].data; + + size_t pml4_diri = _initData.pm_object; + pmle_t *pml4 = vmem_phys_tovirt(_initDirectory.entries[pml4_diri].data); + + //Reserve and map pages for init binary + size_t init_size = initrd_file_size(init_header); + + size_t init_pages = (init_size >> 12); + uintptr_t init_base = 0x1000; + + for(size_t i = 0; i < init_pages + 1; i++) { + s_map_page(pml4, untyped_dir, init_base + (i * 0x1000)); + } + //Copy over init data + memcpy((void*)init_base, (&((tar_block_t*)init_header)[1])->data, init_size); + + //Create a user stack + uintptr_t stack_base = 0x00007FFFFFFFF000; + s_map_page(pml4, untyped_dir, stack_base); + uintptr_t sp = stack_base + 0xFF0; + + //Create a kernel stack for the init TCB + uintptr_t ksp_base = (uintptr_t)s_new_kstack(untyped_dir, &_initDirectory.entries[kstack_diri]); + _initDirectory.entries[kstack_diri] = (objdir_entry_t) { + .type = KO_KERNEL_STACK, + .data = ksp_base + }; + s_init_tcb.ksp = ksp_base + 0xFF0; + + processor_t *proc = (processor_t*)processor_current(); + proc->tss.rsp[0] = ksp_base; + + //Create a message object for init + uintptr_t message_base = init_base + (init_pages << 12); + message_base += ((~(message_base & 0xFFF)) & 0xFFF) + 1; + + s_map_page(pml4, untyped_dir, message_base); + _initDirectory.entries[message_diri] = (objdir_entry_t) { + .type = KO_MESSAGE, + .data = message_base + }; + _initData.message_object_address = message_base; + + //Write init data to user stack. + sp -= sizeof(init_data_t); + memcpy((void*)sp, &_initData, sizeof(init_data_t)); + sp -= sizeof(uintptr_t); + *((uintptr_t*)sp) = sp + sizeof(uintptr_t); + + //Setup usermode and jump + proc->tcb = &s_init_tcb; + proc->tss.rsp[0] = s_init_tcb.ksp; + s_enter_usermode((void*)init_base, (void*)sp); +} |