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unmap lower kernel and some fixes

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This commit is contained in:
rami 2024-07-04 23:44:13 -04:00
parent b2b1fc59b7
commit 7eec8729e3
3 changed files with 27 additions and 12 deletions
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9
kernel/init.asm
View File

@ -34,7 +34,7 @@ _start:
mov edx, 0
.fill_table:
mov ecx, edx
or ecx, 3
or ecx, 7
mov [boot_page_tab-0xC0000000+eax*4], ecx
add edx, 0x1000
inc eax
@ -43,7 +43,7 @@ _start:
mov ecx, boot_page_tab
sub ecx, 0xC0000000
or ecx, 3
or ecx, 7
mov [boot_page_dir-0xC0000000], ecx
mov [boot_page_dir-0xC0000000+768*4], ecx
@ -59,6 +59,11 @@ _start:
section .text
higher_half:
; Un-identity-map kernel
mov dword [boot_page_dir], 2
; Add KERNEL_VMA to the address of the multiboot info struct
add ebx, 0xC0000000
; Load GDT
lgdt [gdtp]
; Offset to kernel data descriptor

16
kernel/kernel.c
View File

@ -37,11 +37,13 @@ typedef struct {
uint32_t cr3;
} task_t;
#define KERNEL_VMA 0xC0000000
void kernel(multiboot_info_t *info) {
if (!CHECK_FLAG(info->flags, 3)) goto halt; // Modules
if (!CHECK_FLAG(info->flags, 6)) goto halt; // Memory map
if (!CHECK_FLAG(info->flags, 12)) goto halt; // VBE data
ctx.multi_mmap = (multi_mmap_t *)info->memmapaddress;
ctx.multi_mmap = (multi_mmap_t *)(info->memmapaddress + KERNEL_VMA);
ctx.multi_mmap_size = info->memmaplength;
if (serial_port_init(COM1)) ctx.log_method = LOG_COM1;
@ -60,7 +62,6 @@ void kernel(multiboot_info_t *info) {
asm volatile ("lidt %0" :: "m"(idtr));
pic_remap(PIC_1_START, PIC_2_START);
/*
asm volatile ("sti" ::);
ctx.ticks = 0;
@ -76,11 +77,12 @@ void kernel(multiboot_info_t *info) {
gdt[5].granularity |= 0x40;
gdt[5].access = 0x89;
tss.ss0 = GDT_SEGMENT_SELECTOR(2, RING0);
tss.esp0 = 0;
uint32_t esp0 = 0;
asm volatile ("mov %%esp, %0" : "=r" (esp0));
tss.esp0 = esp0;
tss.cs = GDT_SEGMENT_SELECTOR(3, RING3);
tss.ss = tss.ds = tss.es = tss.fs = tss.gs = GDT_SEGMENT_SELECTOR(4, RING3);
flush_tss(GDT_SEGMENT_SELECTOR(5, RING3));
*/
#define PAGE_PRESENT (1<<0)
#define PAGE_RW (1<<1)
@ -91,10 +93,10 @@ void kernel(multiboot_info_t *info) {
#define PAGE_OFFSET(x) ((x) & 0xFFF)
uint32_t stack = (uint32_t)mmap_find_first_free_block();
multi_mod_t *init = (multi_mod_t *)info->moduleaddress;
LOG("Switching to ring 3... EIP: 0x%08X ESP: 0x%08X\n", init->mod_start, stack+0x1000);
multi_mod_t *init = (multi_mod_t *)(info->moduleaddress + KERNEL_VMA);
LOG("Switching to ring 3... EIP: 0x%08X ESP: 0x%08X\n", init->mod_start+KERNEL_VMA, stack+0x1000);
//jmp_user_mode(stack+0x1000, init->mod_start);
jmp_user_mode(stack+0x1000, init->mod_start+KERNEL_VMA);
halt:
for (;;) {}

14
kernel/mem.c
View File

@ -13,8 +13,13 @@ void *mmap_block_to_physical(int block) {
uint32_t len = (uint32_t)(entry.len);
uint32_t addr = (uint32_t)(entry.addr);
if (len > offset)
return (void *)(addr + offset);
if (len > offset) {
uint32_t phys = (addr + offset);
if (phys < 0x00400000) {
return (void *)(phys + 0xC0000000);
}
return (void *)phys;
}
}
return 0;
@ -67,7 +72,10 @@ uint8_t mmap_init(void) {
// Create map
struct multiboot_mmap_entry entry = ctx.multi_mmap[index];
//uint32_t addr = (uint32_t)(entry.addr_low | entry.addr_high);
ctx.mmap = (uint32_t *)(uint32_t)(entry.addr & 0xffffffff);
if ((uint32_t)(entry.addr & UINT32_MAX) < 0x00400000)
ctx.mmap = (uint32_t *)((uint32_t)(entry.addr & UINT32_MAX) + 0xC0000000);
else
ctx.mmap = (uint32_t *)(uint32_t)(entry.addr & 0xffffffff);
// Zero the map
memset(ctx.mmap, 0, ctx.mmap_size);
// Reserve the blocks that hold the memory map + 1