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Back to flat segmentation model

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This commit is contained in:
Maciej Krzyżanowski 2023-11-07 21:15:57 +01:00
parent ee09437fb1
commit 0f8bbb8b10
2 changed files with 22 additions and 36 deletions
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11
boot.s
View File

@ -51,17 +51,6 @@ mov $stack_top, %esp
/* Wywołanie kernela */
call kernel_main
mov $0x10, %ax
mov %ax, %ds
mov %ax, %es
mov %ax, %fs
mov %ax, %gs
mov %ax, %ss
jmp $0x08,$cs_refresh
cs_refresh:
mov $0x4000, %esp
push $5
/* Wieczne oczekiwanie po zakończeniu kodu kernela */
cli
1: hlt

47
kernel.c
View File

@ -187,12 +187,13 @@ void terminal_writenumpad(uint64_t number, int base, int pad_length)
number = rest;
}
}
// Write pad_length - size of zeros
// If padding won't be needed (number is longer than pad_legnth)
// then loop won't run at all
while (pad_length > size) {
numChars[31 - size++] = digits[0];
while (pad_length > size)
{
numChars[31 - size++] = digits[0];
}
terminal_write(numChars + (32 - size), size);
@ -355,7 +356,7 @@ void apply_table(struct gdt_table table)
*dest_address = entry_encoded;
}
__asm__("lgdt (%0)" : : "r" (&table));
__asm__("lgdt (%0)": :"r"(&table));
}
void print_texts()
@ -381,8 +382,8 @@ void print_texts()
size_t start_point;
__asm__("mov $_start, %%eax": : :"eax");
__asm__("mov %%eax, %0;": "=r"(start_point):);
__asm__("mov $_start, %%eax": : :"eax");
__asm__("mov %%eax, %0;": "=r"(start_point):);
terminal_writestring("\n\nPoczatek kernela:\n");
terminal_writenum(start_point, 10);
@ -396,40 +397,36 @@ void print_texts()
void gdt_setup()
{
struct gdt_entry kernel_code_entry =
gdt_entry_create(0, 0x400, KERNEL_SEGMENT, CODE_SEGMENT);
gdt_entry_create(0x0, 0x100000, KERNEL_SEGMENT, CODE_SEGMENT);
struct gdt_entry kernel_data_entry =
gdt_entry_create(0x400, 0x400, KERNEL_SEGMENT, DATA_SEGMENT);
gdt_entry_create(0x0, 0x100000, KERNEL_SEGMENT, DATA_SEGMENT);
struct gdt_entry user_code_entry =
gdt_entry_create(0x800, 0x400, USER_SEGMENT, CODE_SEGMENT);
gdt_entry_create(0x0, 0x100000, USER_SEGMENT, CODE_SEGMENT);
struct gdt_entry user_data_entry =
gdt_entry_create(0xC00, 0x400, USER_SEGMENT, DATA_SEGMENT);
gdt_entry_create(0x0, 0x100000, USER_SEGMENT, DATA_SEGMENT);
struct gdt_table gdt_table;
gdt_table.size_in_bytes = 39;
gdt_table.dest_pointer = (uint64_t*)0x400000;
gdt_table.size_in_bytes = 39;
gdt_table.dest_pointer = (uint64_t *) 0x400000;
gdt_table.entries[0] = kernel_code_entry;
gdt_table.entries[1] = kernel_data_entry;
gdt_table.entries[2] = user_code_entry;
gdt_table.entries[3] = user_data_entry;
apply_table(gdt_table);
terminal_writestring("GDT table applied\n");
__asm__ volatile(
"mov $stack_bottom, %%esi;"
"mov $0x500000, %%edi;"
"mov $16384, %%ecx;"
"cld;"
"rep movsb;"
:
:
:
"esi","edi","ecx"
"mov $0x10, %ax;"
"mov %ax, %ds;"
"mov %ax, %es;"
"mov %ax, %fs;"
"mov %ax, %gs;"
"mov %ax, %ss;"
"jmp $0x08,$csrefresh;"
);
__asm__(
"xchg %bx, %bx"
);
__asm__ volatile("csrefresh:");
}
void kernel_main(void)