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-rw-r--r--kernel/include/libk/string.h1
-rw-r--r--kernel/include/paging.h7
-rw-r--r--kernel/src/boot/multiboot2.c6
-rw-r--r--kernel/src/cpu/irq.c2
-rw-r--r--kernel/src/libk/stdio.c8
-rw-r--r--kernel/src/libk/string.c29
-rw-r--r--kernel/src/main.c2
-rw-r--r--kernel/src/mem/paging.c69
8 files changed, 98 insertions, 26 deletions
diff --git a/kernel/include/libk/string.h b/kernel/include/libk/string.h
index 64a7f81..9fe8448 100644
--- a/kernel/include/libk/string.h
+++ b/kernel/include/libk/string.h
@@ -6,6 +6,7 @@
size_t strlen(const char* s);
uint64_t stoi(const char *s);
void itos(uint64_t num, char* s);
+void itoh(uint64_t num, char* s);
void strrev(char *s);
#endif
diff --git a/kernel/include/paging.h b/kernel/include/paging.h
index a61d34d..7c9fcd5 100644
--- a/kernel/include/paging.h
+++ b/kernel/include/paging.h
@@ -3,7 +3,14 @@
#include <types.h>
+#define PAGE_SIZE 0x00200000
+#define FLAG_PRESENT 0x1
+#define FLAG_WRITABLE 0x2
+#define FLAG_HUGE 0x80
+#define KERNEL_VMA 0xc0000000
+
void init_paging(void);
+void map_addr(uint64_t virt, uint64_t phys, uint32_t flags);
void page_fault(uint64_t error);
#endif
diff --git a/kernel/src/boot/multiboot2.c b/kernel/src/boot/multiboot2.c
index 75a1f8d..9c2998f 100644
--- a/kernel/src/boot/multiboot2.c
+++ b/kernel/src/boot/multiboot2.c
@@ -3,6 +3,7 @@
#include <graphics.h>
#include <debug.h>
+#include <paging.h>
#define KERNEL_VMA 0xc0000000
@@ -20,7 +21,6 @@ void init_fb(mb2_tag_header* multiboot_bootinfo, uint32_t multiboot_magic)
// skip first 8 bytes (total_size + reserved)
mb2_tag_header* tag_header = (mb2_tag_header*)((char*)multiboot_bootinfo + 8 + KERNEL_VMA);
- bochs_breakpoint();
while (tag_header->type != MB2_TAG_END) {
// process tag_type
@@ -41,4 +41,8 @@ void init_fb(mb2_tag_header* multiboot_bootinfo, uint32_t multiboot_magic)
main_fb.height = tag_fb->framebuffer_height;
main_fb.pitch = tag_fb->framebuffer_pitch;
main_fb.bpp = tag_fb->framebuffer_bpp;
+
+ // identity map framebuffer address
+ map_addr(main_fb.addr, main_fb.addr, FLAG_PRESENT + FLAG_WRITABLE + FLAG_HUGE);
+ map_addr(main_fb.addr + PAGE_SIZE, main_fb.addr + PAGE_SIZE, FLAG_PRESENT + FLAG_WRITABLE + FLAG_HUGE);
}
diff --git a/kernel/src/cpu/irq.c b/kernel/src/cpu/irq.c
index be0d2a2..dd87b61 100644
--- a/kernel/src/cpu/irq.c
+++ b/kernel/src/cpu/irq.c
@@ -119,8 +119,8 @@ void isr13_handler(uint64_t error)
void isr14_handler(uint64_t error)
{
+ page_fault(error);
printf("%s\n", exception_name[14]);
- printf("error: %d\n", error);
}
void isr15_handler(void)
diff --git a/kernel/src/libk/stdio.c b/kernel/src/libk/stdio.c
index b8ddb67..be75b73 100644
--- a/kernel/src/libk/stdio.c
+++ b/kernel/src/libk/stdio.c
@@ -47,6 +47,13 @@ inline void print_int(uint64_t num)
print_string(a);
}
+inline void print_hex(uint64_t num)
+{
+ char a[100];
+ itoh(num, a);
+ print_string(a);
+}
+
void printf(const char *s, ...)
{
size_t count = 0;
@@ -63,6 +70,7 @@ void printf(const char *s, ...)
if(s[i] == 'c') print_char((char)va_arg(list, uint32_t));
else if(s[i] == 's') print_string(va_arg(list, char*));
else if(s[i] == 'd') print_int((uint64_t)va_arg(list, uint64_t));
+ else if(s[i] == 'x') print_hex((uint64_t)va_arg(list, uint64_t));
else
{
print_string("Wrong format using printf\n");
diff --git a/kernel/src/libk/string.c b/kernel/src/libk/string.c
index fde9645..6d7ab69 100644
--- a/kernel/src/libk/string.c
+++ b/kernel/src/libk/string.c
@@ -35,9 +35,34 @@ void strrev(char *s)
void itos(uint64_t num, char* s)
{
+ if (num == 0) {
+ s[0] = '0';
+ s[1] = '\0';
+ return;
+ }
+
+ size_t i;
+ for (i = 0; num; num /= 10, i++) {
+ s[i] = (char)('0' + num % 10);
+ }
+ s[i] = '\0';
+ strrev(s);
+}
+
+void itoh(uint64_t num, char* s)
+{
+ if (num == 0) {
+ s[0] = '0';
+ s[1] = '\0';
+ return;
+ }
+
size_t i;
- for (i = 0; num; num/=10, i++) {
- s[i] = (char)('0' + num%10);
+ for (i = 0; num; num /= 16, i++) {
+ if (num % 16 < 10)
+ s[i] = (char)('0' + num % 16);
+ else
+ s[i] = (char)('A' + num % 16 - 10);
}
s[i] = '\0';
strrev(s);
diff --git a/kernel/src/main.c b/kernel/src/main.c
index 80b0d6a..b562c74 100644
--- a/kernel/src/main.c
+++ b/kernel/src/main.c
@@ -16,7 +16,7 @@ int kernel_main(mb2_tag_header* multiboot_bootinfo, uint32_t multiboot_magic)
init_idt();
init_fb(multiboot_bootinfo, multiboot_magic);
- __asm__ volatile ("int $2;");
+ __asm__ volatile ("movl $4, 0x500000");
for(;;) {
__asm__ volatile ("hlt;");
diff --git a/kernel/src/mem/paging.c b/kernel/src/mem/paging.c
index fdd1dd2..cd1cb68 100644
--- a/kernel/src/mem/paging.c
+++ b/kernel/src/mem/paging.c
@@ -2,42 +2,69 @@
#include <paging.h>
#include <libk/stdio.h>
+#include <debug.h>
void load_pt_lvl4(uint64_t*);
__attribute__((aligned(4096))) uint64_t page_table_lvl4[512];
__attribute__((aligned(4096))) uint64_t page_table_lvl3[512];
-__attribute__((aligned(4096))) uint64_t page_table_lvl2_hh[512];
+__attribute__((aligned(4096))) uint64_t page_table_lvl2_0[512];
+__attribute__((aligned(4096))) uint64_t page_table_lvl2_1[512];
+__attribute__((aligned(4096))) uint64_t page_table_lvl2_2[512];
+__attribute__((aligned(4096))) uint64_t page_table_lvl2_3[512];
-#define PAGE_SIZE 0x00200000
-#define FLAG_PRESENT 0x1
-#define FLAG_WRITABLE 0x2
-#define FLAG_HUGE 0x80
-#define KERNEL_VMA 0xc0000000
-
-void init_paging(void)
+void map_addr(uint64_t virt, uint64_t phys, uint32_t flags)
{
- page_table_lvl4[0] = (uint64_t)page_table_lvl3 + FLAG_PRESENT + FLAG_WRITABLE - KERNEL_VMA;
- page_table_lvl3[3] = (uint64_t)page_table_lvl2_hh + FLAG_PRESENT + FLAG_WRITABLE - KERNEL_VMA;
+ virt -= virt % 0x00200000;
+ phys -= phys % 0x00200000;
- // higher half kernel
- // 0xc0000000 - 0xc0400000 : 0xc0000000 - 0xc0400000
- for (uint64_t i = 0; i < 2; i++) {
- page_table_lvl2_hh[i] = i * PAGE_SIZE + FLAG_PRESENT + FLAG_WRITABLE + FLAG_HUGE;
+ // i is in range [0, 511]
+ size_t pt_lvl4_i = (virt >> 39) % 0x200; // 512gb entry
+ size_t pt_lvl3_i = (virt >> 30) % 0x200; // 1gb entry
+ size_t pt_lvl2_i = (virt >> 21) % 0x200; // 2mb entry
+// size_t pt_lvl1_i = (virt >> 12) % 0x200; // 4kb entry
+
+ // first 4gb
+ if (pt_lvl4_i == 0) {
+ switch(pt_lvl3_i) {
+ case 0:
+ page_table_lvl2_0[pt_lvl2_i] = phys | flags;
+ break;
+ case 1:
+ page_table_lvl2_1[pt_lvl2_i] = phys | flags;
+ break;
+ case 2:
+ page_table_lvl2_2[pt_lvl2_i] = phys | flags;
+ break;
+ case 3:
+ page_table_lvl2_3[pt_lvl2_i] = phys | flags;
+ break;
+ }
}
+}
- // TODO: remove initial mapping for fb and instead page on demand
+void init_paging(void)
+{
+ page_table_lvl4[0] = (uint64_t)page_table_lvl3 + FLAG_PRESENT + FLAG_WRITABLE - KERNEL_VMA;
+ page_table_lvl3[0] = (uint64_t)page_table_lvl2_0 + FLAG_PRESENT + FLAG_WRITABLE - KERNEL_VMA;
+ page_table_lvl3[1] = (uint64_t)page_table_lvl2_1 + FLAG_PRESENT + FLAG_WRITABLE - KERNEL_VMA;
+ page_table_lvl3[2] = (uint64_t)page_table_lvl2_2 + FLAG_PRESENT + FLAG_WRITABLE - KERNEL_VMA;
+ page_table_lvl3[3] = (uint64_t)page_table_lvl2_3 + FLAG_PRESENT + FLAG_WRITABLE - KERNEL_VMA;
- // identity paged for fb
- // 0xe0000000 - 0xffffffff : 0xe0000000 - 0xffffffff
- for (uint64_t i = 2; i < 512; i++) {
- page_table_lvl2_hh[i] = i * PAGE_SIZE + 0xc0000000 + FLAG_PRESENT + FLAG_WRITABLE + FLAG_HUGE;
- }
+ // higher half map first 4mb
+ map_addr(KERNEL_VMA, 0x00000000, FLAG_PRESENT + FLAG_WRITABLE + FLAG_HUGE);
+ map_addr(KERNEL_VMA + PAGE_SIZE, 0x00000000 + PAGE_SIZE, FLAG_PRESENT + FLAG_WRITABLE + FLAG_HUGE);
load_pt_lvl4(page_table_lvl4);
}
+
void page_fault(uint64_t error)
{
- printf("%d\n", error);
+ uint64_t addr;
+ __asm__ volatile ("mov %%cr2, %0" : "=r"(addr) : : "memory");
+
+ map_addr(addr, addr, FLAG_PRESENT | FLAG_WRITABLE | FLAG_HUGE);
+
+ printf("address: 0x%x, error code: %d\n", addr, error);
}
generated by cgit v1.2.3 (git 2.46.0) at 2025-12-17 08:49:49 +0000