Non-dynamic working approach

5 files changed, 52 insertions, 61 deletions

diff --git a/src/kernel/fs/elf.c b/src/kernel/fs/elf.c
index a67ab6a..ba9251a 100644
--- a/src/kernel/fs/elf.c
+++ b/src/kernel/fs/elf.c
@@ -25,6 +25,12 @@ int is_elf(struct elf_header *header)
 
 struct process *elf_load(char *path)
 {
+	u32 *prev_dir;
+	if (current_proc)
+		prev_dir = current_proc->cr3;
+	else
+		prev_dir = current_page_directory;
+
 	u8 *file = read_file(path);
 	if (!file) {
 		warn("File or directory not found: %s", path);
@@ -71,6 +77,6 @@ struct process *elf_load(char *path)
 		}
 	}
 
-	paging_switch_directory(paging_kernel_directory);
+	paging_switch_directory(prev_dir);
 	return proc;
-}
\ No newline at end of file
+}
diff --git a/src/kernel/memory/paging.c b/src/kernel/memory/paging.c
index 516f0f1..de93ffb 100644
--- a/src/kernel/memory/paging.c
+++ b/src/kernel/memory/paging.c
@@ -4,57 +4,47 @@
 #include <stdint.h>
 #include <system.h>
 
-int paging_enabled = 0;
+u32 *current_page_directory;
+u32 (*current_page_tables)[1024];
+u32 kernel_page_directory[1024] __attribute__((aligned(4096)));
+u32 kernel_page_tables[1024][1024] __attribute__((aligned(4096)));
 
-u32 tmp[1024][1024] __attribute__((aligned(4096)));
-struct page_directory *paging_kernel_directory __attribute__((aligned(4096))) =
-	(struct page_directory *)tmp;
-struct page_directory *paging_directory __attribute__((aligned(4096))); // Current
-
-void paging_init(struct page_directory *dir, int user)
+void paging_init(u32 *dir, int user)
 {
 	for (u32 i = 0; i < 1024; i++) {
 		for (u32 j = 0; j < 1024; j++) {
-			dir->tables[i]->pages[j] =
-				((j * 0x1000) + (i * PAGE_SIZE)) | PT_RW | (user ? PT_USER : 0);
+			current_page_tables[i][j] = ((j * 0x1000) + (i * 0x400000)) | PT_RW;
 		}
 	}
 
 	for (u32 i = 0; i < 1024; i++) {
-		dir->tables[i] = ((u32)dir->tables[i]) | PD_RW | PD_PRESENT | (user ? PD_USER : 0);
+		current_page_directory[i] = ((u32)current_page_tables[i]) | PD_RW | PD_PRESENT;
 	}
 }
 
-struct page_directory *paging_make_directory(int user)
-{
-	struct page_directory *dir = (struct page_directory *)malloc(sizeof(struct page_directory));
-
-	paging_init(dir, user);
-
-	return dir;
-}
-
 extern void KERNEL_END();
 void paging_install(u32 multiboot_address)
 {
-	paging_switch_directory(paging_kernel_directory);
-	paging_init(paging_directory, 0);
+	paging_switch_directory(kernel_page_directory);
+	paging_init(current_page_directory, 0);
 
+	// if mmap approach didn't work
 	if (!memory_init(multiboot_address))
-		paging_set_present(0, memory_get_all() >> 3);
+		paging_set_present(0, memory_get_all() >> 3); // /4
 	paging_set_used(0, ((u32)KERNEL_END >> 12) + 1); // /4096
+	// paging_set_user(0, memory_get_all() >> 3); // HMM
 
-	log("Enabling");
 	paging_enable();
 	log("Installed paging");
+}
+
+u32 *paging_make_directory(int user)
+{
+	u32 *dir = malloc(1024 * 1024 * 32);
 
-	u32 a = (u32)malloc(4096);
-	u32 b = (u32)malloc(4096);
-	free((void *)b);
-	free((void *)a);
-	u32 c = (u32)malloc(2048);
-	assert(a == c);
-	info("kmalloc test succeeded!");
+	paging_init(dir, user);
+
+	return dir;
 }
 
 void paging_disable()
@@ -68,6 +58,7 @@ void paging_disable()
 
 void paging_enable()
 {
+	asm("mov %0, %%cr3" ::"r"(current_page_directory));
 	u32 cr0;
 	asm("mov %%cr0, %0" : "=r"(cr0));
 	cr0 |= 0x80000000;
@@ -75,10 +66,11 @@ void paging_enable()
 	paging_enabled = 1;
 }
 
-void paging_switch_directory(struct page_directory *dir)
+void paging_switch_directory(u32 *dir)
 {
-	paging_directory = dir;
-	asm("mov %0, %%cr3" ::"r"(dir));
+	current_page_tables = kernel_page_tables;
+	current_page_directory = dir;
+	asm("mov %0, %%cr3" ::"r"(current_page_directory));
 }
 
 void invlpg(u32 addr)
@@ -90,7 +82,7 @@ void paging_map(u32 phy, u32 virt, u16 flags)
 {
 	u32 pdi = virt >> 22;
 	u32 pti = virt >> 12 & 0x03FF;
-	paging_directory->tables[pdi]->pages[pti] = phy | flags;
+	current_page_tables[pdi][pti] = phy | flags;
 	invlpg(virt);
 }
 
@@ -98,21 +90,21 @@ u32 paging_get_phys(u32 virt)
 {
 	u32 pdi = virt >> 22;
 	u32 pti = (virt >> 12) & 0x03FF;
-	return paging_directory->tables[pdi]->pages[pti] & 0xFFFFF000;
+	return current_page_tables[pdi][pti] & 0xFFFFF000;
 }
 
 u16 paging_get_flags(u32 virt)
 {
 	u32 pdi = virt >> 22;
 	u32 pti = (virt >> 12) & 0x03FF;
-	return paging_directory->tables[pdi]->pages[pti] & 0xFFF;
+	return current_page_tables[pdi][pti] & 0xFFF;
 }
 
 void paging_set_flag_up(u32 virt, u32 count, u32 flag)
 {
 	u32 page_n = virt / 0x1000;
 	for (u32 i = page_n; i < page_n + count; i++) {
-		paging_directory->tables[i / 1024]->pages[i % 1024] |= flag;
+		current_page_tables[i / 1024][i % 1024] |= flag;
 		invlpg(i * 0x1000);
 	}
 }
@@ -121,7 +113,7 @@ void paging_set_flag_down(u32 virt, u32 count, u32 flag)
 {
 	u32 page_n = virt / 0x1000;
 	for (u32 i = page_n; i < page_n + count; i++) {
-		paging_directory->tables[i / 1024]->pages[i % 1024] &= ~flag;
+		current_page_tables[i / 1024][i % 1024] &= ~flag;
 		invlpg(i * 0x1000);
 	}
 }
@@ -150,7 +142,7 @@ void paging_set_user(u32 virt, u32 count)
 {
 	u32 page_n = virt / 0x1000;
 	for (u32 i = page_n; i < page_n + count; i += 1024) {
-		paging_directory->tables[i] = ((u32)paging_directory->tables[i]) | PD_USER;
+		current_page_directory[i / 1024] |= PD_USER;
 	}
 	paging_set_flag_up(virt, count, PT_USER);
 }
@@ -162,8 +154,8 @@ u32 paging_find_pages(u32 count)
 	u32 start_page = 0;
 	for (u32 i = 0; i < 1024; i++) {
 		for (u32 j = 0; j < 1024; j++) {
-			if (!(paging_directory->tables[i]->pages[j] & PT_PRESENT) ||
-			    (paging_directory->tables[i]->pages[j] & PT_USED)) {
+			if (!(current_page_tables[i][j] & PT_PRESENT) ||
+			    (current_page_tables[i][j] & PT_USED)) {
 				continuous = 0;
 				start_dir = i;
 				start_page = j + 1;
@@ -191,10 +183,10 @@ u32 paging_get_used_pages()
 	u32 n = 0;
 	for (u32 i = 0; i < 1024; i++) {
 		for (u32 j = 0; j < 1024; j++) {
-			u8 flags = paging_directory->tables[i]->pages[j] & PT_USED;
+			u8 flags = current_page_tables[i][j] & PT_USED;
 			if (flags == 1)
 				n++;
 		}
 	}
 	return n;
-}
\ No newline at end of file
+}
diff --git a/src/kernel/memory/paging.h b/src/kernel/memory/paging.h
index bf82cf5..8857381 100644
--- a/src/kernel/memory/paging.h
+++ b/src/kernel/memory/paging.h
@@ -23,23 +23,16 @@
 #define PT_GLOBAL 1 << 8
 #define PT_USED 1 << 9
 
-struct page_table {
-	u32 pages[1024] __attribute__((aligned(4096)));
-};
-
-struct page_directory {
-	struct page_table *tables[1024] __attribute__((aligned(4096)));
-};
-
-struct page_directory *paging_kernel_directory __attribute__((aligned(4096)));
+u32 *current_page_directory;
+u32 kernel_page_directory[1024] __attribute__((aligned(4096)));
 int paging_enabled;
 
 void paging_install(u32 multiboot_address);
 void paging_enable();
 void paging_disable();
 
-struct page_directory *paging_make_directory(int user);
-void paging_switch_directory(struct page_directory *dir);
+u32 *paging_make_directory(int user);
+void paging_switch_directory(u32 *dir);
 
 void paging_map(u32 phy, u32 virt, u16 flags);
 u32 paging_get_phys(u32 virt);
@@ -58,4 +51,4 @@ void paging_set_user(u32 virt, u32 count);
 u32 paging_find_pages(u32 count);
 u32 paging_alloc_pages(u32 count);
 
-#endif
\ No newline at end of file
+#endif
diff --git a/src/kernel/tasks/process.c b/src/kernel/tasks/process.c
index c4ab74a..75419ba 100644
--- a/src/kernel/tasks/process.c
+++ b/src/kernel/tasks/process.c
@@ -188,7 +188,7 @@ struct process *process_make_new()
 	proc->brk = 0x50000000;
 
 	for (int i = 0; i < 1024; i++)
-		proc->cr3->tables[i] = paging_kernel_directory->tables[i];
+		proc->cr3[i] = kernel_page_directory[i];
 
 	proc->pid = pid++;
 	return proc;
@@ -232,4 +232,4 @@ u32 uspawn(char *path)
 	log("Spawned");
 	process_force_switch();
 	return 0;
-}
\ No newline at end of file
+}
diff --git a/src/kernel/tasks/process.h b/src/kernel/tasks/process.h
index 08b30ed..00f0f07 100644
--- a/src/kernel/tasks/process.h
+++ b/src/kernel/tasks/process.h
@@ -13,7 +13,7 @@ struct mmap {
 };
 
 struct process {
-	struct page_directory *cr3;
+	u32 *cr3;
 	struct regs registers;
 
 	u32 pid;
@@ -65,4 +65,4 @@ extern u32 stack_hold;
 #define WAIT_ERROR (-1)
 #define WAIT_OKAY 0
 
-#endif
\ No newline at end of file
+#endif