Start work on syscalls, advanced tasking, segmentation

11 files changed, 333 insertions, 133 deletions

diff --git a/src/stem/Makefile b/src/stem/Makefile
index c72f06b..d212216 100644
--- a/src/stem/Makefile
+++ b/src/stem/Makefile
@@ -12,7 +12,7 @@ OBJECTS = core/loader_.o core/kmain.o core/sys.o \
 		  core/monitor.o task/timer.o \
 		  task/idt.o task/idt_.o task/task.o task/task_.o task/syscall.o \
 		  lib/stdlib.o lib/bitset.o \
-		  mem/mem.o mem/paging.o mem/gdt.o mem/heap.o
+		  mem/mem.o mem/paging.o mem/gdt.o mem/heap.o mem/seg.o
 OUT = stem.elf
 
 all: $(OBJECTS)
diff --git a/src/stem/core/loader_.asm b/src/stem/core/loader_.asm
index e1031b4..d3b92cf 100644
--- a/src/stem/core/loader_.asm
+++ b/src/stem/core/loader_.asm
@@ -1,8 +1,7 @@
 [GLOBAL loader]           ; making entry point visible to linker
 [EXTERN kmain]            ; kmain is defined in kmain.c
+[EXTERN tasking_tmpStack] ; a temporary 4k stack used by tasking, and used when setting up kernel stuff
 
-STACKSIZE equ 0x4000                  ; that's 16k.
- 
 ; setting up the Multiboot header - see GRUB docs for details
 MODULEALIGN equ  1<<0                   ; align loaded modules on page boundaries
 MEMINFO     equ  1<<1                   ; provide memory map
@@ -32,7 +31,7 @@ loader:		;here, we load our false GDT, used for having the kernel in higher half
 section .text
 higherhalf:		; now we're running in higher half
 
-   mov esp, stack+STACKSIZE           ; set up the stack
+   mov esp, tasking_tmpStack+0x4000           ; set up the stack
    push eax                           ; pass Multiboot magic number
    add ebx, 0xE0000000				  ; update the MB info structure so that it is in the new seg
    push ebx                           ; pass Multiboot info structure
@@ -56,8 +55,3 @@ gdt:
    db 0xFF, 0xFF, 0, 0, 0, 10010010b, 11001111b, 0x20	; kernel data segment
 
 gdt_end:
- 
-[section .bss]
-align 32
-stack:
-   resb STACKSIZE                     ; reserve 16k stack on a quadword boundary
diff --git a/src/stem/mem/paging.c b/src/stem/mem/paging.c
index 5ce3aae..4cc861c 100644
--- a/src/stem/mem/paging.c
+++ b/src/stem/mem/paging.c
@@ -3,7 +3,9 @@
 #include <stdlib.h>
 #include <core/monitor.h>
 #include "mem.h"
+#include "seg.h"
 #include <core/sys.h>
+#include <task/task.h>
 
 static struct bitset frames;
 
@@ -66,17 +68,45 @@ void pagedir_switch(struct page_directory *pd) {
 	asm volatile("mov %0, %%cr0" : : "r"(cr0));
 }
 
+struct page_directory *pagedir_new() {
+	uint32_t i;
+
+	struct page_directory *pd = kmalloc(sizeof(struct page_directory));
+	pd->tablesPhysical = kmalloc_page(&pd->physicalAddr);
+
+	for (i = 768; i < 1024; i++) {
+		pd->tables[i] = kernel_pagedir->tables[i];
+		pd->tablesPhysical[i] = kernel_pagedir->tablesPhysical[i];
+	}
+
+	return pd;
+}
+
 uint32_t paging_fault(struct registers *regs) {
 	size_t addr;
+	struct segment_map *seg = 0;
 	asm volatile("mov %%cr2, %0" : "=r"(addr));
-	monitor_write("PageFault ");
-	if (regs->err_code & 0x1) monitor_write("present ");
-	if (regs->err_code & 0x2) monitor_write("write ");
-	if (regs->err_code & 0x4) monitor_write("user ");
-	if (regs->err_code & 0x8) monitor_write("rsvd ");
-	if (regs->err_code & 0x10) monitor_write("instructionfetch ");
-	monitor_write("@"); monitor_writeHex(addr); monitor_write("\n");
-	PANIC("Page fault");
+
+	seg = current_pagedir->mappedSegs;
+	while (seg) {
+		if (seg->start >= addr && seg->start + seg->len < addr) break;
+		seg = seg->next;
+	}
+
+	if (seg != 0) {
+		if (seg->seg->handle_fault(seg, addr, (regs->err_code & 0x2)) != 0) seg = 0;
+	}
+
+	if (seg == 0) {
+		monitor_write("PageFault ");
+		if (regs->err_code & 0x1) monitor_write("present ");
+		if (regs->err_code & 0x2) monitor_write("write ");
+		if (regs->err_code & 0x4) monitor_write("user ");
+		if (regs->err_code & 0x8) monitor_write("rsvd ");
+		if (regs->err_code & 0x10) monitor_write("instructionfetch ");
+		monitor_write("@"); monitor_writeHex(addr); monitor_write("\n");
+		return 1;
+	}
 	return 0;
 }
 
@@ -88,6 +118,8 @@ struct page *pagedir_getPage(struct page_directory *pd, uint32_t address, int ma
 		return &pd->tables[table_idx]->pages[address %  1024];
 	} else if (make) {
 		pd->tables[table_idx] = kmalloc_page(pd->tablesPhysical + table_idx);
+		if (table_idx >= 768)
+			tasking_updateKernelPagetable(table_idx, pd->tables[table_idx], pd->tablesPhysical[table_idx]);
 		memset((uint8_t*)pd->tables[table_idx], 0, 0x1000);
 		pd->tablesPhysical[table_idx] |= 0x07;
 		return &pd->tables[table_idx]->pages[address %  1024];
diff --git a/src/stem/mem/paging.h b/src/stem/mem/paging.h
index 72078cf..9ee6c4c 100644
--- a/src/stem/mem/paging.h
+++ b/src/stem/mem/paging.h
@@ -18,10 +18,12 @@ struct page_table {
 	struct page pages[1024];
 };
 
+struct segment_map;
 struct page_directory {
 	struct page_table *tables[1024];	//Virtual addresses of page tables
 	uint32_t *tablesPhysical;			//Pointer to the virtual address of the page directory (contain phys addr of pt)
 	uint32_t physicalAddr;				//Physical address of info above
+	struct segment_map *mappedSegs;
 };
 
 extern struct page_directory *kernel_pagedir;
@@ -32,11 +34,12 @@ void frame_free(uint32_t id);
 void paging_init(size_t totalRam);
 void paging_cleanup();
 void pagedir_switch(struct page_directory *pd);
+struct page_directory *pagedir_new();	//Creates a brand new empty page directory for a process, with kernel pages
 struct page *pagedir_getPage(struct page_directory *pd, uint32_t address, int make);
 void page_map(struct page *page, uint32_t frame, uint32_t user, uint32_t rw);
 void page_unmap(struct page *page);
 void page_unmapFree(struct page *page);
 
-uint32_t paging_fault(struct registers *regs);	//returns a boolean
+uint32_t paging_fault(struct registers *regs);	//returns a boolean : 1 if unhandled, 0 if ok
 
 #endif
diff --git a/src/stem/mem/seg.c b/src/stem/mem/seg.c
new file mode 100644
index 0000000..f340c63
--- /dev/null
+++ b/src/stem/mem/seg.c
@@ -0,0 +1,73 @@
+#include "seg.h"
+#include "mem.h"
+
+struct segment_map *seg_map(struct segment* seg, struct page_directory *pagedir) {
+	struct segment_map *sm = seg->map(seg, pagedir);
+	if (sm == 0) return 0;
+	seg->mappings++;
+	sm->seg = seg;
+	sm->pagedir = pagedir;
+	sm->next = pagedir->mappedSegs;
+	pagedir->mappedSegs = sm->next;
+	return sm;
+}
+
+void seg_unmap(struct segment_map *map) {
+	map->seg->unmap(map);
+	if (map->pagedir->mappedSegs == map) {
+		map->pagedir->mappedSegs = map->pagedir->mappedSegs->next;
+	} else {
+		struct segment_map *m = map->pagedir->mappedSegs;
+		while (m->next != 0 && m->next != map) m = m->next;
+		if (m->next == map) m->next = map->next;
+	}
+	map->seg->mappings--;
+	if (map->seg->mappings == 0) {
+		map->seg->delete(map->seg);
+		kfree(map->seg->seg_data);
+		kfree(map->seg);
+	}
+	kfree (map);
+}
+
+// ************************************   SIMPLESEG stuff *************
+
+struct segment* simpleseg_make(size_t start, size_t len, int writable) {
+	struct simpleseg *ss = kmalloc(sizeof(struct simpleseg));
+	struct segment *se = kmalloc(sizeof(struct segment));
+	se->seg_data = ss;
+	se->mappings = 0;
+	se->map = simpleseg_map;
+	se->unmap = simpleseg_unmap;
+	se->delete = simpleseg_delete;
+	se->handle_fault = simpleseg_handleFault;
+	ss->writable = writable; ss->start = start; ss->len = len;
+	return se;
+}
+
+struct segment_map* simpleseg_map(struct segment* seg, struct page_directory* pagedir) {
+	struct segment_map *sm = kmalloc(sizeof(struct segment_map));
+	sm->start = ((struct simpleseg*)(seg->seg_data))->start;
+	sm->len = ((struct simpleseg*)(seg->seg_data))->len;
+	return sm;
+}
+
+void simpleseg_unmap(struct segment_map* sm) {
+	size_t i;
+	for (i = sm->start; i < sm->start + sm->len; i += 0x1000) {
+		page_unmapFree(pagedir_getPage(sm->pagedir, i, 0));
+	}
+}
+
+int simpleseg_handleFault(struct segment_map* sm, size_t addr, int write) {
+	struct simpleseg *ss = sm->seg->seg_data;
+	if (write && !ss->writable) return 1;
+	addr &= 0xFFFFF000;
+	struct page *p = pagedir_getPage(sm->pagedir, addr, 1);
+	if (p->frame != 0) return 1;
+	page_map(p, frame_alloc(), 1, ss->writable);
+	return 0;
+}
+
+void simpleseg_delete(struct segment* seg) {
+}
diff --git a/src/stem/mem/seg.h b/src/stem/mem/seg.h
new file mode 100644
index 0000000..022d38e
--- /dev/null
+++ b/src/stem/mem/seg.h
@@ -0,0 +1,40 @@
+#ifndef DEF_SEG_H
+#define DEF_SEG_H
+
+#include "paging.h"
+
+struct segment_map;
+struct segment {
+	void* seg_data;
+	int mappings;
+
+	struct segment_map* (*map)(struct segment* seg, struct page_directory* pagedir);
+	void (*unmap)(struct segment_map*);
+	void (*delete)(struct segment* seg);
+	int (*handle_fault)(struct segment_map* map, size_t addr, int write);	//0 if ok, 1 if segfault
+};
+
+struct segment_map {
+	struct segment* seg;
+	struct page_directory* pagedir;
+	size_t start, len;
+	struct segment_map *next;
+};
+
+struct segment_map *seg_map(struct segment* seg, struct page_directory* pagedir);
+void seg_unmap(struct segment_map* map);
+
+/// *************************************     SIMPLESEG stuff *****************
+
+struct simpleseg {
+	int writable;
+	size_t start, len;
+};
+
+struct segment* simpleseg_make(size_t start, size_t len, int writable); 
+struct segment_map* simpleseg_map(struct segment* seg, struct page_directory* pagedir);
+void simpleseg_unmap(struct segment_map*);
+void simpleseg_delete(struct segment *seg);
+int simpleseg_handleFault(struct segment_map* map, size_t addr, int write);
+
+#endif
diff --git a/src/stem/stem.map b/src/stem/stem.map
index dca785f..a2d1d98 100644
--- a/src/stem/stem.map
+++ b/src/stem/stem.map
@@ -4,7 +4,10 @@ Common symbol       size              file
 
 idt_ptr             0x6               task/idt.o
 mem_placementAddr   0x4               mem/mem.o
+tasking_tmpStack    0x10000           task/task.o
 idt_entries         0x800             task/idt.o
+kernel_process      0x4               task/task.o
+idle_thread         0x4               task/task.o
 current_pagedir     0x4               mem/paging.o
 kernel_pagedir      0x4               mem/paging.o
 
@@ -23,7 +26,7 @@ Linker script and memory map
                 0x00100000                loader
                 0xe010003a                . = (. + 0xe0000000)
 
-.text           0xe0100040     0x29b0 load address 0x00100040
+.text           0xe0100040     0x2eed load address 0x00100040
  *(.text)
  .text          0xe0100040       0x25 core/loader_.o
  *fill*         0xe0100065        0x3 00
@@ -111,61 +114,72 @@ Linker script and memory map
                 0xe01012df                irq15
                 0xe01012e9                syscall64
  *fill*         0xe01012f3        0x1 00
- .text          0xe01012f4      0x2e8 task/task.o
+ .text          0xe01012f4      0x3dd task/task.o
                 0xe01012f4                tasking_init
-                0xe01013e7                tasking_switch
-                0xe0101479                tasking_handleException
-                0xe01014f9                thread_new
- *fill*         0xe01015dc        0x4 00
- .text          0xe01015e0        0xa task/task_.o
-                0xe01015e0                read_eip
-                0xe01015e3                task_idle
- *fill*         0xe01015ea        0x2 00
- .text          0xe01015ec       0x15 task/syscall.o
- *fill*         0xe0101601        0x3 00
- .text          0xe0101604       0xca lib/stdlib.o
-                0xe0101604                memcpy
-                0xe0101641                memset
-                0xe0101670                memsetw
-                0xe01016a6                strlen
- *fill*         0xe01016ce        0x2 00
- .text          0xe01016d0      0x173 lib/bitset.o
-                0xe01016d0                bitset_set
-                0xe0101724                bitset_clear
-                0xe010177a                bitset_test
-                0xe01017bc                bitset_firstFree
- *fill*         0xe0101843        0x1 00
- .text          0xe0101844      0x29f mem/mem.o
-                0xe01019aa                kmalloc_page
-                0xe01019f1                kfree_page
-                0xe0101a2c                kheap_init
-                0xe0101a81                kmalloc
-                0xe0101abf                kfree
- *fill*         0xe0101ae3        0x1 00
- .text          0xe0101ae4      0x513 mem/paging.o
-                0xe0101ae4                frame_alloc
-                0xe0101b11                frame_free
-                0xe0101b2c                paging_init
-                0xe0101cc4                paging_cleanup
-                0xe0101d1f                pagedir_switch
-                0xe0101d4e                paging_fault
-                0xe0101e29                pagedir_getPage
-                0xe0101f08                page_map
-                0xe0101f90                page_unmap
-                0xe0101fb3                page_unmapFree
- *fill*         0xe0101ff7        0x1 00
- .text          0xe0101ff8      0x19f mem/gdt.o
-                0xe0102087                gdt_init
- *fill*         0xe0102197        0x1 00
- .text          0xe0102198      0x858 mem/heap.o
-                0xe0102328                heap_create
-                0xe01026fb                heap_alloc
-                0xe010285c                heap_free
+                0xe0101410                tasking_switch
+                0xe01014a2                tasking_updateKernelPagetable
+                0xe01014ec                tasking_handleException
+                0xe010156c                thread_new
+                0xe0101661                process_new
+ *fill*         0xe01016d1        0xf 00
+ .text          0xe01016e0        0xa task/task_.o
+                0xe01016e0                read_eip
+                0xe01016e3                task_idle
+ *fill*         0xe01016ea        0x2 00
+ .text          0xe01016ec       0x33 task/syscall.o
+ *fill*         0xe010171f        0x1 00
+ .text          0xe0101720       0xca lib/stdlib.o
+                0xe0101720                memcpy
+                0xe010175d                memset
+                0xe010178c                memsetw
+                0xe01017c2                strlen
+ *fill*         0xe01017ea        0x2 00
+ .text          0xe01017ec      0x173 lib/bitset.o
+                0xe01017ec                bitset_set
+                0xe0101840                bitset_clear
+                0xe0101896                bitset_test
+                0xe01018d8                bitset_firstFree
+ *fill*         0xe010195f        0x1 00
+ .text          0xe0101960      0x29f mem/mem.o
+                0xe0101ac6                kmalloc_page
+                0xe0101b0d                kfree_page
+                0xe0101b48                kheap_init
+                0xe0101b9d                kmalloc
+                0xe0101bdb                kfree
+ *fill*         0xe0101bff        0x1 00
+ .text          0xe0101c00      0x645 mem/paging.o
+                0xe0101c00                frame_alloc
+                0xe0101c2d                frame_free
+                0xe0101c48                paging_init
+                0xe0101de0                paging_cleanup
+                0xe0101e3b                pagedir_switch
+                0xe0101e6a                pagedir_new
+                0xe0101ef2                paging_fault
+                0xe010203f                pagedir_getPage
+                0xe0102156                page_map
+                0xe01021de                page_unmap
+                0xe0102201                page_unmapFree
+ *fill*         0xe0102245        0x3 00
+ .text          0xe0102248      0x19f mem/gdt.o
+                0xe01022d7                gdt_init
+ *fill*         0xe01023e7        0x1 00
+ .text          0xe01023e8      0x858 mem/heap.o
+                0xe0102578                heap_create
+                0xe010294b                heap_alloc
+                0xe0102aac                heap_free
+ .text          0xe0102c40      0x2ed mem/seg.o
+                0xe0102c40                seg_map
+                0xe0102cae                seg_unmap
+                0xe0102d8d                simpleseg_make
+                0xe0102e0a                simpleseg_map
+                0xe0102e40                simpleseg_unmap
+                0xe0102e93                simpleseg_handleFault
+                0xe0102f28                simpleseg_delete
 
-.iplt           0xe01029f0        0x0 load address 0x001029f0
+.iplt           0xe0102f30        0x0 load address 0x00102f2d
  .iplt          0x00000000        0x0 core/loader_.o
 
-.rodata         0xe0103000      0x1bb load address 0x00103000
+.rodata         0xe0103000      0x1a3 load address 0x00103000
  *(.rodata)
  .rodata        0xe0103000       0x52 core/kmain.o
  .rodata        0xe0103052       0x2c core/sys.o
@@ -174,14 +188,14 @@ Linker script and memory map
  .rodata        0xe0103090       0x78 task/idt.o
  .rodata        0xe0103108       0x12 task/task.o
  .rodata        0xe010311a       0x10 mem/mem.o
- .rodata        0xe010312a       0x89 mem/paging.o
- .rodata        0xe01031b3        0x8 mem/gdt.o
+ .rodata        0xe010312a       0x71 mem/paging.o
+ .rodata        0xe010319b        0x8 mem/gdt.o
 
-.rel.dyn        0xe01031bc        0x0 load address 0x001031bb
+.rel.dyn        0xe01031a4        0x0 load address 0x001031a3
  .rel.iplt      0x00000000        0x0 core/loader_.o
  .rel.text      0x00000000        0x0 core/loader_.o
 
-.data           0xe0104000       0x20 load address 0x00104000
+.data           0xe0104000       0x24 load address 0x00104000
  *(.data)
  .data          0xe0104000        0x0 core/kmain.o
  .data          0xe0104000        0x4 core/sys.o
@@ -189,56 +203,61 @@ Linker script and memory map
  .data          0xe0104008        0x0 task/timer.o
  .data          0xe0104008        0x0 task/idt.o
  .data          0xe0104008        0x4 task/task.o
-                0xe0104008                nextpid
- .data          0xe010400c       0x14 task/syscall.o
+ .data          0xe010400c       0x18 task/syscall.o
                 0xe010400c                syscalls
- .data          0xe0104020        0x0 lib/stdlib.o
- .data          0xe0104020        0x0 lib/bitset.o
- .data          0xe0104020        0x0 mem/mem.o
- .data          0xe0104020        0x0 mem/paging.o
- .data          0xe0104020        0x0 mem/gdt.o
- .data          0xe0104020        0x0 mem/heap.o
+ .data          0xe0104024        0x0 lib/stdlib.o
+ .data          0xe0104024        0x0 lib/bitset.o
+ .data          0xe0104024        0x0 mem/mem.o
+ .data          0xe0104024        0x0 mem/paging.o
+ .data          0xe0104024        0x0 mem/gdt.o
+ .data          0xe0104024        0x0 mem/heap.o
+ .data          0xe0104024        0x0 mem/seg.o
 
-.igot.plt       0xe0104020        0x0 load address 0x00104020
+.igot.plt       0xe0104024        0x0 load address 0x00104024
  .igot.plt      0x00000000        0x0 core/loader_.o
 
-.bss            0xe0104020     0x4950 load address 0x00104020
-                0xe0104020                sbss = .
+.bss            0xe0104040    0x10970 load address 0x00104040
+                0xe0104040                sbss = .
  *(COMMON)
- COMMON         0xe0104020      0x820 task/idt.o
-                0xe0104020                idt_ptr
-                0xe0104040                idt_entries
- COMMON         0xe0104840        0x4 mem/mem.o
-                0xe0104840                mem_placementAddr
- COMMON         0xe0104844        0x8 mem/paging.o
-                0xe0104844                current_pagedir
-                0xe0104848                kernel_pagedir
+ COMMON         0xe0104040      0x820 task/idt.o
+                0xe0104040                idt_ptr
+                0xe0104060                idt_entries
+ COMMON         0xe0104860    0x10008 task/task.o
+                0xe0104860                tasking_tmpStack
+                0xe0114860                kernel_process
+                0xe0114864                idle_thread
+ COMMON         0xe0114868        0x4 mem/mem.o
+                0xe0114868                mem_placementAddr
+ COMMON         0xe011486c        0x8 mem/paging.o
+                0xe011486c                current_pagedir
+                0xe0114870                kernel_pagedir
  *(.bss)
- .bss           0xe010484c     0x4000 core/loader_.o
- .bss           0xe010884c        0x0 core/kmain.o
- .bss           0xe010884c        0x0 core/sys.o
- .bss           0xe010884c        0x8 core/monitor.o
- .bss           0xe0108854        0xc task/timer.o
- .bss           0xe0108860       0x40 task/idt.o
- .bss           0xe01088a0        0xc task/task.o
-                0xe01088a0                processes
-                0xe01088a4                threads
-                0xe01088a8                current_thread
- .bss           0xe01088ac        0x0 task/syscall.o
- .bss           0xe01088ac        0x0 lib/stdlib.o
- .bss           0xe01088ac        0x0 lib/bitset.o
- *fill*         0xe01088ac       0x14 00
- .bss           0xe01088c0       0x60 mem/mem.o
-                0xe01088c0                freepagecount
- .bss           0xe0108920        0x8 mem/paging.o
- *fill*         0xe0108928       0x18 00
- .bss           0xe0108940       0x2e mem/gdt.o
- *fill*         0xe010896e        0x2 00
- .bss           0xe0108970        0x0 mem/heap.o
-                0xe0108970                ebss = .
-                0xe0108970                end = .
-                0xe0108970                _end = .
-                0xe0108970                __end = .
+ .bss           0xe0114874        0x0 core/kmain.o
+ .bss           0xe0114874        0x0 core/sys.o
+ .bss           0xe0114874        0x8 core/monitor.o
+ .bss           0xe011487c        0xc task/timer.o
+ *fill*         0xe0114888       0x18 00
+ .bss           0xe01148a0       0x40 task/idt.o
+ .bss           0xe01148e0        0xc task/task.o
+                0xe01148e0                processes
+                0xe01148e4                threads
+                0xe01148e8                current_thread
+ .bss           0xe01148ec        0x0 task/syscall.o
+ .bss           0xe01148ec        0x0 lib/stdlib.o
+ .bss           0xe01148ec        0x0 lib/bitset.o
+ *fill*         0xe01148ec       0x14 00
+ .bss           0xe0114900       0x60 mem/mem.o
+                0xe0114900                freepagecount
+ .bss           0xe0114960        0x8 mem/paging.o
+ *fill*         0xe0114968       0x18 00
+ .bss           0xe0114980       0x2e mem/gdt.o
+ *fill*         0xe01149ae        0x2 00
+ .bss           0xe01149b0        0x0 mem/heap.o
+ .bss           0xe01149b0        0x0 mem/seg.o
+                0xe01149b0                ebss = .
+                0xe01149b0                end = .
+                0xe01149b0                _end = .
+                0xe01149b0                __end = .
 LOAD core/loader_.o
 LOAD core/kmain.o
 LOAD core/sys.o
@@ -255,6 +274,7 @@ LOAD mem/mem.o
 LOAD mem/paging.o
 LOAD mem/gdt.o
 LOAD mem/heap.o
+LOAD mem/seg.o
 OUTPUT(stem.elf elf32-i386)
 
 .comment        0x00000000       0x11
@@ -272,6 +292,7 @@ OUTPUT(stem.elf elf32-i386)
  .comment       0x00000000       0x12 mem/paging.o
  .comment       0x00000000       0x12 mem/gdt.o
  .comment       0x00000000       0x12 mem/heap.o
+ .comment       0x00000000       0x12 mem/seg.o
 
 .note.GNU-stack
                 0x00000000        0x0
@@ -301,3 +322,5 @@ OUTPUT(stem.elf elf32-i386)
                 0x00000000        0x0 mem/gdt.o
  .note.GNU-stack
                 0x00000000        0x0 mem/heap.o
+ .note.GNU-stack
+                0x00000000        0x0 mem/seg.o
diff --git a/src/stem/task/idt.c b/src/stem/task/idt.c
index 7c05e2e..4866550 100644
--- a/src/stem/task/idt.c
+++ b/src/stem/task/idt.c
@@ -67,7 +67,7 @@ struct idt_ptr idt_ptr;
 static int_callback irq_handlers[16] = {0};
 
 void idt_isrHandler(struct registers regs) {
-	if ((regs.int_no == 14 && paging_fault(&regs) == 0) || regs.int_no != 14) {
+	if ((regs.int_no == 14 && paging_fault(&regs) != 0) || regs.int_no != 14) {
 		if (tasking_handleException(&regs) == 0) {
 			monitor_write("  >>  >> SOMETHING BAD HAPPENNED << <<\n");
 			monitor_write("Unhandled exception ");
diff --git a/src/stem/task/syscall.c b/src/stem/task/syscall.c
index 281d680..6964b34 100644
--- a/src/stem/task/syscall.c
+++ b/src/stem/task/syscall.c
@@ -7,10 +7,12 @@
 	r->eax = name(r->ebx, r->ecx); }
 
 CALL0(tasking_switch, schedule_sc);
+CALL1(monitor_write, printk_sc);
 
 int_callback syscalls[] = {
 	0,			//Syscall 0 will be thread_exit
 	schedule_sc,
 	0,			//Syscall 2 will be thread_sleep
 	0,			//Syscall 3 will be process_exit
+	printk_sc,
 	0 };
diff --git a/src/stem/task/task.c b/src/stem/task/task.c
index 39c2482..8ed5190 100644
--- a/src/stem/task/task.c
+++ b/src/stem/task/task.c
@@ -12,21 +12,24 @@ extern void task_idle(void*);
 
 static uint32_t thread_runnable(struct thread *th);
 
-uint32_t nextpid = 1;
+static uint32_t nextpid = 1;
 
-struct process *processes = 0;
-struct thread *threads = 0, *current_thread = 0;
+struct process *processes = 0, *kernel_process;
+struct thread *threads = 0, *current_thread = 0, *idle_thread;
+
+uint32_t tasking_tmpStack[0x4000];
 
 void tasking_init(thread_entry whereToGo, void *data) {
 	cli();
-	struct process *pr = kmalloc(sizeof(struct process));	//This process must be hidden to users
-	pr->pid = pr->uid = 0;
-	pr->parent = pr;
-	pr->pagedir = kernel_pagedir;
-	pr->next = 0;
+	kernel_process = kmalloc(sizeof(struct process));	//This process must be hidden to users
+	kernel_process->pid = kernel_process->uid = kernel_process->threads = 0;
+	kernel_process->privilege = PL_KERNEL;
+	kernel_process->parent = kernel_process;
+	kernel_process->pagedir = kernel_pagedir;
+	kernel_process->next = 0;
 	current_thread = 0;
-	thread_new(pr, task_idle, 0);
-	thread_new(pr, whereToGo, data);
+	thread_new(kernel_process, task_idle, 0);
+	thread_new(kernel_process, whereToGo, data);
 	sti();
 	monitor_write("Tasking starting\n");
 	tasking_switch();
@@ -75,6 +78,15 @@ void tasking_switch() {
 		: : "r"(current_thread->ebp), "r"(current_thread->esp), "r"(current_thread->eip));
 }
 
+void tasking_updateKernelPagetable(uint32_t idx, struct page_table *table, uint32_t tablephysical) {
+	struct process* it = processes;
+	while (it != 0) {
+		it->pagedir->tables[idx] = table;
+		it->pagedir->tablesPhysical[idx] = tablephysical;
+		it = it->next;
+	}
+}
+
 uint32_t tasking_handleException(struct registers *regs) {
 	if (threads == 0) return 0;	//No tasking yet
 	return 0;
@@ -87,15 +99,16 @@ static uint32_t thread_runnable(struct thread *t) {
 }
 
 static void thread_run(struct thread *thread, thread_entry entry_point, void *data) {
-	pagedir_switch(thread->process->pagedir);
+	pagedir_switch(thread->process->pagedir);	//TODO : take into account privilege level
 	asm volatile("sti");
 	entry_point(data);
 	asm volatile("int $64");
 }
 
-void thread_new(struct process *proc, thread_entry entry_point, void *data) {
+struct thread *thread_new(struct process *proc, thread_entry entry_point, void *data) {
 	struct thread *t = kmalloc(sizeof(struct thread));
 	t->process = proc;
+	proc->threads++;
 	t->kernelStack_addr = kmalloc(KSTACKSIZE);
 	t->kernelStack_size = KSTACKSIZE;
 
@@ -119,5 +132,18 @@ void thread_new(struct process *proc, thread_entry entry_point, void *data) {
 		while (i->next != 0) i = i->next;
 		i->next = t;
 	}
+	return t;
 }
 
+struct process *process_new(struct process* parent, uint32_t uid, uint32_t privilege) {
+	struct process* p = kmalloc(sizeof(struct process));
+	p->pid = (nextpid++);
+	p->uid = uid;
+	p->threads = 0;
+	p->privilege = privilege;
+	p->parent = parent;
+	p->pagedir = pagedir_new();
+	p->next = processes;
+	processes = p;
+	return p;
+}
diff --git a/src/stem/task/task.h b/src/stem/task/task.h
index e91aa8b..f59bb2b 100644
--- a/src/stem/task/task.h
+++ b/src/stem/task/task.h
@@ -6,7 +6,7 @@
 #include "idt.h"
 
 struct process {
-	uint32_t pid, uid;
+	uint32_t pid, uid, privilege, threads;
 	struct process *parent;
 	struct page_directory *pagedir;
 
@@ -17,6 +17,11 @@ struct process {
 #define TS_SLEEPING 1	//Sleeping for a defined amount of time
 #define TS_WAIKWAIT 2	//Waiting to be waked up by something precise (thread currently blocked)
 
+#define PL_USER 3
+#define PL_SERVICE 2
+#define PL_DRIVER 1
+#define PL_KERNEL 0
+
 typedef void (*thread_entry)(void*);
 
 struct thread {
@@ -34,8 +39,10 @@ extern struct thread *current_thread;
 
 void tasking_init(thread_entry whereToGo, void *data);
 void tasking_switch();
+void tasking_updateKernelPagetable(uint32_t idx, struct page_table *table, uint32_t tablePhysical);
 uint32_t tasking_handleException(struct registers *regs);
 
-void thread_new(struct process *proc, thread_entry entry_point, void *data);
+struct thread * thread_new(struct process *proc, thread_entry entry_point, void *data);
+struct process* process_new(struct process *parent, uint32_t uid, uint32_t privilege);
 
 #endif