From 4886faa3dce410543eda2139221e03959e73a747 Mon Sep 17 00:00:00 2001
From: Alexis211 <alexis211@gmail.com>
Date: Tue, 9 Feb 2010 12:44:06 +0100
Subject: Added user mode support and monitor_writeDec

---
 src/kernel/core/kmain.c   |  2 +-
 src/kernel/core/monitor.c | 21 ++++++++++++++++++
 src/kernel/core/monitor.h |  3 +++
 src/kernel/core/sys.c     |  3 ++-
 src/kernel/core/sys.h     |  2 ++
 src/kernel/linker/elf.c   |  4 ++--
 src/kernel/linker/elf.h   |  2 +-
 src/kernel/mem/gdt.c      | 24 +++++++++++++++++++-
 src/kernel/mem/gdt.h      | 31 ++++++++++++++++++++++++++
 src/kernel/mem/paging.c   |  2 +-
 src/kernel/task/idt.c     |  2 +-
 src/kernel/task/idt_.asm  |  6 +++++
 src/kernel/task/task.c    | 56 ++++++++++++++++++++++++++++++++++++++++++-----
 src/kernel/task/task.h    |  4 ++++
 src/library/start.c       |  4 +++-
 src/modules/test/Makefile |  2 +-
 src/modules/test/main.c   |  8 +++++--
 17 files changed, 159 insertions(+), 17 deletions(-)

diff --git a/src/kernel/core/kmain.c b/src/kernel/core/kmain.c
index ef92dff..4a4da05 100644
--- a/src/kernel/core/kmain.c
+++ b/src/kernel/core/kmain.c
@@ -49,7 +49,7 @@ void kmain(struct multiboot_info_t* mbd, int32_t magic) {
 		if (elf_check((uint8_t*)mods[i].mod_start)) {
 			monitor_write(" : Invalid ELF file\n");
 		} else {
-			if (elf_exec((uint8_t*)mods[i].mod_start) == 0) {
+			if (elf_exec((uint8_t*)mods[i].mod_start, PL_SERVICE) == 0) {
 				monitor_write(" : Error loading\n");
 			} else {
 				monitor_write(" : OK\n");
diff --git a/src/kernel/core/monitor.c b/src/kernel/core/monitor.c
index 8c4744a..6660fe0 100644
--- a/src/kernel/core/monitor.c
+++ b/src/kernel/core/monitor.c
@@ -88,3 +88,24 @@ void monitor_writeHex(uint32_t v) {
 		v = v << 4;
 	}
 }
+
+void monitor_writeDec(uint32_t v) {
+	if (v == 0) {
+		monitor_put('0');
+		return;
+	}
+
+	char numbers[] = "0123456789";
+	while (v > 0) {
+		int order = 1, no = 1;
+		while (v / order > 0) order *= 10;
+		order /= 10;
+		monitor_put(numbers[v / order]);
+		v = v - (v / order * order);
+		while (v / no > 0) no *= 10;
+		while (no < order) {
+			monitor_put('0');
+			no *= 10;
+		}
+	}
+}
diff --git a/src/kernel/core/monitor.h b/src/kernel/core/monitor.h
index 3abe072..19201ed 100644
--- a/src/kernel/core/monitor.h
+++ b/src/kernel/core/monitor.h
@@ -7,6 +7,9 @@ void monitor_put(char c);
 void monitor_clear();
 void monitor_write(char *s);
 void monitor_writeHex(uint32_t v);
+void monitor_writeDec(uint32_t v);
+
+#define NL monitor_put("\n");
 
 #endif
 
diff --git a/src/kernel/core/sys.c b/src/kernel/core/sys.c
index d31c20e..1045cff 100644
--- a/src/kernel/core/sys.c
+++ b/src/kernel/core/sys.c
@@ -23,7 +23,8 @@ uint16_t inw(uint16_t port) {
 
 void panic(char* message, char* file, int line) {
 	monitor_write("\n>> PANIC: >>");
-	monitor_write(message); monitor_write("<< in file "); monitor_write(file);
+	monitor_write(message); monitor_write("<< at "); monitor_write(file);
+	monitor_write(":"); monitor_writeDec(line);
 	monitor_write("\nSystem halted T_T");
 	asm volatile("cli; hlt");
 }
diff --git a/src/kernel/core/sys.h b/src/kernel/core/sys.h
index 76e3560..2f8cd5e 100644
--- a/src/kernel/core/sys.h
+++ b/src/kernel/core/sys.h
@@ -14,4 +14,6 @@ void panic(char* message, char* file, int line);
 void sti();		//GLOBAL SYSTEM MUTEX
 void cli();
 
+#define WHERE { monitor_write("(kernel:"); monitor_write(__FILE__); monitor_write(":"); monitor_writeDec(__LINE__); monitor_write(") "); }
+
 #endif
diff --git a/src/kernel/linker/elf.c b/src/kernel/linker/elf.c
index dc7481b..59f4bdd 100644
--- a/src/kernel/linker/elf.c
+++ b/src/kernel/linker/elf.c
@@ -31,10 +31,10 @@ thread_entry elf_load(uint8_t *data, struct process* process) {
 	return (thread_entry)ehdr->e_entry;
 }
 
-struct process* elf_exec(uint8_t *data) {
+struct process* elf_exec(uint8_t *data, int privilege) {
 	if (elf_check(data)) return 0;
 	
-	struct process* p = process_new(0, 0, PL_DRIVER);
+	struct process* p = process_new(0, 0, privilege);
 
 	thread_entry e = elf_load(data, p);
 
diff --git a/src/kernel/linker/elf.h b/src/kernel/linker/elf.h
index f84bb62..c32cce0 100644
--- a/src/kernel/linker/elf.h
+++ b/src/kernel/linker/elf.h
@@ -58,6 +58,6 @@ struct phdr {
 
 int elf_check(uint8_t *data);	//0 if ok, 1 if not a valid ELF
 thread_entry elf_load(uint8_t *data, struct process* process);	//Load an ELF to a process, return entry point
-struct process* elf_exec(uint8_t *data);	//Creates a new process and a thread for running ELF file
+struct process* elf_exec(uint8_t *data, int privilege);	//Creates a new process and a thread for running ELF file
 
 #endif
diff --git a/src/kernel/mem/gdt.c b/src/kernel/mem/gdt.c
index 5aaad41..18a5fa7 100644
--- a/src/kernel/mem/gdt.c
+++ b/src/kernel/mem/gdt.c
@@ -3,12 +3,18 @@
 #include <core/monitor.h>
 
 extern void gdt_flush(uint32_t);	//ASM (idt_.asm)
+extern void tss_flush();
 
-#define GDT_ENTRIES 5
+#define GDT_ENTRIES 6
 
+static struct tss_entry tss_entry;
 static struct gdt_entry gdt_entries[GDT_ENTRIES];
 static struct gdt_ptr gdt_ptr;
 
+void gdt_setKernelStack(uint32_t esp0) {
+	tss_entry.esp0 = esp0;
+}
+
 static void gdt_setGate(int num, uint32_t base, uint32_t limit, uint8_t access, uint8_t gran) {
 	gdt_entries[num].base_low = (base & 0xFFFF);
 	gdt_entries[num].base_middle = (base >> 16) & 0xFF;
@@ -20,6 +26,20 @@ static void gdt_setGate(int num, uint32_t base, uint32_t limit, uint8_t access,
 	gdt_entries[num].access = access;
 }
 
+static void gdt_writeTss(int num, uint32_t ss0, uint32_t esp0) {
+	uint32_t base = (uint32_t)&tss_entry;
+	uint32_t limit = base + sizeof(struct tss_entry);
+
+	gdt_setGate(num, base, limit, 0xE9, 0);
+
+	memset(&tss_entry, 0, sizeof(struct tss_entry));
+
+	tss_entry.ss0 = ss0; tss_entry.esp0 = esp0;
+
+	tss_entry.cs = 0x0b;
+	tss_entry.ss = tss_entry.ds = tss_entry.es = tss_entry.fs = tss_entry.gs = 0x13;
+}
+
 void gdt_init() {
 	gdt_ptr.limit = (sizeof(struct gdt_entry) * GDT_ENTRIES) - 1;
 	gdt_ptr.base = (uint32_t)&gdt_entries;
@@ -29,8 +49,10 @@ void gdt_init() {
 	gdt_setGate(2, 0, 0xFFFFFFFF, 0x92, 0xCF);	//Kernel data segment
 	gdt_setGate(3, 0, 0xFFFFFFFF, 0xFA, 0xCF);	//User code segment
 	gdt_setGate(4, 0, 0xFFFFFFFF, 0xF2, 0xCF);	//User data segment
+	gdt_writeTss(5, 0x10, 0);
 
 	gdt_flush((uint32_t)&gdt_ptr);
+	tss_flush();
 
 	monitor_write("GDT ok\n");
 }
diff --git a/src/kernel/mem/gdt.h b/src/kernel/mem/gdt.h
index aac16bb..485002b 100644
--- a/src/kernel/mem/gdt.h
+++ b/src/kernel/mem/gdt.h
@@ -17,7 +17,38 @@ struct gdt_ptr {
 	uint32_t base;
 } __attribute__((packed));
 
+struct tss_entry {
+	uint32_t prev_tss;   // The previous TSS - if we used hardware task switching this would form a linked list.
+	uint32_t esp0;       // The stack pointer to load when we change to kernel mode.
+	uint32_t ss0;        // The stack segment to load when we change to kernel mode.
+	uint32_t esp1;       // Unused...
+	uint32_t ss1;
+	uint32_t esp2;
+	uint32_t ss2;
+	uint32_t cr3;
+	uint32_t eip;
+	uint32_t eflags;
+	uint32_t eax;
+	uint32_t ecx;
+	uint32_t edx;
+	uint32_t ebx;
+	uint32_t esp;
+	uint32_t ebp;
+	uint32_t esi;
+	uint32_t edi;
+	uint32_t es;         // The value to load into ES when we change to kernel mode.
+	uint32_t cs;         // The value to load into CS when we change to kernel mode.
+	uint32_t ss;         // The value to load into SS when we change to kernel mode.
+	uint32_t ds;         // The value to load into DS when we change to kernel mode.
+	uint32_t fs;         // The value to load into FS when we change to kernel mode.
+	uint32_t gs;         // The value to load into GS when we change to kernel mode.
+	uint32_t ldt;        // Unused...
+	uint16_t trap;
+	uint16_t iomap_base;
+} __attribute__((packed));
+
 void gdt_init();
+void gdt_setKernelStack(uint32_t esp0);
 
 #endif
 
diff --git a/src/kernel/mem/paging.c b/src/kernel/mem/paging.c
index 27ce043..d478e05 100644
--- a/src/kernel/mem/paging.c
+++ b/src/kernel/mem/paging.c
@@ -116,7 +116,7 @@ uint32_t paging_fault(struct registers *regs) {
 	}
 
 	if (seg == 0) {
-		monitor_write("(paging.c:119) Unhandled Page Fault ");
+		WHERE; monitor_write("Unhandled Page Fault ");
 		if (regs->err_code & 0x1) monitor_write("present ");
 		if (regs->err_code & 0x2) monitor_write("write ");
 		if (regs->err_code & 0x4) monitor_write("user ");
diff --git a/src/kernel/task/idt.c b/src/kernel/task/idt.c
index 360ac91..72a3d54 100644
--- a/src/kernel/task/idt.c
+++ b/src/kernel/task/idt.c
@@ -108,7 +108,7 @@ static void idt_setGate(uint8_t num, uint32_t base, uint16_t sel, uint8_t flags)
 
 	idt_entries[num].sel = sel;
 	idt_entries[num].always0 = 0;
-	idt_entries[num].flags = flags;
+	idt_entries[num].flags = flags | 0x60;
 }
 
 void idt_init() {
diff --git a/src/kernel/task/idt_.asm b/src/kernel/task/idt_.asm
index 63d1570..1a594ca 100644
--- a/src/kernel/task/idt_.asm
+++ b/src/kernel/task/idt_.asm
@@ -1,6 +1,7 @@
 ; UNRELATED
 
 [GLOBAL gdt_flush]
+[GLOBAL tss_flush]
 
 gdt_flush:
   mov eax, [esp+4]
@@ -17,6 +18,11 @@ gdt_flush:
 .flush:
   ret
 
+tss_flush:
+	mov ax, 0x2B
+	ltr ax
+	ret
+
 ; RELATED
 
 [GLOBAL idt_flush]
diff --git a/src/kernel/task/task.c b/src/kernel/task/task.c
index 804adc2..a37d44b 100644
--- a/src/kernel/task/task.c
+++ b/src/kernel/task/task.c
@@ -2,6 +2,8 @@
 #include <core/sys.h>
 #include <core/monitor.h>
 #include <mem/mem.h>
+#include <mem/seg.h>
+#include <mem/gdt.h>
 #include "timer.h"
 
 #define KSTACKSIZE 0x8000
@@ -75,6 +77,8 @@ void tasking_switch() {
 
 	current_thread = thread_next();
 
+	gdt_setKernelStack(((uint32_t)current_thread->kernelStack_addr) + current_thread->kernelStack_size);
+
 	asm volatile("			\
 			mov %0, %%ebp;	\
 			mov %1, %%esp;	\
@@ -96,14 +100,14 @@ void tasking_updateKernelPagetable(uint32_t idx, struct page_table *table, uint3
 
 uint32_t tasking_handleException(struct registers *regs) {
 	if (current_thread == 0) return 0;	//No tasking yet
-	monitor_write("\n(task.c:99) Unhandled exception : ");
+	NL; WHERE; monitor_write("Unhandled exception : ");
 	char *exception_messages[] = {"Division By Zero","Debug","Non Maskable Interrupt","Breakpoint",
     "Into Detected Overflow","Out of Bounds","Invalid Opcode","No Coprocessor", "Double Fault",
     "Coprocessor Segment Overrun","Bad TSS","Segment Not Present","Stack Fault","General Protection Fault",
     "Page Fault","Unknown Interrupt","Coprocessor Fault","Alignment Check","Machine Check"};
 	monitor_write(exception_messages[regs->int_no]);
 	monitor_write(" at "); monitor_writeHex(regs->eip);
-	monitor_write(" >>> Thread exiting.\n");
+	monitor_write("\n>>> Thread exiting.\n");
 	thread_exit_stackJmp(EX_TH_EXCEPTION);
 	PANIC("This should never have happened. Please report this.");
 }
@@ -163,9 +167,44 @@ 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);	//TODO : take into account privilege level
-	asm volatile("sti");
-	entry_point(data);
+	pagedir_switch(thread->process->pagedir);
+	if (thread->process->privilege >= PL_SERVICE) {	//User mode !
+		uint32_t *stack = (uint32_t*)(thread->userStack_seg->start + thread->userStack_seg->len);
+
+		stack--; *stack = (uint32_t)data;
+		stack--; *stack = 0;
+		size_t esp = (size_t)stack, eip = (size_t)entry_point;
+		//Setup a false structure for returning from an interrupt :
+		//value for esp is in ebx, for eip is in ecx
+		//- update data segments to 0x23 = user data segment with RPL=3
+		//- push value for ss : 0x23 (user data seg rpl3)
+		//- push value for esp
+		//- push flags
+		//- update flags, set IF = 1 (interrupts flag)
+		//- push value for cs : 0x1B = user code segment with RPL=3
+		//- push eip
+		//- return from fake interrupt
+		asm volatile("				\
+				mov $0x23, %%ax;	\
+				mov %%ax, %%ds;		\
+				mov %%ax, %%es;		\
+				mov %%ax, %%fs;		\
+				mov %%ax, %%gs;		\
+									\
+				pushl $0x23;		\
+				pushl %%ebx;		\
+				pushf;				\
+				pop %%eax;			\
+				or $0x200, %%eax;	\
+				push %%eax;			\
+				pushl $0x1B;		\
+				push %%ecx;			\
+				iret;				\
+				" : : "b"(esp), "c"(eip));
+	} else {
+		asm volatile("sti");
+		entry_point(data);
+	}
 	thread_exit(0);
 }
 
@@ -173,6 +212,12 @@ struct thread *thread_new(struct process *proc, thread_entry entry_point, void *
 	struct thread *t = kmalloc(sizeof(struct thread));
 	t->process = proc;
 	proc->threads++;
+
+	if (proc->privilege >= PL_SERVICE) {	//We are running in user mode
+		proc->stacksBottom -= USER_STACK_SIZE;
+		t->userStack_seg = seg_map(simpleseg_make(proc->stacksBottom, USER_STACK_SIZE, 1), proc->pagedir);
+	}
+
 	t->kernelStack_addr = kmalloc(KSTACKSIZE);
 	t->kernelStack_size = KSTACKSIZE;
 
@@ -208,6 +253,7 @@ struct process *process_new(struct process* parent, uint32_t uid, uint32_t privi
 	p->parent = parent;
 	p->pagedir = pagedir_new();
 	p->next = processes;
+	p->stacksBottom = 0xDF000000;
 	processes = p;
 	return p;
 }
diff --git a/src/kernel/task/task.h b/src/kernel/task/task.h
index c9f1794..d363333 100644
--- a/src/kernel/task/task.h
+++ b/src/kernel/task/task.h
@@ -18,12 +18,15 @@
 #define EX_TH_EXCEPTION 0x10001		//ERROR code : just one thread exits, because of an unhandled exception
 #define EX_PR_EXCEPTION 0x10002		//ERROR code : all process finishes, because of an unhandled exception
 
+#define USER_STACK_SIZE 0x8000	//32k, but pages will be mapped one by one as used
+
 typedef void (*thread_entry)(void*);
 
 struct process {
 	uint32_t pid, uid, privilege, threads;
 	struct process *parent;
 	struct page_directory *pagedir;
+	size_t stacksBottom;
 
 	struct process *next;	//Forms a linked list
 };
@@ -35,6 +38,7 @@ struct thread {
 	uint32_t timeWait;
 	void* kernelStack_addr;
 	uint32_t kernelStack_size;
+	struct segment_map *userStack_seg;
 
 	struct thread *next;	//Forms a linked list
 };
diff --git a/src/library/start.c b/src/library/start.c
index 9324ccb..8f83a23 100644
--- a/src/library/start.c
+++ b/src/library/start.c
@@ -1,6 +1,8 @@
+#include "grapes/syscall.h"
+
 extern int main();
 
 void start() {
 	int ret = main();
-	asm volatile("int $64" : : "a"(3), "b"(ret));
+	process_exit(ret);
 }
diff --git a/src/modules/test/Makefile b/src/modules/test/Makefile
index 105aa54..d12e57d 100644
--- a/src/modules/test/Makefile
+++ b/src/modules/test/Makefile
@@ -4,7 +4,7 @@ CC = gcc
 CFLAGS = -nostdlib -nostartfiles -nodefaultlibs -fno-builtin -fno-stack-protector -Wall -Wextra -I ../../library
 
 LD = ld
-LDFLAGS = -T ../../library/link.ld -L ../../library
+LDFLAGS = -T ../../library/link.ld -L ../../library -Map main.map
 
 Objects = main.o
 Outfile = test.elf
diff --git a/src/modules/test/main.c b/src/modules/test/main.c
index 3ac5cb5..fbb6eb8 100644
--- a/src/modules/test/main.c
+++ b/src/modules/test/main.c
@@ -2,7 +2,11 @@
 
 int main() {
 	printk("[module:test] Hi world !\n");
-	thread_sleep(5000);
-	printk("[module:test] 5sec later...\n");
+	thread_sleep(2000);
+	printk("[module:test] 2sec later...\n");
+	printk("[module:test] Performing illegal read in kernel space...\n");
+	int *a = (int*)0xE0000004;
+	if (*a == 0) printk("is null...\n");
+	printk("[module:test] HAHA !!!!\n");
 	return 0;
 }
-- 
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