finally working ring 3

7 files changed, 274 insertions, 54 deletions

diff --git a/kernel/GDT.c b/kernel/GDT.c
new file mode 100644
index 0000000..4bc7ca2
--- /dev/null
+++ b/kernel/GDT.c
@@ -0,0 +1,136 @@
+// http://wiki.osdev.org/GDT_Tutorial
+#include "lib/logger/log.h"
+#include "usermode.h"
+#define FOOLOS_MODULE_NAME "GDT"
+
+#include <stdint.h>
+#define GDT_SIZE 6
+
+extern sys_tss;
+
+typedef struct GDT_struct
+{
+    uint32_t base;
+    uint32_t limit;
+    uint32_t type;
+
+}GDT;
+
+//alternative
+struct gdt_entry_bits
+{
+	unsigned int limit_low:16;
+	unsigned int base_low : 24;
+     //attribute byte split into bitfields
+	unsigned int accessed :1;
+	unsigned int read_write :1; //readable for code, writable for data
+	unsigned int conforming_expand_down :1; //conforming for code, expand down for data
+	unsigned int code :1; //1 for code, 0 for data
+	unsigned int always_1 :1; //should be 1 for everything but TSS and LDT
+	unsigned int DPL :2; //priveledge level
+	unsigned int present :1;
+     //and now into granularity
+	unsigned int limit_high :4;
+	unsigned int available :1;
+	unsigned int always_0 :1; //should always be 0
+	unsigned int big :1; //32bit opcodes for code, uint32_t stack for data
+	unsigned int gran :1; //1 to use 4k page addressing, 0 for byte addressing
+	unsigned int base_high :8;
+} __packed; //or __attribute__((packed))
+
+
+static GDT myGDT[GDT_SIZE];
+static uint8_t gdt_struct[GDT_SIZE*8];
+
+/**
+ * \param target A pointer to the 8-byte GDT entry
+ * \param source An arbitrary structure describing the GDT entry
+ */
+void encodeGdtEntry(uint8_t *target, GDT source)
+{
+    // Check the limit to make sure that it can be encoded
+    if ((source.limit > 65536) && (source.limit & 0xFFF) != 0xFFF)
+    {
+	panic(FOOLOS_MODULE_NAME,"trying to set an invalid GDT source.limit!");
+    }
+    if (source.limit > 65536) {
+        // Adjust granularity if required
+        source.limit = source.limit >> 12;
+        target[6] = 0xC0;
+    } else {
+	target[6] = 0x40;
+    }
+ 
+    // Encode the limit
+    target[0] = source.limit & 0xFF;
+    target[1] = (source.limit >> 8) & 0xFF;
+ 
+    // Encode the base 
+    target[2] = source.base & 0xFF;
+    target[3] = (source.base >> 8) & 0xFF;
+    target[4] = (source.base >> 16) & 0xFF;
+    target[7] = (source.base >> 24) & 0xFF;
+
+    target[5] = source.type;
+    target[6] |= (source.limit >> 16) & 0xF;
+ 
+    // And... Type
+
+    /*
+
+0 1 dw 0xffff	    ;limit
+2 3 dw 0x0	    ;base
+4   db 0x0	    ;base
+5   db 10011010b    ;flags
+6   db 11001111b    ;flags & seg.limit
+7   db 0x0	    ;base
+    */
+
+
+}
+
+void gdt_setup()
+{
+    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"setting up Global Descriptor Table");
+    //selector 0x0
+    myGDT[0].base=0;
+    myGDT[0].limit=0;
+    myGDT[0].type=0;
+
+    //selector 0x8 code
+    myGDT[1].base=0;
+    myGDT[1].limit=0xffffffff;
+    myGDT[1].type=0x9a;
+
+    //selector 0x10 data
+    myGDT[2].base=0;
+    myGDT[2].limit=0xffffffff;
+    myGDT[2].type=0x92;
+
+    //selector 0x18 code user
+    myGDT[3].base=0;
+    myGDT[3].limit=0xffffffff;
+    myGDT[3].type=0xFa;
+
+    //selector 0x20 data user
+    myGDT[4].base=0;
+    myGDT[4].limit=0xffffffff;
+    myGDT[4].type=0xF2;
+
+    //TSS 0x28
+    myGDT[5].base=&sys_tss; //tss start?
+    myGDT[5].limit=sizeof(tss_struct); //tss end?
+    myGDT[5].type=0x89;
+
+
+    // transcript to format the processor wants
+    for(int i=0;i<GDT_SIZE;i++)
+        encodeGdtEntry(&gdt_struct[8*i],myGDT[i]);
+
+
+    // updat
+    install_tss();
+    setup_gdt(&gdt_struct[0],8*GDT_SIZE);
+
+
+}
diff --git a/kernel/interrupts.c b/kernel/interrupts.c
index 51d8f8e..a7e021c 100644
--- a/kernel/interrupts.c
+++ b/kernel/interrupts.c
@@ -7,6 +7,18 @@
 #include "console.h"
 #include "x86.h"
 
+void errlog(uint32_t error_code)
+{
+    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"error_code: 0x%08X",error_code);
+}
+
+void deflog(uint32_t eip, uint16_t cs, uint32_t flags)
+{
+    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"eip: 0x%08X",eip);
+    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"segment: 0x%08X",cs);
+    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"eflags: 0x%08X",flags);
+}
+
 void int_install_ir(int irq, uint16_t flags, uint16_t sel, void *addr);
 //void mouse_handler(); 
 
@@ -36,17 +48,6 @@ void exception_handle()
    panic(FOOLOS_MODULE_NAME,"exception interrupt");
 }
 
-void exception_handle_14(uint32_t error_code)
-{
-   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"error_code: 0x%08X",error_code);
-   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"error_code_P: %d",error_code&1);
-   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"error_code_W/R: %d",error_code&2);
-   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"error_code_U/S: %d",error_code&4);
-   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"error_code_RSVD: %d",error_code&8);
-   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"error_code_I/D: %d",error_code&16);
-   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"at addr: 0x%08X",x86_get_cr2());
-   panic(FOOLOS_MODULE_NAME,"page fault !");
-}
 void int_default()
 {
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"default handler");
@@ -76,15 +77,26 @@ void exception_handle_10(){   panic(FOOLOS_MODULE_NAME,"Invalid TSS");    }
 void exception_handle_11(){   panic(FOOLOS_MODULE_NAME,"Segment Not Present");    }
 void exception_handle_12(){   panic(FOOLOS_MODULE_NAME,"Stack Segment Overrun");    }
 
-void exception_handle_13()
+void exception_handle_13(uint32_t error_code,uint32_t eip,uint16_t cs,uint16_t unused, uint32_t flags)
 {
-     
-    uint32_t err;
-    asm("pop %eax");  // get Error Code
-    asm ("mov %%eax, %0":"=r"(err));
-    show_error(err);
+    errlog(error_code);
+    deflog(eip,cs,flags);
+
+    panic(FOOLOS_MODULE_NAME,"Exception: Fault: General Protection Fault");   
+}
 
-    panic(FOOLOS_MODULE_NAME,"General Protection Fault");   
+void exception_handle_14(uint32_t error_code,uint32_t eip,uint16_t cs,uint16_t unused, uint32_t flags)
+{
+   errlog(error_code);
+   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"error_code_P: %d",error_code&1?1:0);
+   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"error_code_W/R: %d",error_code&2?1:0);
+   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"error_code_U/S: %d",error_code&4?1:0);
+   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"error_code_RSVD: %d",error_code&8?1:0);
+   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"error_code_I/D: %d",error_code&16?1:0);
+   log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"at addr: 0x%08X",x86_get_cr2());
+   
+    deflog(eip,cs,flags);
+   panic(FOOLOS_MODULE_NAME,"Exception: Fault: Page Fault");
 }
 
 void exception_handle_15(){   panic(FOOLOS_MODULE_NAME,"Unassigned");    }
@@ -158,7 +170,7 @@ void int_init(uint16_t sel)
 //    int_install_ir(44, 0b10001110, 0x08,&mouse_handler);
 
     //system calls
-    int_install_ir(0x80, 0b10001110, 0x08,&int_syscall_handler);
+    int_install_ir(0x80, 0b11101110, 0x08,&int_syscall_handler);
 
 
     int_install();
diff --git a/kernel/kernel.c b/kernel/kernel.c
index 7b29730..2ce84fb 100644
--- a/kernel/kernel.c
+++ b/kernel/kernel.c
@@ -4,7 +4,6 @@
 #error "Watchout! this is not Linux but FoolOS. Use a cross-compiler"
 #endif
 
-
 #include "kernel.h"
 
 #include <stdint.h>
@@ -18,7 +17,6 @@
 #include "interrupts.h"
 #include "multiboot.h"
 
-
 #include "console.h"
 
 #include <stddef.h> 
@@ -29,6 +27,7 @@
 #include "video/vesa.h"
 #include "multiboot.h"
 
+
 void kernel_main(uint32_t eax,uint32_t ebx)
 {
 
@@ -37,21 +36,31 @@ void kernel_main(uint32_t eax,uint32_t ebx)
     // 
     console_init();
 
+
     //
     // PR
     //
     log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"%s - compiled on %s at %s",KERNEL_VERSION,__DATE__,__TIME__);
 
+
     //
     // Configuring the PIT timer.
     //
     timer_init();
 
+
+    //
+    // GDT
+    //
+    gdt_setup();
+
+
     // 
     // Process Multiboot Header
     //
     multiboot_information *info=get_multiboot(eax, ebx);
 
+
     //
     //	Memory Init
     //
@@ -60,17 +69,20 @@ void kernel_main(uint32_t eax,uint32_t ebx)
     //
     uint32_t kernel_blocks=mem_init(info);
 
+
+
     //
     // Activate Virtual Memory (paging)
     //
     pdirectory *dir=vmem_init(kernel_blocks);
 
+
     //
     // Setup Interrupts (code segment: 0x08)
     //
-    
     int_init(0x08);
 
+  
     //
     // Scan the PCI Bus
     // 
@@ -98,23 +110,22 @@ void kernel_main(uint32_t eax,uint32_t ebx)
     //smp_log_procdata(&procdata);
     //smp_start_aps(&procdata,0x80000);	// starts at 0x80000 
 					// but it will be copied over mbr
+    
     //
     // Mount Root EXT2 ramimage
     // 
-    
     fs_mount(info);
     
 
     //
     // Initialize Multitasking
     //
-
     task_init(dir); 
 
+
     //
-    // Abvoe should never return
+    // Abvoe should never returon
     //
-
     panic(FOOLOS_MODULE_NAME,"reached end of kernel.c !!");
  
 }
diff --git a/kernel/task.c b/kernel/task.c
index 1474a64..000dc74 100644
--- a/kernel/task.c
+++ b/kernel/task.c
@@ -82,6 +82,7 @@ volatile uint32_t my_scheduler(uint32_t oldesp)
 // this gets called by our clock interrupt regularly!
 volatile uint32_t task_switch_next(uint32_t oldesp)
 {
+    asm volatile("sti");
 
     timer_tick();
 
@@ -146,12 +147,12 @@ volatile uint32_t task_fork(uint32_t oldesp)
    return pid;
 }
 
-char *argv_init[]={"/bin/init",NULL};
-char *env_init[]={NULL};
 
 // init task (root of all other tasks / processes) //
 volatile void task_init(pdirectory *dir)
 {
+
+
     // this is our main task on slot 0 
     task_list[0].parent=0;
     task_list[0].active=true;
@@ -159,10 +160,12 @@ volatile void task_init(pdirectory *dir)
     task_list[0].vmem=dir;
     task_list[0].esp = 0; // will be set by next task_switch_next() call.
     current_task=0;
+    
+
+    switch_to_user_mode();
 
-    syscall_execve("/bin/init",argv_init,env_init); 
     //syscall_execve("/bin/foolshell",argv_init,env_init); 
-//    syscall_execve("/bin/tput",argv,env); 
+    //syscall_execve("/bin/tput",argv,env); 
 }
 
 
diff --git a/kernel/usermode.c b/kernel/usermode.c
index afad9df..339045d 100644
--- a/kernel/usermode.c
+++ b/kernel/usermode.c
@@ -1,32 +1,85 @@
 #include "usermode.h"
+#define FOOLOS_MODULE_NAME "usermode"
+#include "lib/logger/log.h"
+#include "syscalls.h"
 
 
+tss_struct sys_tss; //Define the TSS as a global structure
+
+
+// generic syscall interface!
+int syscall(int call, int p1, int p2, int p3)
+{
+	int ebx; // will hold return value;
+
+	asm("pusha");
+
+	// select syscall
+	asm("mov %0, %%eax"::"m"(call)); 
+
+	// pass params
+	asm("mov %0,%%edx"::"m"(p1));
+	asm("mov %0,%%ecx"::"m"(p2));
+	asm("mov %0,%%ebx"::"m"(p3));
+
+	// interrrupt
+	asm("int $0x80");
+
+	// get return value
+        asm("mov %%ebx, %0": "=b" (ebx));
+
+	asm("popa");
+
+	return ebx;
+}
+int write(int file, char *ptr, int len) 
+{
+    return syscall(SYSCALL_WRITE,file,ptr,len);
+}
+int execve(char *name, char **argv, char **env) 
+{
+    return syscall(SYSCALL_EXECVE,name,argv,env);
+}
+
 void install_tss(int cpu_no){
+
     // now fill each value
     // set values necessary
-    sys_tss.ss0 = 0x10;
-              // now set the IO bitmap (not necessary, so set above limit)       
-    sys_tss.iomap = ( unsigned short ) sizeof( tss_struct ); 
+    sys_tss.ss0 = 0x10; //kernel data
+    sys_tss.esp0 = 0x9000; //kernel stack
+
+    // now set the IO bitmap (not necessary, so set above limit)       
+    // sys_tss.iomap = ( unsigned short ) sizeof( tss_struct ); 
+}
+
+
+void switch_to_user_mode() 
+{
+    char text[]="internal";
+    write(1,text,10);
+    asm_usermode();
+    while(1); // will not be reached?
 }
 
-void switch_to_user_mode() {
-    // Set up a stack structure for switching to user mode.
-    asm volatile("  \
-        cli; \
-        mov $0x23, %ax; \
-        mov %ax, %ds; \
-        mov %ax, %es; \
-        mov %ax, %fs; \
-        mov %ax, %gs; \
-                \ 
-        mov %esp, %eax; \
-        pushl $0x23; \
-        pushl %eax; \
-        pushf; \
-        mov $0x200, %eax; \
-        push %eax; \
-        pushl $0x1B; \
-        push $1f; \
-        iret; \    1: \
-    "); 
+char *argv_init[]={"/bin/init",NULL};
+char *env_init[]={NULL};
+
+// THIS WILL BE RUN IN RING 3!
+void userfunc()
+{
+
+    execve("/bin/init",argv_init,env_init); 
+
+    for(int i=0;i<3;i++)
+    {
+	log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"we are usermode!");
+    }
+
+
+    while(1) 
+    {
+	
+    char text[]="syscalling!";
+    write(1,text,10);
+    }
 }
diff --git a/kernel/usermode.h b/kernel/usermode.h
index e9195e1..fafad5b 100644
--- a/kernel/usermode.h
+++ b/kernel/usermode.h
@@ -43,4 +43,3 @@ typedef volatile struct strtss{
     unsigned short   iomap;  
 }__attribute__((packed)) tss_struct;  
 
-tss_struct sys_tss; //Define the TSS as a global structure
diff --git a/kernel/vmem.c b/kernel/vmem.c
index a8e4008..f49689f 100644
--- a/kernel/vmem.c
+++ b/kernel/vmem.c
@@ -277,6 +277,7 @@ pdirectory* vmem_new_space_dir(pdirectory *copy_dir)
 		pt_entry page=0;
 		pt_entry_add_attrib (&page, I86_PTE_PRESENT);
 		pt_entry_add_attrib (&page, I86_PTE_WRITABLE);
+		pt_entry_add_attrib (&page, I86_PTE_USER);
 		pt_entry_set_frame (&page, frame);
 
 		//! ...and add it to the page table
@@ -287,6 +288,7 @@ pdirectory* vmem_new_space_dir(pdirectory *copy_dir)
 	    *entry=0;
 	    pd_entry_add_attrib (entry, I86_PDE_PRESENT);
 	    pd_entry_add_attrib (entry, I86_PDE_WRITABLE);
+	    pt_entry_add_attrib (entry, I86_PTE_USER);
 	    pd_entry_set_frame (entry, (physical_addr)table);
 
 	}
@@ -344,6 +346,7 @@ pdirectory* vmem_new_space_dir(pdirectory *copy_dir)
 	    pt_entry page=0;
 	    pt_entry_add_attrib (&page, I86_PTE_PRESENT);
 	    pt_entry_add_attrib (&page, I86_PTE_WRITABLE);
+	    pt_entry_add_attrib (&page, I86_PTE_USER);
 	    pt_entry_set_frame (&page, frame);
 
 
@@ -356,6 +359,7 @@ pdirectory* vmem_new_space_dir(pdirectory *copy_dir)
 	*entry=0;
 	pd_entry_add_attrib (entry, I86_PDE_PRESENT);
 	pd_entry_add_attrib (entry, I86_PDE_WRITABLE);
+	    pt_entry_add_attrib (entry, I86_PTE_USER);
 	pd_entry_set_frame (entry, (physical_addr)table);
 
 	virt_addr+=1024*4096;
@@ -401,6 +405,7 @@ pdirectory* vmem_new_space_dir(pdirectory *copy_dir)
 	    pt_entry page=0;
 	    pt_entry_add_attrib (&page, I86_PTE_PRESENT);
 	    pt_entry_add_attrib (&page, I86_PTE_WRITABLE);
+	    pt_entry_add_attrib (&page, I86_PTE_USER);
 	    pt_entry_set_frame (&page, frame);
 
 
@@ -413,6 +418,7 @@ pdirectory* vmem_new_space_dir(pdirectory *copy_dir)
 	*entry=0;
 	pd_entry_add_attrib (entry, I86_PDE_PRESENT);
 	pd_entry_add_attrib (entry, I86_PDE_WRITABLE);
+        pt_entry_add_attrib (entry, I86_PTE_USER);
 	pd_entry_set_frame (entry, (physical_addr)table);
 
 	virt_addr+=1024*4096;