From 6c926175afbf1f9ec2715fb007acc28588b36c4a Mon Sep 17 00:00:00 2001
From: Miguel <m.i@gmx.at>
Date: Tue, 21 Aug 2018 17:54:28 +0200
Subject: cleaning up multitasking

---
 kernel/interrupts.c |  1 +
 kernel/kernel.c     |  8 +++----
 kernel/task.c       | 67 ++++++++++++++++++++++++++++++++++++++++++++++++-----
 kernel/usermode.c   | 15 ++++++++----
 4 files changed, 76 insertions(+), 15 deletions(-)

(limited to 'kernel')

diff --git a/kernel/interrupts.c b/kernel/interrupts.c
index 96446f3..9b08475 100644
--- a/kernel/interrupts.c
+++ b/kernel/interrupts.c
@@ -51,6 +51,7 @@ void exception_handle()
 void int_default()
 {
    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"default handler");
+   panic(FOOLOS_MODULE_NAME,"unhandled interrupt (is this a panic or should just iognore?)");
 }
 
 void show_error(uint32_t err)
diff --git a/kernel/kernel.c b/kernel/kernel.c
index ea14869..e1076a9 100644
--- a/kernel/kernel.c
+++ b/kernel/kernel.c
@@ -35,6 +35,7 @@ void kernel_main(uint32_t eax,uint32_t ebx)
 
     // KEYBOARD DRIVER
     keyboard_init(0); //sstdin
+    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"Keyboard Initialized");
 
     // MOUSE DRIVER
     mouse_init();
@@ -80,13 +81,10 @@ void kernel_main(uint32_t eax,uint32_t ebx)
     uint32_t sstdout = syscall_open("term",0,0);    // stdout 1
     uint32_t sstderr = syscall_open("stderr",0,0);  // stderr 2
 
-    // START INTERRUPTS (code segment: 0x08)
+    // INSTALL INTERRUPTS (code segment: 0x08)
     int_init(0x08);
 
-    // INIT MULTITASKING (and switch to our pseudo-usermode)
+    // INIT MULTITASKING (and start scheduler)
     task_init(dir); 
 
-    // we should never reach this
-    panic(FOOLOS_MODULE_NAME,"reached end of kernel.c !!");
-
 }
diff --git a/kernel/task.c b/kernel/task.c
index c281821..395c196 100644
--- a/kernel/task.c
+++ b/kernel/task.c
@@ -45,7 +45,6 @@ volatile int add_task(uint32_t esp, uint32_t vmem)
 	    task_list[i].waiting=false;
 	    task_list[i].skipwait=false;
 	    task_list[i].brk=task_list[current_task].brk;
-
 	    return i;
 	}
     }
@@ -53,9 +52,29 @@ volatile int add_task(uint32_t esp, uint32_t vmem)
     panic(FOOLOS_MODULE_NAME,"out of task slots!");
 }
 
+//
+// REMEMBER WE ARE INSIDE AN INTERRUPT HERE - DON'T WASTE TIME!
+//
+// oldesp - is the adress of the stack pointer when pit_interrupt_handler was entered.
+// registers have been pushed with pusha to this old stack.
+//
+// stack pointer was moved to the 16kb stack we have from multiboot.s
+//
+// we need to return a NEW stack pointer where popa will get the registers the new task requires
+//
+static int first=1;
 volatile uint32_t my_scheduler(uint32_t oldesp)
 {
-    task_list[current_task].esp=oldesp;
+
+    // allows skipping scheduling from gdb 
+    volatile int skippy=0;
+    if(skippy)return oldesp;
+
+    if(!first)
+    {
+	task_list[current_task].esp=oldesp;
+    }
+	first=0;
 
     for(int i=0;i<MAX_TASKS;i++)
     {
@@ -89,6 +108,7 @@ volatile uint32_t task_switch_next(uint32_t oldesp)
 //TODO: notify waiting parent when child finished;
 volatile uint32_t task_exit(uint32_t oldesp)
 { 
+
     task_list[current_task].active=false;
     int parent_pid=task_list[current_task].parent;
 
@@ -140,16 +160,51 @@ volatile uint32_t task_fork(uint32_t oldesp)
 // init task (root of all other tasks / processes) //
 volatile void task_init(pdirectory *dir)
 {
-
+    current_task=0;
+    
     // this is our main task on slot 0 
     task_list[0].parent=0;
     task_list[0].active=true;
     task_list[0].waiting=false;
     task_list[0].vmem=dir;
-    task_list[0].esp = 0; // will be set by next task_switch_next() call.
+    task_list[0].esp = kballoc(4); //  0; // will be set by next task_switch_next() call.
+
+    task_list[1].parent=0;
+    task_list[1].active=true;
+    task_list[1].waiting=false;
+    task_list[1].vmem=dir;
+    task_list[1].esp = kballoc(4); // fresh 16kb stack from here.
+
+    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"fresh esp on: 0x%08X",1,task_list[1].esp);
+    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"fresh esp on: 0x%08X",0,task_list[0].esp);
+
+    task_pusha(task_list[1].esp); // pusha but to alternative location
+    task_pusha(task_list[0].esp); // pusha but to alternative location
+
+    /*
     current_task=0;
-    
-    switch_to_user_mode();
+    unsigned esp, ebp, eax, ebx, ecx, edx;
+
+    asm(
+        "movl %%esp, %0;"
+        "movl %%ebp, %1;"
+        "movl %%eax, %2;"
+        "movl %%ebx, %3;"
+        "movl %%ecx, %4;"
+        "movl %%edx, %5;"
+        :"=r"(esp), "=r"(ebp), "=r"(eax), "=r"(ebx), "=r"(ecx), "=r"(edx)
+        );
+
+    // TODO: prepare stack so popa get's what it wants!
+    int i=task_fork(esp);
+    */
+
+    // finally enable interrrupts so the scheduler is called (by timer)
+    x86_sti(); 
+
+    // loop until scheduler kicks in and reschedules us...
+    while(1);
+
 }
 
 volatile int task_get_current_pid()
diff --git a/kernel/usermode.c b/kernel/usermode.c
index 76558d8..81dc5c1 100644
--- a/kernel/usermode.c
+++ b/kernel/usermode.c
@@ -26,11 +26,18 @@ void install_tss(int cpu_no){
     // sys_tss.iomap = ( unsigned short ) sizeof( tss_struct ); 
 }
 
-// THIS IS THE FUNCTION TO BE RUN IN RING 3 // USER MODE
-static void userfunc()
+void userfunc()
 {
-    syscall(SYSCALL_EXECVE,BIN_INIT,NULL,NULL); 
-    while(1); // we should never get here.
+    // we need enable here again (since the pushed eflags have it disabled)!
+    x86_sti(); 
+
+    // if we are pid 0, replace ourselves with /bin/init TODO: switch to usermode before!
+    if(task_get_current_pid()==0)syscall(SYSCALL_EXECVE,BIN_INIT,NULL,NULL); 
+
+    // kernel worker thread
+    if(task_get_current_pid()==1)
+    {
+    }
 }
 
 void switch_to_user_mode() 
-- 
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