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Enable tasks execution and syscalls

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This commit is contained in:
Loic Guegan 2021-04-10 17:24:13 +02:00
parent c6aa00eea7
commit 242fe4a575
6 changed files with 88 additions and 16 deletions
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34
src/bringelle.c
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@ -2,10 +2,15 @@
#include "utils/pic.h"
#include "boot/multiboot.h"
#include "utils/mem.h"
#include "utils/gdt.h"
char show_tics=0;
extern GDT_TSS TSS;
void utask(){
char msg[]="Message from the task :D";
asm("mov $0x1, %%eax;int $0x30"::"b"(msg));
while(1);
}
@ -15,14 +20,33 @@ void bringelle(){
// Kernel boot sequence
pic_enable_interrupt();
print("Interrupts enabled!\n");
print("Interrupts enabled\n");
print("Kernel started !\n");
// Utask
memcpy((void*)utask,(void*)0x300000, 100); // 100 bytes seems reasonable to load utask
print("Kernel started ");
print("Launch user task ");
show_tics=1;
memcpy((void*)utask,(void*)0x300000, 100); // 100 bytes seems reasonable to load utask
asm (
"cli \n\t" // Ensure we do not get interrupted
"movl %%ss, %%eax \n\t"
"movl %%eax, %0 \n\t" // Save kernel ss segment into the TSS
"movl %%esp, %1 \n\t" // Save kernel esp into the TSS BEFORE setting up the stack
"pushl $0x33 \n\t" // Push task ss which is 0x30 along with prlv which is 0x3
"pushl $0x400000 \n\t" // Push task esp
"pushfl \n\t" // Retrieve flags
"popl %%eax \n\t"
"orl $0x200, %%eax \n\t" // Enable interrupt for the user task
"and $0xffffbfff, %%eax \n\t" // Clear the NT flags
"push %%eax \n\t" // Push task flags
"push $0x23 \n\t" // Push task cs which is 0x20 along with prlv which is 0x3
"push $0 \n\t" // Push task entry point
"mov $0x2B, %%eax \n\t" // GDT entry 0x28 along with prlv which is 0x3
"mov %%eax, %%ds \n\t" // Setting up user data segment
"iret \n\t" // Launch user task
: "=m" (TSS.ss0), "=m" (TSS.esp0)
);
while(1);
}