stv0g/metalsvm
1
0
Fork 0
Code Issues Pull requests Releases Wiki Activity

fix bug in the TSS initialization for a new task, which is a copy of the current task

Browse source
This commit is contained in:
Stefan Lankes 2011-04-18 12:18:59 -07:00
parent bd703f6be4
commit 4fc507bc6b
1 changed files with 19 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

23
arch/x86/kernel/gdt.c
View file

@ -58,6 +58,8 @@ int register_task(task_t* task) {
int arch_fork(task_t* task)
{
uint16_t cs = 0x08;
uint16_t ds = 0x10;
uint32_t id;
task_t* curr_task = per_core(current_task);
@ -65,11 +67,24 @@ int arch_fork(task_t* task)
return -EINVAL;
id = task->id;
memcpy(task_state_segments+id, task_state_segments+curr_task->id, sizeof(tss_t));
// copy kernel stack of the current task
memcpy(kstacks[id], kstacks[curr_task->id], KERNEL_STACK_SIZE);
// reset TSS
memset(task_state_segments+id, 0x00, sizeof(tss_t));
// set default values of all registers
task_state_segments[id].cs = cs;
task_state_segments[id].ss = ds;
task_state_segments[id].ds = ds;
task_state_segments[id].fs = ds;
task_state_segments[id].gs = ds;
task_state_segments[id].es = ds;
task_state_segments[id].cr3 = (uint32_t) (virt_to_phys((size_t)task->pgd));
task_state_segments[id].ss0 = ds;
task_state_segments[id].esp0 = (uint32_t) kstacks[id] + KERNEL_STACK_SIZE - sizeof(size_t);
// save curret task context
asm volatile("mov %%esp, %0" : "=r"(task_state_segments[id].esp));
task_state_segments[id].esp -= (uint32_t) kstacks[curr_task->id];
task_state_segments[id].esp += (uint32_t) kstacks[id];
@ -90,9 +105,9 @@ int arch_fork(task_t* task)
// store current EFLAGS and set IF flag
// => the parent task will enable the interrupt handling
task_state_segments[id].eflags = read_eflags() | (1 << 9);
asm volatile ("pushf; pop %%eax; or $2,%%ah" : "=a"(task_state_segments[id].eflags));
// This will be the entry point for the new task.
task_state_segments[id].eip = read_eip();
asm volatile ("call read_eip" : "=a"(task_state_segments[id].eip));
return 0;
}
@ -111,7 +126,7 @@ int create_default_frame(task_t* task, entry_point_t ep, void* arg)
memset(task_state_segments+id, 0x00, sizeof(tss_t));
memset(kstacks[id], 0xCD, KERNEL_STACK_SIZE);
/* set default values of all regsiters */
/* set default values of all registers */
task_state_segments[id].cs = cs;
task_state_segments[id].ss = ds;
task_state_segments[id].ds = ds;