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during the context switch, we have to update esp0 in TSS

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This commit is contained in:
Stefan Lankes 2014-01-22 16:47:01 +01:00
parent aed7b1ce8d
commit b3fb07c4f6
2 changed files with 17 additions and 4 deletions
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4
arch/x86/kernel/entry.asm
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@ -199,6 +199,7 @@ isrstub_pseudo_error 9
extern irq_handler extern irq_handler
extern get_current_stack extern get_current_stack
extern finish_task_switch extern finish_task_switch
extern set_kernel_stack
global switch_context global switch_context
ALIGN 4 ALIGN 4
@ -249,6 +250,9 @@ common_switch:
or eax, 8 or eax, 8
mov cr0, eax mov cr0, eax
; set esp0 in the task state segment
call set_kernel_stack
; call cleanup code ; call cleanup code
call finish_task_switch call finish_task_switch

17
arch/x86/kernel/gdt.c
View file

@ -35,7 +35,7 @@
#include <asm/gdt.h> #include <asm/gdt.h>
#include <asm/tss.h> #include <asm/tss.h>
gdt_ptr_t gp; gdt_ptr_t gp;
static tss_t task_state_segment __attribute__ ((aligned (PAGE_SIZE))); static tss_t task_state_segment __attribute__ ((aligned (PAGE_SIZE)));
// currently, our kernel has full access to the ioports // currently, our kernel has full access to the ioports
static gdt_entry_t gdt[GDT_ENTRIES] = {[0 ... GDT_ENTRIES-1] = {0, 0, 0, 0, 0, 0}}; static gdt_entry_t gdt[GDT_ENTRIES] = {[0 ... GDT_ENTRIES-1] = {0, 0, 0, 0, 0, 0}};
@ -46,6 +46,13 @@ static gdt_entry_t gdt[GDT_ENTRIES] = {[0 ... GDT_ENTRIES-1] = {0, 0, 0, 0, 0,
*/ */
extern void gdt_flush(void); extern void gdt_flush(void);
void set_kernel_stack(void)
{
task_t* curr_task = current_task;
task_state_segment.esp0 = (size_t) curr_task->stack + KERNEL_STACK_SIZE-16;
}
/* Setup a descriptor in the Global Descriptor Table */ /* Setup a descriptor in the Global Descriptor Table */
void gdt_set_gate(int num, unsigned long base, unsigned long limit, void gdt_set_gate(int num, unsigned long base, unsigned long limit,
unsigned char access, unsigned char gran) unsigned char access, unsigned char gran)
@ -122,13 +129,15 @@ void gdt_install(void)
* Create data segement for userspace applications (ring 3) * Create data segement for userspace applications (ring 3)
*/ */
gdt_set_gate(4, 0, limit, gdt_set_gate(4, 0, limit,
GDT_FLAG_RING3 | GDT_FLAG_SEGMENT | GDT_FLAG_DATASEG | GDT_FLAG_PRESENT, GDT_FLAG_RING3 | GDT_FLAG_SEGMENT | GDT_FLAG_DATASEG | GDT_FLAG_PRESENT,
GDT_FLAG_4K_GRAN | mode); GDT_FLAG_4K_GRAN | mode);
/* set default values */ /* set default values */
task_state_segment.eflags = 0x1202; task_state_segment.eflags = 0x1202;
task_state_segment.ss0 = 0x10; // data segment task_state_segment.ss0 = 0x10; // data segment
task_state_segment.esp0 = 0xDEADBEEF; // invalid pseudo address task_state_segment.esp0 = 0xDEADBEEF; // invalid pseudo address
task_state_segment.cs = 0x0b;
task_state_segment.ss = task_state_segment.ds = task_state_segment.es = task_state_segment.fs = task_state_segment.gs = 0x13;
gdt_set_gate(5, (unsigned long) (&task_state_segment), sizeof(tss_t)-1, gdt_set_gate(5, (unsigned long) (&task_state_segment), sizeof(tss_t)-1,
GDT_FLAG_PRESENT | GDT_FLAG_TSS | GDT_FLAG_RING0, mode); GDT_FLAG_PRESENT | GDT_FLAG_TSS | GDT_FLAG_RING0, mode);