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authorAlex Auvolat <alex.auvolat@ens.fr>2014-12-08 14:16:11 +0100
committerAlex Auvolat <alex.auvolat@ens.fr>2014-12-08 14:16:11 +0100
commitfa495da049037c356b8bb4a3a29416aeb335887c (patch)
tree8acba9c707b0ee8d0b96a029e2335b6f5a292c4b /kernel/l0
parent0a88479bf59b8f6dcea55340cb121bc644f4cfac (diff)
downloadmacroscope-fa495da049037c356b8bb4a3a29416aeb335887c.tar.gz
macroscope-fa495da049037c356b8bb4a3a29416aeb335887c.zip
Implement create_pagedir and delete_pagedir (not really tested yet)
Diffstat (limited to 'kernel/l0')
-rw-r--r--kernel/l0/paging.c68
1 files changed, 66 insertions, 2 deletions
diff --git a/kernel/l0/paging.c b/kernel/l0/paging.c
index 9879c9f..b8fd454 100644
--- a/kernel/l0/paging.c
+++ b/kernel/l0/paging.c
@@ -5,6 +5,7 @@
#include <region.h>
#include <mutex.h>
#include <task.h>
+#include <kmalloc.h>
#define PAGE_OF_ADDR(x) (((size_t)x >> PAGE_SHIFT) % N_PAGES_IN_PT)
#define PT_OF_ADDR(x) ((size_t)x >> (PAGE_SHIFT + PT_SHIFT))
@@ -225,10 +226,73 @@ void pd_unmap_page(void* vaddr) {
// Creation and deletion of page directories
pagedir_t *create_pagedir() {
- return 0; // TODO
+ uint32_t pd_phys = 0;
+ pagedir_t *pd = 0;
+ void* temp = 0;
+
+ pd_phys = frame_alloc(1);
+ if (pd_phys == 0) goto error;
+
+ pd = (pagedir_t*)kmalloc(sizeof(pagedir_t));
+ if (pd == 0) goto error;
+
+ temp = region_alloc(PAGE_SIZE, 0, 0);
+ if (temp == 0) goto error;
+
+ int error = pd_map_page(temp, pd_phys, true);
+ if (error) goto error;
+
+ pd->phys_addr = pd_phys * PAGE_SIZE;
+ pd->mutex = MUTEX_UNLOCKED;
+
+ // initialize PD with zeroes
+ pagetable_t *pt = (pagetable_t*)temp;
+ for (size_t i = 0; i < N_PAGES_IN_PT; i++) {
+ pt->page[i] = 0;
+ }
+ // use kernel page tables
+ for(size_t i = FIRST_KERNEL_PT; i < N_PAGES_IN_PT-1; i++) {
+ pt->page[i] = kernel_pd.page[i];
+ }
+ // set up mirroring
+ pt->page[N_PAGES_IN_PT-1] = pd->phys_addr | PTE_PRESENT | PTE_RW;
+
+ region_free_unmap(temp);
+
+ return pd;
+
+ error:
+ if (pd_phys != 0) frame_free(pd_phys, 1);
+ if (pd != 0) kfree(pd);
+ if (temp != 0) region_free(temp);
+ return 0;
}
+
void delete_pagedir(pagedir_t *pd) {
- return; // TODO
+ pagedir_t *restore_pd = get_current_pagedir();
+ if (restore_pd == pd) restore_pd = &kernel_pd_d;
+
+ // make a copy of page directory on the stack
+ switch_pagedir(pd);
+ pagetable_t backup;
+ for (size_t i = 0; i < N_PAGES_IN_PT; i++) {
+ backup.page[i] = current_pd->page[i];
+ }
+ switch_pagedir(restore_pd);
+
+ // free the page tables
+ for (size_t i = 0; i < FIRST_KERNEL_PT; i++) {
+ if (backup.page[i] & PTE_PRESENT)
+ frame_free(backup.page[i] >> PTE_FRAME_SHIFT, 1);
+ }
+ // free the page directory page
+ uint32_t pd_phys = pd->phys_addr / PAGE_SIZE;
+ ASSERT(pd_phys == (backup.page[N_PAGES_IN_PT-1] >> PTE_FRAME_SHIFT));
+ frame_free(pd_phys, 1);
+ // free the pagedir_t structure
+ kfree(pd);
+
+ return;
}
/* vim: set ts=4 sw=4 tw=0 noet :*/