From fa495da049037c356b8bb4a3a29416aeb335887c Mon Sep 17 00:00:00 2001 From: Alex Auvolat Date: Mon, 8 Dec 2014 14:16:11 +0100 Subject: Implement create_pagedir and delete_pagedir (not really tested yet) --- kernel/l0/paging.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file 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 #include #include +#include #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 :*/ -- cgit v1.2.3