diff options
Diffstat (limited to 'kernel/vm')
| -rw-r--r-- | kernel/vm/pagefault.c | 81 | ||||
| -rw-r--r-- | kernel/vm/shadow.c | 111 | ||||
| -rw-r--r-- | kernel/vm/vmmap.c | 4 |
3 files changed, 98 insertions, 98 deletions
diff --git a/kernel/vm/pagefault.c b/kernel/vm/pagefault.c index b289537..39e5776 100644 --- a/kernel/vm/pagefault.c +++ b/kernel/vm/pagefault.c @@ -49,80 +49,87 @@ void handle_pagefault(uintptr_t vaddr, uintptr_t cause) { dbg(DBG_VM, "vaddr = 0x%p (0x%p), cause = %lu\n", (void *)vaddr, PAGE_ALIGN_DOWN(vaddr), cause); + // NOT_YET_IMPLEMENTED("VM: handle_pagefault"); - // 1) Find the vmarea that contains vaddr, if it exists. - // check that the vaddr is valid - if (vaddr < USER_MEM_LOW || vaddr > USER_MEM_HIGH) + // Check that the vaddr is valid + if (vaddr < USER_MEM_LOW) { do_exit(EFAULT); } - // lookup the vmarea for this addr - vmarea_t *vma = vmmap_lookup(curproc->p_vmmap, ADDR_TO_PN(vaddr)); - if (vma == NULL) + if (vaddr > USER_MEM_HIGH) { do_exit(EFAULT); } - // 2) Check the vmarea's protections (see the vmarea_t struct) against the 'cause' - // error out if the fault has cause write and we don't have write permission in the area - if ((cause & FAULT_WRITE) && !(vma->vma_prot & PROT_WRITE)) + // Lookup the vmarea for this address + size_t pn = ADDR_TO_PN(vaddr); + vmarea_t* vma = vmmap_lookup(curproc->p_vmmap, pn); + if (!vma) { do_exit(EFAULT); } - // error out if the fault has cause exec and we don't have exec permission in the area - if ((cause & FAULT_EXEC) && !(vma->vma_prot & PROT_EXEC)) + + // Error out if we don't have any permission in the area + if (vma->vma_prot == PROT_NONE) { do_exit(EFAULT); } - // error out if we don't have read permission in the area - if (!(vma->vma_prot & PROT_READ)) + + // Check the vmarea's protections (see the vmarea_t struct) against the 'cause' of the pagefault + if ((cause & FAULT_WRITE) && !(vma->vma_prot & PROT_WRITE)) { do_exit(EFAULT); - } - // error our if we don't have any permission in the area - if (vma->vma_prot == PROT_NONE) + } + else if ((cause & FAULT_EXEC) && !(vma->vma_prot & PROT_EXEC)) + { + do_exit(EFAULT); + } + else if (!(vma->vma_prot & PROT_READ)) { do_exit(EFAULT); } - // 3) Obtain the corresponding pframe from the vmarea's mobj. - pframe_t *pf; + // Obtain the corresponding pframe from the vmarea's mobj + long forwrite = 0; + if (cause & FAULT_WRITE) + { + forwrite = 1; + } + pframe_t* pfp; mobj_lock(vma->vma_obj); - int ret = mobj_get_pframe( + long status = mobj_get_pframe( vma->vma_obj, - vma->vma_off + ADDR_TO_PN(vaddr) - vma->vma_start, - cause & FAULT_WRITE ? 1 : 0, - &pf + pn - vma->vma_start + vma->vma_off, + forwrite, + &pfp ); mobj_unlock(vma->vma_obj); - if (ret < 0) + if (status < 0) { do_exit(EFAULT); } - // 4) Finally, set up a call to pt_map to insert a new mapping into the appropriate pagetable - uintptr_t paddr = pt_virt_to_phys(pf->pf_addr); - pframe_release(&pf); - int pdflags = PT_PRESENT | PT_WRITE | PT_USER; - int ptflags = PT_PRESENT | PT_USER; - if (cause & FAULT_WRITE) + // Set up a call to pt_map to insert a new mapping into the appropriate pagetable + uintptr_t paddr = pt_virt_to_phys((uintptr_t) pfp->pf_addr); + pframe_release(&pfp); + uint32_t ptflags = PT_PRESENT | PT_USER; + if (cause & FAULT_WRITE) { ptflags |= PT_WRITE; } - - int err = pt_map( + status = pt_map( curproc->p_pml4, - paddr, - (uintptr_t) PAGE_ALIGN_DOWN(vaddr), - pdflags, + paddr, + (uintptr_t) PAGE_ALIGN_DOWN(vaddr), + PT_PRESENT | PT_USER | PT_WRITE, ptflags ); - if (err < 0) + if (status < 0) { do_exit(EFAULT); } - // 5) Flush the TLB - tlb_flush((uintptr_t) PAGE_ALIGN_DOWN(vaddr)); + // Flush the TLB + tlb_flush(vaddr); } diff --git a/kernel/vm/shadow.c b/kernel/vm/shadow.c index 06cf20d..4883160 100644 --- a/kernel/vm/shadow.c +++ b/kernel/vm/shadow.c @@ -43,6 +43,7 @@ void shadow_init() { // NOT_YET_IMPLEMENTED("VM: shadow_init"); shadow_allocator = slab_allocator_create("shadow", sizeof(mobj_shadow_t)); + KASSERT(shadow_allocator); } /* @@ -55,7 +56,7 @@ void shadow_init() * 2) Set up the bottom object of the shadow chain, which could have two cases: * a) Either shadowed is a shadow object, and you can use its bottom_mobj * b) Or shadowed is not a shadow object, in which case it is the bottom - * object of this chain. + * object of this chain.shadow_create * * Make sure to manage the refcounts correctly. */ @@ -63,6 +64,11 @@ mobj_t *shadow_create(mobj_t *shadowed) { // NOT_YET_IMPLEMENTED("VM: shadow_create"); + if (!shadowed) + { + return NULL; + } + // create a new shadow object mobj_shadow_t *so = (mobj_shadow_t *)slab_obj_alloc(shadow_allocator); if (!so) @@ -142,46 +148,41 @@ static long shadow_get_pframe(mobj_t *o, size_t pagenum, long forwrite, pframe_t **pfp) { // NOT_YET_IMPLEMENTED("VM: shadow_get_pframe"); - - // if forwrite is set, use mobj_default_get_pframe + // return 0; if (forwrite) { return mobj_default_get_pframe(o, pagenum, forwrite, pfp); } - - // else, check if the object already contains the desired frame + // check if o already contains the desired frame. pframe_t *pf = NULL; mobj_find_pframe(o, pagenum, &pf); if (pf) { - // if it does, return the pframe *pfp = pf; return 0; } - // iterate through the shadow chain to find the nearest shadow mobj that has the frame - mobj_shadow_t *so = MOBJ_TO_SO(o); - mobj_t *iter = so->shadowed; - while (iter && iter->mo_type == MOBJ_SHADOW) + mobj_shadow_t *shadow = MOBJ_TO_SO(o); + mobj_t *current = shadow->shadowed; + + while (current && current->mo_type == MOBJ_SHADOW) { - mobj_lock(iter); - mobj_find_pframe(iter, pagenum, &pf); - mobj_unlock(iter); + mobj_lock(current); + mobj_find_pframe(current, pagenum, &pf); + mobj_unlock(current); + if (pf) { *pfp = pf; return 0; } - // update the iterator - so = MOBJ_TO_SO(iter); - iter = so->shadowed; - } - // if no shadow objects have the page, call mobj_get_pframe() to get the page from the bottom object - // at this point, iter is the bottom object - mobj_lock(so->bottom_mobj); - long ret = mobj_get_pframe(so->bottom_mobj, pagenum, forwrite, pfp); - mobj_unlock(so->bottom_mobj); + shadow = MOBJ_TO_SO(current); + current = shadow->shadowed; + } + mobj_lock(shadow->bottom_mobj); + long ret = mobj_get_pframe(shadow->bottom_mobj, pagenum, forwrite, pfp); + mobj_unlock(shadow->bottom_mobj); return ret; } @@ -208,48 +209,39 @@ static long shadow_get_pframe(mobj_t *o, size_t pagenum, long forwrite, */ static long shadow_fill_pframe(mobj_t *o, pframe_t *pf) { - // NOT_YET_IMPLEMENTEDshadow_fill_pframe"); + // NOT_YET_IMPLEMENTED("VM: shadow_fill_pframe"); + // return -1; + pframe_t *pf_shadow = NULL; + long ret = 0; + - // get the mobj_shadow_t mobj_shadow_t *so = MOBJ_TO_SO(o); - // iterate over the shadow chain - mobj_t *iter = so->shadowed; - while (iter && iter->mo_type == MOBJ_SHADOW) + mobj_t *shadowed = so->shadowed; + while (shadowed && shadowed->mo_type == MOBJ_SHADOW) { - // get the pframe from the shadow object - pframe_t *spf = NULL; - mobj_lock(iter); - mobj_find_pframe(iter, pf->pf_pagenum, &spf); - mobj_unlock(iter); + mobj_lock(shadowed); + mobj_find_pframe(shadowed, pf->pf_pagenum, &pf_shadow); + mobj_unlock(shadowed); - // if the pframe is found, copy the contents into pf - // then release the pframe - if (spf) + if (pf_shadow) { - memcpy(pf->pf_addr, spf->pf_addr, PAGE_SIZE); - pframe_release(&spf); + memcpy(pf->pf_addr, pf_shadow->pf_addr, PAGE_SIZE); + pframe_release(&pf_shadow); return 0; } - // update the iterator - so = MOBJ_TO_SO(iter); - iter = so->shadowed; + so = MOBJ_TO_SO(shadowed); + shadowed = so->shadowed; } - - // if none of the shadow objects have a copy of the frame, use mobj_get_pframe on the bottom object - pframe_t *spf = NULL; mobj_lock(so->bottom_mobj); - long ret = mobj_get_pframe(so->bottom_mobj, pf->pf_pagenum, 0, &spf); + ret = mobj_get_pframe(so->bottom_mobj, pf->pf_pagenum, 0, &pf_shadow); mobj_unlock(so->bottom_mobj); - // check if the operation was sucessful, memcpy the contents into pf - // and release the pframe - if (ret >= 0) - { - memcpy(pf->pf_addr, spf->pf_addr, PAGE_SIZE); - pframe_release(&spf); + if (ret < 0) { + return ret; } - - return ret; + memcpy(pf->pf_addr, pf_shadow->pf_addr, PAGE_SIZE); + pframe_release(&pf_shadow); + return 0; } /* @@ -264,6 +256,7 @@ static long shadow_fill_pframe(mobj_t *o, pframe_t *pf) static long shadow_flush_pframe(mobj_t *o, pframe_t *pf) { // NOT_YET_IMPLEMENTED("VM: shadow_flush_pframe"); + // return -1; return 0; } @@ -280,17 +273,17 @@ static long shadow_flush_pframe(mobj_t *o, pframe_t *pf) static void shadow_destructor(mobj_t *o) { // NOT_YET_IMPLEMENTED("VM: shadow_destructor"); + mobj_default_destructor(o); - // get the mobj_shadow_t mobj_shadow_t *so = MOBJ_TO_SO(o); + // dbg(DBG_PROC, "shadow_destructor: refcount bottom: %d\n", so->bottom_mobj->mo_refcount); + // dbg(DBG_PROC, "shadow_destructor: refcount: %d\n", so->shadowed->mo_refcount); - // call the default destructor - mobj_default_destructor(o); - - // put the shadow and bottom_mobj + // put the shadow and bottom_mobj members of the shadow object mobj_put(&so->shadowed); mobj_put(&so->bottom_mobj); - // free the slab slab_obj_free(shadow_allocator, so); -}
\ No newline at end of file + + return; +} diff --git a/kernel/vm/vmmap.c b/kernel/vm/vmmap.c index 8c1a455..5f8e575 100644 --- a/kernel/vm/vmmap.c +++ b/kernel/vm/vmmap.c @@ -169,7 +169,7 @@ void vmmap_insert(vmmap_t *map, vmarea_t *new_vma) */ ssize_t vmmap_find_range(vmmap_t *map, size_t npages, int dir) { - // NOT_YET_IMPLEMENTED("VM: vmmap_find_range"); + // : vmmap_find_range"); // case 1: dir is VMMAP_DIR_LOHI if (dir == VMMAP_DIR_LOHI) @@ -871,4 +871,4 @@ end: buf[osize - 1] = '\0'; } return osize - size; -} +}
\ No newline at end of file |