From 1d49cf3e7dc4bf8bc8a646b22365b23099ea8932 Mon Sep 17 00:00:00 2001 From: Ben Pfaff Date: Thu, 13 Apr 2006 17:35:41 +0000 Subject: [PATCH 1/1] Improve wording. --- src/userprog/pagedir.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/src/userprog/pagedir.c b/src/userprog/pagedir.c index ea3c1f4..b242d3b 100644 --- a/src/userprog/pagedir.c +++ b/src/userprog/pagedir.c @@ -85,8 +85,9 @@ lookup_page (uint32_t *pd, const void *vaddr, bool create) return &pt[pt_no (vaddr)]; } -/* Adds a mapping from user virtual page UPAGE to kernel virtual - address KPAGE in page directory PD. +/* Adds a mapping in page directory PD from user virtual page + UPAGE to the physical frame identified by kernel virtual + address KPAGE. UPAGE must not already be mapped. KPAGE should probably be a page obtained from the user pool with palloc_get_page(). @@ -118,9 +119,10 @@ pagedir_set_page (uint32_t *pd, void *upage, void *kpage, return false; } -/* Returns the kernel virtual address that user virtual address - UADDR is mapped to in PD, or a null pointer if UADDR is not - present. */ +/* Looks up the physical address that corresponds to user virtual + address UADDR in PD. Returns the kernel virtual address + corresponding to that physical address, or a null pointer if + UADDR is unmapped. */ void * pagedir_get_page (uint32_t *pd, const void *uaddr) { @@ -255,8 +257,7 @@ invalidate_pagedir (uint32_t *pd) { if (active_pd () == pd) { - /* We cleared a page-table entry in the active page table, - so we have to invalidate the TLB. See [IA32-v3a] 3.12 + /* Re-activating PD clears the TLB. See [IA32-v3a] 3.12 "Translation Lookaside Buffers (TLBs)". */ pagedir_activate (pd); } -- 2.30.2