Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262366AbVDGBLB (ORCPT ); Wed, 6 Apr 2005 21:11:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262367AbVDGBLB (ORCPT ); Wed, 6 Apr 2005 21:11:01 -0400 Received: from bay-bridge.veritas.com ([143.127.3.10]:13566 "EHLO MTVMIME03.enterprise.veritas.com") by vger.kernel.org with ESMTP id S262366AbVDGBKW (ORCPT ); Wed, 6 Apr 2005 21:10:22 -0400 Date: Thu, 7 Apr 2005 02:10:27 +0100 (BST) From: Hugh Dickins X-X-Sender: hugh@goblin.wat.veritas.com To: Andrew Morton cc: Nick Piggin , Russell King , linux-kernel@vger.kernel.org Subject: [PATCH 1/6] freepgt2: free_pgtables from FIRST_USER_ADDRESS Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2577 Lines: 65 The patches to free_pgtables by vma left problems on any architectures which leave some user address page table entries unencapsulated by vma. Andi has fixed the 32-bit vDSO on x86_64 to use a vma. Now fix arm (and arm26), whose first PAGE_SIZE is reserved (perhaps) for machine vectors. Our calls to free_pgtables must not touch that area, and exit_mmap's BUG_ON(nr_ptes) must allow that arm's get_pgd_slow may (or may not) have allocated an extra page table, which its free_pgd_slow would free later. FIRST_USER_PGD_NR has misled me and others: until all the arches define FIRST_USER_ADDRESS instead, a hack in mmap.c to derive one from t'other. This patch fixes the bugs, the remaining patches just clean it up. Signed-off-by: Hugh Dickins --- mm/mmap.c | 11 ++++++++--- 1 files changed, 8 insertions(+), 3 deletions(-) --- 2.6.12-rc2-mm1/mm/mmap.c 2005-04-05 15:23:00.000000000 +0100 +++ linux/mm/mmap.c 2005-04-05 18:59:01.000000000 +0100 @@ -1608,6 +1608,11 @@ static void unmap_vma_list(struct mm_str validate_mm(mm); } +#ifndef FIRST_USER_ADDRESS /* temporary hack */ +#define THIS_IS_ARM FIRST_USER_PGD_NR +#define FIRST_USER_ADDRESS (THIS_IS_ARM * PAGE_SIZE) +#endif + /* * Get rid of page table information in the indicated region. * @@ -1626,7 +1631,7 @@ static void unmap_region(struct mm_struc tlb = tlb_gather_mmu(mm, 0); unmap_vmas(&tlb, mm, vma, start, end, &nr_accounted, NULL); vm_unacct_memory(nr_accounted); - free_pgtables(&tlb, vma, prev? prev->vm_end: 0, + free_pgtables(&tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS, next? next->vm_start: 0); tlb_finish_mmu(tlb, start, end); spin_unlock(&mm->page_table_lock); @@ -1906,7 +1911,7 @@ void exit_mmap(struct mm_struct *mm) /* Use -1 here to ensure all VMAs in the mm are unmapped */ end = unmap_vmas(&tlb, mm, vma, 0, -1, &nr_accounted, NULL); vm_unacct_memory(nr_accounted); - free_pgtables(&tlb, vma, 0, 0); + free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); tlb_finish_mmu(tlb, 0, end); mm->mmap = mm->mmap_cache = NULL; @@ -1927,7 +1932,7 @@ void exit_mmap(struct mm_struct *mm) vma = next; } - BUG_ON(mm->nr_ptes); /* This is just debugging */ + BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); } /* Insert vm structure into process list sorted by address - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/