From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933873Ab3BMLj7 (ORCPT ); Wed, 13 Feb 2013 06:39:59 -0500 Received: from fw-tnat.cambridge.arm.com ([217.140.96.21]:55630 "EHLO cam-smtp0.cambridge.arm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754611Ab3BMLj4 (ORCPT ); Wed, 13 Feb 2013 06:39:56 -0500 From: Catalin Marinas To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, Andrea Arcangeli , Russell King Subject: [PATCH] mm: Limit pgd range freeing to mm->task_size Date: Wed, 13 Feb 2013 11:39:29 +0000 Message-Id: <1360755569-27282-1-git-send-email-catalin.marinas@arm.com> X-Mailer: git-send-email 1.7.12.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ARM processors with LPAE enabled use 3 levels of page tables, with an entry in the top level (pgd) covering 1GB of virtual space. Because of the branch relocation limitations on ARM, the loadable modules are mapped 16MB below PAGE_OFFSET, making the corresponding 1GB pgd shared between kernel modules and user space. Since free_pgtables() is called with ceiling == 0, free_pgd_range() (and subsequently called functions) also frees the page table shared between user space and kernel modules (which is normally handled by the ARM-specific pgd_free() function). This patch changes the ceiling argument to mm->task_size for the free_pgtables() and free_pgd_range() function calls. We cannot use TASK_SIZE since this macro may not be a run-time constant on 64-bit systems supporting compat applications. Signed-off-by: Catalin Marinas Cc: Andrea Arcangeli Cc: Russell King --- Hi Andrew, I posted this patch a couple of times in the past. The latest incarnation (using mm->task_size instead of TASK_SIZE) is a result of discussions I had with Andrea and benh at the last KS. Do you have any comments on it? It fixes a problem on ARM (32-bit) with LPAE. Thanks. fs/exec.c | 4 ++-- mm/mmap.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 20df02c..04c1534 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -613,7 +613,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) * when the old and new regions overlap clear from new_end. */ free_pgd_range(&tlb, new_end, old_end, new_end, - vma->vm_next ? vma->vm_next->vm_start : 0); + vma->vm_next ? vma->vm_next->vm_start : mm->task_size); } else { /* * otherwise, clean from old_start; this is done to not touch @@ -622,7 +622,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) * for the others its just a little faster. */ free_pgd_range(&tlb, old_start, old_end, new_end, - vma->vm_next ? vma->vm_next->vm_start : 0); + vma->vm_next ? vma->vm_next->vm_start : mm->task_size); } tlb_finish_mmu(&tlb, new_end, old_end); diff --git a/mm/mmap.c b/mm/mmap.c index 35730ee..e15d294 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2262,7 +2262,7 @@ static void unmap_region(struct mm_struct *mm, update_hiwater_rss(mm); unmap_vmas(&tlb, vma, start, end); free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, - next ? next->vm_start : 0); + next ? next->vm_start : mm->task_size); tlb_finish_mmu(&tlb, start, end); } @@ -2640,7 +2640,7 @@ void exit_mmap(struct mm_struct *mm) /* Use -1 here to ensure all VMAs in the mm are unmapped */ unmap_vmas(&tlb, vma, 0, -1); - free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); + free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, mm->task_size); tlb_finish_mmu(&tlb, 0, -1); /* From mboxrd@z Thu Jan 1 00:00:00 1970 From: Catalin Marinas Subject: [PATCH] mm: Limit pgd range freeing to mm->task_size Date: Wed, 13 Feb 2013 11:39:29 +0000 Message-ID: <1360755569-27282-1-git-send-email-catalin.marinas@arm.com> Return-path: Sender: owner-linux-mm@kvack.org To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, Andrea Arcangeli , Russell King List-Id: linux-arch.vger.kernel.org ARM processors with LPAE enabled use 3 levels of page tables, with an entry in the top level (pgd) covering 1GB of virtual space. Because of the branch relocation limitations on ARM, the loadable modules are mapped 16MB below PAGE_OFFSET, making the corresponding 1GB pgd shared between kernel modules and user space. Since free_pgtables() is called with ceiling == 0, free_pgd_range() (and subsequently called functions) also frees the page table shared between user space and kernel modules (which is normally handled by the ARM-specific pgd_free() function). This patch changes the ceiling argument to mm->task_size for the free_pgtables() and free_pgd_range() function calls. We cannot use TASK_SIZE since this macro may not be a run-time constant on 64-bit systems supporting compat applications. Signed-off-by: Catalin Marinas Cc: Andrea Arcangeli Cc: Russell King --- Hi Andrew, I posted this patch a couple of times in the past. The latest incarnation (using mm->task_size instead of TASK_SIZE) is a result of discussions I had with Andrea and benh at the last KS. Do you have any comments on it? It fixes a problem on ARM (32-bit) with LPAE. Thanks. fs/exec.c | 4 ++-- mm/mmap.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 20df02c..04c1534 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -613,7 +613,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) * when the old and new regions overlap clear from new_end. */ free_pgd_range(&tlb, new_end, old_end, new_end, - vma->vm_next ? vma->vm_next->vm_start : 0); + vma->vm_next ? vma->vm_next->vm_start : mm->task_size); } else { /* * otherwise, clean from old_start; this is done to not touch @@ -622,7 +622,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) * for the others its just a little faster. */ free_pgd_range(&tlb, old_start, old_end, new_end, - vma->vm_next ? vma->vm_next->vm_start : 0); + vma->vm_next ? vma->vm_next->vm_start : mm->task_size); } tlb_finish_mmu(&tlb, new_end, old_end); diff --git a/mm/mmap.c b/mm/mmap.c index 35730ee..e15d294 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2262,7 +2262,7 @@ static void unmap_region(struct mm_struct *mm, update_hiwater_rss(mm); unmap_vmas(&tlb, vma, start, end); free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, - next ? next->vm_start : 0); + next ? next->vm_start : mm->task_size); tlb_finish_mmu(&tlb, start, end); } @@ -2640,7 +2640,7 @@ void exit_mmap(struct mm_struct *mm) /* Use -1 here to ensure all VMAs in the mm are unmapped */ unmap_vmas(&tlb, vma, 0, -1); - free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); + free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, mm->task_size); tlb_finish_mmu(&tlb, 0, -1); /* -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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