From mboxrd@z Thu Jan 1 00:00:00 1970 From: guoren@kernel.org Subject: [PATCH] csky: Fixup wrong update_mmu_cache implementation Date: Wed, 10 Apr 2019 14:18:19 +0800 Message-ID: <1554877099-30927-1-git-send-email-guoren@kernel.org> Return-path: Sender: linux-kernel-owner@vger.kernel.org To: arnd@arndb.de Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Guo Ren List-Id: linux-arch.vger.kernel.org From: Guo Ren In our stress test, we found some crash problem caused by: if (!(vma->vm_flags & VM_EXEC)) return; in update_mmu_cache(). Seems current update_mmu_cache implementation is wrong and we retread to the conservative implementation. Also the usage of kmap_atomic in update_mmu_cache is risky, page-virtual may be scheduled out and changed, so we must use preempt_disable & pagefault_disable which is called by kmap_atomic(). Signed-off-by: Guo Ren Cc: Arnd Bergmann --- arch/csky/abiv2/cacheflush.c | 13 ++----------- 1 file changed, 2 insertions(+), 11 deletions(-) diff --git a/arch/csky/abiv2/cacheflush.c b/arch/csky/abiv2/cacheflush.c index d22c95f..5bb887b 100644 --- a/arch/csky/abiv2/cacheflush.c +++ b/arch/csky/abiv2/cacheflush.c @@ -34,10 +34,6 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, { unsigned long addr, pfn; struct page *page; - void *va; - - if (!(vma->vm_flags & VM_EXEC)) - return; pfn = pte_pfn(*pte); if (unlikely(!pfn_valid(pfn))) @@ -47,14 +43,9 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, if (page == ZERO_PAGE(0)) return; - va = page_address(page); - addr = (unsigned long) va; - - if (va == NULL && PageHighMem(page)) - addr = (unsigned long) kmap_atomic(page); + addr = (unsigned long) kmap_atomic(page); cache_wbinv_range(addr, addr + PAGE_SIZE); - if (va == NULL && PageHighMem(page)) - kunmap_atomic((void *) addr); + kunmap_atomic((void *) addr); } -- 2.7.4 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:45418 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726909AbfDJGUs (ORCPT ); Wed, 10 Apr 2019 02:20:48 -0400 From: guoren@kernel.org Subject: [PATCH] csky: Fixup wrong update_mmu_cache implementation Date: Wed, 10 Apr 2019 14:18:19 +0800 Message-ID: <1554877099-30927-1-git-send-email-guoren@kernel.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: arnd@arndb.de Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Guo Ren Message-ID: <20190410061819.svNGXhzkIcJujPQv1m6kCgUGZM8bo_rXsVqas2O2Q0Q@z> From: Guo Ren In our stress test, we found some crash problem caused by: if (!(vma->vm_flags & VM_EXEC)) return; in update_mmu_cache(). Seems current update_mmu_cache implementation is wrong and we retread to the conservative implementation. Also the usage of kmap_atomic in update_mmu_cache is risky, page-virtual may be scheduled out and changed, so we must use preempt_disable & pagefault_disable which is called by kmap_atomic(). Signed-off-by: Guo Ren Cc: Arnd Bergmann --- arch/csky/abiv2/cacheflush.c | 13 ++----------- 1 file changed, 2 insertions(+), 11 deletions(-) diff --git a/arch/csky/abiv2/cacheflush.c b/arch/csky/abiv2/cacheflush.c index d22c95f..5bb887b 100644 --- a/arch/csky/abiv2/cacheflush.c +++ b/arch/csky/abiv2/cacheflush.c @@ -34,10 +34,6 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, { unsigned long addr, pfn; struct page *page; - void *va; - - if (!(vma->vm_flags & VM_EXEC)) - return; pfn = pte_pfn(*pte); if (unlikely(!pfn_valid(pfn))) @@ -47,14 +43,9 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, if (page == ZERO_PAGE(0)) return; - va = page_address(page); - addr = (unsigned long) va; - - if (va == NULL && PageHighMem(page)) - addr = (unsigned long) kmap_atomic(page); + addr = (unsigned long) kmap_atomic(page); cache_wbinv_range(addr, addr + PAGE_SIZE); - if (va == NULL && PageHighMem(page)) - kunmap_atomic((void *) addr); + kunmap_atomic((void *) addr); } -- 2.7.4