From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx131.postini.com [74.125.245.131]) by kanga.kvack.org (Postfix) with SMTP id 1E1BB6B000C for ; Mon, 21 Jan 2013 12:52:58 -0500 (EST) Received: from /spool/local by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 21 Jan 2013 10:52:56 -0700 Received: from d03relay05.boulder.ibm.com (d03relay05.boulder.ibm.com [9.17.195.107]) by d03dlp01.boulder.ibm.com (Postfix) with ESMTP id 3D6B71FF003F for ; Mon, 21 Jan 2013 10:52:40 -0700 (MST) Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by d03relay05.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r0LHqotC131996 for ; Mon, 21 Jan 2013 10:52:50 -0700 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r0LHqno3025493 for ; Mon, 21 Jan 2013 10:52:49 -0700 Subject: [PATCH 4/5] create slow_virt_to_phys() From: Dave Hansen Date: Mon, 21 Jan 2013 09:52:49 -0800 References: <20130121175244.E5839E06@kernel.stglabs.ibm.com> In-Reply-To: <20130121175244.E5839E06@kernel.stglabs.ibm.com> Message-Id: <20130121175249.AFE9EAD7@kernel.stglabs.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, Gleb Natapov , "H. Peter Anvin" , x86@kernel.org, Marcelo Tosatti , Rik van Riel , Dave Hansen This is necessary because __pa() does not work on some kinds of memory, like vmalloc() or the alloc_remap() areas on 32-bit NUMA systems. We have some functions to do conversions _like_ this in the vmalloc() code (like vmalloc_to_page()), but they do not work on sizes other than 4k pages. We would potentially need to be able to handle all the page sizes that we use for the kernel linear mapping (4k, 2M, 1G). In practice, on 32-bit NUMA systems, the percpu areas get stuck in the alloc_remap() area. Any __pa() call on them will break and basically return garbage. This patch introduces a new function slow_virt_to_phys(), which walks the kernel page tables on x86 and should do precisely the same logical thing as __pa(), but actually work on a wider range of memory. It should work on the normal linear mapping, vmalloc(), kmap(), etc... Signed-off-by: Dave Hansen Acked-by: Rik van Riel --- linux-2.6.git-dave/arch/x86/include/asm/pgtable_types.h | 1 linux-2.6.git-dave/arch/x86/mm/pageattr.c | 31 ++++++++++++++++ 2 files changed, 32 insertions(+) diff -puN arch/x86/include/asm/pgtable_types.h~create-slow_virt_to_phys arch/x86/include/asm/pgtable_types.h --- linux-2.6.git/arch/x86/include/asm/pgtable_types.h~create-slow_virt_to_phys 2013-01-17 10:22:26.590434129 -0800 +++ linux-2.6.git-dave/arch/x86/include/asm/pgtable_types.h 2013-01-17 10:22:26.598434199 -0800 @@ -352,6 +352,7 @@ static inline void update_page_count(int * as a pte too. */ extern pte_t *lookup_address(unsigned long address, unsigned int *level); +extern phys_addr_t slow_virt_to_phys(void *__address); #endif /* !__ASSEMBLY__ */ diff -puN arch/x86/mm/pageattr.c~create-slow_virt_to_phys arch/x86/mm/pageattr.c --- linux-2.6.git/arch/x86/mm/pageattr.c~create-slow_virt_to_phys 2013-01-17 10:22:26.594434163 -0800 +++ linux-2.6.git-dave/arch/x86/mm/pageattr.c 2013-01-17 10:22:26.598434199 -0800 @@ -364,6 +364,37 @@ pte_t *lookup_address(unsigned long addr EXPORT_SYMBOL_GPL(lookup_address); /* + * This is necessary because __pa() does not work on some + * kinds of memory, like vmalloc() or the alloc_remap() + * areas on 32-bit NUMA systems. The percpu areas can + * end up in this kind of memory, for instance. + * + * This could be optimized, but it is only intended to be + * used at inititalization time, and keeping it + * unoptimized should increase the testing coverage for + * the more obscure platforms. + */ +phys_addr_t slow_virt_to_phys(void *__virt_addr) +{ + unsigned long virt_addr = (unsigned long)__virt_addr; + phys_addr_t phys_addr; + unsigned long offset; + unsigned int level = -1; + unsigned long psize = 0; + unsigned long pmask = 0; + pte_t *pte; + + pte = lookup_address(virt_addr, &level); + BUG_ON(!pte); + psize = page_level_size(level); + pmask = page_level_mask(level); + offset = virt_addr & ~pmask; + phys_addr = pte_pfn(*pte) << PAGE_SHIFT; + return (phys_addr | offset); +} +EXPORT_SYMBOL_GPL(slow_virt_to_phys); + +/* * Set the new pmd in all the pgds we know about: */ static void __set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte) _ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org