Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754650Ab1BGS6Y (ORCPT ); Mon, 7 Feb 2011 13:58:24 -0500 Received: from smtp.ctxuk.citrix.com ([62.200.22.115]:32795 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753936Ab1BGS6X (ORCPT ); Mon, 7 Feb 2011 13:58:23 -0500 X-IronPort-AV: E=Sophos;i="4.60,438,1291593600"; d="scan'208";a="4200454" Date: Mon, 7 Feb 2011 19:00:25 +0000 From: Stefano Stabellini X-X-Sender: sstabellini@kaball-desktop To: Stefano Stabellini CC: Yinghai Lu , "H. Peter Anvin" , Jeremy Fitzhardinge , "linux-kernel@vger.kernel.org" , "tglx@linutronix.de" , "x86@kernel.org" , Konrad Rzeszutek Wilk , Jan Beulich Subject: Re: [PATCH] x86/mm/init: respect memblock reserved regions when destroying mappings In-Reply-To: Message-ID: References: <4D4A3782.3050702@zytor.com> <4D4ADFAD.7060507@zytor.com> <4D4CA568.70907@goop.org> <4D4E4E0D.2080806@zytor.com> <4D4EF553.6000000@kernel.org> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6037 Lines: 183 On Mon, 7 Feb 2011, Stefano Stabellini wrote: > On Sun, 6 Feb 2011, Yinghai Lu wrote: > > On 02/05/2011 11:30 PM, H. Peter Anvin wrote: > > > On 02/05/2011 11:02 PM, Yinghai Lu wrote: > > >> why not just move calling cleanup_highmap down? > > >> > > >> something like attached patch. > > > > > > This patch looks very clean and looks on the surface of it like it is > > > removing some ugly ad hoc code, but (as always) it needs a description > > > about the problem it solves and why it is correct. > > > > Sure. > > > > > > Jeremy and xen guys, can you please check if it works well with xen ? > > > > Actually this patch makes things worse on xen, because before > cleanup_highmap() wasn't called at all on xen (on purpose) and now it > is, fully destroying all the mappings we have at _end. > > Can we add a check on memblock reserved regions in cleanup_highmap()? In case you are wondering how Yinghai Lu's patch would look like with the added check, here it is: diff --git a/arch/x86/include/asm/memblock.h b/arch/x86/include/asm/memblock.h index 19ae14b..184f778 100644 --- a/arch/x86/include/asm/memblock.h +++ b/arch/x86/include/asm/memblock.h @@ -3,6 +3,7 @@ #define ARCH_DISCARD_MEMBLOCK +bool memblock_check_reserved_size(u64 *addrp, u64 *sizep, u64 align); u64 memblock_x86_find_in_range_size(u64 start, u64 *sizep, u64 align); void memblock_x86_to_bootmem(u64 start, u64 end); diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h index 975f709..28686b6 100644 --- a/arch/x86/include/asm/pgtable_64.h +++ b/arch/x86/include/asm/pgtable_64.h @@ -165,7 +165,7 @@ static inline int pgd_large(pgd_t pgd) { return 0; } #define __swp_entry_to_pte(x) ((pte_t) { .pte = (x).val }) extern int kern_addr_valid(unsigned long addr); -extern void cleanup_highmap(void); +extern void cleanup_highmap(unsigned long end); #define HAVE_ARCH_UNMAPPED_AREA #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 2d2673c..5655c22 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -77,9 +77,6 @@ void __init x86_64_start_kernel(char * real_mode_data) /* Make NULL pointers segfault */ zap_identity_mappings(); - /* Cleanup the over mapped high alias */ - cleanup_highmap(); - max_pfn_mapped = KERNEL_IMAGE_SIZE >> PAGE_SHIFT; for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) { diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index d3cfe26..91afde6 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -297,6 +297,9 @@ static void __init init_gbpages(void) static inline void init_gbpages(void) { } +static void __init cleanup_highmap(unsigned long end) +{ +} #endif static void __init reserve_brk(void) @@ -922,6 +925,9 @@ void __init setup_arch(char **cmdline_p) */ reserve_brk(); + /* Cleanup the over mapped high alias after _brk_end*/ + cleanup_highmap(_brk_end); + memblock.current_limit = get_max_mapped(); memblock_x86_fill(); diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 947f42a..f13ff3a 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -279,25 +279,6 @@ unsigned long __init_refok init_memory_mapping(unsigned long start, load_cr3(swapper_pg_dir); #endif -#ifdef CONFIG_X86_64 - if (!after_bootmem && !start) { - pud_t *pud; - pmd_t *pmd; - - mmu_cr4_features = read_cr4(); - - /* - * _brk_end cannot change anymore, but it and _end may be - * located on different 2M pages. cleanup_highmap(), however, - * can only consider _end when it runs, so destroy any - * mappings beyond _brk_end here. - */ - pud = pud_offset(pgd_offset_k(_brk_end), _brk_end); - pmd = pmd_offset(pud, _brk_end - 1); - while (++pmd <= pmd_offset(pud, (unsigned long)_end - 1)) - pmd_clear(pmd); - } -#endif __flush_tlb_all(); if (!after_bootmem && e820_table_end > e820_table_start) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 71a5929..028c49e 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -297,18 +297,26 @@ void __init init_extra_mapping_uc(unsigned long phys, unsigned long size) * rounded up to the 2MB boundary. This catches the invalid pmds as * well, as they are located before _text: */ -void __init cleanup_highmap(void) +void __init cleanup_highmap(unsigned long end) { unsigned long vaddr = __START_KERNEL_map; - unsigned long end = roundup((unsigned long)_end, PMD_SIZE) - 1; pmd_t *pmd = level2_kernel_pgt; pmd_t *last_pmd = pmd + PTRS_PER_PMD; + u64 size, addrp; + bool changed; + + end = roundup(end, PMD_SIZE) - 1; for (; pmd < last_pmd; pmd++, vaddr += PMD_SIZE) { if (pmd_none(*pmd)) continue; - if (vaddr < (unsigned long) _text || vaddr > end) - set_pmd(pmd, __pmd(0)); + if (vaddr < (unsigned long) _text || vaddr > end) { + addrp = __pa(vaddr); + size = PMD_SIZE; + changed = memblock_check_reserved_size(&addrp, &size, PMD_SIZE); + if (!changed && size) + set_pmd(pmd, __pmd(0)); + } } } diff --git a/arch/x86/mm/memblock.c b/arch/x86/mm/memblock.c index aa11693..fac21d4 100644 --- a/arch/x86/mm/memblock.c +++ b/arch/x86/mm/memblock.c @@ -8,7 +8,7 @@ #include /* Check for already reserved areas */ -static bool __init check_with_memblock_reserved_size(u64 *addrp, u64 *sizep, u64 align) +bool __init memblock_check_reserved_size(u64 *addrp, u64 *sizep, u64 align) { struct memblock_region *r; u64 addr = *addrp, last; @@ -59,7 +59,7 @@ u64 __init memblock_x86_find_in_range_size(u64 start, u64 *sizep, u64 align) if (addr >= ei_last) continue; *sizep = ei_last - addr; - while (check_with_memblock_reserved_size(&addr, sizep, align)) + while (memblock_check_reserved_size(&addr, sizep, align)) ; if (*sizep) -- 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/