Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757637Ab0DHJAS (ORCPT ); Thu, 8 Apr 2010 05:00:18 -0400 Received: from mail.windriver.com ([147.11.1.11]:55908 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752567Ab0DHJAO (ORCPT ); Thu, 8 Apr 2010 05:00:14 -0400 Date: Thu, 8 Apr 2010 16:58:14 +0800 From: Liang Li To: Yinghai Cc: Jeremy Fitzhardinge , Rusty Russell , akpm@linux-foundation.org, hpa@zytor.com, mingo@elte.hu, tglx@linutronix.de, wangchen@cn.fujitsu.com, "linux-kernel@vger.kernel.org" Subject: Re: + x86-fix-handling-of-the-reservetop-boot-option.patch added to -mm tree Message-ID: <20100408085814.GD26543@localhost> Reply-To: Liang Li References: <201004072200.o37M0d19009878@imap1.linux-foundation.org> <4BBD1AA3.4000204@oracle.com> <20100408010558.GA4053@localhost> <4BBD2DD4.1060101@oracle.com> <20100408015353.GB4053@localhost> <4BBD5BEF.3000406@oracle.com> <20100408045945.GB26543@localhost> <4BBD7E52.80507@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4BBD7E52.80507@oracle.com> User-Agent: Mutt/1.5.20 (2009-08-17) X-OriginalArrivalTime: 08 Apr 2010 08:59:33.0413 (UTC) FILETIME=[CE8E8D50:01CAD6F9] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8839 Lines: 247 On Wed, Apr 07, 2010 at 11:57:22PM -0700, Yinghai wrote: > On 04/07/2010 09:59 PM, Liang Li wrote: > > On Wed, Apr 07, 2010 at 09:30:39PM -0700, Yinghai wrote: > >> On 04/07/2010 06:53 PM, Liang Li wrote: > >>> Does this similar modification like this is more preferred? > >>> > >>> diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h > >>> index a1dcfa3..30a3e97 100644 > >>> --- a/arch/x86/include/asm/io.h > >>> +++ b/arch/x86/include/asm/io.h > >>> @@ -347,6 +347,7 @@ extern void __iomem *early_ioremap(resource_size_t phys_addr, > >>> extern void __iomem *early_memremap(resource_size_t phys_addr, > >>> unsigned long size); > >>> extern void early_iounmap(void __iomem *addr, unsigned long size); > >>> +extern void fixup_early_ioremap(void); > >>> > >>> #define IO_SPACE_LIMIT 0xffff > >>> > >>> diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c > >>> index ea82ef0..fe06296 100644 > >>> --- a/arch/x86/mm/ioremap.c > >>> +++ b/arch/x86/mm/ioremap.c > >>> @@ -448,6 +448,23 @@ static inline void __init early_clear_fixmap(enum fixed_addresses idx) > >>> static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata; > >>> static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata; > >>> > >>> +void __init fixup_early_ioremap(void) > >>> +{ > >>> + int i; > >>> + for (i = 0; i < FIX_BTMAPS_SLOTS; i++) { > >>> + if (prev_map[i]) > >>> + break; > >>> + } > >>> + > >>> + if (i == FIX_BTMAPS_SLOTS) > >> < > >>> + WARN_ON(1); > >> BUG_ON() > >>> + > >>> + for (i = 0; i < FIX_BTMAPS_SLOTS; i++) > >>> + slot_virt[i] = __fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS * i); > >>> + > >> need to clear the old PMD, and set new PMD. > >> > >> so you can clear old PMD and call early_ioremap_init() in fixup_early_ioremap() > > > > Call early_ioremap_init will do the update PMD work. So the preferred > > patch would be: > > --------------- > > From 61fe7a116cbbf6eef98a49b88ed5861ed9ebd32d Mon Sep 17 00:00:00 2001 > > From: Liang Li > > Date: Mon, 22 Mar 2010 18:38:14 +0800 > > Subject: [PATCH] x86: let 'reservetop' functioning right > > > > When specify 'reservetop=0xbadc0de' kernel parameter, the kernel will > > stop booting due to a early_ioremap bug that relate to commit 8827247ff. > > > > The root cause of boot failure problem is the value of 'slot_virt[i]' > > was initialized in setup_arch->early_ioremap_init. But later in > > setup_arch, the function 'parse_early_param' will modify 'FIXADDR_TOP' > > when 'reservetop=0xbadc0de' being specified. > > > > When reservetop being handled then FIXADDR_TOP get adjusted, Hence check > > prev_map then re-initialize slot_virt and PMD based on new FIXADDR_TOP. > > > > Signed-off-by: Liang Li > > Cc: Wang Chen > > Cc: Ingo Molnar > > Cc: Thomas Gleixner > > Cc: "H. Peter Anvin" > > Cc: Yinghai Lu > > Cc: Andrew Morton > > --- > > arch/x86/include/asm/io.h | 1 + > > arch/x86/mm/ioremap.c | 15 +++++++++++++++ > > arch/x86/mm/pgtable.c | 2 ++ > > 3 files changed, 18 insertions(+), 0 deletions(-) > > > > diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h > > index a1dcfa3..30a3e97 100644 > > --- a/arch/x86/include/asm/io.h > > +++ b/arch/x86/include/asm/io.h > > @@ -347,6 +347,7 @@ extern void __iomem *early_ioremap(resource_size_t phys_addr, > > extern void __iomem *early_memremap(resource_size_t phys_addr, > > unsigned long size); > > extern void early_iounmap(void __iomem *addr, unsigned long size); > > +extern void fixup_early_ioremap(void); > > > > #define IO_SPACE_LIMIT 0xffff > > > > diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c > > index 5eb1ba7..e4ab706 100644 > > --- a/arch/x86/mm/ioremap.c > > +++ b/arch/x86/mm/ioremap.c > > @@ -448,6 +448,21 @@ static inline void __init early_clear_fixmap(enum fixed_addresses idx) > > static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata; > > static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata; > > > > +void __init fixup_early_ioremap(void) > > +{ > > + int i; > > + for (i = 0; i < FIX_BTMAPS_SLOTS; i++) { > > + if (prev_map[i]) > > + break; > > + } > > + > > + if (i < FIX_BTMAPS_SLOTS) > > + BUG_ON(1); > > + > > + early_ioremap_init(); > > + return; > > +} > > + > > static int __init check_early_ioremap_leak(void) > > { > > int count = 0; > > diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c > > index 5c4ee42..ea4d54c 100644 > > --- a/arch/x86/mm/pgtable.c > > +++ b/arch/x86/mm/pgtable.c > > @@ -4,6 +4,7 @@ > > #include > > #include > > #include > > +#include > > > > #define PGALLOC_GFP GFP_KERNEL | __GFP_NOTRACK | __GFP_REPEAT | __GFP_ZERO > > > > @@ -351,6 +352,7 @@ void __init reserve_top_address(unsigned long reserve) > > printk(KERN_INFO "Reserving virtual address space above 0x%08x\n", > > (int)-reserve); > > __FIXADDR_TOP = -reserve - PAGE_SIZE; > > + fixup_early_ioremap(); > > #endif > > } > > > > ----------- > > Acceptable? > > > good to me. > > may need to ask xen/lguest/vmi related to check that too. > > arch/x86/kernel/vmi_32.c: reserve_top_address(-vmi_rom->virtual_top); > arch/x86/lguest/boot.c: reserve_top_address(lguest_data.reserve_mem); > arch/x86/mm/pgtable_32.c: reserve_top_address(address); > arch/x86/xen/mmu.c: reserve_top_address(-top); When linux as vmi/xen/lguest guest OS, kernel call reserve_top_address before start_kernel. It is far before the start_kernel hence far before setup_arch->early_ioremap_init. So it is unsafe to place fixup_early_ioremap inside reserve_top_address. So I think the patch should be: >From 7cefa9a80c4434f2941a7072d39b1f1ffc08a40f Mon Sep 17 00:00:00 2001 From: Liang Li Date: Mon, 22 Mar 2010 18:38:14 +0800 Subject: [PATCH] x86: let 'reservetop' functioning right When specify 'reservetop=0xbadc0de' kernel parameter, the kernel will stop booting due to a early_ioremap bug that relate to commit 8827247ff. The root cause of boot failure problem is the value of 'slot_virt[i]' was initialized in setup_arch->early_ioremap_init. But later in setup_arch, the function 'parse_early_param' will modify 'FIXADDR_TOP' when 'reservetop=0xbadc0de' being specified. When reservetop being handled then FIXADDR_TOP get adjusted, Hence check prev_map then re-initialize slot_virt and PMD based on new FIXADDR_TOP. Signed-off-by: Liang Li Cc: Wang Chen Cc: Ingo Molnar Cc: Thomas Gleixner Cc: "H. Peter Anvin" Cc: Yinghai Lu Cc: Andrew Morton --- arch/x86/include/asm/io.h | 1 + arch/x86/mm/ioremap.c | 15 +++++++++++++++ arch/x86/mm/pgtable_32.c | 1 + 3 files changed, 17 insertions(+), 0 deletions(-) diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index a1dcfa3..30a3e97 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -347,6 +347,7 @@ extern void __iomem *early_ioremap(resource_size_t phys_addr, extern void __iomem *early_memremap(resource_size_t phys_addr, unsigned long size); extern void early_iounmap(void __iomem *addr, unsigned long size); +extern void fixup_early_ioremap(void); #define IO_SPACE_LIMIT 0xffff diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index 5eb1ba7..e4ab706 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -448,6 +448,21 @@ static inline void __init early_clear_fixmap(enum fixed_addresses idx) static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata; static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata; +void __init fixup_early_ioremap(void) +{ + int i; + for (i = 0; i < FIX_BTMAPS_SLOTS; i++) { + if (prev_map[i]) + break; + } + + if (i < FIX_BTMAPS_SLOTS) + BUG_ON(1); + + early_ioremap_init(); + return; +} + static int __init check_early_ioremap_leak(void) { int count = 0; diff --git a/arch/x86/mm/pgtable_32.c b/arch/x86/mm/pgtable_32.c index 1a8faf0..26eadaa 100644 --- a/arch/x86/mm/pgtable_32.c +++ b/arch/x86/mm/pgtable_32.c @@ -128,6 +128,7 @@ static int __init parse_reservetop(char *arg) address = memparse(arg, &arg); reserve_top_address(address); + fixup_early_ioremap(); return 0; } early_param("reservetop", parse_reservetop); -- 1.6.6 Thanks and best regards, -Liang Li > > > YH -- 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/