Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934050Ab0D3See (ORCPT ); Fri, 30 Apr 2010 14:34:34 -0400 Received: from fallback.mail.elte.hu ([157.181.151.13]:46256 "EHLO fallback.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753890Ab0D3Sdf (ORCPT ); Fri, 30 Apr 2010 14:33:35 -0400 Date: Fri, 30 Apr 2010 12:22:05 +0200 From: Ingo Molnar To: Liang Li Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, wangchen@cn.fujitsu.com, tglx@linutronix.de, hpa@zytor.com, yinghai@kernel.org, jeremy.fitzhardinge@citrix.com, konrad.wilk@oracle.com Subject: Re: [v3 PATCH] x86: let 'reservetop' functioning right Message-ID: <20100430102205.GE14202@elte.hu> References: <1272621711-8683-1-git-send-email-liang.li@windriver.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1272621711-8683-1-git-send-email-liang.li@windriver.com> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5738 Lines: 157 * Liang Li wrote: > 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. > > The simplest fix might be use __fix_to_virt(idx0) to get updated value > of 'FIXADDR_TOP' in '__early_ioremap' instead of reference old value > from slot_virt[slot] directly. > > Changelog since v0: > > -v1: 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. > > -v2: place fixup_early_ioremap hence call early_ioremap_init in > reserve_top_address to re-initialize slot_virt and corresponding PMD > when parse_reservertop > > -v3: move fixup_early_ioremap out of reserve_top_address to make sure > other clients of reserve_top_address like xen/lguest won't broken > > Signed-off-by: Liang Li > Cc: Wang Chen > Cc: Ingo Molnar > Cc: Thomas Gleixner > Cc: "H. Peter Anvin" > Cc: Andrew Morton > Acked-by: Yinghai Lu > Acked-by: Jeremy Fitzhardinge > Tested-by: Konrad Rzeszutek Wilk > --- > Hi all, > > Just resend the patch according to Ingo's demand. > Thanks. > > 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(-) Applied, thanks. Note, i cleaned up the fixup_early_ioremap() code (and changed the BUG_ON to WARN_ON - we dont want to crash the box), mind double checking the end result? See the commit below. Ingo -----------------> >From e67a807f3d9a82fa91817871f1c0e2e04da993b8 Mon Sep 17 00:00:00 2001 From: Liang Li Date: Fri, 30 Apr 2010 18:01:51 +0800 Subject: [PATCH] x86: Fix 'reservetop=' functionality When specifying the 'reservetop=0xbadc0de' kernel parameter, the kernel will stop booting due to a early_ioremap bug that relates 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. The simplest fix might be use __fix_to_virt(idx0) to get updated value of 'FIXADDR_TOP' in '__early_ioremap' instead of reference old value from slot_virt[slot] directly. Changelog since v0: -v1: 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. -v2: place fixup_early_ioremap hence call early_ioremap_init in reserve_top_address to re-initialize slot_virt and corresponding PMD when parse_reservertop -v3: move fixup_early_ioremap out of reserve_top_address to make sure other clients of reserve_top_address like xen/lguest won't broken Signed-off-by: Liang Li Tested-by: Konrad Rzeszutek Wilk Acked-by: Yinghai Lu Acked-by: Jeremy Fitzhardinge Cc: Wang Chen Cc: "H. Peter Anvin" Cc: Andrew Morton LKML-Reference: <1272621711-8683-1-git-send-email-liang.li@windriver.com> [ fixed three small cleanliness details in fixup_early_ioremap() ] Signed-off-by: Ingo Molnar --- arch/x86/include/asm/io.h | 1 + arch/x86/mm/ioremap.c | 14 ++++++++++++++ arch/x86/mm/pgtable_32.c | 1 + 3 files changed, 16 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..12e4d2d 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -448,6 +448,20 @@ 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]) { + WARN_ON(1); + break; + } + } + + early_ioremap_init(); +} + 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); -- 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/