LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Ingo Molnar <mingo@elte.hu>
To: Arjan van de Ven <arjan@linux.intel.com>
Cc: torvalds@linux-foundation.org, hans.rosenfeld@amd.com,
	linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: bisected boot regression post 2.6.25-rc3.. please revert
Date: Mon, 3 Mar 2008 10:13:04 +0100	[thread overview]
Message-ID: <20080303091304.GA17911@elte.hu> (raw)
In-Reply-To: <20080303074620.GC5934@elte.hu>


* Ingo Molnar <mingo@elte.hu> wrote:

> Could you try to hack up a debug patch perhaps? Uninline the 
> fucntion(s) then add two versions (one is that breaks on your box and 
> one is that works on your box) of this same pmd_bad()/pud_bad() 
> functions and do something like this (pseudocode):

i.e. something like the (tested) patch below. It is not clear whether 
your testcase is on 32-bit or 64-bit - so i went for the more likely 
32-bit case first.

	Ingo

------------------>
Subject: x86: patches/x86-debug-bad-page.patch
From: Ingo Molnar <mingo@elte.hu>
Date: Mon Mar 03 09:53:17 CET 2008

Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/mm/pgtable_32.c     |    7 +++++++
 include/asm-x86/pgtable_32.h |    6 +++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

Index: linux-x86.q/arch/x86/mm/pgtable_32.c
===================================================================
--- linux-x86.q.orig/arch/x86/mm/pgtable_32.c
+++ linux-x86.q/arch/x86/mm/pgtable_32.c
@@ -381,3 +381,10 @@ void __pmd_free_tlb(struct mmu_gather *t
 }
 
 #endif
+
+int pmd_bad(pmd_t pmd)
+{
+	WARN_ON_ONCE(pmd_bad_v1(pmd) != pmd_bad_v2(pmd));
+
+	return pmd_bad_v1(pmd);
+}
Index: linux-x86.q/include/asm-x86/pgtable_32.h
===================================================================
--- linux-x86.q.orig/include/asm-x86/pgtable_32.h
+++ linux-x86.q/include/asm-x86/pgtable_32.h
@@ -92,7 +92,11 @@ extern unsigned long pg0[];
 /* To avoid harmful races, pmd_none(x) should check only the lower when PAE */
 #define pmd_none(x)	(!(unsigned long)pmd_val(x))
 #define pmd_present(x)	(pmd_val(x) & _PAGE_PRESENT)
-#define	pmd_bad(x)	((pmd_val(x) \
+
+extern int pmd_bad(pmd_t pmd);
+
+#define pmd_bad_v1(x)	((pmd_val(x) & (~PAGE_MASK & ~_PAGE_USER)) != _KERNPG_TABLE)
+#define	pmd_bad_v2(x)	((pmd_val(x) \
 			  & ~(PAGE_MASK | _PAGE_USER | _PAGE_PSE | _PAGE_NX)) \
 			 != _KERNPG_TABLE)
 

  reply	other threads:[~2008-03-03  9:13 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-01 18:56 Arjan van de Ven
2008-03-03  7:46 ` Ingo Molnar
2008-03-03  9:13   ` Ingo Molnar [this message]
2008-03-03 16:41     ` Arjan van de Ven
2008-03-03 17:40       ` Ingo Molnar
2008-03-03 17:51         ` Nish Aravamudan
2008-03-03 17:55           ` Ingo Molnar
2008-03-03 17:58             ` H. Peter Anvin
2008-03-03 18:36         ` Arjan van de Ven
2008-03-03 18:44           ` Linus Torvalds
2008-03-03 22:00             ` Arjan van de Ven
2008-03-04  1:05               ` Arjan van de Ven
2008-03-04  6:53                 ` Ingo Molnar
2008-03-05 15:35                   ` Arjan van de Ven
2008-03-09 11:56             ` Ingo Molnar
2008-03-09 17:27               ` Linus Torvalds
2008-03-09 18:57                 ` Ingo Molnar
2008-03-10  2:45                 ` Jeremy Fitzhardinge
2008-03-10  4:35                 ` Paul Mackerras
2008-03-03 21:13           ` Segher Boessenkool
2008-03-03 21:22             ` Segher Boessenkool
2008-03-03 22:33               ` Segher Boessenkool
2008-03-03 22:55                 ` H. Peter Anvin
2008-03-03 22:56                 ` Jeremy Fitzhardinge
2008-03-03 23:04                   ` H. Peter Anvin
2008-03-04  6:58             ` Ingo Molnar
2008-03-03 17:15 ` Nish Aravamudan

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20080303091304.GA17911@elte.hu \
    --to=mingo@elte.hu \
    --cc=arjan@linux.intel.com \
    --cc=hans.rosenfeld@amd.com \
    --cc=hpa@zytor.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=tglx@linutronix.de \
    --cc=torvalds@linux-foundation.org \
    --subject='Re: bisected boot regression post 2.6.25-rc3.. please revert' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).