linux-kernel - Re: [PATCH 1/1] x86: fix text

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Message-ID: <20080425162215.GA16273@elte.hu>
Date:	Fri, 25 Apr 2008 18:22:15 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Andi Kleen <andi@...stfloor.org>, Jiri Slaby <jirislaby@...il.com>,
	David Miller <davem@...emloft.net>, zdenek.kabelac@...il.com,
	rjw@...k.pl, paulmck@...ux.vnet.ibm.com, akpm@...ux-foundation.org,
	linux-ext4@...r.kernel.org, herbert@...dor.apana.org.au,
	penberg@...helsinki.fi, clameter@....com,
	linux-kernel@...r.kernel.org,
	Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>,
	pageexec@...email.hu, "H. Peter Anvin" <hpa@...or.com>,
	Jeremy Fitzhardinge <jeremy@...p.org>
Subject: Re: [PATCH 1/1] x86: fix text_poke


* Linus Torvalds <torvalds@...ux-foundation.org> wrote:

> +		spin_lock_irqsave(&poke_lock, flags);
> +		set_fixmap(FIX_POKE, phys);
> +		memcpy((void *)(virt + offset), opcode, len);
> +		spin_unlock_irqrestore(&poke_lock, flags);

hm, right now we've got a debug protection in set_fixmap() to make sure 
it's only ever called once. So it's going to be a noisy bootup. (but 
it's a warning only) The patch below removes that.

	Ingo

------------->
Subject: x86: remove set_fixmap() warning
From: Ingo Molnar <mingo@...e.hu>
Date: Fri Apr 25 18:05:57 CEST 2008

set_fixmap() is safe as long as it's explicitly serialized between
all users.

Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
 arch/x86/mm/init_64.c |    3 ---
 1 file changed, 3 deletions(-)

Index: linux/arch/x86/mm/init_64.c
===================================================================
--- linux.orig/arch/x86/mm/init_64.c
+++ linux/arch/x86/mm/init_64.c
@@ -173,9 +173,6 @@ set_pte_phys(unsigned long vaddr, unsign
 	new_pte = pfn_pte(phys >> PAGE_SHIFT, prot);
 
 	pte = pte_offset_kernel(pmd, vaddr);
-	if (!pte_none(*pte) &&
-	    pte_val(*pte) != (pte_val(new_pte) & __supported_pte_mask))
-		pte_ERROR(*pte);
 	set_pte(pte, new_pte);
 
 	/*
--
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