linux-kernel - [PATCH] [7/19] x86_64: fix page align in e820 allocator

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Message-Id: <20061021165127.1402513C4D@wotan.suse.de>
Date:	Sat, 21 Oct 2006 18:51:27 +0200 (CEST)
From:	Andi Kleen <ak@...e.de>
To:	Vivek Goyal <vgoyal@...ibm.com>, Andi Kleen <ak@....de>,
	patches@...-64.org, linux-kernel@...r.kernel.org
Subject: [PATCH] [7/19] x86_64: fix page align in e820 allocator 


From: Vivek Goyal <vgoyal@...ibm.com>

Currently some code pieces assume that address returned by find_e820_area()
are page aligned.  But looks like find_e820_area() had no such intention
and hence one might end up stomping over some of the data.  One such case
is bootmem allocator initialization code stomped over bss.

This patch modified find_e820_area() to return page aligned address.  This
might be little wasteful of memory but at the same time probably it is
easier to handle page aligned memory.

Signed-off-by: Vivek Goyal <vgoyal@...ibm.com>
Signed-off-by: Andi Kleen <ak@...e.de>
Cc: Andi Kleen <ak@....de>
Signed-off-by: Andrew Morton <akpm@...l.org>
---

 arch/x86_64/kernel/e820.c |   14 +++++++-------
 1 files changed, 7 insertions(+), 7 deletions(-)

Index: linux/arch/x86_64/kernel/e820.c
===================================================================
--- linux.orig/arch/x86_64/kernel/e820.c
+++ linux/arch/x86_64/kernel/e820.c
@@ -54,13 +54,13 @@ static inline int bad_addr(unsigned long
 
 	/* various gunk below that needed for SMP startup */
 	if (addr < 0x8000) { 
-		*addrp = 0x8000;
+		*addrp = PAGE_ALIGN(0x8000);
 		return 1; 
 	}
 
 	/* direct mapping tables of the kernel */
 	if (last >= table_start<<PAGE_SHIFT && addr < table_end<<PAGE_SHIFT) { 
-		*addrp = table_end << PAGE_SHIFT; 
+		*addrp = PAGE_ALIGN(table_end << PAGE_SHIFT);
 		return 1;
 	} 
 
@@ -68,18 +68,18 @@ static inline int bad_addr(unsigned long
 #ifdef CONFIG_BLK_DEV_INITRD
 	if (LOADER_TYPE && INITRD_START && last >= INITRD_START && 
 	    addr < INITRD_START+INITRD_SIZE) { 
-		*addrp = INITRD_START + INITRD_SIZE; 
+		*addrp = PAGE_ALIGN(INITRD_START + INITRD_SIZE);
 		return 1;
 	} 
 #endif
 	/* kernel code */
-	if (last >= __pa_symbol(&_text) && last < __pa_symbol(&_end)) {
-		*addrp = __pa_symbol(&_end);
+	if (last >= __pa_symbol(&_text) && addr < __pa_symbol(&_end)) {
+		*addrp = PAGE_ALIGN(__pa_symbol(&_end));
 		return 1;
 	}
 
 	if (last >= ebda_addr && addr < ebda_addr + ebda_size) {
-		*addrp = ebda_addr + ebda_size;
+		*addrp = PAGE_ALIGN(ebda_addr + ebda_size);
 		return 1;
 	}
 
@@ -152,7 +152,7 @@ unsigned long __init find_e820_area(unsi
 			continue; 
 		while (bad_addr(&addr, size) && addr+size <= ei->addr+ei->size)
 			;
-		last = addr + size;
+		last = PAGE_ALIGN(addr) + size;
 		if (last > ei->addr + ei->size)
 			continue;
 		if (last > end) 
-
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