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From: Alexander van Heukelum <heukelum@mailshack.com>
To: Andi Kleen <ak@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>,
	Alexander van Heukelum <heukelum@fastmail.fm>
Subject: [PATCH] Fix alignment of early reservation for EBDA
Date: Sun, 24 Feb 2008 18:46:05 +0100	[thread overview]
Message-ID: <20080224174605.GA21661@mailshack.com> (raw)

Hi Andi,

My eyes fell on the following table in the boot messages:

early res: 0 [0-fff] BIOS data page
early res: 1 [6000-7fff] SMP_TRAMPOLINE
early res: 2 [200000-374557] TEXT DATA BSS
early res: 3 [9fc00-a0bff] EBDA
early res: 4 [8000-afff] PGTABLE

The memory reserved for the EBDA overflows into the area normally
reserved for the VGA adaptor. It seems that you wanted to force
the allocation to cover whole pages, like:

early res: 3 [9f000-9ffff] EBDA

This is what this patch implements.

Is it really necessary to force the allocation to a page boundary?


Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>

 arch/x86/kernel/head64.c |   12 +++++++-----
 1 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index ad24408..2c52543 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -53,7 +53,7 @@ static void __init copy_bootdata(char *real_mode_data)
 
 static __init void reserve_ebda(void)
 {
-	unsigned ebda_addr, ebda_size;
+	unsigned int ebda_addr, ebda_size, ebda_end;
 
 	/*
 	 * there is a real-mode segmented pointer pointing to the
@@ -70,12 +70,14 @@ static __init void reserve_ebda(void)
 	/* Round EBDA up to pages */
 	if (ebda_size == 0)
 		ebda_size = 1;
+	if (ebda_size > 64)
+		ebda_size = 64;
 	ebda_size <<= 10;
-	ebda_size = round_up(ebda_size + (ebda_addr & ~PAGE_MASK), PAGE_SIZE);
-	if (ebda_size > 64*1024)
-		ebda_size = 64*1024;
+	
+	ebda_end = ALIGN(ebda_addr + ebda_size, PAGE_SIZE);
+	ebda_addr = ALIGN(ebda_addr - PAGE_SIZE, PAGE_SIZE);
 
-	reserve_early(ebda_addr, ebda_addr + ebda_size, "EBDA");
+	reserve_early(ebda_addr, ebda_end, "EBDA");
 }
 
 void __init x86_64_start_kernel(char * real_mode_data)

             reply	other threads:[~2008-02-24 17:46 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-24 17:46 Alexander van Heukelum [this message]
2008-02-24 19:27 ` Andi Kleen
2008-02-24 19:41 ` Ingo Molnar
2008-02-24 20:53   ` Alexander van Heukelum
2008-02-25  2:18 ` H. Peter Anvin
2008-02-25 16:54   ` Alexander van Heukelum
2008-02-25 17:01     ` Ingo Molnar
2008-02-25 18:07       ` [PATCH] reserve_early end-of-conventional-memory to 1MB Alexander van Heukelum
2008-02-25 18:13         ` H. Peter Anvin
2008-02-25 19:46           ` Alexander van Heukelum
2008-02-25 21:17             ` H. Peter Anvin
2008-02-26  9:30             ` Ingo Molnar
2008-02-27 14:26               ` Andi Kleen
2008-02-27 14:38               ` [PATCH] reserve_early end-of-conventional-memory to 1MB II - some numbers to put it into perspective Andi Kleen
2008-02-27 16:44                 ` H. Peter Anvin
2008-02-27 20:01                 ` Alexander van Heukelum
2008-02-28 13:13         ` [PATCH] reserve end-of-conventional-memory to 1MB on 32-bit Alexander van Heukelum
2008-02-28 13:28           ` [RFC] use realmode code to reserve end-of-conventional-memory to 1MB Alexander van Heukelum
2008-02-28 21:12             ` Ian Campbell
2008-02-28 21:14               ` H. Peter Anvin
2008-02-28 23:16                 ` Ian Campbell
2008-02-29 20:00                   ` Ingo Molnar
2008-03-04 11:41                   ` Mark McLoughlin
2008-03-04 14:33                     ` Ingo Molnar
2008-03-04 15:12                       ` Ian Campbell
2008-03-04 15:13                       ` Jeremy Fitzhardinge
2008-03-04 15:25                         ` Ingo Molnar
2008-03-04 16:02                           ` Jeremy Fitzhardinge
2008-03-04 16:15                             ` Ingo Molnar
2008-03-04 16:15                       ` Mark McLoughlin
2008-03-04 16:23                         ` Ingo Molnar
2008-03-04 17:44                   ` Jeremy Fitzhardinge
2008-03-05 15:59                   ` Eduardo Habkost
2008-03-05 16:08                     ` H. Peter Anvin
2008-03-05 16:53                       ` Eduardo Habkost
2008-03-05 17:28                         ` H. Peter Anvin
2008-03-05 17:28                           ` Jeremy Fitzhardinge
2008-03-05 17:38                             ` H. Peter Anvin
2008-03-05 16:38                     ` Jeremy Fitzhardinge
2008-03-05 17:27                       ` H. Peter Anvin
2008-02-28 21:09           ` [PATCH] reserve end-of-conventional-memory to 1MB on 32-bit Ian Campbell
2008-02-29 11:49             ` Alexander van Heukelum
2008-02-29 17:14               ` Mark McLoughlin
2008-02-29 18:38                 ` Alexander van Heukelum
2008-02-29 18:44                   ` H. Peter Anvin
2008-02-29 18:56                     ` Alexander van Heukelum
2008-02-29 22:06                   ` Mark McLoughlin
2008-02-29 22:26                     ` Alexander van Heukelum
2008-03-01 16:09                     ` [PATCH] reserve end-of-conventional-memory to 1MB on 32-bit v2 Alexander van Heukelum
2008-03-01 16:12                       ` [PATCH] reserve end-of-conventional-memory to 1MB on 64-bit add-on Alexander van Heukelum
2008-03-04 11:44                       ` [PATCH] reserve end-of-conventional-memory to 1MB on 32-bit v2 Mark McLoughlin
2008-03-04 13:31                         ` Alexander van Heukelum
2008-03-04 14:49                         ` Ingo Molnar
2008-03-04 15:16                           ` Mark McLoughlin
2008-03-04 15:24                             ` Ingo Molnar
2008-03-04 15:18                         ` Jeremy Fitzhardinge
2008-03-04 16:51                           ` Alexander van Heukelum
2008-03-04 17:05                             ` H. Peter Anvin
2008-03-04 17:11                             ` Jeremy Fitzhardinge
2008-03-04 18:57                               ` [PATCH] reserve end-of-conventional-memory to 1MB, 32-bit, use paravirt_enabled Alexander van Heukelum
2008-03-04 19:12                                 ` [PATCH] reserve end-of-conventional-memory to 1MB, 64-bit, " Alexander van Heukelum
2008-02-27 14:25     ` [PATCH] Fix alignment of early reservation for EBDA Andi Kleen

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