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Date: Thu, 8 Apr 2010 12:59:45 +0800
From: Liang Li <liang.li@...driver.com>
To: Yinghai <yinghai.lu@...cle.com>
Cc: akpm@...ux-foundation.org, hpa@...or.com, mingo@...e.hu,
tglx@...utronix.de, wangchen@...fujitsu.com,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: + x86-fix-handling-of-the-reservetop-boot-option.patch added to
-mm tree
On Wed, Apr 07, 2010 at 09:30:39PM -0700, Yinghai wrote:
> On 04/07/2010 06:53 PM, Liang Li wrote:
> > Does this similar modification like this is more preferred?
> >
> > 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 ea82ef0..fe06296 100644
> > --- a/arch/x86/mm/ioremap.c
> > +++ b/arch/x86/mm/ioremap.c
> > @@ -448,6 +448,23 @@ 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])
> > + break;
> > + }
> > +
> > + if (i == FIX_BTMAPS_SLOTS)
> <
> > + WARN_ON(1);
> BUG_ON()
> > +
> > + for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
> > + slot_virt[i] = __fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS * i);
> > +
> need to clear the old PMD, and set new PMD.
>
> so you can clear old PMD and call early_ioremap_init() in fixup_early_ioremap()
Call early_ioremap_init will do the update PMD work. So the preferred
patch would be:
---------------
>From 61fe7a116cbbf6eef98a49b88ed5861ed9ebd32d Mon Sep 17 00:00:00 2001
From: Liang Li <liang.li@...driver.com>
Date: Mon, 22 Mar 2010 18:38:14 +0800
Subject: [PATCH] x86: let 'reservetop' functioning right
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.
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.
Signed-off-by: Liang Li <liang.li@...driver.com>
Cc: Wang Chen <wangchen@...fujitsu.com>
Cc: Ingo Molnar <mingo@...e.hu>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Yinghai Lu <yinghai@...nel.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>
---
arch/x86/include/asm/io.h | 1 +
arch/x86/mm/ioremap.c | 15 +++++++++++++++
arch/x86/mm/pgtable.c | 2 ++
3 files changed, 18 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..e4ab706 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -448,6 +448,21 @@ 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])
+ break;
+ }
+
+ if (i < FIX_BTMAPS_SLOTS)
+ BUG_ON(1);
+
+ early_ioremap_init();
+ return;
+}
+
static int __init check_early_ioremap_leak(void)
{
int count = 0;
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 5c4ee42..ea4d54c 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -4,6 +4,7 @@
#include <asm/pgtable.h>
#include <asm/tlb.h>
#include <asm/fixmap.h>
+#include <asm/io.h>
#define PGALLOC_GFP GFP_KERNEL | __GFP_NOTRACK | __GFP_REPEAT | __GFP_ZERO
@@ -351,6 +352,7 @@ void __init reserve_top_address(unsigned long reserve)
printk(KERN_INFO "Reserving virtual address space above 0x%08x\n",
(int)-reserve);
__FIXADDR_TOP = -reserve - PAGE_SIZE;
+ fixup_early_ioremap();
#endif
}
-----------
Acceptable?
Thanks and regards,
-Liang Li
--
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