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Date: Fri, 30 Apr 2010 12:22:05 +0200
From: Ingo Molnar <mingo@...e.hu>
To: Liang Li <liang.li@...driver.com>
Cc: linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
wangchen@...fujitsu.com, tglx@...utronix.de, hpa@...or.com,
yinghai@...nel.org, jeremy.fitzhardinge@...rix.com,
konrad.wilk@...cle.com
Subject: Re: [v3 PATCH] x86: let 'reservetop' functioning right
* Liang Li <liang.li@...driver.com> wrote:
> 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.
>
> The simplest fix might be use __fix_to_virt(idx0) to get updated value
> of 'FIXADDR_TOP' in '__early_ioremap' instead of reference old value
> from slot_virt[slot] directly.
>
> Changelog since v0:
>
> -v1: 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.
>
> -v2: place fixup_early_ioremap hence call early_ioremap_init in
> reserve_top_address to re-initialize slot_virt and corresponding PMD
> when parse_reservertop
>
> -v3: move fixup_early_ioremap out of reserve_top_address to make sure
> other clients of reserve_top_address like xen/lguest won't broken
>
> 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: Andrew Morton <akpm@...ux-foundation.org>
> Acked-by: Yinghai Lu <yinghai@...nel.org>
> Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
> Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
> ---
> Hi all,
>
> Just resend the patch according to Ingo's demand.
> Thanks.
>
> arch/x86/include/asm/io.h | 1 +
> arch/x86/mm/ioremap.c | 15 +++++++++++++++
> arch/x86/mm/pgtable_32.c | 1 +
> 3 files changed, 17 insertions(+), 0 deletions(-)
Applied, thanks. Note, i cleaned up the fixup_early_ioremap() code (and
changed the BUG_ON to WARN_ON - we dont want to crash the box), mind double
checking the end result? See the commit below.
Ingo
----------------->
>From e67a807f3d9a82fa91817871f1c0e2e04da993b8 Mon Sep 17 00:00:00 2001
From: Liang Li <liang.li@...driver.com>
Date: Fri, 30 Apr 2010 18:01:51 +0800
Subject: [PATCH] x86: Fix 'reservetop=' functionality
When specifying the 'reservetop=0xbadc0de' kernel parameter,
the kernel will stop booting due to a early_ioremap bug that
relates 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.
The simplest fix might be use __fix_to_virt(idx0) to get updated
value of 'FIXADDR_TOP' in '__early_ioremap' instead of reference
old value from slot_virt[slot] directly.
Changelog since v0:
-v1: 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.
-v2: place fixup_early_ioremap hence call early_ioremap_init in
reserve_top_address to re-initialize slot_virt and
corresponding PMD when parse_reservertop
-v3: move fixup_early_ioremap out of reserve_top_address to make
sure other clients of reserve_top_address like xen/lguest won't
broken
Signed-off-by: Liang Li <liang.li@...driver.com>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Acked-by: Yinghai Lu <yinghai@...nel.org>
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
Cc: Wang Chen <wangchen@...fujitsu.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
LKML-Reference: <1272621711-8683-1-git-send-email-liang.li@...driver.com>
[ fixed three small cleanliness details in fixup_early_ioremap() ]
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
arch/x86/include/asm/io.h | 1 +
arch/x86/mm/ioremap.c | 14 ++++++++++++++
arch/x86/mm/pgtable_32.c | 1 +
3 files changed, 16 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..12e4d2d 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -448,6 +448,20 @@ 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]) {
+ WARN_ON(1);
+ break;
+ }
+ }
+
+ early_ioremap_init();
+}
+
static int __init check_early_ioremap_leak(void)
{
int count = 0;
diff --git a/arch/x86/mm/pgtable_32.c b/arch/x86/mm/pgtable_32.c
index 1a8faf0..26eadaa 100644
--- a/arch/x86/mm/pgtable_32.c
+++ b/arch/x86/mm/pgtable_32.c
@@ -128,6 +128,7 @@ static int __init parse_reservetop(char *arg)
address = memparse(arg, &arg);
reserve_top_address(address);
+ fixup_early_ioremap();
return 0;
}
early_param("reservetop", parse_reservetop);
--
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