lkml.org 
[lkml]   [2010]   [Jan]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
SubjectRe: [PATCH - resend] Memory-Hotplug: Fix the bug on interface /dev/mem for 64-bit kernel(v1)
From
On Tue, Jan 12, 2010 at 5:35 AM, Wu Fengguang <fengguang.wu@intel.com> wrote:
> On Tue, Jan 12, 2010 at 10:39:03AM +0800, KAMEZAWA Hiroyuki wrote:
>> On Tue, 12 Jan 2010 10:33:08 +0800
>> Wu Fengguang <fengguang.wu@intel.com> wrote:
>>
>> > Sure, here it is :)
>> > ---
>> > x86: use the generic page_is_ram()
>> >
>> > The generic resource based page_is_ram() works better with memory
>> > hotplug/hotremove. So switch the x86 e820map based code to it.
>> >
>> > CC: Andi Kleen <andi@firstfloor.org>
>> > CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
>> > Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
>>
>> Ack.
>
> Thank you.
>
>>
>> > +#ifdef CONFIG_X86
>> > +   /*
>> > +    * A special case is the first 4Kb of memory;
>> > +    * This is a BIOS owned area, not kernel ram, but generally
>> > +    * not listed as such in the E820 table.
>> > +    */
>> > +   if (pfn == 0)
>> > +           return 0;
>> > +
>> > +   /*
>> > +    * Second special case: Some BIOSen report the PC BIOS
>> > +    * area (640->1Mb) as ram even though it is not.
>> > +    */
>> > +   if (pfn >= (BIOS_BEGIN >> PAGE_SHIFT) &&
>> > +       pfn <  (BIOS_END   >> PAGE_SHIFT))
>> > +           return 0;
>> > +#endif
>>
>> I'm glad if this part is sorted out in clean way ;)
>
> Two possible solutions are:
>
> - to exclude the above two ranges directly in e820 map;
> - to not add the above two ranges into iomem_resource.
>
> Yinghai, do you have any suggestions?
> We want to get rid of the two explicit tests from page_is_ram().

please check attached patch.

YH
[PATCH] x86: remove bios data range from e820

to prepare move page_is_ram as generic one

Signed-off-by: Yinghai Lu <yinghai@kernel.org.

---
arch/x86/kernel/e820.c | 8 ++++++++
arch/x86/kernel/head32.c | 2 --
arch/x86/kernel/head64.c | 2 --
arch/x86/kernel/setup.c | 19 ++++++++++++++++++-
arch/x86/mm/ioremap.c | 16 ----------------
5 files changed, 26 insertions(+), 21 deletions(-)

Index: linux-2.6/arch/x86/kernel/setup.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/setup.c
+++ linux-2.6/arch/x86/kernel/setup.c
@@ -657,6 +657,23 @@ static struct dmi_system_id __initdata b
{}
};

+static void __init trim_bios_range(void)
+{
+ /*
+ * A special case is the first 4Kb of memory;
+ * This is a BIOS owned area, not kernel ram, but generally
+ * not listed as such in the E820 table.
+ */
+ e820_update_range(0, PAGE_SIZE, E820_RAM, E820_RESERVED);
+ /*
+ * special case: Some BIOSen report the PC BIOS
+ * area (640->1Mb) as ram even though it is not.
+ * take them out.
+ */
+ e820_remove_range(BIOS_BEGIN, BIOS_END - BIOS_BEGIN, E820_RAM, 1);
+ sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
+}
+
/*
* Determine if we were loaded by an EFI loader. If so, then we have also been
* passed the efi memmap, systab, etc., so we should use these data structures
@@ -820,7 +837,7 @@ void __init setup_arch(char **cmdline_p)
insert_resource(&iomem_resource, &data_resource);
insert_resource(&iomem_resource, &bss_resource);

-
+ trim_bios_range();
#ifdef CONFIG_X86_32
if (ppro_with_ram_bug()) {
e820_update_range(0x70000000ULL, 0x40000ULL, E820_RAM,
Index: linux-2.6/arch/x86/kernel/e820.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/e820.c
+++ linux-2.6/arch/x86/kernel/e820.c
@@ -509,11 +509,19 @@ u64 __init e820_remove_range(u64 start,
int checktype)
{
int i;
+ u64 end;
u64 real_removed_size = 0;

if (size > (ULLONG_MAX - start))
size = ULLONG_MAX - start;

+ end = start + size;
+ printk(KERN_DEBUG "e820 remove range: %016Lx - %016Lx ",
+ (unsigned long long) start,
+ (unsigned long long) end);
+ e820_print_type(old_type);
+ printk(KERN_CONT "\n");
+
for (i = 0; i < e820.nr_map; i++) {
struct e820entry *ei = &e820.map[i];
u64 final_start, final_end;
Index: linux-2.6/arch/x86/mm/ioremap.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/ioremap.c
+++ linux-2.6/arch/x86/mm/ioremap.c
@@ -29,22 +29,6 @@ int page_is_ram(unsigned long pagenr)
resource_size_t addr, end;
int i;

- /*
- * A special case is the first 4Kb of memory;
- * This is a BIOS owned area, not kernel ram, but generally
- * not listed as such in the E820 table.
- */
- if (pagenr == 0)
- return 0;
-
- /*
- * Second special case: Some BIOSen report the PC BIOS
- * area (640->1Mb) as ram even though it is not.
- */
- if (pagenr >= (BIOS_BEGIN >> PAGE_SHIFT) &&
- pagenr < (BIOS_END >> PAGE_SHIFT))
- return 0;
-
for (i = 0; i < e820.nr_map; i++) {
/*
* Not usable memory:
Index: linux-2.6/arch/x86/kernel/head32.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/head32.c
+++ linux-2.6/arch/x86/kernel/head32.c
@@ -29,8 +29,6 @@ static void __init i386_default_early_se

void __init i386_start_kernel(void)
{
- reserve_early_overlap_ok(0, PAGE_SIZE, "BIOS data page");
-
#ifdef CONFIG_X86_TRAMPOLINE
/*
* But first pinch a few for the stack/trampoline stuff
Index: linux-2.6/arch/x86/kernel/head64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/head64.c
+++ linux-2.6/arch/x86/kernel/head64.c
@@ -98,8 +98,6 @@ void __init x86_64_start_reservations(ch
{
copy_bootdata(__va(real_mode_data));

- reserve_early_overlap_ok(0, PAGE_SIZE, "BIOS data page");
-
reserve_early(__pa_symbol(&_text), __pa_symbol(&__bss_stop), "TEXT DATA BSS");

#ifdef CONFIG_BLK_DEV_INITRD
\
 
 \ /
  Last update: 2010-01-13 00:05    [W:0.061 / U:0.216 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site