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Message-ID: <4BC51312.6080302@oracle.com>
Date: Tue, 13 Apr 2010 17:57:54 -0700
From: Yinghai <yinghai.lu@...cle.com>
To: "H. Peter Anvin" <hpa@...or.com>,
Andy Isaacson <adi@...apodia.org>, guenter.roeck@...csson.com,
Linus Torvalds <torvalds@...ux-foundation.org>
CC: Yinghai <yinghai.lu@...cle.com>,
Bjorn Helgaas <bjorn.helgaas@...com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
"x86@...nel.org" <x86@...nel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Thomas Renninger <trenn@...e.de>
Subject: Re: [PATCH -v2 1/2] x86: Reserve [0xa0000, 0x100000] in e820 map
On 04/13/2010 02:58 PM, H. Peter Anvin wrote:
> On 04/13/2010 02:42 PM, Yinghai wrote:
>> On 04/13/2010 02:18 PM, H. Peter Anvin wrote:
>>> On 04/13/2010 02:11 PM, Yinghai wrote:
>>>>>
>>>>> I guess the real question (which I haven't looked at myself) is if the
>>>>> E820_RESERVED -> BUSY will cause an explicitly assigned BAR from being
>>>>> moved. That's bad, not so much for this particular range, but from BARs
>>>>> which may be assigned by SMM. Hacking that up in a simulator
>>>>> (Qemu/Bochs) and testing it is probably on the to do list...
>>>>
>>>> no, if some device BAR fall in that range, it should still use that range, and will not be relocated.
>>>>
>>>> will update the change log.
>>>>
>>>
>>> Good, that's what we want.
>>
>> the driver for that device later can not use pci_request_region(). because that region is BUSY already.
>>
>
> That's not good (in general - for devices in this particular range it's
> not such a big deal, but it is potentially really bad for devices marked
> reserved for them not to be moved.)
>
> We have talked about a need to resolve this before.
this one should make both cases work.
Andy, can you check this one together with
v3: x86: Reserve [0xa0000, 0x100000] in e820 map
Guenter, can you try the two patches on the system with special device?
Thanks
Yinghai
--------
Subject: [PATCH] x86, resource: Add reserve_region_with_split_check_child()
It will cover the whole region to BUSY, except that some regions that have
children under them.
those children normally is PCI bar but it is falling into E820_RESERVED.
We can not put BUSY on them, otherwise driver can not use pci_request_region()
later
/proc/iomem will have
00010000-00094fff : System RAM
00095000-0009ffff : reserved
000a0000-000bffff : PCI Bus 0000:00
000a0000-000bffff : reserved
000c0000-000cffff : reserved
000d0000-000dffff : PCI Bus 0000:00
000d0000-000dffff : reserved
000e0000-000fffff : reserved
Signed-off-by: Yinghai Lu <yinghai@...nel.org>
---
arch/x86/kernel/e820.c | 10 +++++++---
include/linux/ioport.h | 3 +++
kernel/resource.c | 24 +++++++++++++++++++-----
3 files changed, 29 insertions(+), 8 deletions(-)
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
@@ -1094,7 +1094,7 @@ void __init e820_reserve_resources(void)
* pci device BAR resource and insert them later in
* pcibios_resource_survey()
*/
- if (e820.map[i].type != E820_RESERVED || res->start < (1ULL<<20)) {
+ if (e820.map[i].type != E820_RESERVED) {
res->flags |= IORESOURCE_BUSY;
insert_resource(&iomem_resource, res);
}
@@ -1135,8 +1135,12 @@ void __init e820_reserve_resources_late(
res = e820_res;
for (i = 0; i < e820.nr_map; i++) {
- if (!res->parent && res->end)
- insert_resource_expand_to_fit(&iomem_resource, res);
+ if (!res->parent && res->end) {
+ if (res->start < (1ULL<<20)) {
+ reserve_region_with_split_check_child(&iomem_resource, res->start, res->end, res->name);
+ } else
+ insert_resource_expand_to_fit(&iomem_resource, res);
+ }
res++;
}
Index: linux-2.6/include/linux/ioport.h
===================================================================
--- linux-2.6.orig/include/linux/ioport.h
+++ linux-2.6/include/linux/ioport.h
@@ -120,6 +120,9 @@ void release_child_resources(struct reso
extern void reserve_region_with_split(struct resource *root,
resource_size_t start, resource_size_t end,
const char *name);
+void reserve_region_with_split_check_child(struct resource *root,
+ resource_size_t start, resource_size_t end,
+ const char *name);
extern struct resource *insert_resource_conflict(struct resource *parent, struct resource *new);
extern int insert_resource(struct resource *parent, struct resource *new);
extern void insert_resource_expand_to_fit(struct resource *root, struct resource *new);
Index: linux-2.6/kernel/resource.c
===================================================================
--- linux-2.6.orig/kernel/resource.c
+++ linux-2.6/kernel/resource.c
@@ -609,7 +609,7 @@ int adjust_resource(struct resource *res
static void __init __reserve_region_with_split(struct resource *root,
resource_size_t start, resource_size_t end,
- const char *name)
+ const char *name, bool check_child)
{
struct resource *parent = root;
struct resource *conflict;
@@ -631,13 +631,18 @@ static void __init __reserve_region_with
kfree(res);
/* conflict covered whole area */
- if (conflict->start <= start && conflict->end >= end)
+ if (conflict->start <= start && conflict->end >= end) {
+ if (check_child && !conflict->child && strstr(conflict->name, "PCI Bus"))
+ __reserve_region_with_split(conflict, start, end, name, false);
return;
+ }
if (conflict->start > start)
- __reserve_region_with_split(root, start, conflict->start-1, name);
+ __reserve_region_with_split(root, start, conflict->start-1, name, check_child);
if (conflict->end < end)
- __reserve_region_with_split(root, conflict->end+1, end, name);
+ __reserve_region_with_split(root, conflict->end+1, end, name, check_child);
+ if (check_child && !conflict->child && strstr(conflict->name, "PCI Bus"))
+ __reserve_region_with_split(conflict, conflict->start, conflict->end, name, false);
}
void __init reserve_region_with_split(struct resource *root,
@@ -645,7 +650,16 @@ void __init reserve_region_with_split(st
const char *name)
{
write_lock(&resource_lock);
- __reserve_region_with_split(root, start, end, name);
+ __reserve_region_with_split(root, start, end, name, false);
+ write_unlock(&resource_lock);
+}
+
+void __init reserve_region_with_split_check_child(struct resource *root,
+ resource_size_t start, resource_size_t end,
+ const char *name)
+{
+ write_lock(&resource_lock);
+ __reserve_region_with_split(root, start, end, name, true);
write_unlock(&resource_lock);
}
--
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