* [PATCH] EFI: Do not use __pa() to get the physical address of an ioremapped memory range
@ 2011-09-01 6:55 Zhang Rui
2011-09-01 8:14 ` Zhang Rui
0 siblings, 1 reply; 11+ messages in thread
From: Zhang Rui @ 2011-09-01 6:55 UTC (permalink / raw)
To: LKML; +Cc: Matthew Garrett, Zhang, Rui
From: Zhang Rui <rui.zhang@intel.com>
Date: Wed, 31 Aug 2011 09:59:01 +0800
Subject: Do not use __pa() to get the physical address of an ioremapped memory range.
set_memory_uc uses __pa() to translate the virtual address to the physical address.
This breaks a EFI_MEMORY_MAPPED_IO memory region in my case as it was ioremapped first.
<1>[ 0.029956] BUG: unable to handle kernel paging request at f7f22280
<1>[ 0.042049] IP: [<c10257b9>] reserve_ram_pages_type+0x89/0x210
<4>[ 0.053465] *pdpt = 0000000001978001 *pde = 0000000001ffb067 *pte = 0000000000000000
<0>[ 0.068781] Oops: 0000 [#1] PREEMPT SMP
<4>[ 0.076441] Modules linked in:
<4>[ 0.082399]
<4>[ 0.085304] Pid: 0, comm: swapper Not tainted 3.0.0-acpi-efi-0805 #3
<4>[ 0.098067] EIP: 0060:[<c10257b9>] EFLAGS: 00010202 CPU: 0
<4>[ 0.108810] EIP is at reserve_ram_pages_type+0x89/0x210
<4>[ 0.119022] EAX: 0070e280 EBX: 38714000 ECX: f7814000 EDX: 00000000
<4>[ 0.131284] ESI: 00000000 EDI: 38715000 EBP: c189fef0 ESP: c189fea8
<4>[ 0.143543] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
<0>[ 0.154099] Process swapper (pid: 0, ti=c189e000 task=c18bbe60 task.ti=c189e000)
<0>[ 0.168576] Stack:
<4>[ 0.172475] 80000200 ff108000 00000000 c189ff00 00038714 00000000 00000000 c189fed0
<4>[ 0.187623] c104f8ca 00038714 00000000 00038715 00000000 00000000 00038715 00000000
<4>[ 0.202777] 00000010 38715000 c189ff48 c1025aff 38715000 00000000 00000010 00000000
<0>[ 0.217930] Call Trace:
<4>[ 0.222722] [<c104f8ca>] ? page_is_ram+0x1a/0x40
<4>[ 0.231916] [<c1025aff>] reserve_memtype+0xdf/0x2f0
<4>[ 0.241622] [<c1024dc9>] set_memory_uc+0x49/0xa0
<4>[ 0.250818] [<c19334d0>] efi_enter_virtual_mode+0x1c2/0x3aa
<4>[ 0.261887] [<c19216d4>] start_kernel+0x291/0x2f2
<4>[ 0.271245] [<c19211c7>] ? loglevel+0x1b/0x1b
<4>[ 0.279929] [<c19210bf>] i386_start_kernel+0xbf/0xc8
---
arch/x86/platform/efi/efi.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
Index: acpi50/arch/x86/platform/efi/efi.c
===================================================================
--- acpi50.orig/arch/x86/platform/efi/efi.c
+++ acpi50/arch/x86/platform/efi/efi.c
@@ -44,6 +44,7 @@
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/x86_init.h>
+#include <asm/pat.h>
#define EFI_DEBUG 1
#define PFX "EFI: "
@@ -687,7 +688,13 @@ void __init efi_enter_virtual_mode(void)
addr = md->virt_addr;
npages = md->num_pages;
memrange_efi_to_native(&addr, &npages);
- set_memory_uc(addr, npages);
+ if (reserve_memtype(md->phys_addr, md->phys_addr + npages * PAGE_SIZE,
+ _PAGE_CACHE_UC_MINUS, NULL)) {
+ printk(KERN_ERR PFX "failed to reserve region as uncacheable\n");
+ } elif (_set_memory_uc(addr, npages)) {
+ printk(KERN_ERR PFX "failed to set region to uncacheable\n");
+ free_memtype(md->phys_addr, md->phys_addr + npages * PAGE_SIZE);
+ }
}
systab = (u64) (unsigned long) efi_phys.systab;
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH] EFI: Do not use __pa() to get the physical address of an ioremapped memory range
2011-09-01 6:55 [PATCH] EFI: Do not use __pa() to get the physical address of an ioremapped memory range Zhang Rui
@ 2011-09-01 8:14 ` Zhang Rui
2011-09-01 12:28 ` Matt Fleming
0 siblings, 1 reply; 11+ messages in thread
From: Zhang Rui @ 2011-09-01 8:14 UTC (permalink / raw)
To: LKML; +Cc: Matthew Garrett
On Thu, 2011-09-01 at 14:55 +0800, Zhang, Rui wrote:
> From: Zhang Rui <rui.zhang@intel.com>
> Date: Wed, 31 Aug 2011 09:59:01 +0800
> Subject: Do not use __pa() to get the physical address of an ioremapped memory range.
>
> set_memory_uc uses __pa() to translate the virtual address to the physical address.
> This breaks a EFI_MEMORY_MAPPED_IO memory region in my case as it was ioremapped first.
>
oops, wrong patch was attached.
here is the correct patch.
From: Zhang Rui <rui.zhang@intel.com>
Date: Wed, 31 Aug 2011 09:59:01 +0800
Subject: Do not use __pa() to get the physical address of an ioremapped memory range.
set_memory_uc uses __pa() to translate the virtual address to the physical address.
This breaks a EFI_MEMORY_MAPPED_IO memory region in my case as it was ioremapped first.
<1>[ 0.029956] BUG: unable to handle kernel paging request at f7f22280
<1>[ 0.042049] IP: [<c10257b9>] reserve_ram_pages_type+0x89/0x210
<4>[ 0.053465] *pdpt = 0000000001978001 *pde = 0000000001ffb067 *pte = 0000000000000000
<0>[ 0.068781] Oops: 0000 [#1] PREEMPT SMP
<4>[ 0.076441] Modules linked in:
<4>[ 0.082399]
<4>[ 0.085304] Pid: 0, comm: swapper Not tainted 3.0.0-acpi-efi-0805 #3
<4>[ 0.098067] EIP: 0060:[<c10257b9>] EFLAGS: 00010202 CPU: 0
<4>[ 0.108810] EIP is at reserve_ram_pages_type+0x89/0x210
<4>[ 0.119022] EAX: 0070e280 EBX: 38714000 ECX: f7814000 EDX: 00000000
<4>[ 0.131284] ESI: 00000000 EDI: 38715000 EBP: c189fef0 ESP: c189fea8
<4>[ 0.143543] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
<0>[ 0.154099] Process swapper (pid: 0, ti=c189e000 task=c18bbe60 task.ti=c189e000)
<0>[ 0.168576] Stack:
<4>[ 0.172475] 80000200 ff108000 00000000 c189ff00 00038714 00000000 00000000 c189fed0
<4>[ 0.187623] c104f8ca 00038714 00000000 00038715 00000000 00000000 00038715 00000000
<4>[ 0.202777] 00000010 38715000 c189ff48 c1025aff 38715000 00000000 00000010 00000000
<0>[ 0.217930] Call Trace:
<4>[ 0.222722] [<c104f8ca>] ? page_is_ram+0x1a/0x40
<4>[ 0.231916] [<c1025aff>] reserve_memtype+0xdf/0x2f0
<4>[ 0.241622] [<c1024dc9>] set_memory_uc+0x49/0xa0
<4>[ 0.250818] [<c19334d0>] efi_enter_virtual_mode+0x1c2/0x3aa
<4>[ 0.261887] [<c19216d4>] start_kernel+0x291/0x2f2
<4>[ 0.271245] [<c19211c7>] ? loglevel+0x1b/0x1b
<4>[ 0.279929] [<c19210bf>] i386_start_kernel+0xbf/0xc8
---
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 3ae4128..89586fe 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -44,6 +44,7 @@
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/x86_init.h>
+#include <asm/pat.h>
#define EFI_DEBUG 1
#define PFX "EFI: "
@@ -687,7 +688,13 @@ void __init efi_enter_virtual_mode(void)
addr = md->virt_addr;
npages = md->num_pages;
memrange_efi_to_native(&addr, &npages);
- set_memory_uc(addr, npages);
+ if (reserve_memtype(md->phys_addr, md->phys_addr + npages * PAGE_SIZE,
+ _PAGE_CACHE_UC_MINUS, NULL)) {
+ printk(KERN_ERR PFX "failed to reserve region as uncacheable\n");
+ } else if (_set_memory_uc(addr, npages)) {
+ printk(KERN_ERR PFX "failed to set region to uncacheable\n");
+ free_memtype(md->phys_addr, md->phys_addr + npages * PAGE_SIZE);
+ }
}
systab = (u64) (unsigned long) efi_phys.systab;
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [PATCH] EFI: Do not use __pa() to get the physical address of an ioremapped memory range
2011-09-01 8:14 ` Zhang Rui
@ 2011-09-01 12:28 ` Matt Fleming
2011-09-02 2:18 ` Zhang Rui
2011-09-02 5:12 ` huang ying
0 siblings, 2 replies; 11+ messages in thread
From: Matt Fleming @ 2011-09-01 12:28 UTC (permalink / raw)
To: Zhang Rui; +Cc: LKML, Matthew Garrett
On Thu, 2011-09-01 at 16:14 +0800, Zhang Rui wrote:
> On Thu, 2011-09-01 at 14:55 +0800, Zhang, Rui wrote:
> > From: Zhang Rui <rui.zhang@intel.com>
> > Date: Wed, 31 Aug 2011 09:59:01 +0800
> > Subject: Do not use __pa() to get the physical address of an ioremapped memory range.
> >
> > set_memory_uc uses __pa() to translate the virtual address to the physical address.
> > This breaks a EFI_MEMORY_MAPPED_IO memory region in my case as it was ioremapped first.
> >
> oops, wrong patch was attached.
>
> here is the correct patch.
>
> From: Zhang Rui <rui.zhang@intel.com>
> Date: Wed, 31 Aug 2011 09:59:01 +0800
> Subject: Do not use __pa() to get the physical address of an ioremapped memory range.
>
> set_memory_uc uses __pa() to translate the virtual address to the physical address.
> This breaks a EFI_MEMORY_MAPPED_IO memory region in my case as it was ioremapped first.
Hmm.. does anyone know why we ioremap_cache() the memory on
CONFIG_X86_32 instead of ioremap_nocache()? In the case of
EFI_MEMORY_MAPPED_IO the memory really needs to be uncached. Then if
we've ioremap'd the memory we should skip set_memory_uc() altogether,
no?
--
Matt Fleming, Intel Open Source Technology Center
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] EFI: Do not use __pa() to get the physical address of an ioremapped memory range
2011-09-01 12:28 ` Matt Fleming
@ 2011-09-02 2:18 ` Zhang Rui
2011-09-02 5:12 ` huang ying
1 sibling, 0 replies; 11+ messages in thread
From: Zhang Rui @ 2011-09-02 2:18 UTC (permalink / raw)
To: Matt Fleming; +Cc: LKML, Matthew Garrett
On Thu, 2011-09-01 at 20:28 +0800, Matt Fleming wrote:
> On Thu, 2011-09-01 at 16:14 +0800, Zhang Rui wrote:
> > On Thu, 2011-09-01 at 14:55 +0800, Zhang, Rui wrote:
> > > From: Zhang Rui <rui.zhang@intel.com>
> > > Date: Wed, 31 Aug 2011 09:59:01 +0800
> > > Subject: Do not use __pa() to get the physical address of an ioremapped memory range.
> > >
> > > set_memory_uc uses __pa() to translate the virtual address to the physical address.
> > > This breaks a EFI_MEMORY_MAPPED_IO memory region in my case as it was ioremapped first.
> > >
> > oops, wrong patch was attached.
> >
> > here is the correct patch.
> >
> > From: Zhang Rui <rui.zhang@intel.com>
> > Date: Wed, 31 Aug 2011 09:59:01 +0800
> > Subject: Do not use __pa() to get the physical address of an ioremapped memory range.
> >
> > set_memory_uc uses __pa() to translate the virtual address to the physical address.
> > This breaks a EFI_MEMORY_MAPPED_IO memory region in my case as it was ioremapped first.
>
> Hmm.. does anyone know why we ioremap_cache() the memory on
> CONFIG_X86_32 instead of ioremap_nocache()?
Perhaps this is because not all the memory range need ioremap_nocache(),
e.g. EFI_BOOT_SERVICES_CODE, EFI_BOOT_SERVICES_DATA, etc?
So the current logic is to use ioremap_cache for all of them first, and
then set all the non-write-back memory ranges to uncacheable.
> In the case of
> EFI_MEMORY_MAPPED_IO the memory really needs to be uncached. Then if
> we've ioremap'd the memory we should skip set_memory_uc() altogether,
> no?
>
In the beginning, I tried to fix efi_ioremap, i.e. use ioremap_nocache
for EFI_MEMORY_MAPPED_IO and ioremap_cache for others.
But I'm not sure if that is the right FIX, as I don't know if there
might be other memory ranges that also need to be set to uncached.
thanks,
rui
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] EFI: Do not use __pa() to get the physical address of an ioremapped memory range
2011-09-01 12:28 ` Matt Fleming
2011-09-02 2:18 ` Zhang Rui
@ 2011-09-02 5:12 ` huang ying
2011-09-12 14:52 ` Matt Fleming
1 sibling, 1 reply; 11+ messages in thread
From: huang ying @ 2011-09-02 5:12 UTC (permalink / raw)
To: Matt Fleming; +Cc: Zhang Rui, LKML, Matthew Garrett
On Thu, Sep 1, 2011 at 8:28 PM, Matt Fleming <matt@console-pimps.org> wrote:
> On Thu, 2011-09-01 at 16:14 +0800, Zhang Rui wrote:
>> On Thu, 2011-09-01 at 14:55 +0800, Zhang, Rui wrote:
>> > From: Zhang Rui <rui.zhang@intel.com>
>> > Date: Wed, 31 Aug 2011 09:59:01 +0800
>> > Subject: Do not use __pa() to get the physical address of an ioremapped memory range.
>> >
>> > set_memory_uc uses __pa() to translate the virtual address to the physical address.
>> > This breaks a EFI_MEMORY_MAPPED_IO memory region in my case as it was ioremapped first.
>> >
>> oops, wrong patch was attached.
>>
>> here is the correct patch.
>>
>> From: Zhang Rui <rui.zhang@intel.com>
>> Date: Wed, 31 Aug 2011 09:59:01 +0800
>> Subject: Do not use __pa() to get the physical address of an ioremapped memory range.
>>
>> set_memory_uc uses __pa() to translate the virtual address to the physical address.
>> This breaks a EFI_MEMORY_MAPPED_IO memory region in my case as it was ioremapped first.
>
> Hmm.. does anyone know why we ioremap_cache() the memory on
> CONFIG_X86_32 instead of ioremap_nocache()? In the case of
> EFI_MEMORY_MAPPED_IO the memory really needs to be uncached. Then if
> we've ioremap'd the memory we should skip set_memory_uc() altogether,
> no?
Because whether the mapping should be cached is determined by md->attr
instead of md->type. And besides UC, we may add WC, etc support.
Best Regards,
Huang Ying
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] EFI: Do not use __pa() to get the physical address of an ioremapped memory range
2011-09-02 5:12 ` huang ying
@ 2011-09-12 14:52 ` Matt Fleming
2011-09-13 8:48 ` huang ying
2011-09-15 1:22 ` Shaohua Li
0 siblings, 2 replies; 11+ messages in thread
From: Matt Fleming @ 2011-09-12 14:52 UTC (permalink / raw)
To: huang ying; +Cc: Zhang Rui, LKML, Matthew Garrett, x86
On Fri, 2011-09-02 at 13:12 +0800, huang ying wrote:
> On Thu, Sep 1, 2011 at 8:28 PM, Matt Fleming <matt@console-pimps.org> wrote:
> >
> > Hmm.. does anyone know why we ioremap_cache() the memory on
> > CONFIG_X86_32 instead of ioremap_nocache()? In the case of
> > EFI_MEMORY_MAPPED_IO the memory really needs to be uncached. Then if
> > we've ioremap'd the memory we should skip set_memory_uc() altogether,
> > no?
>
> Because whether the mapping should be cached is determined by md->attr
> instead of md->type. And besides UC, we may add WC, etc support.
Confused.
The CONFIG_X86_64 version of efi_ioremap() looks like this,
void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
u32 type)
{
unsigned long last_map_pfn;
if (type == EFI_MEMORY_MAPPED_IO)
return ioremap(phys_addr, size);
Which uses md->type to figure out if we should call ioremap(), which on
x86 is #define'd to ioremap_nocache(). CONFIG_X86_32 doesn't do this,
but it looks to me like it should.
Zhang, I agree that calling __pa() on an ioremap()'d region is bogus,
but I don't understand why no one is seeing this crash on x86-64. Is it
something to do with the x86-64 memory map layout such that __pa() works
on an ioremap()'d address?
--
Matt Fleming, Intel Open Source Technology Center
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH] EFI: Do not use __pa() to get the physical address of an ioremapped memory range
2011-09-12 14:52 ` Matt Fleming
@ 2011-09-13 8:48 ` huang ying
2011-09-14 19:16 ` Matt Fleming
2011-09-15 1:22 ` Shaohua Li
1 sibling, 1 reply; 11+ messages in thread
From: huang ying @ 2011-09-13 8:48 UTC (permalink / raw)
To: Matt Fleming; +Cc: Zhang Rui, LKML, Matthew Garrett, x86
On Mon, Sep 12, 2011 at 10:52 PM, Matt Fleming <matt@console-pimps.org> wrote:
> On Fri, 2011-09-02 at 13:12 +0800, huang ying wrote:
>> On Thu, Sep 1, 2011 at 8:28 PM, Matt Fleming <matt@console-pimps.org> wrote:
>> >
>> > Hmm.. does anyone know why we ioremap_cache() the memory on
>> > CONFIG_X86_32 instead of ioremap_nocache()? In the case of
>> > EFI_MEMORY_MAPPED_IO the memory really needs to be uncached. Then if
>> > we've ioremap'd the memory we should skip set_memory_uc() altogether,
>> > no?
>>
>> Because whether the mapping should be cached is determined by md->attr
>> instead of md->type. And besides UC, we may add WC, etc support.
>
> Confused.
>
> The CONFIG_X86_64 version of efi_ioremap() looks like this,
>
> void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
> u32 type)
> {
> unsigned long last_map_pfn;
>
> if (type == EFI_MEMORY_MAPPED_IO)
> return ioremap(phys_addr, size);
>
> Which uses md->type to figure out if we should call ioremap(), which on
> x86 is #define'd to ioremap_nocache(). CONFIG_X86_32 doesn't do this,
> but it looks to me like it should.
I don't think this type based solution is the perfect one.
Best Regards,
Huang Ying
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH] EFI: Do not use __pa() to get the physical address of an ioremapped memory range
2011-09-13 8:48 ` huang ying
@ 2011-09-14 19:16 ` Matt Fleming
0 siblings, 0 replies; 11+ messages in thread
From: Matt Fleming @ 2011-09-14 19:16 UTC (permalink / raw)
To: huang ying; +Cc: Zhang Rui, LKML, Matthew Garrett, x86
On Tue, 2011-09-13 at 16:48 +0800, huang ying wrote:
> On Mon, Sep 12, 2011 at 10:52 PM, Matt Fleming <matt@console-pimps.org> wrote:
> > On Fri, 2011-09-02 at 13:12 +0800, huang ying wrote:
> >> On Thu, Sep 1, 2011 at 8:28 PM, Matt Fleming <matt@console-pimps.org> wrote:
> >> >
> >> > Hmm.. does anyone know why we ioremap_cache() the memory on
> >> > CONFIG_X86_32 instead of ioremap_nocache()? In the case of
> >> > EFI_MEMORY_MAPPED_IO the memory really needs to be uncached. Then if
> >> > we've ioremap'd the memory we should skip set_memory_uc() altogether,
> >> > no?
> >>
> >> Because whether the mapping should be cached is determined by md->attr
> >> instead of md->type. And besides UC, we may add WC, etc support.
> >
> > Confused.
> >
> > The CONFIG_X86_64 version of efi_ioremap() looks like this,
> >
> > void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
> > u32 type)
> > {
> > unsigned long last_map_pfn;
> >
> > if (type == EFI_MEMORY_MAPPED_IO)
> > return ioremap(phys_addr, size);
> >
> > Which uses md->type to figure out if we should call ioremap(), which on
> > x86 is #define'd to ioremap_nocache(). CONFIG_X86_32 doesn't do this,
> > but it looks to me like it should.
>
> I don't think this type based solution is the perfect one.
Why? What else would you suggest?
--
Matt Fleming, Intel Open Source Technology Center
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] EFI: Do not use __pa() to get the physical address of an ioremapped memory range
2011-09-12 14:52 ` Matt Fleming
2011-09-13 8:48 ` huang ying
@ 2011-09-15 1:22 ` Shaohua Li
2011-09-15 1:52 ` Zhang Rui
1 sibling, 1 reply; 11+ messages in thread
From: Shaohua Li @ 2011-09-15 1:22 UTC (permalink / raw)
To: Matt Fleming; +Cc: huang ying, Zhang Rui, LKML, Matthew Garrett, x86
2011/9/12 Matt Fleming <matt@console-pimps.org>:
> On Fri, 2011-09-02 at 13:12 +0800, huang ying wrote:
>> On Thu, Sep 1, 2011 at 8:28 PM, Matt Fleming <matt@console-pimps.org> wrote:
>> >
>> > Hmm.. does anyone know why we ioremap_cache() the memory on
>> > CONFIG_X86_32 instead of ioremap_nocache()? In the case of
>> > EFI_MEMORY_MAPPED_IO the memory really needs to be uncached. Then if
>> > we've ioremap'd the memory we should skip set_memory_uc() altogether,
>> > no?
>>
>> Because whether the mapping should be cached is determined by md->attr
>> instead of md->type. And besides UC, we may add WC, etc support.
>
> Confused.
>
> The CONFIG_X86_64 version of efi_ioremap() looks like this,
>
> void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
> u32 type)
> {
> unsigned long last_map_pfn;
>
> if (type == EFI_MEMORY_MAPPED_IO)
> return ioremap(phys_addr, size);
>
> Which uses md->type to figure out if we should call ioremap(), which on
> x86 is #define'd to ioremap_nocache(). CONFIG_X86_32 doesn't do this,
> but it looks to me like it should.
agree. mapping it wrong and fixing it later makes no sense. we should get
the mapping correct at the first.
> Zhang, I agree that calling __pa() on an ioremap()'d region is bogus,
> but I don't understand why no one is seeing this crash on x86-64. Is it
> something to do with the x86-64 memory map layout such that __pa() works
> on an ioremap()'d address?
x86-64 does identity mapping for larger space (from 0 to the last physical mem
even there is hole). Maybe this is the reason.
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH] EFI: Do not use __pa() to get the physical address of an ioremapped memory range
2011-09-15 1:22 ` Shaohua Li
@ 2011-09-15 1:52 ` Zhang Rui
2011-09-15 3:21 ` huang ying
0 siblings, 1 reply; 11+ messages in thread
From: Zhang Rui @ 2011-09-15 1:52 UTC (permalink / raw)
To: Shaohua Li; +Cc: Matt Fleming, huang ying, LKML, Matthew Garrett, x86
On Thu, 2011-09-15 at 09:22 +0800, Shaohua Li wrote:
> 2011/9/12 Matt Fleming <matt@console-pimps.org>:
> > On Fri, 2011-09-02 at 13:12 +0800, huang ying wrote:
> >> On Thu, Sep 1, 2011 at 8:28 PM, Matt Fleming <matt@console-pimps.org> wrote:
> >> >
> >> > Hmm.. does anyone know why we ioremap_cache() the memory on
> >> > CONFIG_X86_32 instead of ioremap_nocache()? In the case of
> >> > EFI_MEMORY_MAPPED_IO the memory really needs to be uncached. Then if
> >> > we've ioremap'd the memory we should skip set_memory_uc() altogether,
> >> > no?
> >>
> >> Because whether the mapping should be cached is determined by md->attr
> >> instead of md->type. And besides UC, we may add WC, etc support.
> >
> > Confused.
> >
> > The CONFIG_X86_64 version of efi_ioremap() looks like this,
> >
> > void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
> > u32 type)
> > {
> > unsigned long last_map_pfn;
> >
> > if (type == EFI_MEMORY_MAPPED_IO)
> > return ioremap(phys_addr, size);
> >
> > Which uses md->type to figure out if we should call ioremap(), which on
> > x86 is #define'd to ioremap_nocache(). CONFIG_X86_32 doesn't do this,
> > but it looks to me like it should.
> agree. mapping it wrong and fixing it later makes no sense. we should get
> the mapping correct at the first.
>
So what kinds of memory regions need ioremap_nocache?
should we make this decision based on the memory range type or attribute
or even both of them?
-rui
> > Zhang, I agree that calling __pa() on an ioremap()'d region is bogus,
> > but I don't understand why no one is seeing this crash on x86-64. Is it
> > something to do with the x86-64 memory map layout such that __pa() works
> > on an ioremap()'d address?
> x86-64 does identity mapping for larger space (from 0 to the last physical mem
> even there is hole). Maybe this is the reason.
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH] EFI: Do not use __pa() to get the physical address of an ioremapped memory range
2011-09-15 1:52 ` Zhang Rui
@ 2011-09-15 3:21 ` huang ying
0 siblings, 0 replies; 11+ messages in thread
From: huang ying @ 2011-09-15 3:21 UTC (permalink / raw)
To: Zhang Rui; +Cc: Shaohua Li, Matt Fleming, LKML, Matthew Garrett, x86
On Thu, Sep 15, 2011 at 9:52 AM, Zhang Rui <rui.zhang@intel.com> wrote:
> On Thu, 2011-09-15 at 09:22 +0800, Shaohua Li wrote:
>> 2011/9/12 Matt Fleming <matt@console-pimps.org>:
>> > On Fri, 2011-09-02 at 13:12 +0800, huang ying wrote:
>> >> On Thu, Sep 1, 2011 at 8:28 PM, Matt Fleming <matt@console-pimps.org> wrote:
>> >> >
>> >> > Hmm.. does anyone know why we ioremap_cache() the memory on
>> >> > CONFIG_X86_32 instead of ioremap_nocache()? In the case of
>> >> > EFI_MEMORY_MAPPED_IO the memory really needs to be uncached. Then if
>> >> > we've ioremap'd the memory we should skip set_memory_uc() altogether,
>> >> > no?
>> >>
>> >> Because whether the mapping should be cached is determined by md->attr
>> >> instead of md->type. And besides UC, we may add WC, etc support.
>> >
>> > Confused.
>> >
>> > The CONFIG_X86_64 version of efi_ioremap() looks like this,
>> >
>> > void __iomem *__init efi_ioremap(unsigned long phys_addr, unsigned long size,
>> > u32 type)
>> > {
>> > unsigned long last_map_pfn;
>> >
>> > if (type == EFI_MEMORY_MAPPED_IO)
>> > return ioremap(phys_addr, size);
>> >
>> > Which uses md->type to figure out if we should call ioremap(), which on
>> > x86 is #define'd to ioremap_nocache(). CONFIG_X86_32 doesn't do this,
>> > but it looks to me like it should.
>> agree. mapping it wrong and fixing it later makes no sense. we should get
>> the mapping correct at the first.
>>
> So what kinds of memory regions need ioremap_nocache?
> should we make this decision based on the memory range type or attribute
> or even both of them?
I think the decision should be made based on attribute as follow:
- attribute & EFI_MEMORY_WB --> ioremap_cache
- attribute & EFI_MEMORY_WC --> ioremap_wc
- others -> ioremap_nocache
init_memory_mapping in efi_ioremap is used to make kexec support
possible. But ioremap is used anyway, kexec support should be done in
another way. So I think it is ok to just use ioremap_xxx in
efi_ioremap. The efi_ioremap definition for 32bit need to be fixed
too.
Best Regards,
Huang Ying
^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2011-09-15 3:28 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2011-09-01 6:55 [PATCH] EFI: Do not use __pa() to get the physical address of an ioremapped memory range Zhang Rui
2011-09-01 8:14 ` Zhang Rui
2011-09-01 12:28 ` Matt Fleming
2011-09-02 2:18 ` Zhang Rui
2011-09-02 5:12 ` huang ying
2011-09-12 14:52 ` Matt Fleming
2011-09-13 8:48 ` huang ying
2011-09-14 19:16 ` Matt Fleming
2011-09-15 1:22 ` Shaohua Li
2011-09-15 1:52 ` Zhang Rui
2011-09-15 3:21 ` huang ying
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