Re: [PATCH] [8/8] RFC: Fix some EFI problems

2008-02-13 Thread Andi Kleen 
Thomas Gleixner wrote:
> On Tue, 12 Feb 2008, Andi Kleen wrote:
> 
>> On Tuesday 12 February 2008 21:04:06 Thomas Gleixner wrote:
>>
>>> And you just copied the real bug in that logic as well:
>>>
>>>   set_memory_uc(md->virt_addr, size);
>> Oops you're right. I wanted to fix that, but didn't. Ok I'll put up
>> my brown paper back tonight when I go out.
>>  
>>> 
>>>
>>> which is initialized a couple of lines down.
>>>
>>> md->virt_addr = (u64) (unsigned long) va;
>>>
>>> The reordering/optimizing needs to be a separate patch.
>> What optimizing? It wasn't intended to be an optimization.
>> It fixes a bug.
> 
> No, it does not. Please go back and read my mail.

I describe the problem again:

- efi_ioremap on 64bit returns a fixmap address:
void __iomem * __init efi_ioremap(unsigned long phys_addr, unsigned long
size)
{
   ...
return (void __iomem *)__fix_to_virt(FIX_EFI_IO_MAP_FIRST_PAGE -
 (pages_mapped - pages));

}
- __fix_to_virt is:
 (FIXADDR_TOP - ((x) << PAGE_SHIFT)) and x is a small integer <30 or so.
- Fixmap is
#define VSYSCALL_END (-2UL << 20)
#define FIXADDR_TOP (VSYSCALL_END-PAGE_SIZE)
that gives e.g. 0xffdf for the top fixmap; the efi fixmap
is only slightly pages below.
- You pass that into set_memory_uc()
- That eventually calls __pa() on it several times
(in static_protections and in change_page_attr_addr for 64bit to
check for the kernel mapping)
- __pa calls __phys_addr which does
unsigned long __phys_addr(unsigned long x)
{
if (x >= __START_KERNEL_map)
return x - __START_KERNEL_map + phys_base;
return x - PAGE_OFFSET;
}
- Now __START_KERNEL_map is 0x8000.
- That ends up with

x = 0xffdf - smallnumber*PAGE_SIZE

if (x >= 0x8000)(evaluates to true)
return x - 0x8000 + phys_addr
- This ends up with some fictional number in cpa (but likely one
looking like a valid pa address) that has nothing
to do with the address that is mapped below the fixmap
- cpa() does weird things to random unrelated memory then or
might clear rw if you're really unlucky.
- I think on 32bit with a real ioremap it's also not completely kosher
with the right __PAGE_OFFSET (but I have not double checked
that step by step)

This is why I avoided calling set_memory_uc for the fixmap
and instead changed the code to set the correct PAT
attribute into the fixmap directly to avoid this.

I believe the full original change or some Thomasized variant of it
is still needed.

-Andi
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Re: [PATCH] [8/8] RFC: Fix some EFI problems

2008-02-12 Thread Thomas Gleixner 
On Tue, 12 Feb 2008, Andi Kleen wrote:

> On Tuesday 12 February 2008 21:04:06 Thomas Gleixner wrote:
> 
> > 
> > And you just copied the real bug in that logic as well:
> > 
> >   set_memory_uc(md->virt_addr, size);
> 
> Oops you're right. I wanted to fix that, but didn't. Ok I'll put up
> my brown paper back tonight when I go out.
>  
> > 
> > 
> > which is initialized a couple of lines down.
> > 
> > md->virt_addr = (u64) (unsigned long) va;
> > 
> > The reordering/optimizing needs to be a separate patch.
> 
> What optimizing? It wasn't intended to be an optimization.
> It fixes a bug.

No, it does not. Please go back and read my mail.
 
The code had exactly two bugs:

1) the logic of checking EFI_MEMORY_WB was wrong
2) the uninitialized variable

The fix is:

 arch/x86/kernel/efi.c |6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Index: linux-2.6/arch/x86/kernel/efi.c
===
--- linux-2.6.orig/arch/x86/kernel/efi.c
+++ linux-2.6/arch/x86/kernel/efi.c
@@ -428,9 +428,6 @@ void __init efi_enter_virtual_mode(void)
else
va = efi_ioremap(md->phys_addr, size);
 
-   if (md->attribute & EFI_MEMORY_WB)
-   set_memory_uc(md->virt_addr, size);
-
md->virt_addr = (u64) (unsigned long) va;
 
if (!va) {
@@ -439,6 +436,9 @@ void __init efi_enter_virtual_mode(void)
continue;
}
 
+   if (!(md->attribute & EFI_MEMORY_WB))
+   set_memory_uc(md->virt_addr, size);
+
systab = (u64) (unsigned long) efi_phys.systab;
if (md->phys_addr <= systab && systab < end) {
systab += md->virt_addr - md->phys_addr;

The reordering of code is completely irrelevant. It can be done, but
in a separate patch.

Thanks,

tglx
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Re: [PATCH] [8/8] RFC: Fix some EFI problems

2008-02-12 Thread Andi Kleen 
On Tuesday 12 February 2008 21:04:06 Thomas Gleixner wrote:

> 
> And you just copied the real bug in that logic as well:
> 
>   set_memory_uc(md->virt_addr, size);

Oops you're right. I wanted to fix that, but didn't. Ok I'll put up
my brown paper back tonight when I go out.
 
> 
> 
> which is initialized a couple of lines down.
> 
>   md->virt_addr = (u64) (unsigned long) va;
> 
> The reordering/optimizing needs to be a separate patch.

What optimizing? It wasn't intended to be an optimization.
It fixes a bug.

Not doing set_memory_uc on efi_ioremap output is needed because 
set_memory_uc doesn't work on fixmap which is what efi_ioremap
returns. 

(see previous mails on that topic -- i fixed the 'x' case,
but fixing "uc" is too hard imho) 

So I fixed efi_ioremap instead to set the correct caching
mode directly. That is ok because there can be no overlap 
with the direct mapping, so no aliases to fix up.


> Please keep bugfixes and other changes separate.
>  
> > +   /* RED-PEN does not handle overlapped areas */
> 
> Can you please use CHECKME/FIXME which is used everywhere else. No need to
> invent an extra marker.

I've always used RED-PEN

% grep -r RED-PEN arch/x86/* | wc -l
12
%

It comes originally from network code I hacked a long time ago, although
most of those got lost over time (only 2 left, sniff) 

Sorry I don't want to change this now and I doubt that will really cause
a problem for anybody.

I'll send an updated patch with the va thing fixed.

-Andi

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Re: [PATCH] [8/8] RFC: Fix some EFI problems

2008-02-12 Thread Thomas Gleixner 
On Mon, 11 Feb 2008, Andi Kleen wrote:

> >From code review the EFI memory map handling has a couple of problems:
> 
> - The test for _WB memory was reversed so it would set cache able memory
> to uncached
> - It would always set a wrong uninitialized zero address to uncached
> (so I suspect it always set the first few pages in phys memory to uncached,
> that is why it may have gone unnoticed) 
> - It would call set_memory_x() on a fixmap address that it doesn't
> handle correct.
> - Some other problems I commented in the code (but was unable to solve
> for now) 
> 
> I changed the ioremaps to set the correct caching attributes
> and also corrected the ordering so it looks roughly correct now.

The only effective change is:

-   if (md->attribute & EFI_MEMORY_WB)
+   if (!(md->attribute & EFI_MEMORY_WB))

I appreciate that you noticed the reverse logic, which I messed up
when I fixed up rejects.

I pulled this out as it is a real fix. The rest of this patch is just
turning code in circles for nothing, simply because it is functionally
completely irrelevant whether does simply:

if ((end >> PAGE_SHIFT) <= max_pfn_mapped)
va = __va(md->phys_addr);
else
va = efi_ioremap(md->phys_addr, size);

   if (!(md->attribute & EFI_MEMORY_WB))
set_memory_uc(md->virt_addr, size);
or

   if ((end >> PAGE_SHIFT) <= max_pfn_mapped) {
va = __va(md->phys_addr);

if (!(md->attribute & EFI_MEMORY_WB))
set_memory_uc(md->virt_addr, size);
   } else
va = efi_ioremap(md->phys_addr, size,
 !!(md->attribute & EFI_MEMORY_WB));

And you just copied the real bug in that logic as well:

  set_memory_uc(md->virt_addr, size);


which is initialized a couple of lines down.

md->virt_addr = (u64) (unsigned long) va;

The reordering/optimizing needs to be a separate patch.

Please keep bugfixes and other changes separate.
 
> + /* RED-PEN does not handle overlapped areas */

Can you please use CHECKME/FIXME which is used everywhere else. No need to
invent an extra marker.

Thanks,

tglx
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Re: [PATCH] [8/8] RFC: Fix some EFI problems

2008-02-12 Thread Thomas Gleixner 
On Tue, 12 Feb 2008, Andi Kleen wrote:

 On Tuesday 12 February 2008 21:04:06 Thomas Gleixner wrote:
 
  
  And you just copied the real bug in that logic as well:
  
set_memory_uc(md-virt_addr, size);
 
 Oops you're right. I wanted to fix that, but didn't. Ok I'll put up
 my brown paper back tonight when I go out.
  
  
  
  which is initialized a couple of lines down.
  
  md-virt_addr = (u64) (unsigned long) va;
  
  The reordering/optimizing needs to be a separate patch.
 
 What optimizing? It wasn't intended to be an optimization.
 It fixes a bug.

No, it does not. Please go back and read my mail.
 
The code had exactly two bugs:

1) the logic of checking EFI_MEMORY_WB was wrong
2) the uninitialized variable

The fix is:

 arch/x86/kernel/efi.c |6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Index: linux-2.6/arch/x86/kernel/efi.c
===
--- linux-2.6.orig/arch/x86/kernel/efi.c
+++ linux-2.6/arch/x86/kernel/efi.c
@@ -428,9 +428,6 @@ void __init efi_enter_virtual_mode(void)
else
va = efi_ioremap(md-phys_addr, size);
 
-   if (md-attribute  EFI_MEMORY_WB)
-   set_memory_uc(md-virt_addr, size);
-
md-virt_addr = (u64) (unsigned long) va;
 
if (!va) {
@@ -439,6 +436,9 @@ void __init efi_enter_virtual_mode(void)
continue;
}
 
+   if (!(md-attribute  EFI_MEMORY_WB))
+   set_memory_uc(md-virt_addr, size);
+
systab = (u64) (unsigned long) efi_phys.systab;
if (md-phys_addr = systab  systab  end) {
systab += md-virt_addr - md-phys_addr;

The reordering of code is completely irrelevant. It can be done, but
in a separate patch.

Thanks,

tglx
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Re: [PATCH] [8/8] RFC: Fix some EFI problems

2008-02-12 Thread Thomas Gleixner 
On Mon, 11 Feb 2008, Andi Kleen wrote:

 From code review the EFI memory map handling has a couple of problems:
 
 - The test for _WB memory was reversed so it would set cache able memory
 to uncached
 - It would always set a wrong uninitialized zero address to uncached
 (so I suspect it always set the first few pages in phys memory to uncached,
 that is why it may have gone unnoticed) 
 - It would call set_memory_x() on a fixmap address that it doesn't
 handle correct.
 - Some other problems I commented in the code (but was unable to solve
 for now) 
 
 I changed the ioremaps to set the correct caching attributes
 and also corrected the ordering so it looks roughly correct now.

The only effective change is:

-   if (md-attribute  EFI_MEMORY_WB)
+   if (!(md-attribute  EFI_MEMORY_WB))

I appreciate that you noticed the reverse logic, which I messed up
when I fixed up rejects.

I pulled this out as it is a real fix. The rest of this patch is just
turning code in circles for nothing, simply because it is functionally
completely irrelevant whether does simply:

if ((end  PAGE_SHIFT) = max_pfn_mapped)
va = __va(md-phys_addr);
else
va = efi_ioremap(md-phys_addr, size);

   if (!(md-attribute  EFI_MEMORY_WB))
set_memory_uc(md-virt_addr, size);
or

   if ((end  PAGE_SHIFT) = max_pfn_mapped) {
va = __va(md-phys_addr);

if (!(md-attribute  EFI_MEMORY_WB))
set_memory_uc(md-virt_addr, size);
   } else
va = efi_ioremap(md-phys_addr, size,
 !!(md-attribute  EFI_MEMORY_WB));

And you just copied the real bug in that logic as well:

  set_memory_uc(md-virt_addr, size);


which is initialized a couple of lines down.

md-virt_addr = (u64) (unsigned long) va;

The reordering/optimizing needs to be a separate patch.

Please keep bugfixes and other changes separate.
 
 + /* RED-PEN does not handle overlapped areas */

Can you please use CHECKME/FIXME which is used everywhere else. No need to
invent an extra marker.

Thanks,

tglx
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[PATCH] [8/8] RFC: Fix some EFI problems

2008-02-11 Thread Andi Kleen 

>From code review the EFI memory map handling has a couple of problems:

- The test for _WB memory was reversed so it would set cache able memory
to uncached
- It would always set a wrong uninitialized zero address to uncached
(so I suspect it always set the first few pages in phys memory to uncached,
that is why it may have gone unnoticed) 
- It would call set_memory_x() on a fixmap address that it doesn't
handle correct.
- Some other problems I commented in the code (but was unable to solve
for now) 

I changed the ioremaps to set the correct caching attributes
and also corrected the ordering so it looks roughly correct now.

This is an RFC, because I don't have a EFI system to test.

Cc: [EMAIL PROTECTED]

Signed-off-by: Andi Kleen <[EMAIL PROTECTED]>

---
 arch/x86/kernel/efi.c|   14 --
 arch/x86/kernel/efi_64.c |6 --
 include/asm-x86/efi.h|5 +++--
 3 files changed, 15 insertions(+), 10 deletions(-)

Index: linux/arch/x86/kernel/efi.c
===
--- linux.orig/arch/x86/kernel/efi.c
+++ linux/arch/x86/kernel/efi.c
@@ -423,13 +423,15 @@ void __init efi_enter_virtual_mode(void)
size = md->num_pages << EFI_PAGE_SHIFT;
end = md->phys_addr + size;
 
-   if ((end >> PAGE_SHIFT) <= max_pfn_mapped)
+   /* RED-PEN does not handle overlapped areas */
+   if ((end >> PAGE_SHIFT) <= max_pfn_mapped) {
va = __va(md->phys_addr);
-   else
-   va = efi_ioremap(md->phys_addr, size);
-
-   if (md->attribute & EFI_MEMORY_WB)
-   set_memory_uc(md->virt_addr, size);
+   /* RED-PEN spec and ia64 have a lot more flags */
+   if (!(md->attribute & EFI_MEMORY_WB))
+   set_memory_uc(md->virt_addr, size);
+   } else
+   va = efi_ioremap(md->phys_addr, size,
+   !!(md->attribute & EFI_MEMORY_WB));
 
md->virt_addr = (u64) (unsigned long) va;
 
Index: linux/arch/x86/kernel/efi_64.c
===
--- linux.orig/arch/x86/kernel/efi_64.c
+++ linux/arch/x86/kernel/efi_64.c
@@ -109,7 +109,8 @@ void __init efi_reserve_bootmem(void)
memmap.nr_map * memmap.desc_size);
 }
 
-void __iomem * __init efi_ioremap(unsigned long phys_addr, unsigned long size)
+void __iomem * __init efi_ioremap(unsigned long phys_addr, unsigned long size,
+ int cache)
 {
static unsigned pages_mapped;
unsigned i, pages;
@@ -124,7 +125,8 @@ void __iomem * __init efi_ioremap(unsign
 
for (i = 0; i < pages; i++) {
__set_fixmap(FIX_EFI_IO_MAP_FIRST_PAGE - pages_mapped,
-phys_addr, PAGE_KERNEL);
+phys_addr,
+cache ? PAGE_KERNEL : PAGE_KERNEL_NOCACHE);
phys_addr += PAGE_SIZE;
pages_mapped++;
}
Index: linux/include/asm-x86/efi.h
===
--- linux.orig/include/asm-x86/efi.h
+++ linux/include/asm-x86/efi.h
@@ -33,7 +33,8 @@ extern unsigned long asmlinkage efi_call
 #define efi_call_virt6(f, a1, a2, a3, a4, a5, a6)  \
efi_call_virt(f, a1, a2, a3, a4, a5, a6)
 
-#define efi_ioremap(addr, size)ioremap_cache(addr, 
size)
+#define efi_ioremap(addr, size, cache) \
+   (cache ? ioremap_cache(addr, size) : ioremap_nocache(addr, size))
 
 #else /* !CONFIG_X86_32 */
 
@@ -86,7 +87,7 @@ extern u64 efi_call6(void *fp, u64 arg1,
efi_call6((void *)(efi.systab->runtime->f), (u64)(a1), (u64)(a2), \
  (u64)(a3), (u64)(a4), (u64)(a5), (u64)(a6))
 
-extern void *efi_ioremap(unsigned long addr, unsigned long size);
+extern void *efi_ioremap(unsigned long addr, unsigned long size, int cache);
 
 #endif /* CONFIG_X86_32 */
 
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[PATCH] [8/8] RFC: Fix some EFI problems

2008-02-11 Thread Andi Kleen 

From code review the EFI memory map handling has a couple of problems:

- The test for _WB memory was reversed so it would set cache able memory
to uncached
- It would always set a wrong uninitialized zero address to uncached
(so I suspect it always set the first few pages in phys memory to uncached,
that is why it may have gone unnoticed) 
- It would call set_memory_x() on a fixmap address that it doesn't
handle correct.
- Some other problems I commented in the code (but was unable to solve
for now) 

I changed the ioremaps to set the correct caching attributes
and also corrected the ordering so it looks roughly correct now.

This is an RFC, because I don't have a EFI system to test.

Cc: [EMAIL PROTECTED]

Signed-off-by: Andi Kleen [EMAIL PROTECTED]

---
 arch/x86/kernel/efi.c|   14 --
 arch/x86/kernel/efi_64.c |6 --
 include/asm-x86/efi.h|5 +++--
 3 files changed, 15 insertions(+), 10 deletions(-)

Index: linux/arch/x86/kernel/efi.c
===
--- linux.orig/arch/x86/kernel/efi.c
+++ linux/arch/x86/kernel/efi.c
@@ -423,13 +423,15 @@ void __init efi_enter_virtual_mode(void)
size = md-num_pages  EFI_PAGE_SHIFT;
end = md-phys_addr + size;
 
-   if ((end  PAGE_SHIFT) = max_pfn_mapped)
+   /* RED-PEN does not handle overlapped areas */
+   if ((end  PAGE_SHIFT) = max_pfn_mapped) {
va = __va(md-phys_addr);
-   else
-   va = efi_ioremap(md-phys_addr, size);
-
-   if (md-attribute  EFI_MEMORY_WB)
-   set_memory_uc(md-virt_addr, size);
+   /* RED-PEN spec and ia64 have a lot more flags */
+   if (!(md-attribute  EFI_MEMORY_WB))
+   set_memory_uc(md-virt_addr, size);
+   } else
+   va = efi_ioremap(md-phys_addr, size,
+   !!(md-attribute  EFI_MEMORY_WB));
 
md-virt_addr = (u64) (unsigned long) va;
 
Index: linux/arch/x86/kernel/efi_64.c
===
--- linux.orig/arch/x86/kernel/efi_64.c
+++ linux/arch/x86/kernel/efi_64.c
@@ -109,7 +109,8 @@ void __init efi_reserve_bootmem(void)
memmap.nr_map * memmap.desc_size);
 }
 
-void __iomem * __init efi_ioremap(unsigned long phys_addr, unsigned long size)
+void __iomem * __init efi_ioremap(unsigned long phys_addr, unsigned long size,
+ int cache)
 {
static unsigned pages_mapped;
unsigned i, pages;
@@ -124,7 +125,8 @@ void __iomem * __init efi_ioremap(unsign
 
for (i = 0; i  pages; i++) {
__set_fixmap(FIX_EFI_IO_MAP_FIRST_PAGE - pages_mapped,
-phys_addr, PAGE_KERNEL);
+phys_addr,
+cache ? PAGE_KERNEL : PAGE_KERNEL_NOCACHE);
phys_addr += PAGE_SIZE;
pages_mapped++;
}
Index: linux/include/asm-x86/efi.h
===
--- linux.orig/include/asm-x86/efi.h
+++ linux/include/asm-x86/efi.h
@@ -33,7 +33,8 @@ extern unsigned long asmlinkage efi_call
 #define efi_call_virt6(f, a1, a2, a3, a4, a5, a6)  \
efi_call_virt(f, a1, a2, a3, a4, a5, a6)
 
-#define efi_ioremap(addr, size)ioremap_cache(addr, 
size)
+#define efi_ioremap(addr, size, cache) \
+   (cache ? ioremap_cache(addr, size) : ioremap_nocache(addr, size))
 
 #else /* !CONFIG_X86_32 */
 
@@ -86,7 +87,7 @@ extern u64 efi_call6(void *fp, u64 arg1,
efi_call6((void *)(efi.systab-runtime-f), (u64)(a1), (u64)(a2), \
  (u64)(a3), (u64)(a4), (u64)(a5), (u64)(a6))
 
-extern void *efi_ioremap(unsigned long addr, unsigned long size);
+extern void *efi_ioremap(unsigned long addr, unsigned long size, int cache);
 
 #endif /* CONFIG_X86_32 */
 
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