[PATCH] arm64: allow late use of early_ioremap

[PATCH] arm64: allow late use of early_ioremap

[Mark Salter]

Commit 0e63ea48b4d8 (arm64/efi: add missing call to early_ioremap_reset())
added a missing call to early_ioremap_reset(). This triggers a BUG if code
tries using early_ioremap() after the early_ioremap_reset(). This is a
problem for some ACPI code which needs short-lived temporary mappings
after paging_init() but before mm_init(). This patch adds definitions for
the __late_set_fixmap() and __late_clear_fixmap() which avoids the BUG
by allowing later use of early_ioremap().

Signed-off-by: Mark Salter <msalter@redhat.com>
CC: Leif Lindholm <leif.lindholm@linaro.org>
CC: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm64/include/asm/fixmap.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h
index 9ef6eca..e629c70 100644
--- a/arch/arm64/include/asm/fixmap.h
+++ b/arch/arm64/include/asm/fixmap.h
@@ -61,6 +61,9 @@ void __init early_fixmap_init(void);
 
 #define __early_set_fixmap __set_fixmap
 
+#define __late_set_fixmap __set_fixmap
+#define __late_clear_fixmap(idx) __set_fixmap((idx), 0, FIXMAP_PAGE_CLEAR)
+
 extern void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot);
 
 #include <asm-generic/fixmap.h>
-- 
1.8.3.1

[PATCH] arm64: allow late use of early_ioremap

[Will Deacon]

On Mon, Jan 12, 2015 at 04:55:11PM +0000, Mark Salter wrote:
> Commit 0e63ea48b4d8 (arm64/efi: add missing call to early_ioremap_reset())
> added a missing call to early_ioremap_reset(). This triggers a BUG if code
> tries using early_ioremap() after the early_ioremap_reset(). This is a
> problem for some ACPI code which needs short-lived temporary mappings
> after paging_init() but before mm_init(). This patch adds definitions for
> the __late_set_fixmap() and __late_clear_fixmap() which avoids the BUG
> by allowing later use of early_ioremap().
> 
> Signed-off-by: Mark Salter <msalter@redhat.com>
> CC: Leif Lindholm <leif.lindholm@linaro.org>
> CC: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  arch/arm64/include/asm/fixmap.h | 3 +++
>  1 file changed, 3 insertions(+)

Given that we don't support ACPI on arm64 in mainline, I assume this can
wait until at least 3.20?

Will

> diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h
> index 9ef6eca..e629c70 100644
> --- a/arch/arm64/include/asm/fixmap.h
> +++ b/arch/arm64/include/asm/fixmap.h
> @@ -61,6 +61,9 @@ void __init early_fixmap_init(void);
>  
>  #define __early_set_fixmap __set_fixmap
>  
> +#define __late_set_fixmap __set_fixmap
> +#define __late_clear_fixmap(idx) __set_fixmap((idx), 0, FIXMAP_PAGE_CLEAR)
> +
>  extern void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot);
>  
>  #include <asm-generic/fixmap.h>
> -- 
> 1.8.3.1
> 
> 

[PATCH] arm64: allow late use of early_ioremap

[Mark Salter]

On Mon, 2015-01-12 at 17:25 +0000, Will Deacon wrote:
> On Mon, Jan 12, 2015 at 04:55:11PM +0000, Mark Salter wrote:
> > Commit 0e63ea48b4d8 (arm64/efi: add missing call to early_ioremap_reset())
> > added a missing call to early_ioremap_reset(). This triggers a BUG if code
> > tries using early_ioremap() after the early_ioremap_reset(). This is a
> > problem for some ACPI code which needs short-lived temporary mappings
> > after paging_init() but before mm_init(). This patch adds definitions for
> > the __late_set_fixmap() and __late_clear_fixmap() which avoids the BUG
> > by allowing later use of early_ioremap().
> > 
> > Signed-off-by: Mark Salter <msalter@redhat.com>
> > CC: Leif Lindholm <leif.lindholm@linaro.org>
> > CC: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > ---
> >  arch/arm64/include/asm/fixmap.h | 3 +++
> >  1 file changed, 3 insertions(+)
> 
> Given that we don't support ACPI on arm64 in mainline, I assume this can
> wait until at least 3.20?

Sure. Just needs it to go in before ACPI code. And tbh, the ACPI code
could change and make this unneeded.

> 
> Will
> 
> > diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h
> > index 9ef6eca..e629c70 100644
> > --- a/arch/arm64/include/asm/fixmap.h
> > +++ b/arch/arm64/include/asm/fixmap.h
> > @@ -61,6 +61,9 @@ void __init early_fixmap_init(void);
> >  
> >  #define __early_set_fixmap __set_fixmap
> >  
> > +#define __late_set_fixmap __set_fixmap
> > +#define __late_clear_fixmap(idx) __set_fixmap((idx), 0, FIXMAP_PAGE_CLEAR)
> > +
> >  extern void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot);
> >  
> >  #include <asm-generic/fixmap.h>
> > -- 
> > 1.8.3.1
> > 
> > 

[PATCH] arm64: allow late use of early_ioremap

[Hanjun Guo]

Hi Mark,

On 2015?01?13? 03:09, Mark Salter wrote:
> On Mon, 2015-01-12 at 17:25 +0000, Will Deacon wrote:
>> On Mon, Jan 12, 2015 at 04:55:11PM +0000, Mark Salter wrote:
>>> Commit 0e63ea48b4d8 (arm64/efi: add missing call to early_ioremap_reset())
>>> added a missing call to early_ioremap_reset(). This triggers a BUG if code
>>> tries using early_ioremap() after the early_ioremap_reset(). This is a
>>> problem for some ACPI code which needs short-lived temporary mappings
>>> after paging_init() but before mm_init(). This patch adds definitions for

Minor update:
... after paging_init() but before acpi_early_init() in start_kernel().

In ACPI, permanent mapping will be used after acpi_gbl_permanent_mmap
set to 1 in acpi_early_init(), since GIC init and Arch timer init will
be called before acpi_early_init(), early_ioremap() is still needed
after mm_init().

>>> the __late_set_fixmap() and __late_clear_fixmap() which avoids the BUG
>>> by allowing later use of early_ioremap().
>>>
>>> Signed-off-by: Mark Salter <msalter@redhat.com>
>>> CC: Leif Lindholm <leif.lindholm@linaro.org>
>>> CC: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>>> ---
>>>   arch/arm64/include/asm/fixmap.h | 3 +++
>>>   1 file changed, 3 insertions(+)
>>
>> Given that we don't support ACPI on arm64 in mainline, I assume this can
>> wait until at least 3.20?
>
> Sure. Just needs it to go in before ACPI code. And tbh, the ACPI code
> could change and make this unneeded.

This is the best solution for now, so I need to add this patch as the 
first one for ACPI core patch set, is it ok for you?

Thanks
Hanjun

[PATCH] arm64: allow late use of early_ioremap

[Mark Salter]

On Wed, 2015-01-14 at 16:22 +0800, Hanjun Guo wrote:
> Hi Mark,
> 
> On 2015?01?13? 03:09, Mark Salter wrote:
> > On Mon, 2015-01-12 at 17:25 +0000, Will Deacon wrote:
> >> On Mon, Jan 12, 2015 at 04:55:11PM +0000, Mark Salter wrote:
> >>> Commit 0e63ea48b4d8 (arm64/efi: add missing call to early_ioremap_reset())
> >>> added a missing call to early_ioremap_reset(). This triggers a BUG if code
> >>> tries using early_ioremap() after the early_ioremap_reset(). This is a
> >>> problem for some ACPI code which needs short-lived temporary mappings
> >>> after paging_init() but before mm_init(). This patch adds definitions for
> 
> Minor update:
> ... after paging_init() but before acpi_early_init() in start_kernel().
> 
> In ACPI, permanent mapping will be used after acpi_gbl_permanent_mmap
> set to 1 in acpi_early_init(), since GIC init and Arch timer init will
> be called before acpi_early_init(), early_ioremap() is still needed
> after mm_init().
> 
> >>> the __late_set_fixmap() and __late_clear_fixmap() which avoids the BUG
> >>> by allowing later use of early_ioremap().
> >>>
> >>> Signed-off-by: Mark Salter <msalter@redhat.com>
> >>> CC: Leif Lindholm <leif.lindholm@linaro.org>
> >>> CC: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> >>> ---
> >>>   arch/arm64/include/asm/fixmap.h | 3 +++
> >>>   1 file changed, 3 insertions(+)
> >>
> >> Given that we don't support ACPI on arm64 in mainline, I assume this can
> >> wait until at least 3.20?
> >
> > Sure. Just needs it to go in before ACPI code. And tbh, the ACPI code
> > could change and make this unneeded.
> 
> This is the best solution for now, so I need to add this patch as the 
> first one for ACPI core patch set, is it ok for you?

Yes. Thanks.

> 
> Thanks
> Hanjun