* [PATCH] arm64: allow ioremap_cache() to use existing RAM mappings
@ 2013-10-21 13:36 Mark Salter
2013-10-23 9:18 ` Catalin Marinas
0 siblings, 1 reply; 6+ messages in thread
From: Mark Salter @ 2013-10-21 13:36 UTC (permalink / raw)
To: Catalin Marinas; +Cc: Will Deacon, linux-arm-kernel, linux-kernel, Mark Salter
Some drivers (ACPI notably) use ioremap_cache() to map an area which could
either be outside of kernel RAM or in an already mapped reserved area of
RAM. To avoid aliases, __ioremap() does not allow RAM to be remapped. But
for ioremap_cache(), the existing kernel mapping may be used.
Signed-off-by: Mark Salter <msalter@redhat.com>
---
arch/arm64/include/asm/io.h | 2 +-
arch/arm64/mm/ioremap.c | 15 +++++++++++++++
2 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index 1d12f89..b56e5b5 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -224,6 +224,7 @@ extern void __memset_io(volatile void __iomem *, int, size_t);
*/
extern void __iomem *__ioremap(phys_addr_t phys_addr, size_t size, pgprot_t prot);
extern void __iounmap(volatile void __iomem *addr);
+extern void __iomem *ioremap_cache(phys_addr_t phys_addr, size_t size);
#define PROT_DEFAULT (PTE_TYPE_PAGE | PTE_AF | PTE_DIRTY)
#define PROT_DEVICE_nGnRE (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_DEVICE_nGnRE))
@@ -233,7 +234,6 @@ extern void __iounmap(volatile void __iomem *addr);
#define ioremap(addr, size) __ioremap((addr), (size), __pgprot(PROT_DEVICE_nGnRE))
#define ioremap_nocache(addr, size) __ioremap((addr), (size), __pgprot(PROT_DEVICE_nGnRE))
#define ioremap_wc(addr, size) __ioremap((addr), (size), __pgprot(PROT_NORMAL_NC))
-#define ioremap_cached(addr, size) __ioremap((addr), (size), __pgprot(PROT_NORMAL))
#define iounmap __iounmap
#define PROT_SECT_DEFAULT (PMD_TYPE_SECT | PMD_SECT_AF)
diff --git a/arch/arm64/mm/ioremap.c b/arch/arm64/mm/ioremap.c
index 1725cd6..fb44b3d 100644
--- a/arch/arm64/mm/ioremap.c
+++ b/arch/arm64/mm/ioremap.c
@@ -79,6 +79,21 @@ void __iounmap(volatile void __iomem *io_addr)
{
void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
+ /* Nothing to do for normal memory. See ioremap_cache() */
+ if (pfn_valid(__virt_to_phys(addr) >> PAGE_SHIFT))
+ return;
+
vunmap(addr);
}
EXPORT_SYMBOL(__iounmap);
+
+void __iomem *ioremap_cache(phys_addr_t phys_addr, size_t size)
+{
+ /* For normal memory we already have a cacheable mapping. */
+ if (pfn_valid(__phys_to_pfn(phys_addr)))
+ return (void __iomem *)__phys_to_virt(phys_addr);
+
+ return __ioremap_caller(phys_addr, size, __pgprot(PROT_NORMAL),
+ __builtin_return_address(0));
+}
+EXPORT_SYMBOL(ioremap_cache);
--
1.8.3.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] arm64: allow ioremap_cache() to use existing RAM mappings
2013-10-21 13:36 [PATCH] arm64: allow ioremap_cache() to use existing RAM mappings Mark Salter
@ 2013-10-23 9:18 ` Catalin Marinas
2013-10-23 13:46 ` Mark Salter
0 siblings, 1 reply; 6+ messages in thread
From: Catalin Marinas @ 2013-10-23 9:18 UTC (permalink / raw)
To: msalter; +Cc: Will Deacon, linux-arm-kernel, linux-kernel
On Mon, 2013-10-21 at 14:36 +0100, msalter@redhat.com wrote:
> diff --git a/arch/arm64/mm/ioremap.c b/arch/arm64/mm/ioremap.c
> index 1725cd6..fb44b3d 100644
> --- a/arch/arm64/mm/ioremap.c
> +++ b/arch/arm64/mm/ioremap.c
> @@ -79,6 +79,21 @@ void __iounmap(volatile void __iomem *io_addr)
> {
> void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
>
> + /* Nothing to do for normal memory. See ioremap_cache() */
> + if (pfn_valid(__virt_to_phys(addr) >> PAGE_SHIFT))
> + return;
addr here can be some I/O address mapped previously, so __virt_to_phys()
is not valid (you don't actually get the pfn by shifting).
Catalin
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] arm64: allow ioremap_cache() to use existing RAM mappings
2013-10-23 9:18 ` Catalin Marinas
@ 2013-10-23 13:46 ` Mark Salter
2013-10-23 14:37 ` Catalin Marinas
0 siblings, 1 reply; 6+ messages in thread
From: Mark Salter @ 2013-10-23 13:46 UTC (permalink / raw)
To: Catalin Marinas; +Cc: Will Deacon, linux-arm-kernel, linux-kernel
On Wed, 2013-10-23 at 10:18 +0100, Catalin Marinas wrote:
> On Mon, 2013-10-21 at 14:36 +0100, msalter@redhat.com wrote:
> > diff --git a/arch/arm64/mm/ioremap.c b/arch/arm64/mm/ioremap.c
> > index 1725cd6..fb44b3d 100644
> > --- a/arch/arm64/mm/ioremap.c
> > +++ b/arch/arm64/mm/ioremap.c
> > @@ -79,6 +79,21 @@ void __iounmap(volatile void __iomem *io_addr)
> > {
> > void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
> >
> > + /* Nothing to do for normal memory. See ioremap_cache() */
> > + if (pfn_valid(__virt_to_phys(addr) >> PAGE_SHIFT))
> > + return;
>
> addr here can be some I/O address mapped previously, so __virt_to_phys()
> is not valid (you don't actually get the pfn by shifting).
>
Yeah, that's ugly. The thought was that only the kernel mapping of RAM
would yield a valid address from __virt_to_phys(). Anything else, like
a mapping of I/O space would lead to an invalid PFN. There's probably a
clearer way of doing that that. Other than that, is the general concept
of the patch reasonable?
--Mark
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] arm64: allow ioremap_cache() to use existing RAM mappings
2013-10-23 13:46 ` Mark Salter
@ 2013-10-23 14:37 ` Catalin Marinas
2013-10-24 14:54 ` [PATCH v2] " Mark Salter
0 siblings, 1 reply; 6+ messages in thread
From: Catalin Marinas @ 2013-10-23 14:37 UTC (permalink / raw)
To: Mark Salter; +Cc: Will Deacon, linux-arm-kernel, linux-kernel
On Wed, Oct 23, 2013 at 02:46:12PM +0100, Mark Salter wrote:
> On Wed, 2013-10-23 at 10:18 +0100, Catalin Marinas wrote:
> > On Mon, 2013-10-21 at 14:36 +0100, msalter@redhat.com wrote:
> > > diff --git a/arch/arm64/mm/ioremap.c b/arch/arm64/mm/ioremap.c
> > > index 1725cd6..fb44b3d 100644
> > > --- a/arch/arm64/mm/ioremap.c
> > > +++ b/arch/arm64/mm/ioremap.c
> > > @@ -79,6 +79,21 @@ void __iounmap(volatile void __iomem *io_addr)
> > > {
> > > void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
> > >
> > > + /* Nothing to do for normal memory. See ioremap_cache() */
> > > + if (pfn_valid(__virt_to_phys(addr) >> PAGE_SHIFT))
> > > + return;
> >
> > addr here can be some I/O address mapped previously, so __virt_to_phys()
> > is not valid (you don't actually get the pfn by shifting).
> >
>
> Yeah, that's ugly. The thought was that only the kernel mapping of RAM
> would yield a valid address from __virt_to_phys(). Anything else, like
> a mapping of I/O space would lead to an invalid PFN. There's probably a
> clearer way of doing that that. Other than that, is the general concept
> of the patch reasonable?
I think the concept is fine. You could change the check on
VMALLOC_START/END or just always create a new mapping as long as it has
the same caching attributes (PROT_NORMAL).
--
Catalin
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v2] arm64: allow ioremap_cache() to use existing RAM mappings
2013-10-23 14:37 ` Catalin Marinas
@ 2013-10-24 14:54 ` Mark Salter
2013-10-29 16:41 ` Catalin Marinas
0 siblings, 1 reply; 6+ messages in thread
From: Mark Salter @ 2013-10-24 14:54 UTC (permalink / raw)
To: Catalin Marinas; +Cc: Will Deacon, linux-arm-kernel, linux-kernel
Some drivers (ACPI notably) use ioremap_cache() to map an area which could
either be outside of kernel RAM or in an already mapped reserved area of
RAM. To avoid aliases with different caching attributes, ioremap() does
not allow RAM to be remapped. But for ioremap_cache(), the existing kernel
mapping may be used.
Signed-off-by: Mark Salter <msalter@redhat.com>
---
arch/arm64/include/asm/io.h | 2 +-
arch/arm64/mm/ioremap.c | 20 ++++++++++++++++++--
2 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index 1d12f89..b56e5b5 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -224,6 +224,7 @@ extern void __memset_io(volatile void __iomem *, int, size_t);
*/
extern void __iomem *__ioremap(phys_addr_t phys_addr, size_t size, pgprot_t prot);
extern void __iounmap(volatile void __iomem *addr);
+extern void __iomem *ioremap_cache(phys_addr_t phys_addr, size_t size);
#define PROT_DEFAULT (PTE_TYPE_PAGE | PTE_AF | PTE_DIRTY)
#define PROT_DEVICE_nGnRE (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_DEVICE_nGnRE))
@@ -233,7 +234,6 @@ extern void __iounmap(volatile void __iomem *addr);
#define ioremap(addr, size) __ioremap((addr), (size), __pgprot(PROT_DEVICE_nGnRE))
#define ioremap_nocache(addr, size) __ioremap((addr), (size), __pgprot(PROT_DEVICE_nGnRE))
#define ioremap_wc(addr, size) __ioremap((addr), (size), __pgprot(PROT_NORMAL_NC))
-#define ioremap_cached(addr, size) __ioremap((addr), (size), __pgprot(PROT_NORMAL))
#define iounmap __iounmap
#define PROT_SECT_DEFAULT (PMD_TYPE_SECT | PMD_SECT_AF)
diff --git a/arch/arm64/mm/ioremap.c b/arch/arm64/mm/ioremap.c
index 1725cd6..2bb1d58 100644
--- a/arch/arm64/mm/ioremap.c
+++ b/arch/arm64/mm/ioremap.c
@@ -77,8 +77,24 @@ EXPORT_SYMBOL(__ioremap);
void __iounmap(volatile void __iomem *io_addr)
{
- void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
+ unsigned long addr = (unsigned long)io_addr & PAGE_MASK;
- vunmap(addr);
+ /*
+ * We could get an address outside vmalloc range in case
+ * of ioremap_cache() reusing a RAM mapping.
+ */
+ if (VMALLOC_START <= addr && addr < VMALLOC_END)
+ vunmap((void *)addr);
}
EXPORT_SYMBOL(__iounmap);
+
+void __iomem *ioremap_cache(phys_addr_t phys_addr, size_t size)
+{
+ /* For normal memory we already have a cacheable mapping. */
+ if (pfn_valid(__phys_to_pfn(phys_addr)))
+ return (void __iomem *)__phys_to_virt(phys_addr);
+
+ return __ioremap_caller(phys_addr, size, __pgprot(PROT_NORMAL),
+ __builtin_return_address(0));
+}
+EXPORT_SYMBOL(ioremap_cache);
--
1.8.3.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v2] arm64: allow ioremap_cache() to use existing RAM mappings
2013-10-24 14:54 ` [PATCH v2] " Mark Salter
@ 2013-10-29 16:41 ` Catalin Marinas
0 siblings, 0 replies; 6+ messages in thread
From: Catalin Marinas @ 2013-10-29 16:41 UTC (permalink / raw)
To: Mark Salter; +Cc: Will Deacon, linux-arm-kernel, linux-kernel
On Thu, Oct 24, 2013 at 03:54:17PM +0100, Mark Salter wrote:
> Some drivers (ACPI notably) use ioremap_cache() to map an area which could
> either be outside of kernel RAM or in an already mapped reserved area of
> RAM. To avoid aliases with different caching attributes, ioremap() does
> not allow RAM to be remapped. But for ioremap_cache(), the existing kernel
> mapping may be used.
>
> Signed-off-by: Mark Salter <msalter@redhat.com>
Looks good. Thanks.
--
Catalin
^ permalink raw reply [flat|nested] 6+ messages in thread
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2013-10-21 13:36 [PATCH] arm64: allow ioremap_cache() to use existing RAM mappings Mark Salter
2013-10-23 9:18 ` Catalin Marinas
2013-10-23 13:46 ` Mark Salter
2013-10-23 14:37 ` Catalin Marinas
2013-10-24 14:54 ` [PATCH v2] " Mark Salter
2013-10-29 16:41 ` Catalin Marinas
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