2009-03-01 13:55:21

by Stefan Lippers-Hollmann

[permalink] [raw]
Subject: Re: gpu/drm, x86, PAT: io_mapping_create_wc and resource_size_t

Hi

On Samstag, 28. Februar 2009, Linux Kernel Mailing List wrote:
> Gitweb: http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=4ab0d47d0ab311eb181532c1ecb6d02905685071
> Commit: 4ab0d47d0ab311eb181532c1ecb6d02905685071
> Parent: 6644107d57a8fa82b47e4c55da4d9d91a612f29c
> Author: Venkatesh Pallipadi <[email protected]>
> AuthorDate: Tue Feb 24 17:35:12 2009 -0800
> Committer: Ingo Molnar <[email protected]>
> CommitDate: Wed Feb 25 13:09:51 2009 +0100
>
> gpu/drm, x86, PAT: io_mapping_create_wc and resource_size_t
>
> io_mapping_create_wc should take a resource_size_t parameter in place of
> unsigned long. With unsigned long, there will be no way to map greater than 4GB
> address in i386/32 bit.
>
> On x86, greater than 4GB addresses cannot be mapped on i386 without PAE. Return
> error for such a case.
>
> Patch also adds a structure for io_mapping, that saves the base, size and
> type on HAVE_ATOMIC_IOMAP archs, that can be used to verify the offset on
> io_mapping_map calls.
>
> Signed-off-by: Venkatesh Pallipadi <[email protected]>
> Signed-off-by: Suresh Siddha <[email protected]>
> Cc: Dave Airlie <[email protected]>
> Cc: Jesse Barnes <[email protected]>
> Cc: Eric Anholt <[email protected]>
> Cc: Keith Packard <[email protected]>
> Signed-off-by: Ingo Molnar <[email protected]>

This patch, as part of 2.6.29-rc6-git5, fails to build for me on i386 (it
builds on amd64) with the attached (slimmed down) config (CONFIG_X86_PAT=y)
and buildlog:

Building modules, stage 2.
MODPOST 809 modules
ERROR: "pgprot_writecombine" [drivers/gpu/drm/i915/i915.ko] undefined!
ERROR: "is_io_mapping_possible" [drivers/gpu/drm/i915/i915.ko] undefined!
make[1]: *** [__modpost] Error 1
make: *** [modules] Error 2

This is a build regression in comparison to 2.6.29-rc6.

Regards
Stefan Lippers-Hollmann
--

> arch/x86/include/asm/iomap.h | 3 ++
> arch/x86/mm/iomap_32.c | 18 ++++++++++++++++
> include/linux/io-mapping.h | 46 +++++++++++++++++++++++++++++++----------
> 3 files changed, 56 insertions(+), 11 deletions(-)
>
> diff --git a/arch/x86/include/asm/iomap.h b/arch/x86/include/asm/iomap.h
> index c1f0628..86af260 100644
> --- a/arch/x86/include/asm/iomap.h
> +++ b/arch/x86/include/asm/iomap.h
> @@ -23,6 +23,9 @@
> #include <asm/pgtable.h>
> #include <asm/tlbflush.h>
>
> +int
> +is_io_mapping_possible(resource_size_t base, unsigned long size);
> +
> void *
> iomap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot);
>
> diff --git a/arch/x86/mm/iomap_32.c b/arch/x86/mm/iomap_32.c
> index ca53224..6c2b1af 100644
> --- a/arch/x86/mm/iomap_32.c
> +++ b/arch/x86/mm/iomap_32.c
> @@ -20,6 +20,24 @@
> #include <asm/pat.h>
> #include <linux/module.h>
>
> +#ifdef CONFIG_X86_PAE
> +int
> +is_io_mapping_possible(resource_size_t base, unsigned long size)
> +{
> + return 1;
> +}
> +#else
> +int
> +is_io_mapping_possible(resource_size_t base, unsigned long size)
> +{
> + /* There is no way to map greater than 1 << 32 address without PAE */
> + if (base + size > 0x100000000ULL)
> + return 0;
> +
> + return 1;
> +}
> +#endif
> +
> /* Map 'pfn' using fixed map 'type' and protections 'prot'
> */
> void *
> diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h
> index 82df317..cbc2f0c 100644
> --- a/include/linux/io-mapping.h
> +++ b/include/linux/io-mapping.h
> @@ -30,11 +30,14 @@
> * See Documentation/io_mapping.txt
> */
>
> -/* this struct isn't actually defined anywhere */
> -struct io_mapping;
> -
> #ifdef CONFIG_HAVE_ATOMIC_IOMAP
>
> +struct io_mapping {
> + resource_size_t base;
> + unsigned long size;
> + pgprot_t prot;
> +};
> +
> /*
> * For small address space machines, mapping large objects
> * into the kernel virtual space isn't practical. Where
> @@ -43,23 +46,40 @@ struct io_mapping;
> */
>
> static inline struct io_mapping *
> -io_mapping_create_wc(unsigned long base, unsigned long size)
> +io_mapping_create_wc(resource_size_t base, unsigned long size)
> {
> - return (struct io_mapping *) base;
> + struct io_mapping *iomap;
> +
> + if (!is_io_mapping_possible(base, size))
> + return NULL;
> +
> + iomap = kmalloc(sizeof(*iomap), GFP_KERNEL);
> + if (!iomap)
> + return NULL;
> +
> + iomap->base = base;
> + iomap->size = size;
> + iomap->prot = pgprot_writecombine(__pgprot(__PAGE_KERNEL));
> + return iomap;
> }
>
> static inline void
> io_mapping_free(struct io_mapping *mapping)
> {
> + kfree(mapping);
> }
>
> /* Atomic map/unmap */
> static inline void *
> io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset)
> {
> - offset += (unsigned long) mapping;
> - return iomap_atomic_prot_pfn(offset >> PAGE_SHIFT, KM_USER0,
> - __pgprot(__PAGE_KERNEL_WC));
> + resource_size_t phys_addr;
> + unsigned long pfn;
> +
> + BUG_ON(offset >= mapping->size);
> + phys_addr = mapping->base + offset;
> + pfn = (unsigned long) (phys_addr >> PAGE_SHIFT);
> + return iomap_atomic_prot_pfn(pfn, KM_USER0, mapping->prot);
> }
>
> static inline void
> @@ -71,8 +91,9 @@ io_mapping_unmap_atomic(void *vaddr)
> static inline void *
> io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
> {
> - offset += (unsigned long) mapping;
> - return ioremap_wc(offset, PAGE_SIZE);
> + BUG_ON(offset >= mapping->size);
> + resource_size_t phys_addr = mapping->base + offset;
> + return ioremap_wc(phys_addr, PAGE_SIZE);
> }
>
> static inline void
> @@ -83,9 +104,12 @@ io_mapping_unmap(void *vaddr)
>
> #else
>
> +/* this struct isn't actually defined anywhere */
> +struct io_mapping;
> +
> /* Create the io_mapping object*/
> static inline struct io_mapping *
> -io_mapping_create_wc(unsigned long base, unsigned long size)
> +io_mapping_create_wc(resource_size_t base, unsigned long size)
> {
> return (struct io_mapping *) ioremap_wc(base, size);
> }


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2009-03-01 16:53:40

by Pallipadi, Venkatesh

[permalink] [raw]
Subject: Re: gpu/drm, x86, PAT: io_mapping_create_wc and resource_size_t

On Sun, Mar 01, 2009 at 05:54:53AM -0800, Stefan Lippers-Hollmann wrote:
> Hi
>
> On Samstag, 28. Februar 2009, Linux Kernel Mailing List wrote:
> > Gitweb: http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=4ab0d47d0ab311eb181532c1ecb6d02905685071
> > Commit: 4ab0d47d0ab311eb181532c1ecb6d02905685071
> > Parent: 6644107d57a8fa82b47e4c55da4d9d91a612f29c
> > Author: Venkatesh Pallipadi <[email protected]>
> > AuthorDate: Tue Feb 24 17:35:12 2009 -0800
> > Committer: Ingo Molnar <[email protected]>
> > CommitDate: Wed Feb 25 13:09:51 2009 +0100
> >
> > gpu/drm, x86, PAT: io_mapping_create_wc and resource_size_t
> >
> > io_mapping_create_wc should take a resource_size_t parameter in place of
> > unsigned long. With unsigned long, there will be no way to map greater than 4GB
> > address in i386/32 bit.
> >
> > On x86, greater than 4GB addresses cannot be mapped on i386 without PAE. Return
> > error for such a case.
> >
> > Patch also adds a structure for io_mapping, that saves the base, size and
> > type on HAVE_ATOMIC_IOMAP archs, that can be used to verify the offset on
> > io_mapping_map calls.
> >
> > Signed-off-by: Venkatesh Pallipadi <[email protected]>
> > Signed-off-by: Suresh Siddha <[email protected]>
> > Cc: Dave Airlie <[email protected]>
> > Cc: Jesse Barnes <[email protected]>
> > Cc: Eric Anholt <[email protected]>
> > Cc: Keith Packard <[email protected]>
> > Signed-off-by: Ingo Molnar <[email protected]>
>
> This patch, as part of 2.6.29-rc6-git5, fails to build for me on i386 (it
> builds on amd64) with the attached (slimmed down) config (CONFIG_X86_PAT=y)
> and buildlog:
>
> Building modules, stage 2.
> MODPOST 809 modules
> ERROR: "pgprot_writecombine" [drivers/gpu/drm/i915/i915.ko] undefined!
> ERROR: "is_io_mapping_possible" [drivers/gpu/drm/i915/i915.ko] undefined!
> make[1]: *** [__modpost] Error 1
> make: *** [modules] Error 2
>
> This is a build regression in comparison to 2.6.29-rc6.
>

My bad. I had missed drm as module compilation. Below patch should fix it.
Can you please verify.

Thanks,
Venki


Signed-off-by: Venkatesh Pallipadi <[email protected]>

---
arch/x86/mm/iomap_32.c | 1 +
arch/x86/mm/pat.c | 2 ++
include/linux/io-mapping.h | 3 ++-
3 files changed, 5 insertions(+), 1 deletion(-)

Index: linux-2.6/arch/x86/mm/iomap_32.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/iomap_32.c 2009-03-01 08:31:12.000000000 -0800
+++ linux-2.6/arch/x86/mm/iomap_32.c 2009-03-01 08:47:20.000000000 -0800
@@ -37,6 +37,7 @@ is_io_mapping_possible(resource_size_t b
return 1;
}
#endif
+EXPORT_SYMBOL_GPL(is_io_mapping_possible);

/* Map 'pfn' using fixed map 'type' and protections 'prot'
*/
Index: linux-2.6/arch/x86/mm/pat.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/pat.c 2009-03-01 08:31:00.000000000 -0800
+++ linux-2.6/arch/x86/mm/pat.c 2009-03-01 08:45:48.000000000 -0800
@@ -11,6 +11,7 @@
#include <linux/bootmem.h>
#include <linux/debugfs.h>
#include <linux/kernel.h>
+#include <linux/module.h>
#include <linux/gfp.h>
#include <linux/mm.h>
#include <linux/fs.h>
@@ -868,6 +869,7 @@ pgprot_t pgprot_writecombine(pgprot_t pr
else
return pgprot_noncached(prot);
}
+EXPORT_SYMBOL(pgprot_writecombine);

#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT)

Index: linux-2.6/include/linux/io-mapping.h
===================================================================
--- linux-2.6.orig/include/linux/io-mapping.h 2009-03-01 08:31:12.000000000 -0800
+++ linux-2.6/include/linux/io-mapping.h 2009-03-01 08:49:53.000000000 -0800
@@ -91,8 +91,9 @@ io_mapping_unmap_atomic(void *vaddr)
static inline void *
io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
{
+ resource_size_t phys_addr;
BUG_ON(offset >= mapping->size);
- resource_size_t phys_addr = mapping->base + offset;
+ phys_addr = mapping->base + offset;
return ioremap_wc(phys_addr, PAGE_SIZE);
}

2009-03-01 20:55:12

by Stefan Lippers-Hollmann

[permalink] [raw]
Subject: Re: gpu/drm, x86, PAT: io_mapping_create_wc and resource_size_t

Hi

On Sonntag, 1. M?rz 2009, Pallipadi, Venkatesh wrote:
> On Sun, Mar 01, 2009 at 05:54:53AM -0800, Stefan Lippers-Hollmann wrote:
> > Hi
> >
> > On Samstag, 28. Februar 2009, Linux Kernel Mailing List wrote:
> > > Gitweb: http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=4ab0d47d0ab311eb181532c1ecb6d02905685071
> > > Commit: 4ab0d47d0ab311eb181532c1ecb6d02905685071
[...]
> > Building modules, stage 2.
> > MODPOST 809 modules
> > ERROR: "pgprot_writecombine" [drivers/gpu/drm/i915/i915.ko] undefined!
> > ERROR: "is_io_mapping_possible" [drivers/gpu/drm/i915/i915.ko] undefined!
> > make[1]: *** [__modpost] Error 1
> > make: *** [modules] Error 2
> >
> > This is a build regression in comparison to 2.6.29-rc6.
> >
>
> My bad. I had missed drm as module compilation. Below patch should fix it.
> Can you please verify.

Thanks, this builds fine for i386 and amd64 and seems to work on i945GME.

Regards
Stefan Lippers-Hollmann
--
> Thanks,
> Venki
>
>
> Signed-off-by: Venkatesh Pallipadi <[email protected]>
>
> ---
> arch/x86/mm/iomap_32.c | 1 +
> arch/x86/mm/pat.c | 2 ++
> include/linux/io-mapping.h | 3 ++-
> 3 files changed, 5 insertions(+), 1 deletion(-)
>
> Index: linux-2.6/arch/x86/mm/iomap_32.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/mm/iomap_32.c 2009-03-01 08:31:12.000000000 -0800
> +++ linux-2.6/arch/x86/mm/iomap_32.c 2009-03-01 08:47:20.000000000 -0800
> @@ -37,6 +37,7 @@ is_io_mapping_possible(resource_size_t b
> return 1;
> }
> #endif
> +EXPORT_SYMBOL_GPL(is_io_mapping_possible);
>
> /* Map 'pfn' using fixed map 'type' and protections 'prot'
> */
> Index: linux-2.6/arch/x86/mm/pat.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/mm/pat.c 2009-03-01 08:31:00.000000000 -0800
> +++ linux-2.6/arch/x86/mm/pat.c 2009-03-01 08:45:48.000000000 -0800
> @@ -11,6 +11,7 @@
> #include <linux/bootmem.h>
> #include <linux/debugfs.h>
> #include <linux/kernel.h>
> +#include <linux/module.h>
> #include <linux/gfp.h>
> #include <linux/mm.h>
> #include <linux/fs.h>
> @@ -868,6 +869,7 @@ pgprot_t pgprot_writecombine(pgprot_t pr
> else
> return pgprot_noncached(prot);
> }
> +EXPORT_SYMBOL(pgprot_writecombine);
>
> #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT)
>
> Index: linux-2.6/include/linux/io-mapping.h
> ===================================================================
> --- linux-2.6.orig/include/linux/io-mapping.h 2009-03-01 08:31:12.000000000 -0800
> +++ linux-2.6/include/linux/io-mapping.h 2009-03-01 08:49:53.000000000 -0800
> @@ -91,8 +91,9 @@ io_mapping_unmap_atomic(void *vaddr)
> static inline void *
> io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
> {
> + resource_size_t phys_addr;
> BUG_ON(offset >= mapping->size);
> - resource_size_t phys_addr = mapping->base + offset;
> + phys_addr = mapping->base + offset;
> return ioremap_wc(phys_addr, PAGE_SIZE);
> }
>
>