* [PATCH 1/2] dma-mapping: remove bogus test for pfn_valid from dma_map_resource
2021-09-30 1:30 [PATCH 0/2] arm64: retry dropping HAVE_ARCH_PFN_VALID Mike Rapoport
@ 2021-09-30 1:30 ` Mike Rapoport
2021-09-30 5:46 ` Christoph Hellwig
2021-09-30 7:27 ` David Hildenbrand
2021-09-30 1:30 ` [PATCH 2/2] arm64/mm: drop HAVE_ARCH_PFN_VALID Mike Rapoport
2021-10-01 14:01 ` [PATCH 0/2] arm64: retry dropping HAVE_ARCH_PFN_VALID Will Deacon
2 siblings, 2 replies; 6+ messages in thread
From: Mike Rapoport @ 2021-09-30 1:30 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Alex Bee, Andrew Morton, Anshuman Khandual, Catalin Marinas,
Christoph Hellwig, David Hildenbrand, Linux Kernel Mailing List,
Marek Szyprowski, Mike Rapoport, Mike Rapoport, Robin Murphy,
Will Deacon, iommu
From: Mike Rapoport <rppt@linux.ibm.com>
dma_map_resource() uses pfn_valid() to ensure the range is not RAM.
However, pfn_valid() only checks for availability of the memory map for a
PFN but it does not ensure that the PFN is actually backed by RAM.
As dma_map_resource() is the only method in DMA mapping APIs that has this
check, simply drop the pfn_valid() test from dma_map_resource().
Link: https://lore.kernel.org/all/20210824173741.GC623@arm.com/
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
---
kernel/dma/mapping.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 06fec5547e7c..dda8d8b84a55 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -296,10 +296,6 @@ dma_addr_t dma_map_resource(struct device *dev, phys_addr_t phys_addr,
if (WARN_ON_ONCE(!dev->dma_mask))
return DMA_MAPPING_ERROR;
- /* Don't allow RAM to be mapped */
- if (WARN_ON_ONCE(pfn_valid(PHYS_PFN(phys_addr))))
- return DMA_MAPPING_ERROR;
-
if (dma_map_direct(dev, ops))
addr = dma_direct_map_resource(dev, phys_addr, size, dir, attrs);
else if (ops->map_resource)
--
2.28.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] dma-mapping: remove bogus test for pfn_valid from dma_map_resource
2021-09-30 1:30 ` [PATCH 1/2] dma-mapping: remove bogus test for pfn_valid from dma_map_resource Mike Rapoport
@ 2021-09-30 5:46 ` Christoph Hellwig
2021-09-30 7:27 ` David Hildenbrand
1 sibling, 0 replies; 6+ messages in thread
From: Christoph Hellwig @ 2021-09-30 5:46 UTC (permalink / raw)
To: Mike Rapoport
Cc: linux-arm-kernel, Alex Bee, Andrew Morton, Anshuman Khandual,
Catalin Marinas, Christoph Hellwig, David Hildenbrand,
Linux Kernel Mailing List, Marek Szyprowski, Mike Rapoport,
Robin Murphy, Will Deacon, iommu
On Thu, Sep 30, 2021 at 04:30:38AM +0300, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
>
> dma_map_resource() uses pfn_valid() to ensure the range is not RAM.
> However, pfn_valid() only checks for availability of the memory map for a
> PFN but it does not ensure that the PFN is actually backed by RAM.
>
> As dma_map_resource() is the only method in DMA mapping APIs that has this
> check, simply drop the pfn_valid() test from dma_map_resource().
>
> Link: https://lore.kernel.org/all/20210824173741.GC623@arm.com/
> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
We'll lose a bit of a sanity check with this, but given the problems it
caused:
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] dma-mapping: remove bogus test for pfn_valid from dma_map_resource
2021-09-30 1:30 ` [PATCH 1/2] dma-mapping: remove bogus test for pfn_valid from dma_map_resource Mike Rapoport
2021-09-30 5:46 ` Christoph Hellwig
@ 2021-09-30 7:27 ` David Hildenbrand
1 sibling, 0 replies; 6+ messages in thread
From: David Hildenbrand @ 2021-09-30 7:27 UTC (permalink / raw)
To: Mike Rapoport, linux-arm-kernel
Cc: Alex Bee, Andrew Morton, Anshuman Khandual, Catalin Marinas,
Christoph Hellwig, Linux Kernel Mailing List, Marek Szyprowski,
Mike Rapoport, Robin Murphy, Will Deacon, iommu
On 30.09.21 03:30, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
>
> dma_map_resource() uses pfn_valid() to ensure the range is not RAM.
> However, pfn_valid() only checks for availability of the memory map for a
> PFN but it does not ensure that the PFN is actually backed by RAM.
>
> As dma_map_resource() is the only method in DMA mapping APIs that has this
> check, simply drop the pfn_valid() test from dma_map_resource().
>
> Link: https://lore.kernel.org/all/20210824173741.GC623@arm.com/
> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
> ---
Acked-by: David Hildenbrand <david@redhat.com>
--
Thanks,
David / dhildenb
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 2/2] arm64/mm: drop HAVE_ARCH_PFN_VALID
2021-09-30 1:30 [PATCH 0/2] arm64: retry dropping HAVE_ARCH_PFN_VALID Mike Rapoport
2021-09-30 1:30 ` [PATCH 1/2] dma-mapping: remove bogus test for pfn_valid from dma_map_resource Mike Rapoport
@ 2021-09-30 1:30 ` Mike Rapoport
2021-10-01 14:01 ` [PATCH 0/2] arm64: retry dropping HAVE_ARCH_PFN_VALID Will Deacon
2 siblings, 0 replies; 6+ messages in thread
From: Mike Rapoport @ 2021-09-30 1:30 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Alex Bee, Andrew Morton, Anshuman Khandual, Catalin Marinas,
Christoph Hellwig, David Hildenbrand, Linux Kernel Mailing List,
Marek Szyprowski, Mike Rapoport, Mike Rapoport, Robin Murphy,
Will Deacon, iommu
From: Anshuman Khandual <anshuman.khandual@arm.com>
CONFIG_SPARSEMEM_VMEMMAP is now the only available memory model on arm64
platforms and free_unused_memmap() would just return without creating any
holes in the memmap mapping. There is no need for any special handling in
pfn_valid() and HAVE_ARCH_PFN_VALID can just be dropped. This also moves
the pfn upper bits sanity check into generic pfn_valid().
[rppt: rebased on v5.15-rc3]
Link: https://lkml.kernel.org/r/1621947349-25421-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
---
arch/arm64/Kconfig | 1 -
arch/arm64/include/asm/page.h | 1 -
arch/arm64/mm/init.c | 37 -----------------------------------
3 files changed, 39 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 5c7ae4c3954b..53dd23f305be 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -154,7 +154,6 @@ config ARM64
select HAVE_ARCH_KGDB
select HAVE_ARCH_MMAP_RND_BITS
select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
- select HAVE_ARCH_PFN_VALID
select HAVE_ARCH_PREL32_RELOCATIONS
select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
select HAVE_ARCH_SECCOMP_FILTER
diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
index f98c91bbd7c1..993a27ea6f54 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -41,7 +41,6 @@ void tag_clear_highpage(struct page *to);
typedef struct page *pgtable_t;
-int pfn_valid(unsigned long pfn);
int pfn_is_map_memory(unsigned long pfn);
#include <asm/memory.h>
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 37a81754d9b6..e60c6eb813b7 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -160,43 +160,6 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
free_area_init(max_zone_pfns);
}
-int pfn_valid(unsigned long pfn)
-{
- phys_addr_t addr = PFN_PHYS(pfn);
- struct mem_section *ms;
-
- /*
- * Ensure the upper PAGE_SHIFT bits are clear in the
- * pfn. Else it might lead to false positives when
- * some of the upper bits are set, but the lower bits
- * match a valid pfn.
- */
- if (PHYS_PFN(addr) != pfn)
- return 0;
-
- if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
- return 0;
-
- ms = __pfn_to_section(pfn);
- if (!valid_section(ms))
- return 0;
-
- /*
- * ZONE_DEVICE memory does not have the memblock entries.
- * memblock_is_map_memory() check for ZONE_DEVICE based
- * addresses will always fail. Even the normal hotplugged
- * memory will never have MEMBLOCK_NOMAP flag set in their
- * memblock entries. Skip memblock search for all non early
- * memory sections covering all of hotplug memory including
- * both normal and ZONE_DEVICE based.
- */
- if (!early_section(ms))
- return pfn_section_valid(ms, pfn);
-
- return memblock_is_memory(addr);
-}
-EXPORT_SYMBOL(pfn_valid);
-
int pfn_is_map_memory(unsigned long pfn)
{
phys_addr_t addr = PFN_PHYS(pfn);
--
2.28.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH 0/2] arm64: retry dropping HAVE_ARCH_PFN_VALID
2021-09-30 1:30 [PATCH 0/2] arm64: retry dropping HAVE_ARCH_PFN_VALID Mike Rapoport
2021-09-30 1:30 ` [PATCH 1/2] dma-mapping: remove bogus test for pfn_valid from dma_map_resource Mike Rapoport
2021-09-30 1:30 ` [PATCH 2/2] arm64/mm: drop HAVE_ARCH_PFN_VALID Mike Rapoport
@ 2021-10-01 14:01 ` Will Deacon
2 siblings, 0 replies; 6+ messages in thread
From: Will Deacon @ 2021-10-01 14:01 UTC (permalink / raw)
To: Mike Rapoport, linux-arm-kernel
Cc: catalin.marinas, kernel-team, Will Deacon, David Hildenbrand,
Robin Murphy, Christoph Hellwig, Andrew Morton, Mike Rapoport,
Linux Kernel Mailing List, Marek Szyprowski, Alex Bee,
Anshuman Khandual, iommu
On Thu, 30 Sep 2021 04:30:37 +0300, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
>
> Hi,
>
> This is a new attempt to drop HAVE_ARCH_PFN_VALID on arm64 and start using
> the generic implementation of pfn_valid().
>
> [...]
Applied to arm64 (for-next/pfn-valid), thanks!
[1/2] dma-mapping: remove bogus test for pfn_valid from dma_map_resource
https://git.kernel.org/arm64/c/a9c38c5d267c
[2/2] arm64/mm: drop HAVE_ARCH_PFN_VALID
https://git.kernel.org/arm64/c/3de360c3fdb3
Cheers,
--
Will
https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev
^ permalink raw reply [flat|nested] 6+ messages in thread