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authorLinus Torvalds <torvalds@linux-foundation.org>2021-08-26 11:26:00 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-08-26 11:26:00 -0700
commit1a6d80ff2419e8ad627b4bf4775a8b4c70af535d (patch)
tree83b814e10525c0fa9dd56d57879112c79edc4c68
parent97d8cc20085f63cfbf0b123295e12cf9ad66a03c (diff)
parent3eb9cdffb39701743973382860f214026f4d7825 (diff)
Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fix from Will Deacon: "We received a report this week that the generic version of pfn_valid(), which we switched to this merge window in 16c9afc77660 ("arm64/mm: drop HAVE_ARCH_PFN_VALID"), interacts badly with dma_map_resource() due to the following check: /* Don't allow RAM to be mapped */ if (WARN_ON_ONCE(pfn_valid(PHYS_PFN(phys_addr)))) return DMA_MAPPING_ERROR; Since the ongoing saga to determine the semantics of pfn_valid() is unlikely to be resolved this week (does it indicate valid memory, or just the presence of a struct page, or whether that struct page has been initialised?), just revert back to our old version of pfn_valid() for 5.14. Summary: - Fix dma_map_resource() by reverting back to old pfn_valid() code" * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: Partially revert "arm64/mm: drop HAVE_ARCH_PFN_VALID"
-rw-r--r--arch/arm64/Kconfig1
-rw-r--r--arch/arm64/include/asm/page.h1
-rw-r--r--arch/arm64/mm/init.c37
3 files changed, 39 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index fdcd54d39c1e..62c3c1d2190f 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -156,6 +156,7 @@ 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 993a27ea6f54..f98c91bbd7c1 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -41,6 +41,7 @@ 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 8490ed2917ff..1fdb7bb7c198 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -219,6 +219,43 @@ 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);

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