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Message-Id: <1608621144-4001-3-git-send-email-anshuman.khandual@arm.com>
Date: Tue, 22 Dec 2020 12:42:24 +0530
From: Anshuman Khandual <anshuman.khandual@....com>
To: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc: catalin.marinas@....com, will@...nel.org, ardb@...nel.org,
Anshuman Khandual <anshuman.khandual@....com>,
Mark Rutland <mark.rutland@....com>,
James Morse <james.morse@....com>,
Robin Murphy <robin.murphy@....com>,
Jérôme Glisse <jglisse@...hat.com>,
Dan Williams <dan.j.williams@...el.com>,
David Hildenbrand <david@...hat.com>
Subject: [RFC 2/2] arm64/mm: Reorganize pfn_valid()
There are multiple instances of pfn_to_section_nr() and __pfn_to_section()
when CONFIG_SPARSEMEM is enabled. This can be just optimized if the memory
section is fetched earlier. Hence bifurcate pfn_valid() into two different
definitions depending on whether CONFIG_SPARSEMEM is enabled. Also replace
the open coded pfn <--> addr conversion with __[pfn|phys]_to_[phys|pfn]().
This does not cause any functional change.
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will@...nel.org>
Cc: Ard Biesheuvel <ardb@...nel.org>
Cc: linux-arm-kernel@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
---
arch/arm64/mm/init.c | 36 ++++++++++++++++++++++++++++++------
1 file changed, 30 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index ee23bda00c28..c3387798a3be 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -212,18 +212,25 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
free_area_init(max_zone_pfns);
}
+#ifdef CONFIG_SPARSEMEM
int pfn_valid(unsigned long pfn)
{
- phys_addr_t addr = pfn << PAGE_SHIFT;
+ struct mem_section *ms = __pfn_to_section(pfn);
+ phys_addr_t addr = __pfn_to_phys(pfn);
- if ((addr >> PAGE_SHIFT) != pfn)
+ /*
+ * 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_to_pfn(addr) != pfn)
return 0;
-#ifdef CONFIG_SPARSEMEM
if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
return 0;
- if (!valid_section(__pfn_to_section(pfn)))
+ if (!valid_section(ms))
return 0;
/*
@@ -235,11 +242,28 @@ int pfn_valid(unsigned long pfn)
* memory sections covering all of hotplug memory including
* both normal and ZONE_DEVIE based.
*/
- if (!early_section(__pfn_to_section(pfn)))
+ if (!early_section(ms))
return 1;
-#endif
+
return memblock_is_map_memory(addr);
}
+#else
+int pfn_valid(unsigned long pfn)
+{
+ phys_addr_t addr = __pfn_to_phys(pfn);
+
+ /*
+ * 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_to_pfn(addr) != pfn)
+ return 0;
+
+ return memblock_is_map_memory(addr);
+}
+#endif
EXPORT_SYMBOL(pfn_valid);
static phys_addr_t memory_limit = PHYS_ADDR_MAX;
--
2.20.1
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