[PATCH V4 08/11] arm64: mm: Separate out vmemmap

[Steve Capper <steve.capper@arm.com>]

vmemmap is a preprocessor definition that depends on a variable,
memstart_addr. In a later patch we will need to expand the size of
the VMEMMAP region and optionally modify vmemmap depending upon
whether or not hardware support is available for 52-bit virtual
addresses.

This patch changes vmemmap to be a variable. As the old definition
depended on a variable load, this should not affect performance
noticeably.

Signed-off-by: Steve Capper <steve.capper@arm.com>
---
 arch/arm64/include/asm/pgtable.h | 4 ++--
 arch/arm64/mm/init.c             | 5 +++++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index d274ea9a5f86..0eedf8664ecc 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -23,8 +23,6 @@
 #define VMALLOC_START		(MODULES_END)
 #define VMALLOC_END		(- PUD_SIZE - VMEMMAP_SIZE - SZ_64K)
 
-#define vmemmap			((struct page *)VMEMMAP_START - (memstart_addr >> PAGE_SHIFT))
-
 #define FIRST_USER_ADDRESS	0UL
 
 #ifndef __ASSEMBLY__
@@ -35,6 +33,8 @@
 #include <linux/mm_types.h>
 #include <linux/sched.h>
 
+extern struct page *vmemmap;
+
 extern void __pte_error(const char *file, int line, unsigned long val);
 extern void __pmd_error(const char *file, int line, unsigned long val);
 extern void __pud_error(const char *file, int line, unsigned long val);
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 189177672567..310e63b0dd22 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -53,6 +53,9 @@ EXPORT_SYMBOL(memstart_addr);
 s64 physvirt_offset __ro_after_init;
 EXPORT_SYMBOL(physvirt_offset);
 
+struct page *vmemmap __ro_after_init;
+EXPORT_SYMBOL(vmemmap);
+
 phys_addr_t arm64_dma_phys_limit __ro_after_init;
 
 #ifdef CONFIG_KEXEC_CORE
@@ -320,6 +323,8 @@ void __init arm64_memblock_init(void)
 
 	physvirt_offset = PHYS_OFFSET - PAGE_OFFSET;
 
+	vmemmap = ((struct page *)VMEMMAP_START - (memstart_addr >> PAGE_SHIFT));
+
 	/*
 	 * Remove the memory that we will not be able to cover with the
 	 * linear mapping. Take care not to clip the kernel which may be
-- 
2.20.1


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