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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2016-03-30 14:25:47 +0200
committerWill Deacon <will.deacon@arm.com>2016-04-14 17:15:08 +0200
commit06e9bf2fd9b372bc1c757995b6ca1cfab0720acb (patch)
tree04c3b47416a9ccfdd302c76fa75c3fa4052dd26d /arch/arm64/include/asm/kernel-pgtable.h
parentarm64/mm: ensure memstart_addr remains sufficiently aligned (diff)
downloadlinux-06e9bf2fd9b372bc1c757995b6ca1cfab0720acb.tar.xz
linux-06e9bf2fd9b372bc1c757995b6ca1cfab0720acb.zip
arm64: choose memstart_addr based on minimum sparsemem section alignment
This redefines ARM64_MEMSTART_ALIGN in terms of the minimal alignment required by sparsemem vmemmap. This comes down to using 1 GB for all translation granules if CONFIG_SPARSEMEM_VMEMMAP is enabled. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/kernel-pgtable.h')
-rw-r--r--arch/arm64/include/asm/kernel-pgtable.h21
1 files changed, 18 insertions, 3 deletions
diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h
index 5c6375d8528b..7e51d1b57c0c 100644
--- a/arch/arm64/include/asm/kernel-pgtable.h
+++ b/arch/arm64/include/asm/kernel-pgtable.h
@@ -19,6 +19,7 @@
#ifndef __ASM_KERNEL_PGTABLE_H
#define __ASM_KERNEL_PGTABLE_H
+#include <asm/sparsemem.h>
/*
* The linear mapping and the start of memory are both 2M aligned (per
@@ -86,10 +87,24 @@
* (64k granule), or a multiple that can be mapped using contiguous bits
* in the page tables: 32 * PMD_SIZE (16k granule)
*/
-#ifdef CONFIG_ARM64_64K_PAGES
-#define ARM64_MEMSTART_ALIGN SZ_512M
+#if defined(CONFIG_ARM64_4K_PAGES)
+#define ARM64_MEMSTART_SHIFT PUD_SHIFT
+#elif defined(CONFIG_ARM64_16K_PAGES)
+#define ARM64_MEMSTART_SHIFT (PMD_SHIFT + 5)
#else
-#define ARM64_MEMSTART_ALIGN SZ_1G
+#define ARM64_MEMSTART_SHIFT PMD_SHIFT
+#endif
+
+/*
+ * sparsemem vmemmap imposes an additional requirement on the alignment of
+ * memstart_addr, due to the fact that the base of the vmemmap region
+ * has a direct correspondence, and needs to appear sufficiently aligned
+ * in the virtual address space.
+ */
+#if defined(CONFIG_SPARSEMEM_VMEMMAP) && ARM64_MEMSTART_SHIFT < SECTION_SIZE_BITS
+#define ARM64_MEMSTART_ALIGN (1UL << SECTION_SIZE_BITS)
+#else
+#define ARM64_MEMSTART_ALIGN (1UL << ARM64_MEMSTART_SHIFT)
#endif
#endif /* __ASM_KERNEL_PGTABLE_H */