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Commit 06e9bf2f authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Will Deacon
Browse files

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: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 2958987f

arch/arm64/include/asm/kernel-pgtable.h

+18 −3
Original line number Diff line number Diff line
@@ -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 */