From mboxrd@z Thu Jan 1 00:00:00 1970 From: ard.biesheuvel@linaro.org (Ard Biesheuvel) Date: Wed, 30 Mar 2016 14:25:47 +0200 Subject: [PATCH v2 2/3] arm64: choose memstart_addr based on minimum sparsemem section alignment In-Reply-To: <1459340748-14975-1-git-send-email-ard.biesheuvel@linaro.org> References: <1459340748-14975-1-git-send-email-ard.biesheuvel@linaro.org> Message-ID: <1459340748-14975-3-git-send-email-ard.biesheuvel@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 --- arch/arm64/include/asm/kernel-pgtable.h | 21 +++++++++++++++++--- 1 file 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 /* * 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 */ -- 2.5.0