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From: Anshuman Khandual <anshuman.khandual@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Anshuman Khandual <anshuman.khandual@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>
Subject: [PATCH] arm64/mm: Drop ARM64_KERNEL_USES_PMD_MAPS
Date: Fri, 23 Sep 2022 18:38:41 +0530	[thread overview]
Message-ID: <20220923130841.1382741-1-anshuman.khandual@arm.com> (raw)

Currently ARM64_KERNEL_USES_PMD_MAPS is an unnecessary abstraction. Kernel
mapping at PMD (aka huge page aka block) level, is only applicable with 4K
base page, which makes it 2MB aligned, a necessary requirement for linear
mapping and physical memory start address. This can be easily achieved by
directly checking against base page size itself. This drops off the macro
ARM64_KERNE_USES_PMD_MAPS which is redundant.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
This applies on v6.0-rc6 after the following patch.

https://lore.kernel.org/all/20220920014951.196191-1-wangkefeng.wang@huawei.com/

 arch/arm64/include/asm/kernel-pgtable.h | 33 +++++++++----------------
 arch/arm64/mm/mmu.c                     |  2 +-
 2 files changed, 12 insertions(+), 23 deletions(-)

diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h
index 32d14f481f0c..5c2f72bae2ca 100644
--- a/arch/arm64/include/asm/kernel-pgtable.h
+++ b/arch/arm64/include/asm/kernel-pgtable.h
@@ -18,11 +18,6 @@
  * with 4K (section size = 2M) but not with 16K (section size = 32M) or
  * 64K (section size = 512M).
  */
-#ifdef CONFIG_ARM64_4K_PAGES
-#define ARM64_KERNEL_USES_PMD_MAPS 1
-#else
-#define ARM64_KERNEL_USES_PMD_MAPS 0
-#endif
 
 /*
  * The idmap and swapper page tables need some space reserved in the kernel
@@ -34,10 +29,20 @@
  * VA range, so pages required to map highest possible PA are reserved in all
  * cases.
  */
-#if ARM64_KERNEL_USES_PMD_MAPS
+#ifdef CONFIG_ARM64_4K_PAGES
 #define SWAPPER_PGTABLE_LEVELS	(CONFIG_PGTABLE_LEVELS - 1)
+#define SWAPPER_BLOCK_SHIFT	PMD_SHIFT
+#define SWAPPER_BLOCK_SIZE	PMD_SIZE
+#define SWAPPER_TABLE_SHIFT	PUD_SHIFT
+#define SWAPPER_RW_MMUFLAGS	(PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS)
+#define SWAPPER_RX_MMUFLAGS	(SWAPPER_RW_MMUFLAGS | PMD_SECT_RDONLY)
 #else
 #define SWAPPER_PGTABLE_LEVELS	(CONFIG_PGTABLE_LEVELS)
+#define SWAPPER_BLOCK_SHIFT	PAGE_SHIFT
+#define SWAPPER_BLOCK_SIZE	PAGE_SIZE
+#define SWAPPER_TABLE_SHIFT	PMD_SHIFT
+#define SWAPPER_RW_MMUFLAGS	(PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS)
+#define SWAPPER_RX_MMUFLAGS	(SWAPPER_RW_MMUFLAGS | PTE_RDONLY)
 #endif
 
 
@@ -96,15 +101,6 @@
 #define INIT_IDMAP_DIR_PAGES	EARLY_PAGES(KIMAGE_VADDR, _end + MAX_FDT_SIZE + SWAPPER_BLOCK_SIZE, 1)
 
 /* Initial memory map size */
-#if ARM64_KERNEL_USES_PMD_MAPS
-#define SWAPPER_BLOCK_SHIFT	PMD_SHIFT
-#define SWAPPER_BLOCK_SIZE	PMD_SIZE
-#define SWAPPER_TABLE_SHIFT	PUD_SHIFT
-#else
-#define SWAPPER_BLOCK_SHIFT	PAGE_SHIFT
-#define SWAPPER_BLOCK_SIZE	PAGE_SIZE
-#define SWAPPER_TABLE_SHIFT	PMD_SHIFT
-#endif
 
 /*
  * Initial memory map attributes.
@@ -112,13 +108,6 @@
 #define SWAPPER_PTE_FLAGS	(PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
 #define SWAPPER_PMD_FLAGS	(PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
 
-#if ARM64_KERNEL_USES_PMD_MAPS
-#define SWAPPER_RW_MMUFLAGS	(PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS)
-#define SWAPPER_RX_MMUFLAGS	(SWAPPER_RW_MMUFLAGS | PMD_SECT_RDONLY)
-#else
-#define SWAPPER_RW_MMUFLAGS	(PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS)
-#define SWAPPER_RX_MMUFLAGS	(SWAPPER_RW_MMUFLAGS | PTE_RDONLY)
-#endif
 
 /*
  * To make optimal use of block mappings when laying out the linear
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 69deed27dec8..df1eac788c33 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1192,7 +1192,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
 
 	WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END));
 
-	if (!ARM64_KERNEL_USES_PMD_MAPS)
+	if (!IS_ENABLED(CONFIG_ARM64_4K_PAGES))
 		return vmemmap_populate_basepages(start, end, node, altmap);
 
 	do {
-- 
2.20.1


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             reply	other threads:[~2022-09-23 13:10 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-23 13:08 Anshuman Khandual [this message]
2022-09-23 13:38 ` [PATCH] arm64/mm: Drop ARM64_KERNEL_USES_PMD_MAPS Joey Gouly
2022-09-26  3:18   ` Anshuman Khandual
2022-11-07 15:22     ` Will Deacon
2022-11-08  2:32       ` Anshuman Khandual

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