linux-kernel - [PATCH 04/15] arm64: Calculate size for idmap_pg

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Date:	Tue, 15 Sep 2015 16:41:13 +0100
From:	"Suzuki K. Poulose" <suzuki.poulose@....com>
To:	linux-arm-kernel@...ts.infradead.org
Cc:	linux-kernel@...r.kernel.org, Catalin.Marinas@....com,
	Will.Deacon@....com, Mark.Rutland@....com, Marc.Zyngier@....com,
	kvmarm@...ts.cs.columbia.edu, kvm@...r.kernel.org,
	ard.biesheuvel@...aro.org, suzuki.poulose@....com,
	Mark Rutland <mark.rutland@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will.deacon@....com>
Subject: [PATCH 04/15] arm64: Calculate size for idmap_pg_dir at compile time

From: "Suzuki K. Poulose" <suzuki.poulose@....com>

Now that we can calculate the number of levels required for
mapping a va width, reserve exact number of pages that would
be required to cover the idmap. The idmap should be able to handle
the maximum physical address size supported.

Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will.deacon@....com>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@....com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
---
 arch/arm64/include/asm/boot.h           |    1 +
 arch/arm64/include/asm/kernel-pgtable.h |    7 +++++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/boot.h b/arch/arm64/include/asm/boot.h
index 81151b6..678b63e 100644
--- a/arch/arm64/include/asm/boot.h
+++ b/arch/arm64/include/asm/boot.h
@@ -2,6 +2,7 @@
 #ifndef __ASM_BOOT_H
 #define __ASM_BOOT_H
 
+#include <asm/page.h>
 #include <asm/sizes.h>
 
 /*
diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h
index 5876a36..def7168 100644
--- a/arch/arm64/include/asm/kernel-pgtable.h
+++ b/arch/arm64/include/asm/kernel-pgtable.h
@@ -33,16 +33,19 @@
  * map to pte level. The swapper also maps the FDT (see __create_page_tables
  * for more information). Note that the number of ID map translation levels
  * could be increased on the fly if system RAM is out of reach for the default
- * VA range, so 3 pages are reserved in all cases.
+ * VA range, so pages required to map highest possible PA are reserved in all
+ * cases.
  */
 #if ARM64_SWAPPER_USES_SECTION_MAPS
 #define SWAPPER_PGTABLE_LEVELS	(CONFIG_PGTABLE_LEVELS - 1)
+#define IDMAP_PGTABLE_LEVELS	(ARM64_HW_PGTABLE_LEVELS(PHYS_MASK_SHIFT) - 1)
 #else
 #define SWAPPER_PGTABLE_LEVELS	(CONFIG_PGTABLE_LEVELS)
+#define IDMAP_PGTABLE_LEVELS	(ARM64_HW_PGTABLE_LEVELS(PHYS_MASK_SHIFT))
 #endif
 
 #define SWAPPER_DIR_SIZE	(SWAPPER_PGTABLE_LEVELS * PAGE_SIZE)
-#define IDMAP_DIR_SIZE		(3 * PAGE_SIZE)
+#define IDMAP_DIR_SIZE		(IDMAP_PGTABLE_LEVELS * PAGE_SIZE)
 
 /* Initial memory map size */
 #if ARM64_SWAPPER_USES_SECTION_MAPS
-- 
1.7.9.5

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