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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2015-10-19 16:19:36 +0300
committerCatalin Marinas <catalin.marinas@arm.com>2015-10-19 19:54:41 +0300
commit9d372c9fab34cd8803141871195141995f85c7f7 (patch)
treeaddabfafd3a42eef113fe9e80c3cacaf19bf2755
parent4bf8b96ed3f7e11422d8b4f58cf43896ed02d1f6 (diff)
downloadlinux-9d372c9fab34cd8803141871195141995f85c7f7.tar.xz
arm64: Add page size to the kernel image header
This patch adds the page size to the arm64 kernel image header so that one can infer the PAGESIZE used by the kernel. This will be helpful to diagnose failures to boot the kernel with page size not supported by the CPU. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
-rw-r--r--Documentation/arm64/booting.txt7
-rw-r--r--arch/arm64/kernel/image.h5
2 files changed, 10 insertions, 2 deletions
diff --git a/Documentation/arm64/booting.txt b/Documentation/arm64/booting.txt
index 7d9d3c2286b2..aaf6d77e4148 100644
--- a/Documentation/arm64/booting.txt
+++ b/Documentation/arm64/booting.txt
@@ -104,7 +104,12 @@ Header notes:
- The flags field (introduced in v3.17) is a little-endian 64-bit field
composed as follows:
Bit 0: Kernel endianness. 1 if BE, 0 if LE.
- Bits 1-63: Reserved.
+ Bit 1-2: Kernel Page size.
+ 0 - Unspecified.
+ 1 - 4K
+ 2 - 16K
+ 3 - 64K
+ Bits 3-63: Reserved.
- When image_size is zero, a bootloader should attempt to keep as much
memory as possible free for use by the kernel immediately after the
diff --git a/arch/arm64/kernel/image.h b/arch/arm64/kernel/image.h
index 6eb8fee93321..bc2abb8b1599 100644
--- a/arch/arm64/kernel/image.h
+++ b/arch/arm64/kernel/image.h
@@ -47,7 +47,10 @@
#define __HEAD_FLAG_BE 0
#endif
-#define __HEAD_FLAGS (__HEAD_FLAG_BE << 0)
+#define __HEAD_FLAG_PAGE_SIZE ((PAGE_SHIFT - 10) / 2)
+
+#define __HEAD_FLAGS ((__HEAD_FLAG_BE << 0) | \
+ (__HEAD_FLAG_PAGE_SIZE << 1))
/*
* These will output as part of the Image header, which should be little-endian