| Message ID | 1444821634-1689-10-git-send-email-suzuki.poulose@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Oct 14, 2015 at 12:20:32PM +0100, Suzuki K. Poulose wrote: > From: Ard Biesheuvel <ard.biesheuvel@linaro.org> > > 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> > --- > Documentation/arm64/booting.txt | 7 ++++++- > arch/arm64/kernel/image.h | 5 ++++- > 2 files changed, 10 insertions(+), 2 deletions(-) > > diff --git a/Documentation/arm64/booting.txt b/Documentation/arm64/booting.txt > index 7d9d3c2..aaf6d77 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 6eb8fee..e45759e 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) I'd prefer that we also had brackets around the whole of the __HEAD_FLAGS value, so we don't get caught out later on by some unexpected expansion (though we are safe currently). With that: Acked-by: Mark Rutland <mark.rutland@arm.com> Thanks, Mark.
On 14/10/15 18:27, Mark Rutland wrote: > On Wed, Oct 14, 2015 at 12:20:32PM +0100, Suzuki K. Poulose wrote: >> From: Ard Biesheuvel <ard.biesheuvel@linaro.org> >> >> 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> >> --- >> Documentation/arm64/booting.txt | 7 ++++++- >> arch/arm64/kernel/image.h | 5 ++++- >> 2 files changed, 10 insertions(+), 2 deletions(-) >> >> diff --git a/Documentation/arm64/booting.txt b/Documentation/arm64/booting.txt >> index 7d9d3c2..aaf6d77 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 6eb8fee..e45759e 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) > > I'd prefer that we also had brackets around the whole of the > __HEAD_FLAGS value, so we don't get caught out later on by some > unexpected expansion (though we are safe currently). > Sure, will add that. > With that: > > Acked-by: Mark Rutland <mark.rutland@arm.com> Thanks Suzuki
diff --git a/Documentation/arm64/booting.txt b/Documentation/arm64/booting.txt index 7d9d3c2..aaf6d77 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 6eb8fee..e45759e 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