On Wed, Oct 14, 2015 at 12:20:32PM +0100, Suzuki K. Poulose wrote: > From: Ard Biesheuvel <ard.biesheu...@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.biesheu...@linaro.org> > Signed-off-by: Suzuki K. Poulose <suzuki.poul...@arm.com> > Acked-by: Catalin Marinas <catalin.mari...@arm.com> > Reviewed-by: Christoffer Dall <christoffer.d...@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.rutl...@arm.com> Thanks, Mark. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
