From: will.deacon@arm•com (Will Deacon)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] ARM: kvm: implement replacement for ld's LOG2CEIL()
Date: Mon, 23 Mar 2015 11:40:01 +0000 [thread overview]
Message-ID: <20150323114001.GF11189@arm.com> (raw)
In-Reply-To: <1427107977-18591-1-git-send-email-ard.biesheuvel@linaro.org>
On Mon, Mar 23, 2015 at 10:52:57AM +0000, Ard Biesheuvel wrote:
> Commit 06f75a1f6200 ("ARM, arm64: kvm: get rid of the bounce
> page") uses ld's builtin function LOG2CEIL() to align the
> KVM init code to a log2 upper bound of its size. However,
> this function turns out to be a fairly recent addition to
> binutils, which breaks the build for older toolchains.
>
> So instead, implement a replacement LOG2_ROUNDUP() using
> the C preprocessor.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro•org>
> ---
>
> Linker map output after applying this patch:
>
> 0xc09a2590 __idmap_text_end = .
> [...]
> *fill* 0xc09a2590 0x70
> 0xc09a2600 __hyp_idmap_text_start = .
> *(.hyp.idmap.text)
> .hyp.idmap.text
> 0xc09a2600 0x100 arch/arm/kvm/built-in.o
> 0xc09a2600 __kvm_hyp_init
> 0xc09a26ec __kvm_hyp_init_end
> 0xc09a2700 __hyp_idmap_text_end = .
>
> which confirms that the alignemnt is correct. The size of the region
> is 0xec bytes, and 0x70 bytes of padding are emitted to align it at
> a 0x100 byte boundary
>
> arch/arm/kernel/vmlinux.lds.S | 24 ++++++++++++++++++++++--
> 1 file changed, 22 insertions(+), 2 deletions(-)
Thanks Ard. I pushed this on top of kvm-bounce-page and re-generated
for-next/core.
Will
next prev parent reply other threads:[~2015-03-23 11:40 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-23 10:52 [PATCH] ARM: kvm: implement replacement for ld's LOG2CEIL() Ard Biesheuvel
2015-03-23 11:40 ` Will Deacon [this message]
2015-03-23 16:03 ` Ard Biesheuvel
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