From: Bin Meng <bmeng.cn@gmail.com>
To: Anup Patel <anup@brainfault.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>,
Palmer Dabbelt <palmer@sifive.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>,
Atish Patra <atish.patra@wdc.com>,
linux-riscv@lists.infradead.org
Subject: Re: [PATCH v2] RISC-V: Make BSS section as the last section in vmlinux.lds.S
Date: Thu, 20 Dec 2018 14:16:47 +0800 [thread overview]
Message-ID: <CAEUhbmXNmzHVnzj88T5jxDXs=Rx_kD9fgayZ4r3xvgAOYXKWjw@mail.gmail.com> (raw)
In-Reply-To: <20181219123657.61270-1-anup@brainfault.org>
On Wed, Dec 19, 2018 at 8:37 PM Anup Patel <anup@brainfault.org> wrote:
>
> The objcopy only emits loadable sections when creating flat kernel
> Image. To have minimal possible size of flat kernel Image, we should
> have all non-loadable sections after loadable sections.
>
> Currently, execption table section (loadable section) is after BSS
> section (non-loadable section) in the RISC-V vmlinux.lds.S. This
> is not optimal for having minimal flat kernel Image size hence this
> patch makes BSS section as the last section in RISC-V vmlinux.lds.S.
>
> In addition, we make BSS section aligned to 16byte instead of PAGE
> aligned which further reduces flat kernel Image size by few KBs.
>
> The flat kernel Image size of Linux-4.20-rc4 using GCC 8.2.0 is
> 8819980 bytes with current RISC-V vmlinux.lds.S and it reduces to
> 7991740 bytes with this patch applied. In summary, this patch reduces
> Linux-4.20-rc4 flat kernel Image size by 809 KB.
>
> Signed-off-by: Anup Patel <anup@brainfault.org>
> ---
>
> Changes since v1:
> - Introduce MAX_BYTES_PER_LONG define and use it in-place of
> 0x10 magic value
>
> arch/riscv/kernel/vmlinux.lds.S | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
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prev parent reply other threads:[~2018-12-20 6:17 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-19 12:36 [PATCH v2] RISC-V: Make BSS section as the last section in vmlinux.lds.S Anup Patel
2018-12-20 6:16 ` Bin Meng [this message]
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