[PATCH 1/2] RISC-V: Fix alignment issue in sigjmp_buf

[Kito Cheng]

This patch fix a potential mis-alignment issue in sigjump_buf, load a
double floating value required 8 bytes align, but we just align to
size of long, it's may cause mis-align memory access in rv32imafd.

[Palmer Dabbelt]

> From d23ba9ea7f842dda65b89cb80c396d1254b4e934 Mon Sep 17 00:00:00 2001
> From: Kito Cheng <kito....@gmail.com>
> Date: Fri, 17 Nov 2017 14:50:52 +0800
> Subject: [PATCH 1/2] RISC-V: Fix alignment issue in sigjmp_buf
>
> ---
> newlib/libc/include/machine/setjmp.h | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/newlib/libc/include/machine/setjmp.h b/newlib/libc/include/machine/setjmp.h
> index b33f437..9212f84 100644
> --- a/newlib/libc/include/machine/setjmp.h
> +++ b/newlib/libc/include/machine/setjmp.h
> @@ -359,7 +359,9 @@ _BEGIN_STD_C
> #endif
>
> #ifdef __riscv
> -#define _JBTYPE long
> +/* _JBTYPE using long long to make sure the alignment is align to 8 byte,
> + otherwise in rv32imafd, store/restore FPR may mis-align. */
> +#define _JBTYPE long long
> #ifdef __riscv_32e
> #define _JBLEN ((4*sizeof(long))/sizeof(long))
> #else
> --
> 2.7.4

This looks good to me. Do you want me to co-maintain the RISC-V newlib port?
IIRC you're the only maintainer, which can be a lot of work.

[Jim Wilson]

On 01/18/2018 10:58 AM, Palmer Dabbelt wrote:
> On Wed, 17 Jan 2018 19:04:20 PST (-0800), Kito Cheng wrote:
>> This patch fix a potential mis-alignment issue in sigjump_buf, load a
>> double floating value required 8 bytes align, but we just align to
>> size of long, it's may cause mis-align memory access in rv32imafd.

> This looks good to me.  Do you want me to co-maintain the RISC-V newlib
> port? IIRC you're the only maintainer, which can be a lot of work.

I already have write after approval access for newlib, and have been
reviewing pull requests in the github riscv-newlib project. This patch
was part of
https://github.com/riscv/riscv-newlib/pull/30/
I also checked in the last set of patches that Kito sent. If we need a
co-maintainer, it might make more sense for it to be me.

Jim

[Palmer Dabbelt]

That works for me. Thanks for volunteering!

>
> Jim
>
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