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From: Jisheng Zhang <jszhang3@mail.ustc.edu.cn>
To: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: linux-riscv <linux-riscv@lists.infradead.org>
Subject: Re: [Request for help] issue when add relative extable support to riscv64
Date: Sat, 18 Sep 2021 22:20:48 +0800	[thread overview]
Message-ID: <20210918222048.1e90488e@xhacker> (raw)
In-Reply-To: <7908d27b-1042-61f5-fc8e-f5b00f623b89@huawei.com>

On Sat, 18 Sep 2021 09:23:48 +0800
Kefeng Wang <wangkefeng.wang@huawei.com> wrote:

> On 2021/9/18 0:26, Jisheng Zhang wrote:
> > On Fri, 17 Sep 2021 23:57:33 +0800 Jisheng Zhang wrote:
> >  
> >> Hi,
> >>
> >> Now the extable entry contains 16bytes for riscv64 -- 8bytes for the insn and
> >> another 8bytes for the fixup. This wastes mem a bit. I think we can add
> >> the relative extable support. A draft patch put at the end of this mail. But
> >> I met abnormal build errors:
> >>
> >> FATAL: modpost: The relocation at __ex_table+0x0 references
> >> section "__ex_table" which is not executable, IOW
> >> it is not possible for the kernel to fault
> >> at that address.  Something is seriously wrong
> >> and should be fixed.  
> 
> I try this before, and meet the same issue,  and add norelax to the label,
> 
> but it won't fix the error. seems that we con't find the lable from the 
> text?

I also tried adding --no-relax to LDFLAGS and -mno-relax to AFLAGS and CFLAGS
but still met the error. This is an insteresting issue.

Thanks

> 
> 
>   82 index 1b00badb9f87..cb1aca8e8a23 100644
>   83 --- a/arch/riscv/include/asm/futex.h
>   84 +++ b/arch/riscv/include/asm/futex.h
>   85 @@ -23,17 +23,18 @@
>   86         uintptr_t tmp; \
>   87         __enable_user_access(); \
>   88         __asm__ __volatile__ ( \
>   89 +       "       .option push                            \n" \
>   90 +       "       .option norelax                         \n" \
>   91 +       "       .option norvc                           \n" \
>   92         "1:     " insn "                                \n" \
>   93 +       "       .option pop                             \n" \
>   94         "2:                                             \n" \
> 
> 
> 



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  reply	other threads:[~2021-09-18 14:27 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-17 15:57 [Request for help] issue when add relative extable support to riscv64 Jisheng Zhang
2021-09-17 16:26 ` Jisheng Zhang
2021-09-18  1:23   ` Kefeng Wang
2021-09-18 14:20     ` Jisheng Zhang [this message]
2021-10-10 15:56 ` Jisheng Zhang
2021-10-10 16:59   ` Andreas Schwab

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