linux-kernel - Re: [PATCH] riscv: add correct as-options for assembly in modules

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Message-ID: <36a5d9d8-67be-e128-2798-5bf1989ce06d@codethink.co.uk>
Date:   Fri, 16 Jul 2021 16:33:07 +0100
From:   Ben Dooks <ben.dooks@...ethink.co.uk>
To:     Bin Meng <bmeng.cn@...il.com>
Cc:     linux-kernel@...ts.codethink.co.uk,
        linux-kernel <linux-kernel@...r.kernel.org>,
        linux-riscv <linux-riscv@...ts.infradead.org>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>
Subject: Re: [PATCH] riscv: add correct as-options for assembly in modules

On 16/07/2021 11:44, Bin Meng wrote:
> On Tue, Jul 13, 2021 at 2:28 AM Ben Dooks <ben.dooks@...ethink.co.uk> wrote:
>>
>> When trying to load modules built for riscv which include assembly
> 
> nits: RISC-V
> 
>> the kernel loader errors with "unexpected relocation type 'R_RISCV_ALIGN'"
>> due to R_RISCV_ALIGN relocations being generated by the assembler.
>>
>> In commit 7a8e7da42250138 ("RISC-V: Fixes to module loading")
>> the fix for gcc adds -mno-relax to the command line when building
>> C files. However this was never applied to assembly flags, and gcc
>> does no pass -mno-relax to gas when presented with a .S file.
> 
> does not pass

I'll see if I can make this simpler. Should this get done for a v2?

> FYI
> 
> The GCC bug was fixed recently via:
> https://github.com/gcc-mirror/gcc/commit/3b0a7d624e64eeb81e4d5e8c62c46d86ef521857

thanks, I think it still useful to fix this in the kernel.

>>
>> The fix (other than making gcc always pass -mno-relax to gas) is
>> to add -Wa,-mno-relax to gcc to make sure the as is invoked with
>> the right options.
>>
>> Signed-off-by: Ben Dooks <ben.dooks@...ethink.co.uk>
>> ---
>>   arch/riscv/Makefile | 1 +
>>   1 file changed, 1 insertion(+)
>>
> 
> Otherwise,
> Reviewed-by: Bin Meng <bmeng.cn@...il.com>
> 


-- 
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius

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