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From:   =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn@kernel.org>
To:     Andreas Schwab <schwab@suse.de>,
        Celeste Liu <coelacanthushex@gmail.com>
Cc:     Palmer Dabbelt <palmer@rivosinc.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Albert Ou <aou@eecs.berkeley.edu>, Guo Ren <guoren@kernel.org>,
        =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn@rivosinc.com>,
        Conor Dooley <conor.dooley@microchip.com>,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        Felix Yan <felixonmars@archlinux.org>,
        Ruizhe Pan <c141028@gmail.com>,
        Shiqi Zhang <shiqi@isrc.iscas.ac.cn>
Subject: Re: [PATCH v3] riscv: entry: set a0 = -ENOSYS only when syscall != -1
In-Reply-To: <mvmo7k8cqns.fsf@suse.de>
References: <20230718210037.250665-1-CoelacanthusHex@gmail.com>
 <mvmo7k8cqns.fsf@suse.de>
Date:   Wed, 19 Jul 2023 18:28:47 +0200
Message-ID: <878rbbkgqo.fsf@all.your.base.are.belong.to.us>
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Andreas Schwab <schwab@suse.de> writes:

> On Jul 19 2023, Celeste Liu wrote:
>
>> @@ -308,7 +312,7 @@ asmlinkage __visible __trap_section void do_trap_eca=
ll_u(struct pt_regs *regs)
>>=20=20
>>  		if (syscall < NR_syscalls)
>>  			syscall_handler(regs, syscall);
>> -		else
>> +		else if ((long)syscall !=3D -1L)
>
> You can also use syscall !=3D -1UL or even syscall !=3D -1.

The former is indeed better for the eyes! :-) The latter will get a
-Wsign-compare warning, no?


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