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Date:   Wed, 24 May 2023 21:49:16 +0200
From:   Thomas =?utf-8?Q?Wei=C3=9Fschuh?= <thomas@t-8ch.de>
To:     Zhangjin Wu <falcon@tinylab.org>
Cc:     w@1wt.eu, linux-kernel@vger.kernel.org,
        linux-kselftest@vger.kernel.org, linux-riscv@lists.infradead.org,
        palmer@dabbelt.com, paul.walmsley@sifive.com
Subject: Re: [PATCH 04/13] selftests/nolibc: syscall_args: use __NR_statx for
 rv32
Message-ID: <09d60dc2-e298-4c22-8e2f-8375861bd9be@t-8ch.de>
References: <cover.1684949267.git.falcon@tinylab.org>
 <b306ae7b53d67acad6d1e2f63d43505d79f81241.1684949267.git.falcon@tinylab.org>
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On 2023-05-25 01:48:11+0800, Zhangjin Wu wrote:
> When compile nolibc-test.c for rv32, we got such error:
> 
>     tools/testing/selftests/nolibc/nolibc-test.c:599:57: error: ‘__NR_fstat’ undeclared (first use in this function)
>       599 |   CASE_TEST(syscall_args);      EXPECT_SYSER(1, syscall(__NR_fstat, 0, NULL), -1, EFAULT); break;
> 
> The generic include/uapi/asm-generic/unistd.h used by rv32 doesn't
> support __NR_fstat, use __NR_statx instead:
> 
>     Running test 'syscall'
>     69 syscall_noargs = 1                                            [OK]
>     70 syscall_args = -1 EFAULT                                      [OK]
> 
> As tools/include/nolibc/sys.h shows, __NR_statx is either not supported
> by all platforms, so, both __NR_fstat and __NR_statx are required.
> 
> Btw, the latest riscv libc6-dev package is required, otherwise, we would
> also get such error:
> 
>     In file included from /usr/riscv64-linux-gnu/include/sys/cdefs.h:452,
>                      from /usr/riscv64-linux-gnu/include/features.h:461,
>                      from /usr/riscv64-linux-gnu/include/bits/libc-header-start.h:33,
>                      from /usr/riscv64-linux-gnu/include/limits.h:26,
>                      from /usr/lib/gcc-cross/riscv64-linux-gnu/9/include/limits.h:194,
>                      from /usr/lib/gcc-cross/riscv64-linux-gnu/9/include/syslimits.h:7,
>                      from /usr/lib/gcc-cross/riscv64-linux-gnu/9/include/limits.h:34,
>                      from /labs/linux-lab/src/linux-stable/tools/testing/selftests/nolibc/nolibc-test.c:6:
>     /usr/riscv64-linux-gnu/include/bits/wordsize.h:28:3: error: #error "rv32i-based targets are not supported"
>        28 | # error "rv32i-based targets are not supported"
> 
> The glibc commit 5b6113d62efa ("RISC-V: Support the 32-bit ABI
> implementation") fixed up above error, so, glibc >= 2.33 (who includes
> this commit) is required.

It seems weird to require limits.h from the system libc at all.

The only thing used from there are INT_MAX and INT_MIN.
Instead we could define our own versions of INT_MAX and INT_MIN in
stdint.h.

#ifndef INT_MAX
#define INT_MAX __INT_MAX__
#endif

#ifndef INT_MIN
#define INT_MIN (- __INT_MAX__ - 1)
#endif

Thomas