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From: Willy Tarreau <w@1wt.eu>
To: Zhangjin Wu <falcon@tinylab.org>
Cc: thomas@t-8ch.de, arnd@arndb.de, david.laight@aculab.com,
	linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	linux-riscv@lists.infradead.org
Subject: Re: [PATCH v5 07/14] tools/nolibc: arch-loongarch.h: shrink with SYSCALL_CLOBBERLIST
Date: Sun, 2 Jul 2023 20:50:59 +0200	[thread overview]
Message-ID: <20230702185059.GG16233@1wt.eu> (raw)
In-Reply-To: <a906a8e5bb39d88fee89be8f2bca8bf62307d468.1687957589.git.falcon@tinylab.org>

On Wed, Jun 28, 2023 at 09:22:21PM +0800, Zhangjin Wu wrote:
> my_syscall<N> share a same long clobber list, define a macro for them.
> 
> Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
> ---
>  tools/include/nolibc/arch-loongarch.h | 25 +++++++++++--------------
>  1 file changed, 11 insertions(+), 14 deletions(-)
> 
> diff --git a/tools/include/nolibc/arch-loongarch.h b/tools/include/nolibc/arch-loongarch.h
> index 292d6a58dc87..fbb4844f7993 100644
> --- a/tools/include/nolibc/arch-loongarch.h
> +++ b/tools/include/nolibc/arch-loongarch.h
> @@ -23,6 +23,10 @@
>   */
>  #define __ARCH_WANT_SYS_PSELECT6
>  
> +#define SYSCALL_CLOBBERLIST			\
> +	"memory", "$t0", "$t1", "$t2", "$t3",	\
> +	"$t4", "$t5", "$t6", "$t7", "$t8"
> +

That's a good idea, but please be careful when adding macro definitions,
we're in code that is used by user space we have no control on, and we're
polluting the end user's macro namespace with plenty of names. While one
could argue that it's unlikely that some program already defines and uses
SYSCALL_CLOBBERLIST, actually with low-level code it's fairly possible.

Till now most of the definitions were for stuff that user-space really
needs (e.g. STDIN_FILENO, various integer limits). If we start to declare
random macros for internal use, at least we should probably prefix them
with _NOLIBC_ or something like this to avoid the risk of collision.

Willy

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  reply	other threads:[~2023-07-02 18:51 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-19 15:40 [PATCH v4 00/10] tools/nolibc: add a new syscall helper Zhangjin Wu
2023-06-19 15:41 ` [PATCH v4 01/10] tools/nolibc: sys.h: add a syscall return helper Zhangjin Wu
2023-06-19 15:42 ` [PATCH v4 02/10] tools/nolibc: unistd.h: apply __sysret() helper Zhangjin Wu
2023-06-19 15:44 ` [PATCH v4 03/10] tools/nolibc: sys.h: " Zhangjin Wu
2023-06-19 15:45 ` [PATCH v4 04/10] tools/nolibc: unistd.h: reorder the syscall macros Zhangjin Wu
2023-06-19 15:47 ` [PATCH v4 05/10] tools/nolibc: add missing my_syscall6() for mips Zhangjin Wu
2023-06-19 15:48 ` [PATCH v4 06/10] tools/nolibc: __sysret: support syscalls who return a pointer Zhangjin Wu
2023-06-19 15:51 ` [PATCH v4 07/10] tools/nolibc: clean up mmap() support Zhangjin Wu
2023-06-21 18:48   ` Thomas Weißschuh
2023-06-22 19:08     ` Zhangjin Wu
2023-06-19 15:52 ` [PATCH v4 08/10] selftests/nolibc: add EXPECT_PTREQ, EXPECT_PTRNE and EXPECT_PTRER Zhangjin Wu
2023-06-19 15:54 ` [PATCH v4 09/10] selftests/nolibc: add sbrk_0 to test current brk getting Zhangjin Wu
2023-06-19 15:55 ` [PATCH v4 10/10] selftests/nolibc: add mmap and munmap test cases Zhangjin Wu
2023-06-19 16:14   ` Zhangjin Wu
2023-06-21 18:58   ` Thomas Weißschuh
2023-06-22 19:32     ` Zhangjin Wu
2023-06-22 19:56       ` Thomas Weißschuh
2023-06-24  7:47         ` Zhangjin Wu
2023-06-28 13:07 ` [PATCH v5 00/14] tools/nolibc: add a new syscall helper Zhangjin Wu
2023-06-28 13:08   ` [PATCH v5 01/14] tools/nolibc: sys.h: add a syscall return helper Zhangjin Wu
2023-06-28 13:11   ` [PATCH v5 02/14] tools/nolibc: unistd.h: apply __sysret() helper Zhangjin Wu
2023-06-28 13:13   ` [PATCH v5 03/14] tools/nolibc: sys.h: " Zhangjin Wu
2023-06-28 13:14   ` [PATCH v5 04/14] tools/nolibc: unistd.h: reorder the syscall macros Zhangjin Wu
2023-06-28 13:17   ` [PATCH v5 05/14] tools/nolibc: string.h: clean up multiple whitespaces with tab Zhangjin Wu
2023-06-28 13:19   ` [PATCH v5 06/14] tools/nolibc: arch-*.h: clean up multiple whitespaces Zhangjin Wu
2023-07-02 18:44     ` Willy Tarreau
2023-07-03 14:02       ` Zhangjin Wu
2023-06-28 13:22   ` [PATCH v5 07/14] tools/nolibc: arch-loongarch.h: shrink with SYSCALL_CLOBBERLIST Zhangjin Wu
2023-07-02 18:50     ` Willy Tarreau [this message]
2023-07-03 11:28       ` Zhangjin Wu
2023-06-28 13:31   ` [PATCH v5 08/14] tools/nolibc: arch-mips.h: " Zhangjin Wu
2023-06-28 13:37   ` [PATCH v5 09/14] tools/nolibc: add missing my_syscall6() for mips Zhangjin Wu
2023-07-02 18:55     ` Willy Tarreau
2023-07-03 10:13       ` Zhangjin Wu
2023-06-28 13:39   ` [PATCH v5 10/14] tools/nolibc: __sysret: support syscalls who return a pointer Zhangjin Wu
2023-07-02 19:17     ` Willy Tarreau
2023-07-03  8:36       ` Zhangjin Wu
2023-07-03 10:03         ` Willy Tarreau
2023-07-03 11:15           ` Zhangjin Wu
2023-06-28 13:41   ` [PATCH v5 11/14] tools/nolibc: clean up mmap() support Zhangjin Wu
2023-07-02 19:23     ` Willy Tarreau
2023-07-03  6:51       ` Zhangjin Wu
2023-06-28 13:44   ` [PATCH v5 12/14] selftests/nolibc: add EXPECT_PTREQ, EXPECT_PTRNE and EXPECT_PTRER Zhangjin Wu
2023-06-28 13:46   ` [PATCH v5 13/14] selftests/nolibc: add sbrk_0 to test current brk getting Zhangjin Wu
2023-06-28 13:51   ` [PATCH v5 14/14] selftests/nolibc: add mmap and munmap test cases Zhangjin Wu
2023-07-02 19:33     ` Willy Tarreau
2023-07-03  6:03       ` Zhangjin Wu
2023-07-03  7:25         ` Willy Tarreau
2023-07-03  8:06           ` Zhangjin Wu
2023-07-03  8:20             ` Thomas Weißschuh
2023-07-03  9:15               ` Zhangjin Wu
2023-07-03  9:56             ` Willy Tarreau
2023-07-03 11:24               ` Zhangjin Wu
2023-07-02 19:34   ` [PATCH v5 00/14] tools/nolibc: add a new syscall helper Willy Tarreau

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