From: Ammar Faizi <[email protected]>
To: Alviro Iskandar Setiawan <[email protected]>
Cc: Willy Tarreau <[email protected]>, "Paul E. McKenney" <[email protected]>,
Nugraha <[email protected]>,
Linux Kernel Mailing List <[email protected]>,
GNU/Weeb Mailing List <[email protected]>,
[email protected], [email protected],
David Laight <[email protected]>
Subject: Re: [RFC PATCH v1 3/6] tools/nolibc: i386: Implement syscall with 6 arguments
Date: Sun, 20 Mar 2022 22:09:00 +0700 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAOG64qPyXS-NVE6wV2fs8ho5B88ziZrO9mL3cgZrLRqf6tmmQA@mail.gmail.com>
On 3/20/22 5:42 PM, Alviro Iskandar Setiawan wrote:
> On Sun, Mar 20, 2022 at 5:33 PM Alviro Iskandar Setiawan wrote:
[...]
>> I don't think you can safely use redzone from inline Assembly. The
>> compiler may also use redzone for a leaf function. In case the syscall
>> is done at the same time, your %ebp saving will clobber the redzone
>> that the compiler uses.
It turned out we don't have a redzone for 32-bit.
>>
>> -4(%esp) may be used by the compiler on a leaf call, you can't clobber that.
Yeah, this is still wrong even with a redzone.
> Using xchgl to preserve %ebp in the same place where the arg6 is
> stored in memory is a better solution and doesn't clobber anything.
>
> xchgl %ebp, %[arg6]
> int $0x80
> xchgl %ebp, %[arg6]
Addressed your review in my response to David.
Thanks!
--
Ammar Faizi
next prev parent reply other threads:[~2022-03-20 15:09 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-20 9:37 [RFC PATCH v1 0/6] Add dynamic memory allocator support for nolibc Ammar Faizi
2022-03-20 9:37 ` [RFC PATCH v1 1/6] tools/nolibc: x86-64: Update System V ABI document link Ammar Faizi
2022-03-20 9:37 ` [RFC PATCH v1 2/6] tools/nolibc: Make the entry point not weak for clang Ammar Faizi
2022-03-20 19:16 ` Willy Tarreau
2022-03-21 11:38 ` Ammar Faizi
2022-03-21 17:27 ` Nick Desaulniers
2022-03-20 9:37 ` [RFC PATCH v1 3/6] tools/nolibc: i386: Implement syscall with 6 arguments Ammar Faizi
2022-03-20 10:33 ` Alviro Iskandar Setiawan
2022-03-20 10:42 ` Alviro Iskandar Setiawan
2022-03-20 15:09 ` Ammar Faizi [this message]
2022-03-20 13:10 ` David Laight
2022-03-20 14:01 ` Willy Tarreau
2022-03-20 15:04 ` Ammar Faizi
2022-03-20 18:22 ` David Laight
2022-03-20 9:37 ` [RFC PATCH v1 4/6] tools/nolibc/sys: Implement `mmap()` and `munmap()` Ammar Faizi
2022-03-20 9:37 ` [RFC PATCH v1 5/6] tools/nolibc/stdlib: Implement `malloc()`, `calloc()`, `realloc()` and `free()` Ammar Faizi
2022-03-20 15:50 ` Alviro Iskandar Setiawan
2022-03-20 16:10 ` Ammar Faizi
2022-03-20 16:16 ` Willy Tarreau
2022-03-20 16:36 ` Ammar Faizi
2022-03-20 16:46 ` Willy Tarreau
2022-03-20 9:37 ` [RFC PATCH v1 6/6] tools/include/string: Implement `strdup()` and `strndup()` Ammar Faizi
2022-03-20 15:55 ` Alviro Iskandar Setiawan
2022-03-20 16:10 ` Ammar Faizi
2022-03-21 7:53 ` Willy Tarreau
2022-03-21 8:16 ` Alviro Iskandar Setiawan
2022-03-21 8:51 ` Willy Tarreau
2022-03-21 11:36 ` Ammar Faizi
2022-03-21 11:43 ` Willy Tarreau
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