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From: Ammar Faizi <[email protected]>
To: Willy Tarreau <[email protected]>
Cc: David Laight <[email protected]>,
	"Paul E. McKenney" <[email protected]>,
	Alviro Iskandar Setiawan <[email protected]>,
	Nugraha <[email protected]>,
	Linux Kernel Mailing List <[email protected]>,
	GNU/Weeb Mailing List <[email protected]>,
	"[email protected]" <[email protected]>,
	"[email protected]" <[email protected]>
Subject: Re: [RFC PATCH v2 3/8] tools/nolibc: i386: Implement syscall with 6 arguments
Date: Tue, 22 Mar 2022 20:37:03 +0700	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

On 3/22/22 8:34 PM, Willy Tarreau wrote:
>> I turned out GCC refuses to use "rm" if we compile without -fomit-frame-pointer
>> (e.g. without optimization / -O0). So I will still use "m" here.
> 
> OK that's fine. then you can probably simplify it like this:
> 
>        long _arg6 = (long)(arg6); /* Might be in memory */    \
>                                                               \
>        asm volatile (                                         \
>            "pushl  %%ebp\n\t"                                 \
>            "movl   %[_arg6], %%ebp\n\t"                       \
>            "int    $0x80\n\t"                                 \
>            "popl   %%ebp\n\t"                                 \
>            : "=a"(_ret)                                       \
>            : "r"(_num), "r"(_arg1), "r"(_arg2), "r"(_arg3),   \
>              "r"(_arg4),"r"(_arg5), [_arg6]"m"(_arg6)        \
>            : "memory", "cc"                                   \
>        );                                                     \
> 
> See ? no more push, no more addl, direct load from memory.

Uggh... I crafted the same code like you suggested before, but then
I realized it's buggy, it's buggy because %[_arg6] may live in N(%esp).

When you pushl %ebp, the %esp changes, N(%esp) no longer points to the
6-th argument.

-- 
Ammar Faizi

  reply	other threads:[~2022-03-22 13:37 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-22 10:21 [RFC PATCH v2 0/8] Add dynamic memory allocator support for nolibc Ammar Faizi
2022-03-22 10:21 ` [RFC PATCH v2 1/8] tools/nolibc: x86-64: Update System V ABI document link Ammar Faizi
2022-03-22 10:21 ` [RFC PATCH v2 2/8] tools/nolibc: Remove .global _start from the entry point code Ammar Faizi
2022-03-22 17:09   ` Nick Desaulniers
2022-03-22 17:25     ` Willy Tarreau
2022-03-22 17:30       ` Nick Desaulniers
2022-03-22 17:58         ` Willy Tarreau
2022-03-22 18:07           ` Nick Desaulniers
2022-03-22 18:24             ` Willy Tarreau
2022-03-22 18:38               ` Nick Desaulniers
2022-03-22 10:21 ` [RFC PATCH v2 3/8] tools/nolibc: i386: Implement syscall with 6 arguments Ammar Faizi
2022-03-22 10:57   ` David Laight
2022-03-22 11:23     ` Willy Tarreau
2022-03-22 11:39   ` David Laight
2022-03-22 12:02     ` Ammar Faizi
2022-03-22 12:07       ` Ammar Faizi
2022-03-22 12:13       ` Willy Tarreau
2022-03-22 13:26         ` Ammar Faizi
2022-03-22 13:34           ` Willy Tarreau
2022-03-22 13:37             ` Ammar Faizi [this message]
2022-03-22 13:39               ` David Laight
2022-03-22 13:41                 ` Willy Tarreau
2022-03-22 13:45                   ` Ammar Faizi
2022-03-22 13:54                     ` Ammar Faizi
2022-03-22 13:56                       ` Ammar Faizi
2022-03-22 14:02                         ` Willy Tarreau
2022-03-22 13:37         ` David Laight
2022-03-22 14:47           ` Alviro Iskandar Setiawan
2022-03-22 15:11             ` David Laight
2022-03-23  6:29           ` Ammar Faizi
2022-03-23  6:32             ` Ammar Faizi
2022-03-23  7:10             ` Willy Tarreau
2022-03-22 10:21 ` [RFC PATCH v2 4/8] tools/nolibc/sys: Implement `mmap()` and `munmap()` Ammar Faizi
2022-03-22 10:21 ` [RFC PATCH v2 5/8] tools/nolibc/types: Implement `offsetof()` and `container_of()` macro Ammar Faizi
2022-03-22 10:21 ` [RFC PATCH v2 6/8] tools/nolibc/stdlib: Implement `malloc()`, `calloc()`, `realloc()` and `free()` Ammar Faizi
2022-03-22 11:52   ` David Laight
2022-03-22 12:18     ` Ammar Faizi
2022-03-22 12:36       ` Alviro Iskandar Setiawan
2022-03-22 12:42         ` Ammar Faizi
2022-03-22 12:21     ` Willy Tarreau
2022-03-22 10:21 ` [RFC PATCH v2 7/8] tools/nolibc/string: Implement `strnlen()` Ammar Faizi
2022-03-22 10:21 ` [RFC PATCH v2 8/8] tools/include/string: Implement `strdup()` and `strndup()` Ammar Faizi
2022-03-22 11:27 ` [RFC PATCH v2 0/8] Add dynamic memory allocator support for nolibc Willy Tarreau
2022-03-22 12:43   ` Ammar Faizi

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