From: Andrey Ryabinin <ryabinin.a.a@gmail.com>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: "Matthias Kaehlcke" <mka@chromium.org>,
"Chris J Arges" <chris.j.arges@canonical.com>,
"Borislav Petkov" <bp@suse.de>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"H . Peter Anvin" <hpa@zytor.com>,
"x86@kernel.org" <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
"Douglas Anderson" <dianders@chromium.org>,
"Michael Davidson" <md@google.com>,
"Greg Hackmann" <ghackmann@google.com>,
"Nick Desaulniers" <ndesaulniers@google.com>,
"Stephen Hines" <srhines@google.com>,
"Kees Cook" <keescook@chromium.org>,
"Arnd Bergmann" <arnd@arndb.de>,
"Bernhard Rosenkränzer" <Bernhard.Rosenkranzer@linaro.org>
Subject: Re: [PATCH] Revert "x86/uaccess: Add stack frame output operand in get_user() inline asm"
Date: Thu, 20 Jul 2017 13:01:39 +0300 [thread overview]
Message-ID: <CAPAsAGyyzLC24cj=-EUE4WGPQ_UQTCJNvWKVUKxPQmJmAtU3HA@mail.gmail.com> (raw)
In-Reply-To: <20170719174630.kz5g553evcrnirmr@treble>
2017-07-19 20:46 GMT+03:00 Josh Poimboeuf <jpoimboe@redhat.com>:
>
> After doing some testing, I don't think this approach is going to work
> after all. In addition to forcing the stack frame, it also causes GCC
> to add an unnecessary extra instruction to the epilogue of each affected
> function:
>
> lea -0x10(%rbp),%rsp
>
> We shouldn't be inserting extra instructions like that. I also don't
> think the other suggestion of turning the '__sp' register variable into
> a global variable is a very good solution either, as that just wastes
> memory for no reason.
>
Wastes memory? How is that wastes memory? That doesn't make any sense.
> It would be nice if both compilers could agree on a way to support this.
>
> --
> Josh
next prev parent reply other threads:[~2017-07-20 10:01 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-12 21:27 [PATCH] Revert "x86/uaccess: Add stack frame output operand in get_user() inline asm" Matthias Kaehlcke
2017-07-12 22:12 ` Josh Poimboeuf
2017-07-12 22:20 ` Matthias Kaehlcke
2017-07-12 22:35 ` Josh Poimboeuf
2017-07-12 22:36 ` Josh Poimboeuf
2017-07-12 23:22 ` Matthias Kaehlcke
2017-07-13 18:00 ` Josh Poimboeuf
2017-07-13 18:47 ` Matthias Kaehlcke
2017-07-13 19:25 ` Josh Poimboeuf
2017-07-13 19:38 ` Michael Davidson
2017-07-13 20:18 ` Josh Poimboeuf
2017-07-13 20:20 ` Andrey Rybainin
2017-07-13 20:34 ` Josh Poimboeuf
2017-07-13 21:12 ` Matthias Kaehlcke
2017-07-13 21:34 ` Josh Poimboeuf
2017-07-13 21:57 ` Matthias Kaehlcke
2017-07-19 17:46 ` Josh Poimboeuf
2017-07-19 21:50 ` Matthias Kaehlcke
2017-07-20 10:01 ` Andrey Ryabinin [this message]
2017-07-20 15:18 ` Josh Poimboeuf
2017-07-20 15:30 ` Andrey Ryabinin
2017-07-20 20:56 ` Josh Poimboeuf
2017-07-21 9:13 ` Andrey Ryabinin
2017-07-21 13:24 ` Josh Poimboeuf
2017-07-29 0:38 ` Matthias Kaehlcke
2017-07-29 0:55 ` Josh Poimboeuf
2017-07-29 0:58 ` Josh Poimboeuf
2017-07-29 1:06 ` Matthias Kaehlcke
2017-07-13 21:14 ` Matthias Kaehlcke
2017-07-13 21:25 ` Andrey Rybainin
2017-07-13 21:43 ` Matthias Kaehlcke
2017-07-13 21:52 ` Josh Poimboeuf
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