From: Michael Ellerman <mpe@ellerman.id.au>
To: Segher Boessenkool <segher@kernel.crashing.org>,
Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Ard Biesheuvel <ardb@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
"Jason A . Donenfeld" <Jason@zx2c4.com>,
Eric Biggers <ebiggers@kernel.org>,
Nicholas Piggin <npiggin@gmail.com>,
Naveen N Rao <naveen@kernel.org>,
Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Theodore Ts'o <tytso@mit.edu>,
Andrew Morton <akpm@linux-foundation.org>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
shuah <shuah@kernel.org>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org,
Linux-Arch <linux-arch@vger.kernel.org>,
linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org,
linux-kselftest@vger.kernel.org
Subject: Re: [PATCH v2 05/17] vdso: Avoid call to memset() by getrandom
Date: Fri, 30 Aug 2024 20:01:58 +1000 [thread overview]
Message-ID: <87jzfye3c9.fsf@mail.lhotse> (raw)
In-Reply-To: <20240829180241.GJ29862@gate.crashing.org>
Segher Boessenkool <segher@kernel.crashing.org> writes:
> On Thu, Aug 29, 2024 at 07:36:38PM +0200, Christophe Leroy wrote:
>>
>>
>> Le 28/08/2024 à 19:25, Segher Boessenkool a écrit :
>> >
>> >>Not sure about static binaries, though: do those even use the VDSO?
>> >
>> >With "static binary" people usually mean "a binary not using any DSOs",
>> >I think the VDSO is a DSO, also in this respect? As always, -static
>> >builds are *way* less problematic (and faster and smaller :-) )
>> >
>>
>> AFAIK on powerpc even static binaries use the vDSO, otherwise signals
>> don't work.
>
> How can that work? Non-dynamic binaries do not use ld.so (that is the
> definition of a dynamic binary, even). So they cannot link (at runtime)
> to any DSO (unless that is done manually?!)
At least for signals I don't think the application needs to know
anything about the VDSO. The kernel sets up the return to the signal
trampoline (in the VDSO), and as long as userspace returns from its
signal handler with blr it will land back on the trampoline.
cheers
next prev parent reply other threads:[~2024-08-30 10:02 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-22 7:13 [PATCH v2 00/17] Wire up getrandom() vDSO implementation on powerpc Christophe Leroy
2024-08-22 7:13 ` [PATCH v2 01/17] asm-generic/unaligned.h: Extract common header for vDSO Christophe Leroy
2024-08-26 7:20 ` Jason A. Donenfeld
2024-08-26 7:32 ` Christophe Leroy
2024-08-22 7:13 ` [PATCH v2 02/17] vdso: Clean header inclusion in getrandom Christophe Leroy
2024-08-26 8:07 ` Jason A. Donenfeld
2024-08-26 8:37 ` Christophe Leroy
2024-08-26 8:58 ` Jason A. Donenfeld
2024-08-26 10:45 ` Christophe Leroy
2024-08-26 13:17 ` Jason A. Donenfeld
2024-08-26 13:24 ` Thomas Gleixner
2024-08-22 7:13 ` [PATCH v2 03/17] vdso: Add __arch_get_k_vdso_rng_data() Christophe Leroy
2024-08-26 7:24 ` Jason A. Donenfeld
2024-08-22 7:13 ` [PATCH v2 04/17] vdso: Add missing c-getrandom-y in Makefile Christophe Leroy
2024-08-26 7:40 ` Jason A. Donenfeld
2024-08-22 7:13 ` [PATCH v2 05/17] vdso: Avoid call to memset() by getrandom Christophe Leroy
2024-08-26 8:01 ` Jason A. Donenfeld
2024-08-27 18:08 ` Eric Biggers
2024-08-27 18:22 ` Jason A. Donenfeld
2024-08-27 22:53 ` Segher Boessenkool
2024-08-28 11:18 ` Jason A. Donenfeld
2024-08-28 12:24 ` Arnd Bergmann
2024-08-28 12:26 ` Jason A. Donenfeld
2024-08-28 12:51 ` Segher Boessenkool
2024-08-28 12:45 ` Segher Boessenkool
2024-08-28 15:40 ` Ard Biesheuvel
2024-08-28 16:20 ` Segher Boessenkool
2024-08-28 17:12 ` Ard Biesheuvel
2024-08-28 17:25 ` Segher Boessenkool
2024-08-29 17:36 ` Christophe Leroy
2024-08-29 18:02 ` Segher Boessenkool
2024-08-29 18:50 ` Christophe Leroy
2024-08-30 10:01 ` Michael Ellerman [this message]
2024-08-28 12:33 ` Segher Boessenkool
2024-08-28 12:51 ` Jason A. Donenfeld
2024-08-22 7:13 ` [PATCH v2 06/17] vdso: Change getrandom's generation to unsigned long Christophe Leroy
2024-08-26 7:50 ` Jason A. Donenfeld
2024-08-26 8:01 ` Christophe Leroy
2024-08-26 8:16 ` Jason A. Donenfeld
2024-08-26 9:43 ` Thomas Gleixner
2024-08-26 9:48 ` Jason A. Donenfeld
2024-08-26 10:20 ` LEROY Christophe
2024-08-22 7:13 ` [PATCH v2 07/17] mm: Define VM_DROPPABLE for powerpc/32 Christophe Leroy
2024-08-26 9:53 ` kernel test robot
2024-08-26 10:13 ` kernel test robot
2024-08-26 21:34 ` kernel test robot
2024-08-22 7:13 ` [PATCH v2 08/17] powerpc: Add little endian variants of LWZX_BE and STWX_BE Christophe Leroy
2024-08-22 7:13 ` [PATCH v2 09/17] powerpc/vdso32: Add crtsavres Christophe Leroy
2024-08-22 7:13 ` [PATCH v2 10/17] powerpc/vdso: Refactor CFLAGS for CVDSO build Christophe Leroy
2024-08-22 7:13 ` [PATCH v2 11/17] powerpc/vdso: Wire up getrandom() vDSO implementation Christophe Leroy
2024-08-22 7:13 ` [PATCH v2 12/17] selftests: vdso: Fix powerpc64 vdso_config Christophe Leroy
2024-08-22 7:13 ` [PATCH v2 13/17] selftests: vdso: Don't hard-code location of vDSO sources Christophe Leroy
2024-08-26 7:26 ` Jason A. Donenfeld
2024-08-22 7:13 ` [PATCH v2 14/17] selftests: vdso: Make test_vdso_getrandom look for the right vDSO function Christophe Leroy
2024-08-26 7:28 ` Jason A. Donenfeld
2024-08-26 7:35 ` LEROY Christophe
2024-08-22 7:13 ` [PATCH v2 15/17] selftests: vdso: Fix build of test_vdso_chacha Christophe Leroy
2024-08-26 7:33 ` Jason A. Donenfeld
2024-08-22 7:13 ` [PATCH v2 16/17] selftests: vdso: Make VDSO function call more generic Christophe Leroy
2024-08-26 7:37 ` Jason A. Donenfeld
2024-08-26 7:48 ` LEROY Christophe
2024-08-22 7:13 ` [PATCH v2 17/17] selftests: vdso: Add support for vdso_test_random for powerpc Christophe Leroy
2024-08-26 7:19 ` [PATCH v2 00/17] Wire up getrandom() vDSO implementation on powerpc Jason A. Donenfeld
2024-08-26 8:23 ` Jason A. Donenfeld
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87jzfye3c9.fsf@mail.lhotse \
--to=mpe@ellerman.id.au \
--cc=Jason@zx2c4.com \
--cc=akpm@linux-foundation.org \
--cc=ardb@kernel.org \
--cc=arnd@arndb.de \
--cc=bp@alien8.de \
--cc=christophe.leroy@csgroup.eu \
--cc=dave.hansen@linux.intel.com \
--cc=ebiggers@kernel.org \
--cc=hpa@zytor.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-trace-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=luto@kernel.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=mhiramat@kernel.org \
--cc=mingo@redhat.com \
--cc=naveen@kernel.org \
--cc=npiggin@gmail.com \
--cc=rostedt@goodmis.org \
--cc=segher@kernel.crashing.org \
--cc=shuah@kernel.org \
--cc=tglx@linutronix.de \
--cc=tytso@mit.edu \
--cc=vincenzo.frascino@arm.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).