From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Boqun Feng <boqun.feng@gmail.com>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
Michael Jeanson <mjeanson@efficios.com>
Subject: Re: Failure to build librseq on ppc
Date: Thu, 9 Jul 2020 09:43:47 -0400 (EDT) [thread overview]
Message-ID: <1769596686.6365.1594302227962.JavaMail.zimbra@efficios.com> (raw)
In-Reply-To: <20200709001837.GD3598@gate.crashing.org>
----- On Jul 8, 2020, at 8:18 PM, Segher Boessenkool segher@kernel.crashing.org wrote:
> On Wed, Jul 08, 2020 at 08:01:23PM -0400, Mathieu Desnoyers wrote:
>> > > #define RSEQ_ASM_OP_CMPEQ(var, expect, label)
>> > > \
>> > > LOAD_WORD "%%r17, %[" __rseq_str(var) "]\n\t" \
>> >
>> > The way this hardcodes r17 *will* break, btw. The compiler will not
>> > likely want to use r17 as long as your code (after inlining etc.!) stays
>> > small, but there is Murphy's law.
>>
>> r17 is in the clobber list, so it should be ok.
>
> What protects r17 *after* this asm statement?
As discussed in the other leg of the thread (with the code example),
r17 is in the clobber list of all asm statements using this macro, and
is used as a temporary register within each inline asm.
Thanks,
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
next prev parent reply other threads:[~2020-07-09 13:46 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-07 19:17 Failure to build librseq on ppc Mathieu Desnoyers
2020-07-08 0:59 ` Segher Boessenkool
2020-07-08 12:27 ` Michael Ellerman
2020-07-08 23:53 ` Segher Boessenkool
2020-07-09 0:01 ` Mathieu Desnoyers
2020-07-09 0:18 ` Segher Boessenkool
2020-07-09 13:43 ` Mathieu Desnoyers [this message]
2020-07-09 17:37 ` Segher Boessenkool
2020-07-09 17:42 ` Mathieu Desnoyers
2020-07-09 17:56 ` Mathieu Desnoyers
2020-07-09 20:46 ` Segher Boessenkool
2020-07-09 20:57 ` Mathieu Desnoyers
2020-07-09 20:31 ` Segher Boessenkool
2020-07-08 12:33 ` Mathieu Desnoyers
2020-07-08 14:00 ` Mathieu Desnoyers
2020-07-08 14:21 ` Christophe Leroy
2020-07-08 14:32 ` Mathieu Desnoyers
2020-07-08 16:11 ` Christophe Leroy
2020-07-09 0:15 ` Segher Boessenkool
2020-07-09 0:10 ` Segher Boessenkool
2020-07-09 13:33 ` Mathieu Desnoyers
2020-07-09 17:31 ` Segher Boessenkool
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