From: Joseph Myers <joseph@codesourcery.com>
To: Florian Weimer <fweimer@redhat.com>
Cc: Nicholas Piggin <npiggin@gmail.com>,
<linuxppc-dev@lists.ozlabs.org>, <libc-alpha@sourceware.org>,
Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
Subject: Re: powerpc Linux scv support and scv system call ABI proposal
Date: Tue, 28 Jan 2020 23:18:00 -0000 [thread overview]
Message-ID: <alpine.DEB.2.21.2001282210470.22424@digraph.polyomino.org.uk> (raw)
In-Reply-To: <87tv4fd8wp.fsf@oldenburg2.str.redhat.com>
On Tue, 28 Jan 2020, Florian Weimer wrote:
> I don't think we can save LR in a regular register around the system
> call, explicitly in the inline asm statement, because we still have to
> generate proper unwinding information using CFI directives, something
> that you cannot do from within the asm statement.
What other architectures in glibc have done for code sequences for
syscalls that are problematic for compiler-generated CFI is made the C
syscall macros call separate functions defined in a .S file (see
sysdeps/unix/sysv/linux/arm/libc-do-syscall.S,
sysdeps/unix/sysv/linux/i386/libc-do-syscall.S,
sysdeps/unix/sysv/linux/mips/mips32/mips-syscall[567].S). I don't know if
you can do that in this case and still get the performance benefits of the
new instruction.
--
Joseph S. Myers
joseph@codesourcery.com
prev parent reply other threads:[~2020-01-28 22:17 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-28 12:56 Nicholas Piggin
2020-01-28 13:58 ` Florian Weimer
2020-01-28 15:40 ` Nicholas Piggin
2020-01-28 15:55 ` Segher Boessenkool
2020-01-28 16:19 ` Florian Weimer
2020-01-28 17:02 ` Dan Horák
2020-01-28 20:38 ` Segher Boessenkool
2020-01-29 16:30 ` Florian Weimer
2020-01-29 16:36 ` Segher Boessenkool
2020-01-29 17:40 ` Florian Weimer
2020-01-29 18:59 ` Segher Boessenkool
2020-01-30 11:03 ` Florian Weimer
2020-01-30 12:04 ` Segher Boessenkool
2020-01-30 12:34 ` Florian Weimer
2020-01-30 14:34 ` Segher Boessenkool
2020-01-30 17:59 ` Adhemerval Zanella
2020-01-30 22:05 ` Segher Boessenkool
2020-01-31 11:33 ` Adhemerval Zanella
2020-01-31 12:12 ` Segher Boessenkool
2020-01-28 16:05 ` Florian Weimer
2020-01-29 11:18 ` Nicholas Piggin
2020-01-28 16:25 ` Adhemerval Zanella
[not found] ` <cd9e4b28-d577-8850-7c2b-a488fcb4740d@linaro.org>
[not found] ` <1580273424.ea818exa2c.astroid@bobo.none>
2020-01-29 16:19 ` Tulio Magno Quites Machado Filho
2020-02-19 11:04 ` Nicholas Piggin
2020-01-28 23:18 ` Joseph Myers [this message]
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