From: Jan Beulich <jbeulich@suse.com>
To: Julien Grall <julien@xen.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
George Dunlap <george.dunlap@citrix.com>,
Ian Jackson <iwj@xenproject.org>, Wei Liu <wl@xen.org>,
xen-devel@lists.xenproject.org, Juergen Gross <jgross@suse.com>
Subject: Re: [PATCH v6 1/3] xen/arm: add support for run_in_exception_handler()
Date: Thu, 21 Jan 2021 08:55:27 +0100 [thread overview]
Message-ID: <9437a37b-a32c-c8c9-a539-fcc1ac3bfc3d@suse.com> (raw)
In-Reply-To: <4e8cc6e6-dc55-6dda-ffbc-6487e45d5aaf@xen.org>
On 20.01.2021 19:20, Julien Grall wrote:
> On 16/01/2021 10:33, Juergen Gross wrote:
>> Add support to run a function in an exception handler for Arm. Do it
>> as on x86 via a bug_frame, but pass the function pointer via a
>> register (this needs to be done that way, because inline asm support
>> for 32-bit Arm lacks the needed functionality to reference an
>> arbitrary function via the bugframe).
>
> I was going to commit the series, but then realized the commit message
> and comment needs some tweaking because technically GCC is supporting
> 'i' (I managed to get it working with -fno-pie).
>
> So how about:
>
> "This is needed to be done that way because GCC complains about invalid
> constraint when using a function pointer with "i" and PIE is enabled
> (default on most of GCC shipped with distro). Clang happily accepts it,
> so it may be a bug in GCC."
May I ask why you think it's a bug in gcc? I'd rather consider it
a bug in clang. Taking the address of a symbol doesn't yield a
constant in PIC or PIE code, aiui.
Jan
next prev parent reply other threads:[~2021-01-21 7:55 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-16 10:33 [PATCH v6 0/3] xen: add support for automatic debug key actions in case of crash Juergen Gross
2021-01-16 10:33 ` [PATCH v6 1/3] xen/arm: add support for run_in_exception_handler() Juergen Gross
2021-01-16 17:19 ` Julien Grall
2021-01-16 19:05 ` Jürgen Groß
2021-01-17 17:55 ` Julien Grall
2021-01-20 18:20 ` Julien Grall
2021-01-20 18:34 ` Jürgen Groß
2021-01-21 7:55 ` Jan Beulich [this message]
2021-01-21 8:00 ` Jürgen Groß
2021-01-21 8:56 ` Jan Beulich
2021-01-21 9:50 ` Julien Grall
2021-01-21 10:06 ` Jan Beulich
2021-01-23 11:28 ` Julien Grall
2021-01-16 10:33 ` [PATCH v6 2/3] xen: enable keyhandlers to work without register set specified Juergen Gross
2021-01-20 18:09 ` Julien Grall
2021-01-16 10:33 ` [PATCH v6 3/3] xen: add support for automatic debug key actions in case of crash Juergen Gross
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