From: Will Deacon <will@kernel.org>
To: Szabolcs Nagy <szabolcs.nagy@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
linux-arm-kernel@lists.infradead.org,
Tamas Zsoldos <tamas.zsoldos@arm.com>
Subject: Re: arm64 vdso might miss .eh_frame
Date: Tue, 28 Apr 2020 08:34:35 +0100 [thread overview]
Message-ID: <20200428073435.GC4049@willie-the-truck> (raw)
In-Reply-To: <20200415092336.GK987@arm.com>
On Wed, Apr 15, 2020 at 10:23:36AM +0100, Szabolcs Nagy wrote:
> On aarch64 linux gcc uses -fasynchronous-unwind-tables -funwind-tables
> by default since gcc-8, so now the de facto platform ABI is to allow
> unwinding from async signal handlers.
>
> However on bare metal targets (aarch64-none-elf), and on old gcc,
> async and sync unwind tables are not enabled by default to avoid
> runtime memory costs.
>
> This means if linux is built with a baremetal toolchain the vdso.so
> may not have unwind tables which breaks our (undocumented) platform
> ABI guarantee in userspace. So adding -fasynchronous-unwind-tables
> explicitly to the vgettimeofday.o cflags would be nice (the other
> objects in the vdso seem to be asm).
>
> There was also a report that android clang built linux vdso.so lacks
> .eh_frame completely, that may be a missing --eh-frame-hdr or different
> platform ABI on android, Tamas on cc may be able to verify this.
Vincenzo? Looks like this is a regression caused by the move to C -- please
can you take a look?
Will
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-04-28 7:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-15 9:23 arm64 vdso might miss .eh_frame Szabolcs Nagy
2020-04-28 7:34 ` Will Deacon [this message]
2020-04-28 10:54 ` Vincenzo Frascino
2020-04-28 11:11 ` Mark Rutland
2020-04-28 11:15 ` Vincenzo Frascino
2020-04-28 11:58 ` Will Deacon
2020-04-28 13:40 ` Vincenzo Frascino
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=20200428073435.GC4049@willie-the-truck \
--to=will@kernel.org \
--cc=catalin.marinas@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=mark.rutland@arm.com \
--cc=szabolcs.nagy@arm.com \
--cc=tamas.zsoldos@arm.com \
--cc=vincenzo.frascino@arm.com \
/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