From: Dave Martin <Dave.Martin@arm.com>
To: Szabolcs Nagy <Szabolcs.Nagy@arm.com>
Cc: nd <nd@arm.com>, Will Deacon <Will.Deacon@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Alan Hayward <Alan.Hayward@arm.com>
Subject: Re: [PATCH 0/3] arm64/sve: UAPI: Disentangle ptrace.h from sigcontext.h
Date: Fri, 14 Dec 2018 18:25:18 +0000 [thread overview]
Message-ID: <20181214182518.GH3505@e103592.cambridge.arm.com> (raw)
In-Reply-To: <2abbbd29-cc87-a0ad-80b7-e2a1d039235e@arm.com>
On Fri, Dec 14, 2018 at 06:13:33PM +0000, Szabolcs Nagy wrote:
> On 11/12/2018 19:26, Dave Martin wrote:
> > This patch refactors the UAPI header definitions for the Arm SVE
> > extension to avoid multiple-definition problems when userspace mixes its
> > own sigcontext.h definitions with the kernel's ptrace.h (which is
> > apparently routine).
> >
> > A common backend header is created to hold common definitions, suitably
> > namespaced, and with an appropriate header guard.
> >
> > See the commit message in patch 3 for further explanation of why this
> > is needed.
> >
> > Because of the non-trivial header guard in the new sve_context.h, patch
> > 1 adds support to headers_install.sh to munge #if defined(_UAPI_FOO) in
> > a similar way to the current handling of #ifndef _UAPI_FOO.
> >
>
> thanks for doing this.
>
> the patches fix the gdb build issue on musl libc with an
> additional gdb patch:
> https://sourceware.org/ml/gdb-patches/2018-12/msg00152.html
> (in userspace i'd expect users relying on signal.h providing
> whatever is in asm/sigcontext.h.)
>
> i think sve_context.h could be made to work with direct include,
> even if that's not useful because there is no public api there.
> (and then you dont need the first patch)
My general view is that if you want the sigframe types userspace should
usually include <ucontext.h> and refer to mcontext_t.
Because the prototype for sa_sigaction() specifies a void * for the
ucontext argument, I've generally assumed that <signal.h> is not
sufficient to get ucontext_t (or mcontext_t) (but maybe I'm too paranoid
there).
Non-POSIX-flavoured software might include <asm/sigcontext.h> directly.
In glibc/musl libc will that conflict with <signal.h>, or can the two
coexist?
Cheers
---Dave
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next prev parent reply other threads:[~2018-12-14 18:25 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-11 19:26 [PATCH 0/3] arm64/sve: UAPI: Disentangle ptrace.h from sigcontext.h Dave Martin
2018-12-11 19:26 ` [PATCH 1/3] kbuild: install_headers.sh: Strip _UAPI from #if-defined() guards Dave Martin
2018-12-11 19:26 ` [PATCH 2/3] arm64/sve: ptrace: Fix SVE_PT_REGS_OFFSET definition Dave Martin
2018-12-11 19:26 ` [PATCH 3/3] arm64/sve: Disentangle <uapi/asm/ptrace.h> from <uapi/asm/sigcontext.h> Dave Martin
2018-12-15 9:20 ` kbuild test robot
2018-12-18 12:14 ` Dave Martin
2018-12-19 15:11 ` Szabolcs Nagy
2018-12-19 15:23 ` Dave Martin
2018-12-19 15:26 ` Szabolcs Nagy
2018-12-14 18:13 ` [PATCH 0/3] arm64/sve: UAPI: Disentangle ptrace.h from sigcontext.h Szabolcs Nagy
2018-12-14 18:25 ` Dave Martin [this message]
2018-12-14 19:00 ` Szabolcs Nagy
2018-12-14 19:28 ` Dave P Martin
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