From: Mark Rutland <mark.rutland@arm.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-arch <linux-arch@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Kees Cook <keescook@chromium.org>,
Andrew Lutomirski <luto@kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 3/3] thread_info: include <current.h> for THREAD_INFO_IN_TASK
Date: Fri, 28 Oct 2016 11:48:06 +0100 [thread overview]
Message-ID: <20161028104806.GF5806@leverpostej> (raw)
In-Reply-To: <CALCETrUqApnWBwFPwkToTp1_Wm68tbPAW=UH+X5mZrNS+3rHjA@mail.gmail.com>
On Thu, Oct 27, 2016 at 04:13:49PM -0700, Andy Lutomirski wrote:
> On Wed, Oct 19, 2016 at 11:28 AM, Mark Rutland <mark.rutland@arm.com> wrote:
> > When CONFIG_THREAD_INFO_IN_TASK is selected, the current_thread_info()
> > macro relies on current having been defined prior to its use. However,
> > not all users of current_thread_info() include <asm/current.h>, and thus
> > current is not guaranteed to be defined.
> >
> > When CONFIG_THREAD_INFO_IN_TASK is not selected, it's possible that
> > get_current() / current are based upon current_thread_info(), and
> > <asm/current.h> includes <asm/thread_info.h>. Thus always including
> > <asm/current.h> would result in circular dependences on some platforms.
> >
> > To ensure both cases work, this patch includes <asm/current.h>, but only
> > when CONFIG_THREAD_INFO_IN_TASK is selected.
>
> Reviewed-by: Andy Lutomirski <luto@kernel.org>
Cheers!
> although it would be nice if you moved your description of why the
> include is conditional into a comment.
Agreed. I've folded in the below:
#ifdef CONFIG_THREAD_INFO_IN_TASK
/*
* For CONFIG_THREAD_INFO_IN_TASK kernels we need <asm/current.h> for the
* definition of current, but for !CONFIG_THREAD_INFO_IN_TASK kernels,
* including <asm/current.h> can cause a circular dependency on some platforms.
*/
#include <asm/current.h>
#define current_thread_info() ((struct thread_info *)current)
#endif
Thanks,
Mark.
next prev parent reply other threads:[~2016-10-28 10:48 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-19 18:28 [PATCH 0/3] THREAD_INFO_IN_TASK prep work for arm64+s390 Mark Rutland
2016-10-19 18:28 ` [PATCH 1/3] sched/core,x86: make struct thread_info arch specific again Mark Rutland
2016-10-19 18:28 ` Mark Rutland
2016-10-19 23:19 ` Andy Lutomirski
2016-10-20 6:40 ` Ingo Molnar
2016-10-20 9:33 ` Mark Rutland
2016-10-19 18:28 ` [PATCH 2/3] thread_info: factor out restart_block Mark Rutland
2016-10-19 18:28 ` Mark Rutland
2016-10-19 23:31 ` Andy Lutomirski
2016-10-24 9:45 ` Mark Rutland
2016-10-19 18:28 ` [PATCH 3/3] thread_info: include <current.h> for THREAD_INFO_IN_TASK Mark Rutland
2016-10-19 18:28 ` Mark Rutland
2016-10-20 10:29 ` Heiko Carstens
2016-10-24 9:49 ` Mark Rutland
2016-10-27 23:13 ` Andy Lutomirski
2016-10-27 23:13 ` Andy Lutomirski
2016-10-28 10:48 ` Mark Rutland [this message]
2016-10-24 10:12 ` [PATCH 0/3] THREAD_INFO_IN_TASK prep work for arm64+s390 Mark Rutland
2016-10-24 10:12 ` Mark Rutland
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