From: Michael Ellerman <mpe@ellerman•id.au>
To: David Long <dave.long@linaro•org>
Cc: Rob Herring <robherring2@gmail•com>,
"H. Peter Anvin" <hpa@zytor•com>,
Andy Lutomirski <luto@amacapital•net>,
Anton Blanchard <anton@samba•org>,
Behan Webster <behanw@converseincode•com>,
Benjamin Herrenschmidt <benh@kernel•crashing.org>,
Eric Paris <eparis@redhat•com>,
Heiko Carstens <heiko.carstens@de•ibm.com>,
Ingo Molnar <mingo@redhat•com>, Jan Willeke <willeke@de•ibm.com>,
Kees Cook <keescook@chromium•org>,
Martin Schwidefsky <schwidefsky@de•ibm.com>,
Nikolay Borisov <Nikolay.Borisov@arm•com>,
Oleg Nesterov <oleg@redhat•com>,
Paul Mackerras <paulus@samba•org>,
Richard Kuo <rkuo@codeaurora•org>,
Robert Richter <rric@kernel•org>,
Roland McGrath <roland@hack•frob.com>,
Russell King <linux@arm•linux.org.uk>, Tejun Heo <tj@kernel•org>,
Thomas Gleixner <tglx@linutronix•de>,
Will Deacon <will.deacon@arm•com>,
"linux-arm-kernel@lists•infradead.org"
<linux-arm-kernel@lists•infradead.org>,
linux-hexagon@vger•kernel.org,
"linux-kernel@vger•kernel.org" <linux-kernel@vger•kernel.org>,
linux-s390@vger•kernel.org, SH-Linux <linux-sh@vger•kernel.org>,
linux390@de•ibm.com, linuxppc-dev <linuxppc-dev@lists•ozlabs.org>,
"x86@kernel•org" <x86@kernel•org>
Subject: Re: [PATCH 1/2] Move the pt_regs_offset struct definition from arch to common include file
Date: Wed, 22 Jul 2015 15:11:29 +1000 [thread overview]
Message-ID: <1437541889.16792.11.camel@ellerman.id.au> (raw)
In-Reply-To: <55AF2037.2000803@linaro.org>
On Wed, 2015-07-22 at 00:46 -0400, David Long wrote:
> On 06/29/15 23:29, Michael Ellerman wrote:
> > On Wed, 2015-06-17 at 14:30 -0400, David Long wrote:
> >> On 06/16/15 09:17, Rob Herring wrote:
> >>> On Mon, Jun 15, 2015 at 11:42 AM, David Long <dave.long@linaro•org> wrote:
> >>>>
> >>>> #define REG_OFFSET_NAME(r) \
> >>>> {.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)}
> >>>> #define REG_OFFSET_END {.name = NULL, .offset = 0}
> >>>
> >>> Can't you also move these? ARM is complicated with the "ARM_"
> >>> prefixing, but the others appear to be the same. Maybe you can remove
> >>> the prefix or redefine the macro for ARM.
> >>
> >> That would mandate that all the architecture-specific pt_regs structures
> >> would have to use a top-level named field for each named register.
> >
> > Why does it mandate that?
> >
> > See eg. powerpc where we use REG_OFFSET_NAME for the top-level named fields and
> > then a different macro for the array elements:
> >
> > #define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
> > #define GPR_OFFSET_NAME(num) \
> > {.name = STR(gpr##num), .offset = offsetof(struct pt_regs, gpr[num])}
> >
> > static const struct pt_regs_offset regoffset_table[] = {
> > GPR_OFFSET_NAME(0),
> > GPR_OFFSET_NAME(1),
> > GPR_OFFSET_NAME(2),
> > GPR_OFFSET_NAME(3),
> > ...
> > REG_OFFSET_NAME(nip),
> > REG_OFFSET_NAME(msr),
> >
> >
> > So I don't see why REG_OFFSET_NAME couldn't be common.
> >
>
> Sorry for the delay in responding to this.
>
> OK, so you're saying architectures that don't want this constraint can
> make their own macro. Seems to make this whole exercise slightly less
> useful, but whatever.
Well yeah.
In fact of the 4 arches that use REG_OFFSET_NAME, 2 already have another macro
for specially named registers (powerpc & sh).
> I see three ways to go here:
>
> 1) Leave it as is.
> 2) Force all architectures to use a common definition.
> 3) Provide a common definition that all architectures (except "arm")
> currently using this functionality will use.
>
> I have a v2 patch to implement #3, ready to post. Do we think this is
> the way to go?
Yeah I think it is. How are you making it conditional? Just #ifndef REG_OFFSET_NAME?
> I don't like #2 because I really don't want to rename all
> uses of the current register fields for arm since this is
> architecture-specific code to begin with and since it affects code in 39
> arm source files.
I guess you're talking about renaming all the ARM_x regs to x. That would
likely cause problems because they're implemented as #defines,
eg. #define r0 uregs[0] would probably confuse your assembler.
The clean thing to do would be to have the in-kernel struct pt_regs have actual
named members, but that would still be an intrusive change.
cheers
next prev parent reply other threads:[~2015-07-22 5:11 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-15 16:42 [PATCH 0/2] Consolidate redundant register/stack access code David Long
2015-06-15 16:42 ` [PATCH 1/2] Move the pt_regs_offset struct definition from arch to common include file David Long
2015-06-16 13:17 ` Rob Herring
2015-06-17 18:30 ` David Long
2015-06-30 3:29 ` Michael Ellerman
2015-07-22 4:46 ` David Long
2015-07-22 5:11 ` Michael Ellerman [this message]
2015-07-22 13:30 ` David Long
2015-06-19 4:19 ` Michael Ellerman
2015-06-19 14:12 ` David Long
2015-06-19 16:58 ` Kees Cook
2015-06-26 18:35 ` David Long
2015-06-23 3:32 ` Michael Ellerman
2015-06-23 13:48 ` David Long
2015-06-24 4:07 ` Michael Ellerman
2015-06-24 13:49 ` David Long
2015-06-15 16:42 ` [PATCH 2/2] Consolidate redundant register/stack access code David Long
2015-06-18 18:13 ` rkuo
2015-06-15 20:44 ` [PATCH 0/2] " Kees Cook
2015-06-15 20:58 ` David Long
2015-06-16 8:12 ` Martin Schwidefsky
2015-06-16 17:39 ` Will Deacon
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=1437541889.16792.11.camel@ellerman.id.au \
--to=mpe@ellerman$(echo .)id.au \
--cc=Nikolay.Borisov@arm$(echo .)com \
--cc=anton@samba$(echo .)org \
--cc=behanw@converseincode$(echo .)com \
--cc=benh@kernel$(echo .)crashing.org \
--cc=dave.long@linaro$(echo .)org \
--cc=eparis@redhat$(echo .)com \
--cc=heiko.carstens@de$(echo .)ibm.com \
--cc=hpa@zytor$(echo .)com \
--cc=keescook@chromium$(echo .)org \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
--cc=linux-hexagon@vger$(echo .)kernel.org \
--cc=linux-kernel@vger$(echo .)kernel.org \
--cc=linux-s390@vger$(echo .)kernel.org \
--cc=linux-sh@vger$(echo .)kernel.org \
--cc=linux390@de$(echo .)ibm.com \
--cc=linux@arm$(echo .)linux.org.uk \
--cc=linuxppc-dev@lists$(echo .)ozlabs.org \
--cc=luto@amacapital$(echo .)net \
--cc=mingo@redhat$(echo .)com \
--cc=oleg@redhat$(echo .)com \
--cc=paulus@samba$(echo .)org \
--cc=rkuo@codeaurora$(echo .)org \
--cc=robherring2@gmail$(echo .)com \
--cc=roland@hack$(echo .)frob.com \
--cc=rric@kernel$(echo .)org \
--cc=schwidefsky@de$(echo .)ibm.com \
--cc=tglx@linutronix$(echo .)de \
--cc=tj@kernel$(echo .)org \
--cc=will.deacon@arm$(echo .)com \
--cc=willeke@de$(echo .)ibm.com \
--cc=x86@kernel$(echo .)org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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