From: LEROY Christophe <christophe.leroy@c-s.fr>
To: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
Cc: linux-kernel@vger.kernel.org,
Alastair D'Silva <alastair@d-silva.org>,
Andrew Donnellan <andrew.donnellan@au1.ibm.com>,
Balbir Singh <bsingharora@gmail.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Cyril Bur <cyrilbur@gmail.com>,
"Eric W . Biederman" <ebiederm@xmission.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Michael Neuling <mikey@neuling.org>,
Nicholas Piggin <npiggin@gmail.com>,
Paul Mackerras <paulus@samba.org>,
Simon Guo <wei.guo.simon@gmail.com>,
Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>,
"Tobin C . Harding" <me@tobin.cc>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 04/10] powerpc/traps: Use REG_FMT in show_signal_msg()
Date: Mon, 30 Jul 2018 18:30:47 +0200 [thread overview]
Message-ID: <20180730183047.Horde.g9hQ_3EXmF6St0upNs2DDw1@messagerie.si.c-s.fr> (raw)
In-Reply-To: <20180730152838.GA23704@kermit-br-ibm-com>
Murilo Opsfelder Araujo <muriloo@linux.ibm.com> a écrit :
> Hi, Christophe.
>
> On Fri, Jul 27, 2018 at 06:40:23PM +0200, LEROY Christophe wrote:
>> Murilo Opsfelder Araujo <muriloo@linux.ibm.com> a écrit :
>>
>> > Simplify the message format by using REG_FMT as the register format. This
>> > avoids having two different formats and avoids checking for MSR_64BIT.
>>
>> Are you sure it is what we want ?
>
> Yes.
>
>> Won't it change the behaviour for a 32 bits app running on a 64bits kernel ?
>
> In fact, this changes how many zeroes are prefixed when displaying
> the registers
> (%016lx vs. %08lx format). For example, 32-bits userspace, 64-bits kernel:
Indeed that's what I suspected. What is the real benefit of this
change ? Why not keep the current format for 32bits userspace ? All
those leading zeroes are pointless to me.
>
> before this series:
> [66475.002900] segv[4599]: unhandled signal 11 at 00000000 nip
> 10000420 lr 0fe61854 code 1
>
> after this series:
> [ 73.414535] segv[3759]: segfault (11) at 0000000000000000 nip
> 0000000010000420 lr 000000000fe61854 code 1 in segv[10000000+10000]
> [ 73.414641] segv[3759]: code: 4e800421 80010014 38210010
> 7c0803a6 4bffff30 9421ffd0 93e1002c 7c3f0b78
> [ 73.414665] segv[3759]: code: 39200000 913f001c 813f001c
> 39400001 <91490000> 39200000 7d234b78 397f0030
>
> Have you spotted any other behaviour change?
Not as of today
Christophe
>
> Cheers
> Murilo
next prev parent reply other threads:[~2018-07-30 16:30 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-27 14:58 [PATCH v2 00/10] powerpc: Modernize unhandled signals message Murilo Opsfelder Araujo
2018-07-27 14:58 ` [PATCH v2 01/10] powerpc/traps: Print unhandled signals in a separate function Murilo Opsfelder Araujo
2018-07-27 14:58 ` [PATCH v2 02/10] powerpc/traps: Return early in show_signal_msg() Murilo Opsfelder Araujo
2018-07-27 14:58 ` [PATCH v2 03/10] powerpc/reg: Add REG_FMT definition Murilo Opsfelder Araujo
2018-07-27 14:58 ` [PATCH v2 04/10] powerpc/traps: Use REG_FMT in show_signal_msg() Murilo Opsfelder Araujo
2018-07-27 16:40 ` LEROY Christophe
2018-07-27 17:18 ` Joe Perches
2018-07-30 15:28 ` Murilo Opsfelder Araujo
2018-07-30 16:30 ` LEROY Christophe [this message]
2018-07-30 23:17 ` Murilo Opsfelder Araujo
2018-07-31 9:32 ` Michael Ellerman
2018-07-31 9:52 ` Alastair D'Silva
2018-07-27 14:58 ` [PATCH v2 05/10] powerpc/traps: Print VMA for unhandled signals Murilo Opsfelder Araujo
2018-07-27 14:58 ` [PATCH v2 06/10] powerpc/traps: Print signal name " Murilo Opsfelder Araujo
2018-07-27 14:58 ` [PATCH v2 07/10] powerpc: Do not call __kernel_text_address() in show_instructions() Murilo Opsfelder Araujo
2018-07-27 14:58 ` [PATCH v2 08/10] powerpc: Add stacktrace.h header Murilo Opsfelder Araujo
2018-07-27 14:58 ` [PATCH v2 09/10] powerpc/traps: Show instructions on exceptions Murilo Opsfelder Araujo
2018-07-27 14:58 ` [PATCH v2 10/10] powerpc/traps: Add line prefix in show_instructions() Murilo Opsfelder Araujo
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