From: Chris Metcalf <cmetcalf@ezchip.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: linux-arch@vger.kernel.org, benh@kernel.crashing.org,
davem@davemloft.net, mpe@ellerman.id.au, deller@gmx.de,
hpa@zytor.com, heiko.carstens@de.ibm.com,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Will Deacon <Will.Deacon@arm.com>,
jejb@parisc-linux.org, "lizefan@huawei.com" <lizefan@huawei.com>,
Bamvor Jian Zhang <bamvor.zhangjian@huawei.com>,
ralf@linux-mips.org,
"dingtianhong@huawei.com" <dingtianhong@huawei.com>,
schwidefsky@de.ibm.com, paulus@samba.org, tglx@linutronix.de,
mingo@redhat.com,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] compat: Fix endian issue in union sigval
Date: Fri, 20 Feb 2015 23:05:15 -0500 [thread overview]
Message-ID: <54E803FB.901@ezchip.com> (raw)
In-Reply-To: <20150214112220.GB10246@MBP.local>
On 2/14/2015 6:22 AM, Catalin Marinas wrote:
> 1. user populates sival_int compat_sigevent and invokes
> compat_sys_mq_notify()
> 2. kernel get_compat_sigevent() copies compat_sigevent into the native
> sigevent. compat and native sival_int are the same, no problem so
> far. The other half of 64-bit sival_ptr is zeroed by a memset in this
> function (this other half can be top or bottom, depending on
> endianness)
> 3. signal is about to be delivered to user via arch code. The
> compat_ptr(from->si_ptr) conversion always takes the least
> significant part of the native si_ptr. On big endian 64-bit, this is
> zero because get_compat_sigevent() populated the top part of si_ptr
> with si_int.
Thanks, that makes sense. I was missing the fact that the conversion
issue was actually around the in-kernel 64-bit version of the structure.
Using si_int consistently does seem like it should do the right thing;
I'll post a patch for tilegx32 big-endian to do the right thing here.
--
Chris Metcalf, EZChip Semiconductor
http://www.ezchip.com
WARNING: multiple messages have this Message-ID (diff)
From: Chris Metcalf <cmetcalf@ezchip.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Bamvor Jian Zhang <bamvor.zhangjian@huawei.com>,
linux-arch@vger.kernel.org, mpe@ellerman.id.au,
benh@kernel.crashing.org, deller@gmx.de,
"dingtianhong@huawei.com" <dingtianhong@huawei.com>,
heiko.carstens@de.ibm.com,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Will Deacon <Will.Deacon@arm.com>,
jejb@parisc-linux.org, "lizefan@huawei.com" <lizefan@huawei.com>,
paulus@samba.org, ralf@linux-mips.org, hpa@zytor.com,
schwidefsky@de.ibm.com, tglx@linutronix.de, mingo@redhat.com,
davem@davemloft.net,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] compat: Fix endian issue in union sigval
Date: Fri, 20 Feb 2015 23:05:15 -0500 [thread overview]
Message-ID: <54E803FB.901@ezchip.com> (raw)
Message-ID: <20150221040515.qcHuJKNy9Mi1E0KUNcY-04cCIktimcF3qjET4hDD07I@z> (raw)
In-Reply-To: <20150214112220.GB10246@MBP.local>
On 2/14/2015 6:22 AM, Catalin Marinas wrote:
> 1. user populates sival_int compat_sigevent and invokes
> compat_sys_mq_notify()
> 2. kernel get_compat_sigevent() copies compat_sigevent into the native
> sigevent. compat and native sival_int are the same, no problem so
> far. The other half of 64-bit sival_ptr is zeroed by a memset in this
> function (this other half can be top or bottom, depending on
> endianness)
> 3. signal is about to be delivered to user via arch code. The
> compat_ptr(from->si_ptr) conversion always takes the least
> significant part of the native si_ptr. On big endian 64-bit, this is
> zero because get_compat_sigevent() populated the top part of si_ptr
> with si_int.
Thanks, that makes sense. I was missing the fact that the conversion
issue was actually around the in-kernel 64-bit version of the structure.
Using si_int consistently does seem like it should do the right thing;
I'll post a patch for tilegx32 big-endian to do the right thing here.
--
Chris Metcalf, EZChip Semiconductor
http://www.ezchip.com
next prev parent reply other threads:[~2015-02-21 4:05 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1423563011-12377-1-git-send-email-bamvor.zhangjian@huawei.com>
2015-02-10 12:27 ` [PATCH] compat: Fix endian issue in union sigval Catalin Marinas
2015-02-10 12:27 ` Catalin Marinas
2015-02-11 11:22 ` Bamvor Jian Zhang
2015-02-11 15:40 ` Catalin Marinas
2015-02-11 15:40 ` Catalin Marinas
2015-02-13 8:00 ` Bamvor Jian Zhang
2015-02-13 10:44 ` Catalin Marinas
2015-02-13 21:56 ` Chris Metcalf
2015-02-13 21:56 ` Chris Metcalf
2015-02-14 11:22 ` Catalin Marinas
2015-02-14 11:22 ` Catalin Marinas
2015-02-17 6:42 ` Bamvor Jian Zhang
2015-02-17 6:42 ` Bamvor Jian Zhang
2015-02-21 4:05 ` Chris Metcalf [this message]
2015-02-21 4:05 ` Chris Metcalf
2015-02-24 21:54 ` Chris Metcalf
2015-02-24 21:54 ` Chris Metcalf
2015-02-25 10:37 ` Catalin Marinas
2015-03-16 19:04 ` [PATCH] tile: use si_int instead of si_ptr for compat_siginfo Chris Metcalf
2015-03-16 19:04 ` Chris Metcalf
2015-03-23 12:02 ` Catalin Marinas
2015-03-24 20:51 ` Chris Metcalf
2015-03-24 20:51 ` Chris Metcalf
2015-04-17 16:56 ` Chris Metcalf
2015-04-17 16:56 ` Chris Metcalf
2015-02-17 7:15 ` [PATCH] compat: Fix endian issue in union sigval Bamvor Jian Zhang
2015-02-17 7:15 ` Bamvor Jian Zhang
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