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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


WARNING: multiple messages have this Message-ID (diff)
From: cmetcalf@ezchip.com (Chris Metcalf)
To: linux-arm-kernel@lists.infradead.org
Subject: [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)
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


  parent reply	other threads:[~2015-02-21  4:05 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-10 10:10 [PATCH] compat: Fix endian issue in union sigval Zhang Jian(Bamvor)
2015-02-10 10:10 ` Zhang Jian(Bamvor)
2015-02-10 12:27 ` Catalin Marinas
2015-02-10 12:27   ` Catalin Marinas
2015-02-11 11:22   ` Bamvor Jian Zhang
2015-02-11 11:22     ` Bamvor Jian Zhang
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  8:00         ` Bamvor Jian Zhang
2015-02-13  8:00         ` Bamvor Jian Zhang
2015-02-13 10:44         ` Catalin Marinas
2015-02-13 10:44           ` Catalin Marinas
2015-02-13 21:56           ` Chris Metcalf
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
2015-02-14 11:22               ` Catalin Marinas
2015-02-17  6:42               ` Bamvor Jian Zhang
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
2015-02-21  4:05                 ` Chris Metcalf
2015-02-21  4:05                 ` Chris Metcalf
2015-02-24 21:54               ` Chris Metcalf
2015-02-24 21:54                 ` Chris Metcalf
2015-02-24 21:54                 ` Chris Metcalf
2015-02-24 21:54                 ` Chris Metcalf
2015-02-25 10:37                 ` Catalin Marinas
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
2015-03-16 19:04                     ` Chris Metcalf
2015-03-23 12:02                     ` Catalin Marinas
2015-03-23 12:02                       ` Catalin Marinas
2015-03-24 20:51                       ` Chris Metcalf
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
2015-04-17 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
2015-02-17  7:15             ` Bamvor Jian Zhang
2015-02-17  7:15             ` Bamvor Jian Zhang

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