From: "Jon Medhurst (Tixy)" <jon.medhurst@linaro.org>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Dave Martin <dave.martin@linaro.org>,
Laura Abbott <lauraa@codeaurora.org>,
Nicolas Pitre <nico@fluxnic.net>,
Catalin Marinas <catalin.marinas@arm.com>,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm: Add unwinding annotations for 64bit division functions
Date: Thu, 22 Sep 2011 08:28:08 +0100 [thread overview]
Message-ID: <1316676488.2053.9.camel@linaro1> (raw)
In-Reply-To: <20110921115553.GF17169@n2100.arm.linux.org.uk>
On Wed, 2011-09-21 at 12:55 +0100, Russell King - ARM Linux wrote:
> Instructions such as VFP, kprobes tracing, etc are expected fault
> locations, and those are fairly well controlled where they can be placed.
> With things like ftrace, it certainly is the case that the unwinder can
> theoretically be called from almost anywhere in a function.
Actually, kprobes can be places on any instruction in the kernel that
isn't in the section .kprobes.text.
I also strongly suspect that stack unwinding won't happen correctly
across the boundary between the kprobes handling code and the function
which was probed - there's an awful lot of stack jiggery pokery going on
there.
--
Tixy
WARNING: multiple messages have this Message-ID (diff)
From: jon.medhurst@linaro.org (Jon Medhurst (Tixy))
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm: Add unwinding annotations for 64bit division functions
Date: Thu, 22 Sep 2011 08:28:08 +0100 [thread overview]
Message-ID: <1316676488.2053.9.camel@linaro1> (raw)
In-Reply-To: <20110921115553.GF17169@n2100.arm.linux.org.uk>
On Wed, 2011-09-21 at 12:55 +0100, Russell King - ARM Linux wrote:
> Instructions such as VFP, kprobes tracing, etc are expected fault
> locations, and those are fairly well controlled where they can be placed.
> With things like ftrace, it certainly is the case that the unwinder can
> theoretically be called from almost anywhere in a function.
Actually, kprobes can be places on any instruction in the kernel that
isn't in the section .kprobes.text.
I also strongly suspect that stack unwinding won't happen correctly
across the boundary between the kprobes handling code and the function
which was probed - there's an awful lot of stack jiggery pokery going on
there.
--
Tixy
next prev parent reply other threads:[~2011-09-22 7:28 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-19 22:11 [PATCH] arm: Add unwinding annotations for 64bit division functions Laura Abbott
2011-09-19 22:11 ` Laura Abbott
2011-09-19 23:22 ` Nicolas Pitre
2011-09-19 23:22 ` Nicolas Pitre
2011-09-20 1:55 ` Laura Abbott
2011-09-20 1:55 ` Laura Abbott
2011-09-20 1:55 ` Laura Abbott
2011-09-20 13:27 ` Nicolas Pitre
2011-09-20 13:27 ` Nicolas Pitre
2011-09-20 14:57 ` Catalin Marinas
2011-09-20 14:57 ` Catalin Marinas
2011-09-21 11:39 ` Dave Martin
2011-09-21 11:39 ` Dave Martin
2011-09-21 11:55 ` Russell King - ARM Linux
2011-09-21 11:55 ` Russell King - ARM Linux
2011-09-21 13:33 ` Dave Martin
2011-09-21 13:33 ` Dave Martin
2011-09-22 7:28 ` Jon Medhurst (Tixy) [this message]
2011-09-22 7:28 ` Jon Medhurst (Tixy)
2011-09-22 9:48 ` Catalin Marinas
2011-09-22 9:48 ` Catalin Marinas
2011-09-22 11:06 ` Jon Medhurst (Tixy)
2011-09-22 11:06 ` Jon Medhurst (Tixy)
2011-09-22 11:57 ` Catalin Marinas
2011-09-22 11:57 ` Catalin Marinas
2011-09-22 12:13 ` Jon Medhurst (Tixy)
2011-09-22 12:13 ` Jon Medhurst (Tixy)
2011-09-22 13:00 ` Catalin Marinas
2011-09-22 13:00 ` Catalin Marinas
2011-09-22 13:19 ` Jon Medhurst (Tixy)
2011-09-22 13:19 ` Jon Medhurst (Tixy)
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