From: Will Deacon <will@kernel.org>
To: Douglas Anderson <dianders@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
Pratyush Anand <panand@redhat.com>,
Pavel Labath <labath@google.com>,
Russell King <linux@armlinux.org.uk>,
linux-kernel@vger.kernel.org, kinaba@google.com,
mka@chromium.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] ARM: hw_breakpoint: Handle inexact watchpoint addresses
Date: Wed, 20 Nov 2019 19:18:13 +0000 [thread overview]
Message-ID: <20191120191813.GD4799@willie-the-truck> (raw)
In-Reply-To: <20191019111216.1.I82eae759ca6dc28a245b043f485ca490e3015321@changeid>
On Sat, Oct 19, 2019 at 11:12:26AM -0700, Douglas Anderson wrote:
> This is commit fdfeff0f9e3d ("arm64: hw_breakpoint: Handle inexact
> watchpoint addresses") but ported to arm32, which has the same
> problem.
>
> This problem was found by Android CTS tests, notably the
> "watchpoint_imprecise" test [1]. I tested locally against a copycat
> (simplified) version of the test though.
>
> [1] https://android.googlesource.com/platform/bionic/+/master/tests/sys_ptrace_test.cpp
>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> ---
>
> arch/arm/kernel/hw_breakpoint.c | 96 ++++++++++++++++++++++++---------
> 1 file changed, 70 insertions(+), 26 deletions(-)
Sorry for taking so long to look at this. After wrapping my head around the
logic again, I think it looks fine, so please put it into the patch system
with my Ack:
Acked-by: Will Deacon <will@kernel.org>
One interesting difference between the implementation here and the arm64
code is that I think if you have multiple watchpoints, all of which fire
with a distance != 0, then arm32 will actually report them all whereas
you'd only get one on arm64.
Will
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next prev parent reply other threads:[~2019-11-20 19:18 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-19 18:12 [PATCH] ARM: hw_breakpoint: Handle inexact watchpoint addresses Douglas Anderson
2019-10-21 18:46 ` Matthias Kaehlcke
2019-10-21 23:49 ` Doug Anderson
2019-10-22 16:39 ` Matthias Kaehlcke
2019-11-20 19:18 ` Will Deacon [this message]
2019-12-02 16:36 ` Doug Anderson
2020-01-06 17:40 ` Will Deacon
2020-08-06 15:05 ` Doug Anderson
2020-08-06 15:41 ` Russell King - ARM Linux admin
2020-08-06 15:45 ` Doug Anderson
2020-08-06 18:28 ` Doug Anderson
2020-08-06 22:02 ` Russell King - ARM Linux admin
2020-08-06 22:26 ` Doug Anderson
2020-08-06 22:28 ` Russell King - ARM Linux admin
2020-08-06 16:16 ` Russell King - ARM Linux admin
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