Re: [PATCH] ARM: hw_breakpoint: Handle inexact watchpoint addresses
From: Will Deacon <will@kernel.org>
Date: 2019-11-20 19:18:20
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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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel