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SubjectRe: [PATCH] ARM: hw_breakpoint: Handle inexact watchpoint addresses
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]
> Signed-off-by: Douglas Anderson <>
> ---
> 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 <>

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.


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