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Re: [RFA/commit] arm-tdep.c: Do not single-step after hitting a watchpoint.
- From: Marcus Shawcroft <marcus dot shawcroft at gmail dot com>
- To: Pedro Alves <palves at redhat dot com>
- Cc: Terry Guo <terry dot guo at arm dot com>, Marcus Shawcroft <marcus dot shawcroft at arm dot com>, lgustavo at codesourcery dot com, Joel Brobecker <brobecker at adacore dot com>, Yao Qi <yao at codesourcery dot com>, "gdb-patches at sourceware dot org" <gdb-patches at sourceware dot org>, Will Deacon <will dot deacon at arm dot com>, peter dot maydell at arm dot com
- Date: Thu, 18 Sep 2014 12:40:33 +0100
- Subject: Re: [RFA/commit] arm-tdep.c: Do not single-step after hitting a watchpoint.
- Authentication-results: sourceware.org; auth=none
- References: <1410786062-19274-1-git-send-email-brobecker at adacore dot com> <87bnqf2578 dot fsf at codesourcery dot com> <20140916115936 dot GM4871 at adacore dot com> <5418279A dot 1040604 at codesourcery dot com> <20140916124814 dot GO4871 at adacore dot com> <54183681 dot 3010504 at codesourcery dot com> <5418556E dot 7010502 at redhat dot com>
On 16 September 2014 16:21, Pedro Alves <email@example.com> wrote:
> Hi Terry, Marcus,
> Can someone at ARM shed some light on this, please?
> This thread is here:
> And the discussion started in another thread here:
> I've just added a test that hopefully helps with this, btw:
> I'm also wondering whether Aarch64 needs adjustment as well.
> Pedro Alves
In aarch32 execution state a watch point event is taken as a data
abort with the PC containing the address of the faulting instruction +
8 irrespective of thumb mode.
The linux kernel adjusts the reported PC by subtracting 8 such that
the ptrace interface will indicate the address of the faulting
Peter Maydell's proposed qemu patch referenced in the thread above
appears to me to align the gdbstub behaviour in qemu with the linux
kernel ptrace() interface behaviour.
w.r.t DBGWFAR, it's use is described as deprecated in ARM ARMv7-A&R
Issue C.c c11.11.45. It is not used by linux kernel.