From mboxrd@z Thu Jan 1 00:00:00 1970 From: panand@redhat.com (Pratyush Anand) Date: Thu, 13 Oct 2016 15:52:17 +0530 Subject: [PATCH 3/4] arm64: Allow hw watchpoint of length 3,5,6 and 7 In-Reply-To: References: Message-ID: <1bc0dce6-eb26-dbf5-dd0c-d36055f5f1fe@redhat.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wednesday 12 October 2016 04:46 PM, Yao Qi wrote: > On Wed, Oct 12, 2016 at 6:58 AM, Pratyush Anand wrote: >> Since, arm64 can support all offset within a double word limit. Therefore, >> now support other lengths within that range as well. > > How does ptracer (like GDB) detect kernel has already supported all byte > address select values? I suppose ptrace(NT_ARM_HW_WATCH, ) with > len is 3 or 5 fail on current kernel but is of success after your patches > applied. > Thanks for testing these patches. I do not know if we can know that other than the failure of ptrace(PTRACE_SETREGSET, .., NT_ARM_HW_WATCH, ..). I do not see any such option in `man ptrace`. > GDB is aware of the byte address select limitation in kernel, so it always > sets 1,2,4,8 in len in ctrl. GDB needs to know whether the limitation is still > there or not. > Not sure if other than "kernel version" anything will help here. ~Pratyush