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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200421142603.3894-20-catalin.marinas@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi Catalin, On 4/21/20 11:25 AM, Catalin Marinas wrote: > Add support for bulk setting/getting of the MTE tags in a tracee's > address space at 'addr' in the ptrace() syscall prototype. 'data' points > to a struct iovec in the tracer's address space with iov_base > representing the address of a tracer's buffer of length iov_len. The > tags to be copied to/from the tracer's buffer are stored as one tag per > byte. > > On successfully copying at least one tag, ptrace() returns 0 and updates > the tracer's iov_len with the number of tags copied. In case of error, > either -EIO or -EFAULT is returned, trying to follow the ptrace() man > page. > > Note that the tag copying functions are not performance critical, > therefore they lack optimisations found in typical memory copy routines. > > Signed-off-by: Catalin Marinas > Cc: Will Deacon > Cc: Alan Hayward > Cc: Luis Machado > Cc: Omair Javaid > --- > > Notes: > New in v3. > > arch/arm64/include/asm/mte.h | 17 ++++ > arch/arm64/include/uapi/asm/ptrace.h | 3 + > arch/arm64/kernel/mte.c | 127 +++++++++++++++++++++++++++ > arch/arm64/kernel/ptrace.c | 15 +++- > arch/arm64/lib/mte.S | 50 +++++++++++ > 5 files changed, 211 insertions(+), 1 deletion(-) > I started working on MTE support for GDB and I'm wondering if we've already defined a way to check for runtime MTE support (as opposed to a HWCAP2-based check) in a traced process. Originally we were going to do it via empty-parameter ptrace calls, but you had mentioned something about a proc-based method, if I'm not mistaken. Regards, Luis