From mboxrd@z Thu Jan  1 00:00:00 1970
From: Luis Machado <luis.machado@linaro.org>
Subject: Re: [PATCH v3 19/23] arm64: mte: Add PTRACE_{PEEK,POKE}MTETAGS
 support
Date: Tue, 5 May 2020 15:03:29 -0300
Message-ID: <b78fe0c4-f89e-9347-7d7d-a68085f70b1d@linaro.org>
References: <20200421142603.3894-1-catalin.marinas@arm.com>
 <20200421142603.3894-20-catalin.marinas@arm.com>
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To: Catalin Marinas <catalin.marinas@arm.com>, linux-arm-kernel@lists.infradead.org
Cc: Will Deacon <will@kernel.org>, Vincenzo Frascino <vincenzo.frascino@arm.com>, Szabolcs Nagy <szabolcs.nagy@arm.com>, Richard Earnshaw <Richard.Earnshaw@arm.com>, Kevin Brodsky <kevin.brodsky@arm.com>, Andrey Konovalov <andreyknvl@google.com>, Peter Collingbourne <pcc@google.com>, linux-mm@kvack.org, linux-arch@vger.kernel.org, Alan Hayward <Alan.Hayward@arm.com>, Omair Javaid <omair.javaid@linaro.org>

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 <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Alan Hayward <Alan.Hayward@arm.com>
> Cc: Luis Machado <luis.machado@linaro.org>
> Cc: Omair Javaid <omair.javaid@linaro.org>
> ---
> 
> 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'll try to exercise the new ptrace requests with QEMU and GDB.