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Fri, 23 Jun 2023 05:40:39 -0700 (PDT) MIME-Version: 1.0 References: <20230623075805.1630-1-chanho.min@lge.com> In-Reply-To: <20230623075805.1630-1-chanho.min@lge.com> From: Andrey Konovalov Date: Fri, 23 Jun 2023 14:40:28 +0200 Message-ID: Subject: Re: [PATCH v2] kasan: fix mention for KASAN_HW_TAGS To: Chanho Min Cc: dvyukov@google.com, elver@google.com, glider@google.com, gunho.lee@lge.com, kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ryabinin.a.a@gmail.com, vincenzo.frascino@arm.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 65346C000B X-Rspam-User: X-Stat-Signature: 7p35tb83pqstq9i15e973jt5ab5krwh5 X-Rspamd-Server: rspam03 X-HE-Tag: 1687524040-434665 X-HE-Meta: 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 rQHQi2Mk 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 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: On Fri, Jun 23, 2023 at 9:58=E2=80=AFAM Chanho Min wro= te: > > This patch fixes description of the KASAN_HW_TAGS's memory consumption. > KASAN_HW_TAGS are dependent on the HW implementation and are not reserved > from system memory like shadow memory. > > Suggested-by: Andrey Konovalov > Signed-off-by: Chanho Min > --- > lib/Kconfig.kasan | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan > index fdca89c05745..f8f9e12510b7 100644 > --- a/lib/Kconfig.kasan > +++ b/lib/Kconfig.kasan > @@ -124,7 +124,8 @@ config KASAN_HW_TAGS > Supported only on arm64 CPUs starting from ARMv8.5 and relies o= n > Memory Tagging Extension and Top Byte Ignore. > > - Consumes about 1/32nd of available memory. > + Does not consume memory by itself but relies on the 1/32nd of > + available memory being reserved by the firmware when MTE is ena= bled. > > May potentially introduce problems related to pointer casting a= nd > comparison, as it embeds a tag into the top byte of each pointe= r. > -- > 2.17.1 > Reviewed-by: Andrey Konovalov Thank you!