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c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=aZg/3dO+K+3/7egp9giqF6NxjGJW8QC5duS9to8aMlY=; b=KlAlxJIc7sm9E+anxbuRZ1hHAcLmwyEf5ZfOkkQJQW6YTuneXocGfXq4ervZz3kvjW mCjCJnTCm+y8bAFjHsLXCkPOlk0je3DC9jT4vK8hN62yKecy77qSVcWtjsuelnaoZ9ns onAa1YxuqJnC1h845ckEaluCf3sPVXBcC0x2vI9iwKip1vXdVHB52jFebE6U+FawwfSy 3c7ZmRJi1EUf0DjHRSbyeuGU55aDUefcmDAxUsv5rELuG4B08+WlLcv0geLDQiEDA3un KlHRRyGLppr4Ljsy+9OW5pEEUG5e+vzRG+s/sMGM40TiaF6wjnzTI2VgViOIMSG2aMu9 UEjw== X-Gm-Message-State: AOAM530XskzQqszf/IVThX9+FZovjKODLiTc0EuZC+SqjTeFtNcMK8Su eIMEZqtmHvfyAyP4aferptJ8k2JI/ts+Ce7aZFRCpw== X-Google-Smtp-Source: ABdhPJy0oA37tH29jq6K/3f8eXTURhzdJBnfxbCpoDa4SIF888pNpma8ToBbSmYwnn/LMwKyWPnPeW4+dy1W+1T0FZk= X-Received: by 2002:a0c:9e53:: with SMTP id z19mr24630768qve.23.1605104005104; Wed, 11 Nov 2020 06:13:25 -0800 (PST) MIME-Version: 1.0 References: <85aba371903b749412fac34e44e54c89e5ddae30.1605046192.git.andreyknvl@google.com> In-Reply-To: <85aba371903b749412fac34e44e54c89e5ddae30.1605046192.git.andreyknvl@google.com> From: Alexander Potapenko Date: Wed, 11 Nov 2020 15:13:13 +0100 Message-ID: Subject: Re: [PATCH v9 10/44] kasan: define KASAN_GRANULE_PAGE To: Andrey Konovalov Cc: Catalin Marinas , Will Deacon , Vincenzo Frascino , Dmitry Vyukov , Andrey Ryabinin , Marco Elver , Evgenii Stepanov , Branislav Rankov , Kevin Brodsky , Andrew Morton , kasan-dev , Linux ARM , Linux Memory Management List , LKML Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable 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 Tue, Nov 10, 2020 at 11:11 PM Andrey Konovalov w= rote: > > Define KASAN_GRANULE_PAGE as (KASAN_GRANULE_SIZE << PAGE_SHIFT), which is > the same as (KASAN_GRANULE_SIZE * PAGE_SIZE), and use it across KASAN cod= e > to simplify it. What's the physical sense behind KASAN_GRANULE_PAGE? Is it something more than just a product of two constants? The name suggests it might be something page-sized, but in reality it is no= t. > > Signed-off-by: Andrey Konovalov > Signed-off-by: Vincenzo Frascino > Reviewed-by: Marco Elver > --- > Change-Id: I0b627b24187d06c8b9bb2f1d04d94b3d06945e73 > --- > mm/kasan/init.c | 10 ++++------ > mm/kasan/kasan.h | 1 + > mm/kasan/shadow.c | 16 +++++++--------- > 3 files changed, 12 insertions(+), 15 deletions(-) > > diff --git a/mm/kasan/init.c b/mm/kasan/init.c > index 1a71eaa8c5f9..26b2663b3a42 100644 > --- a/mm/kasan/init.c > +++ b/mm/kasan/init.c > @@ -441,9 +441,8 @@ void kasan_remove_zero_shadow(void *start, unsigned l= ong size) > addr =3D (unsigned long)kasan_mem_to_shadow(start); > end =3D addr + (size >> KASAN_SHADOW_SCALE_SHIFT); > > - if (WARN_ON((unsigned long)start % > - (KASAN_GRANULE_SIZE * PAGE_SIZE)) || > - WARN_ON(size % (KASAN_GRANULE_SIZE * PAGE_SIZE))) > + if (WARN_ON((unsigned long)start % KASAN_GRANULE_PAGE) || > + WARN_ON(size % KASAN_GRANULE_PAGE)) > return; > > for (; addr < end; addr =3D next) { > @@ -476,9 +475,8 @@ int kasan_add_zero_shadow(void *start, unsigned long = size) > shadow_start =3D kasan_mem_to_shadow(start); > shadow_end =3D shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT); > > - if (WARN_ON((unsigned long)start % > - (KASAN_GRANULE_SIZE * PAGE_SIZE)) || > - WARN_ON(size % (KASAN_GRANULE_SIZE * PAGE_SIZE))) > + if (WARN_ON((unsigned long)start % KASAN_GRANULE_PAGE) || > + WARN_ON(size % KASAN_GRANULE_PAGE)) > return -EINVAL; > > ret =3D kasan_populate_early_shadow(shadow_start, shadow_end); > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h > index c31e2c739301..1865bb92d47a 100644 > --- a/mm/kasan/kasan.h > +++ b/mm/kasan/kasan.h > @@ -7,6 +7,7 @@ > > #define KASAN_GRANULE_SIZE (1UL << KASAN_SHADOW_SCALE_SHIFT) > #define KASAN_GRANULE_MASK (KASAN_GRANULE_SIZE - 1) > +#define KASAN_GRANULE_PAGE (KASAN_GRANULE_SIZE << PAGE_SHIFT) > > #define KASAN_TAG_KERNEL 0xFF /* native kernel pointers tag */ > #define KASAN_TAG_INVALID 0xFE /* inaccessible memory tag */ > diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c > index ca0cc4c31454..1fadd4930d54 100644 > --- a/mm/kasan/shadow.c > +++ b/mm/kasan/shadow.c > @@ -161,7 +161,7 @@ static int __meminit kasan_mem_notifier(struct notifi= er_block *nb, > shadow_end =3D shadow_start + shadow_size; > > if (WARN_ON(mem_data->nr_pages % KASAN_GRANULE_SIZE) || > - WARN_ON(start_kaddr % (KASAN_GRANULE_SIZE << PAGE_SHIFT))= ) > + WARN_ON(start_kaddr % KASAN_GRANULE_PAGE)) > return NOTIFY_BAD; > > switch (action) { > @@ -432,22 +432,20 @@ void kasan_release_vmalloc(unsigned long start, uns= igned long end, > unsigned long region_start, region_end; > unsigned long size; > > - region_start =3D ALIGN(start, PAGE_SIZE * KASAN_GRANULE_SIZE); > - region_end =3D ALIGN_DOWN(end, PAGE_SIZE * KASAN_GRANULE_SIZE); > + region_start =3D ALIGN(start, KASAN_GRANULE_PAGE); > + region_end =3D ALIGN_DOWN(end, KASAN_GRANULE_PAGE); > > - free_region_start =3D ALIGN(free_region_start, > - PAGE_SIZE * KASAN_GRANULE_SIZE); > + free_region_start =3D ALIGN(free_region_start, KASAN_GRANULE_PAGE= ); > > if (start !=3D region_start && > free_region_start < region_start) > - region_start -=3D PAGE_SIZE * KASAN_GRANULE_SIZE; > + region_start -=3D KASAN_GRANULE_PAGE; > > - free_region_end =3D ALIGN_DOWN(free_region_end, > - PAGE_SIZE * KASAN_GRANULE_SIZE); > + free_region_end =3D ALIGN_DOWN(free_region_end, KASAN_GRANULE_PAG= E); > > if (end !=3D region_end && > free_region_end > region_end) > - region_end +=3D PAGE_SIZE * KASAN_GRANULE_SIZE; > + region_end +=3D KASAN_GRANULE_PAGE; > > shadow_start =3D kasan_mem_to_shadow((void *)region_start); > shadow_end =3D kasan_mem_to_shadow((void *)region_end); > -- > 2.29.2.222.g5d2a92d10f8-goog > --=20 Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Stra=C3=9Fe, 33 80636 M=C3=BCnchen Gesch=C3=A4ftsf=C3=BChrer: Paul Manicle, Halimah DeLaine Prado Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg