Andrey Konovalov 61dbe70839 BACKPORT: FROMGIT: kasan, page_alloc: allow skipping unpoisoning for HW_TAGS ...

(Backport: adapt the patch to account for added GFP flags and
 __GFP_BITS_SHIFT definition changes;
 don't try to pack all flags to avoid macro mess.)

Add a new GFP flag __GFP_SKIP_KASAN_UNPOISON that allows skipping KASAN
poisoning for page_alloc allocations.  The flag is only effective with
HW_TAGS KASAN.

This flag will be used by vmalloc code for page_alloc allocations backing
vmalloc() mappings in a following patch.  The reason to skip KASAN
poisoning for these pages in page_alloc is because vmalloc code will be
poisoning them instead.

Also reword the comment for __GFP_SKIP_KASAN_POISON.

Link: https://lkml.kernel.org/r/35c97d77a704f6ff971dd3bfe4be95855744108e.1643047180.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
(cherry picked from commit 9a47b06547a9c28d2899b27888bc006422d29554
 git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git akpm)
Bug: 217222520
Change-Id: I9c52fa6370c6fd19d23edaed1a082cae946e2ef5
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

2022-02-15 17:59:15 +01:00

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