Re: [PATCH v2 0/4] arm64: kasan: support CONFIG_KASAN_VMALLOC

From: Will Deacon <will@kernel.org>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Linux Memory Management List <linux-mm@kvack.org>,
	kasan-dev <kasan-dev@googlegroups.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Alexander Potapenko <glider@google.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"moderated list:ARM/Mediatek SoC..." 
	<linux-mediatek@lists.infradead.org>,
	yj.chiang@mediatek.com, Catalin Marinas <catalin.marinas@arm.com>,
	Ard Biesheuvel <ardb@kernel.org>, Mark Brown <broonie@kernel.org>,
	Guenter Roeck <linux@roeck-us.net>,
	rppt@kernel.org, tyhicks@linux.microsoft.com,
	Robin Murphy <robin.murphy@arm.com>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	gustavoars@kernel.org, Lecopzer Chen <lecopzer@gmail.com>,
	Lecopzer Chen <lecopzer.chen@mediatek.com>
Subject: Re: [PATCH v2 0/4] arm64: kasan: support CONFIG_KASAN_VMALLOC
Date: Fri, 22 Jan 2021 19:05:01 +0000	[thread overview]
Message-ID: <20210122190501.GA25471@willie-the-truck> (raw)
In-Reply-To: <CAAeHK+z3oYx4WqX7Xor7gD=eqYkzW0UBS4h4is00HnfNnNkpDA@mail.gmail.com>

On Thu, Jan 21, 2021 at 06:44:14PM +0100, Andrey Konovalov wrote:
> On Sat, Jan 9, 2021 at 11:33 AM Lecopzer Chen <lecopzer@gmail.com> wrote:
> >
> > Linux supports KAsan for VMALLOC since commit 3c5c3cfb9ef4da9
> > ("kasan: support backing vmalloc space with real shadow memory")
> >
> > Acroding to how x86 ported it [1], they early allocated p4d and pgd,
> > but in arm64 I just simulate how KAsan supports MODULES_VADDR in arm64
> > by not to populate the vmalloc area except for kimg address.
> >
> > Test environment:
> >     4G and 8G Qemu virt,
> >     39-bit VA + 4k PAGE_SIZE with 3-level page table,
> >     test by lib/test_kasan.ko and lib/test_kasan_module.ko
> >
> > It also works in Kaslr with CONFIG_RANDOMIZE_MODULE_REGION_FULL
> > and randomize module region inside vmalloc area.
> >
> >
> > [1]: commit 0609ae011deb41c ("x86/kasan: support KASAN_VMALLOC")
> >
> > Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com>
> > Acked-by: Andrey Konovalov <andreyknvl@google.com>
> > Tested-by: Andrey Konovalov <andreyknvl@google.com>
> >
> >
> > v2 -> v1
> >         1. kasan_init.c tweak indent
> >         2. change Kconfig depends only on HAVE_ARCH_KASAN
> >         3. support randomized module region.
> >
> > v1:
> > https://lore.kernel.org/lkml/20210103171137.153834-1-lecopzer@gmail.com/
> >
> > Lecopzer Chen (4):
> >   arm64: kasan: don't populate vmalloc area for CONFIG_KASAN_VMALLOC
> >   arm64: kasan: abstract _text and _end to KERNEL_START/END
> >   arm64: Kconfig: support CONFIG_KASAN_VMALLOC
> >   arm64: kaslr: support randomized module area with KASAN_VMALLOC
> >
> >  arch/arm64/Kconfig         |  1 +
> >  arch/arm64/kernel/kaslr.c  | 18 ++++++++++--------
> >  arch/arm64/kernel/module.c | 16 +++++++++-------
> >  arch/arm64/mm/kasan_init.c | 29 +++++++++++++++++++++--------
> >  4 files changed, 41 insertions(+), 23 deletions(-)
> >
> > --
> > 2.25.1
> >
> 
> Hi Will,
> 
> Could you PTAL at the arm64 changes?

Sorry, wanted to get to this today but I ran out of time in the end. On the
list for next week!

Will