From: Daniel Axtens <dja@axtens.net>
To: Balbir Singh <bsingharora@gmail.com>
Cc: aneesh.kumar@linux.ibm.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, kasan-dev@googlegroups.com,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v11 6/6] powerpc: Book3S 64-bit outline-only KASAN support
Date: Mon, 22 Mar 2021 11:55:08 +1100 [thread overview]
Message-ID: <87o8fcatxv.fsf@dja-thinkpad.axtens.net> (raw)
In-Reply-To: <20210320060259.GF77072@balbir-desktop>
Hi Balbir,
> Could you highlight the changes from
> https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20170729140901.5887-1-bsingharora@gmail.com/?
>
> Feel free to use my signed-off-by if you need to and add/update copyright
> headers if appropriate.
There's not really anything in common any more:
- ppc32 KASAN landed, so there was already a kasan.h for powerpc, the
explicit memcpy changes, the support for non-instrumented files,
prom_check.sh, etc. all already landed.
- I locate the shadow region differently and don't resize any virtual
memory areas.
- The ARCH_DEFINES_KASAN_ZERO_PTE handling changed upstream and our
handling for that is now handled more by patch 3.
- The outline hook is now an inline function rather than a #define.
- The init function has been totally rewritten as it's gone from
supporting real mode to not supporting real mode and back.
- The list of non-instrumented files has grown a lot.
- There's new stuff: stack walking is now safe, KASAN vmalloc support
means modules are better supported now, ptdump works, and there's
documentation.
It's been a while now, but I don't think when I started this process 2
years ago that I directly reused much of your code. So I'm not sure that
a signed-off-by makes sense here? Would a different tag (Originally-by?)
make more sense?
>> + * The shadow ends before the highest accessible address
>> + * because we don't need a shadow for the shadow. Instead:
>> + * c00e000000000000 << 3 + a80e 0000 0000 0000 000 = c00fc00000000000
>
> The comment has one extra 0 in a80e.., I did the math and had to use
> the data from the defines :)
3 extra 0s, even! Fixed.
>> +void __init kasan_init(void)
>> +{
>> + /*
>> + * We want to do the following things:
>> + * 1) Map real memory into the shadow for all physical memblocks
>> + * This takes us from c000... to c008...
>> + * 2) Leave a hole over the shadow of vmalloc space. KASAN_VMALLOC
>> + * will manage this for us.
>> + * This takes us from c008... to c00a...
>> + * 3) Map the 'early shadow'/zero page over iomap and vmemmap space.
>> + * This takes us up to where we start at c00e...
>> + */
>> +
>
> assuming we have
> #define VMEMMAP_END R_VMEMMAP_END
> and ditto for hash we probably need
>
> BUILD_BUG_ON(VMEMMAP_END + KASAN_SHADOW_OFFSET != KASAN_SHADOW_END);
Sorry, I'm not sure what this is supposed to be testing? In what
situation would this trigger?
Kind regards,
Daniel
>
> Looks good otherwise, I've not been able to test it yet
>
> Balbir Singh.
next prev parent reply other threads:[~2021-03-22 0:55 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-19 14:40 [PATCH v11 0/6] KASAN for powerpc64 radix Daniel Axtens
2021-03-19 14:40 ` [PATCH v11 1/6] kasan: allow an architecture to disable inline instrumentation Daniel Axtens
2021-03-20 1:46 ` Balbir Singh
2021-03-22 0:29 ` Daniel Axtens
2021-03-22 11:08 ` Michael Ellerman
2021-03-22 8:18 ` Marco Elver
2021-03-19 14:40 ` [PATCH v11 2/6] kasan: allow architectures to provide an outline readiness check Daniel Axtens
2021-03-22 8:17 ` Marco Elver
2021-03-19 14:40 ` [PATCH v11 3/6] kasan: define and use MAX_PTRS_PER_* for early shadow tables Daniel Axtens
2021-03-19 14:40 ` [PATCH v11 4/6] kasan: Document support on 32-bit powerpc Daniel Axtens
2021-03-19 14:40 ` [PATCH v11 5/6] powerpc/mm/kasan: rename kasan_init_32.c to init_32.c Daniel Axtens
2021-03-19 14:40 ` [PATCH v11 6/6] powerpc: Book3S 64-bit outline-only KASAN support Daniel Axtens
2021-03-20 6:02 ` Balbir Singh
2021-03-22 0:55 ` Daniel Axtens [this message]
2021-03-22 2:59 ` Balbir Singh
2021-03-22 5:52 ` Daniel Axtens
2021-03-22 15:14 ` Christophe Leroy
2021-04-21 12:29 ` Christophe Leroy
2021-03-20 1:40 ` [PATCH v11 0/6] KASAN for powerpc64 radix Balbir Singh
2021-03-22 14:32 ` Christophe Leroy
2021-03-23 1:21 ` Daniel Axtens
2021-03-23 13:27 ` Christophe Leroy
2021-03-29 23:53 ` Michael Ellerman
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