From: Michael Ellerman <mpe@ellerman.id.au>
To: Daniel Axtens <dja@axtens.net>, 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 1/6] kasan: allow an architecture to disable inline instrumentation
Date: Mon, 22 Mar 2021 22:08:05 +1100 [thread overview]
Message-ID: <87v99jh2ei.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <87r1k8av4j.fsf@dja-thinkpad.axtens.net>
Daniel Axtens <dja@axtens.net> writes:
> Balbir Singh <bsingharora@gmail.com> writes:
>
>> On Sat, Mar 20, 2021 at 01:40:53AM +1100, Daniel Axtens wrote:
>>> For annoying architectural reasons, it's very difficult to support inline
>>> instrumentation on powerpc64.
>>
>> I think we can expand here and talk about how in hash mode, the vmalloc
>> address space is in a region of memory different than where kernel virtual
>> addresses are mapped. Did I recollect the reason correctly?
>
> I think that's _a_ reason, but for radix mode (which is all I support at
> the moment), the reason is a bit simpler.
Actually Aneesh fixed that in:
0034d395f89d ("powerpc/mm/hash64: Map all the kernel regions in the same 0xc range")
The problem we had prior to that was that the linear mapping was at
(0xc << 60), vmalloc was at (0xd << 60), and vmemap was at (0xf << 60).
Meaning our shadow region would need to be more than (3 << 60) in size.
cheers
WARNING: multiple messages have this Message-ID (diff)
From: Michael Ellerman <mpe@ellerman.id.au>
To: Daniel Axtens <dja@axtens.net>, Balbir Singh <bsingharora@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linuxppc-dev@lists.ozlabs.org, kasan-dev@googlegroups.com,
christophe.leroy@csgroup.eu, aneesh.kumar@linux.ibm.com
Subject: Re: [PATCH v11 1/6] kasan: allow an architecture to disable inline instrumentation
Date: Mon, 22 Mar 2021 22:08:05 +1100 [thread overview]
Message-ID: <87v99jh2ei.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <87r1k8av4j.fsf@dja-thinkpad.axtens.net>
Daniel Axtens <dja@axtens.net> writes:
> Balbir Singh <bsingharora@gmail.com> writes:
>
>> On Sat, Mar 20, 2021 at 01:40:53AM +1100, Daniel Axtens wrote:
>>> For annoying architectural reasons, it's very difficult to support inline
>>> instrumentation on powerpc64.
>>
>> I think we can expand here and talk about how in hash mode, the vmalloc
>> address space is in a region of memory different than where kernel virtual
>> addresses are mapped. Did I recollect the reason correctly?
>
> I think that's _a_ reason, but for radix mode (which is all I support at
> the moment), the reason is a bit simpler.
Actually Aneesh fixed that in:
0034d395f89d ("powerpc/mm/hash64: Map all the kernel regions in the same 0xc range")
The problem we had prior to that was that the linear mapping was at
(0xc << 60), vmalloc was at (0xd << 60), and vmemap was at (0xf << 60).
Meaning our shadow region would need to be more than (3 << 60) in size.
cheers
next prev parent reply other threads:[~2021-03-22 11:08 UTC|newest]
Thread overview: 34+ 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
2021-03-20 1:46 ` Balbir Singh
2021-03-22 0:29 ` Daniel Axtens
2021-03-22 0:29 ` Daniel Axtens
2021-03-22 11:08 ` Michael Ellerman [this message]
2021-03-22 11:08 ` Michael Ellerman
2021-03-22 8:18 ` Marco Elver
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
2021-03-19 14:40 ` Daniel Axtens
2021-03-22 8:17 ` Marco Elver
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
2021-03-20 6:02 ` Balbir Singh
2021-03-22 0:55 ` Daniel Axtens
2021-03-22 0:55 ` Daniel Axtens
2021-03-22 2:59 ` Balbir Singh
2021-03-22 2:59 ` Balbir Singh
2021-03-22 5:52 ` Daniel Axtens
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
2021-03-20 1:40 ` 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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