From: Michael Ellerman <mpe@ellerman•id.au>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux•ibm.com>,
linuxppc-dev@lists•ozlabs.org
Cc: linuxram@us•ibm.com, bauerman@linux•ibm.com
Subject: Re: [PATCH v5 18/26] powerpc/book3s64/keys/kuap: Reset AMR/IAMR values on kexec
Date: Tue, 07 Jul 2020 11:07:24 +1000 [thread overview]
Message-ID: <87wo3g3zg3.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <2739323b-51c0-c713-0986-aa0bdaab3184@linux.ibm.com>
"Aneesh Kumar K.V" <aneesh.kumar@linux•ibm.com> writes:
> On 7/6/20 5:59 PM, Michael Ellerman wrote:
>> "Aneesh Kumar K.V" <aneesh.kumar@linux•ibm.com> writes:
>>> As we kexec across kernels that use AMR/IAMR for different purposes
>>> we need to ensure that new kernels get kexec'd with a reset value
>>> of AMR/IAMR. For ex: the new kernel can use key 0 for kernel mapping and the old
>>> AMR value prevents access to key 0.
>>>
>>> This patch also removes reset if IAMR and AMOR in kexec_sequence. Reset of AMOR
>>> is not needed and the IAMR reset is partial (it doesn't do the reset
>>> on secondary cpus) and is redundant with this patch.
>>
>> I like the idea of cleaning this stuff up.
>>
>> But I think tying it into kup/kuep/kuap and the MMU features and ifdefs
>> and so on is overly complicated.
>>
>> We should just have eg:
>>
>> void reset_sprs(void)
>> {
>> if (early_cpu_has_feature(CPU_FTR_ARCH_206)) {
>> mtspr(SPRN_AMR, 0);
>> mtspr(SPRN_UAMOR, 0);
>> }
>>
>> if (early_cpu_has_feature(CPU_FTR_ARCH_207S)) {
>> mtspr(SPRN_IAMR, 0);
>> }
>> }
>>
>> And call that from the kexec paths.
>
> Will fix. Should that be early_cpu_has_feature()? cpu_has_feature()
> should work there right?
Yeah I guess. I was thinking if we crashed before code patching was
done, but if that happens we can't kdump anyway. So I'm probably being
over paranoid.
cheers
next prev parent reply other threads:[~2020-07-07 1:07 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-19 13:58 [PATCH v5 00/26] powerpc/book3s/64/pkeys: Simplify the code Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 01/26] powerpc/book3s64/pkeys: Fixup bit numbering Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 02/26] powerpc/book3s64/pkeys: pkeys are supported only on hash on book3s Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 03/26] powerpc/book3s64/pkeys: Move pkey related bits in the linux page table Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 04/26] powerpc/book3s64/pkeys: Explain key 1 reservation details Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 05/26] powerpc/book3s64/pkeys: Simplify the key initialization Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 06/26] powerpc/book3s64/pkeys: Prevent key 1 modification from userspace Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 07/26] powerpc/book3s64/pkeys: kill cpu feature key CPU_FTR_PKEY Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 08/26] powerpc/book3s64/pkeys: Convert execute key support to static key Aneesh Kumar K.V
2020-07-06 7:19 ` Michael Ellerman
2020-07-06 8:47 ` Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 09/26] powerpc/book3s64/pkeys: Simplify pkey disable branch Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 10/26] powerpc/book3s64/pkeys: Convert pkey_total to max_pkey Aneesh Kumar K.V
2020-07-06 7:04 ` Michael Ellerman
2020-07-06 7:20 ` Aneesh Kumar K.V
2020-07-07 1:26 ` Michael Ellerman
2020-06-19 13:58 ` [PATCH v5 11/26] powerpc/book3s64/pkeys: Make initial_allocation_mask static Aneesh Kumar K.V
2020-07-06 7:04 ` Michael Ellerman
2020-07-06 8:48 ` Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 12/26] powerpc/book3s64/pkeys: Mark all the pkeys above max pkey as reserved Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 13/26] powerpc/book3s64/pkeys: Enable MMU_FTR_PKEY Aneesh Kumar K.V
2020-07-06 13:10 ` Michael Ellerman
2020-07-06 14:09 ` Aneesh Kumar K.V
2020-07-06 17:17 ` Aneesh Kumar K.V
2020-07-07 1:02 ` Michael Ellerman
2020-06-19 13:58 ` [PATCH v5 14/26] powerpc/book3s64/kuep: Add MMU_FTR_KUEP Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 15/26] powerpc/book3s64/pkeys: Use execute_pkey_disable static key Aneesh Kumar K.V
2020-07-06 7:20 ` Michael Ellerman
2020-07-06 8:49 ` Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 16/26] powerpc/book3s64/pkeys: Use MMU_FTR_PKEY instead of pkey_disabled " Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 17/26] powerpc/book3s64/keys: Print information during boot Aneesh Kumar K.V
2020-07-06 7:52 ` Michael Ellerman
2020-06-19 13:58 ` [PATCH v5 18/26] powerpc/book3s64/keys/kuap: Reset AMR/IAMR values on kexec Aneesh Kumar K.V
2020-07-06 12:29 ` Michael Ellerman
2020-07-06 14:39 ` Aneesh Kumar K.V
2020-07-07 1:07 ` Michael Ellerman [this message]
2020-06-19 13:58 ` [PATCH v5 19/26] powerpc/book3s64/kuap: Move KUAP related function outside radix Aneesh Kumar K.V
2020-07-06 12:41 ` Michael Ellerman
2020-07-06 14:41 ` Aneesh Kumar K.V
2020-07-07 1:22 ` Michael Ellerman
2020-06-19 13:58 ` [PATCH v5 20/26] powerpc/book3s64/kuep: Move KUEP " Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 21/26] powerpc/book3s64/kuap: Rename MMU_FTR_RADIX_KUAP to MMU_FTR_KUAP Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 22/26] powerpc/book3s64/kuap/kuep: Make KUAP and KUEP a subfeature of PPC_MEM_KEYS Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 23/26] powerpc/book3s64/kuap: Move UAMOR setup to key init function Aneesh Kumar K.V
2020-07-07 6:05 ` Michael Ellerman
2020-07-07 11:25 ` Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 24/26] powerpc/selftest/ptrave-pkey: Rename variables to make it easier to follow code Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 25/26] powerpc/selftest/ptrace-pkey: Update the test to mark an invalid pkey correctly Aneesh Kumar K.V
2020-06-19 13:58 ` [PATCH v5 26/26] powerpc/selftest/ptrace-pkey: IAMR and uamor cannot be updated by ptrace Aneesh Kumar K.V
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