From: Michael Ellerman <mpe@ellerman•id.au>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux•ibm.com>,
linuxppc-dev@lists•ozlabs.org
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux•ibm.com>
Subject: Re: [PATCH v6 04/22] powerpc/book3s64/kuap/kuep: Move uamor setup to pkey init
Date: Thu, 26 Nov 2020 14:28:15 +1100 [thread overview]
Message-ID: <87tutcyey8.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <20201125051634.509286-5-aneesh.kumar@linux.ibm.com>
"Aneesh Kumar K.V" <aneesh.kumar@linux•ibm.com> writes:
> This patch consolidates UAMOR update across pkey, kuap and kuep features.
> The boot cpu initialize UAMOR via pkey init and both radix/hash do the
> secondary cpu UAMOR init in early_init_mmu_secondary.
>
> We don't check for mmu_feature in radix secondary init because UAMOR
> is a supported SPRN with all CPUs supporting radix translation.
> The old code was not updating UAMOR if we had smap disabled and smep enabled.
> This change handles that case.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux•ibm.com>
> ---
> arch/powerpc/mm/book3s64/radix_pgtable.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
> index 3adcf730f478..bfe441af916a 100644
> --- a/arch/powerpc/mm/book3s64/radix_pgtable.c
> +++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
> @@ -620,9 +620,6 @@ void setup_kuap(bool disabled)
> cur_cpu_spec->mmu_features |= MMU_FTR_RADIX_KUAP;
> }
>
> - /* Make sure userspace can't change the AMR */
> - mtspr(SPRN_UAMOR, 0);
> -
> /*
> * Set the default kernel AMR values on all cpus.
> */
> @@ -721,6 +718,11 @@ void radix__early_init_mmu_secondary(void)
>
> radix__switch_mmu_context(NULL, &init_mm);
> tlbiel_all();
> +
> +#ifdef CONFIG_PPC_PKEY
> + /* Make sure userspace can't change the AMR */
> + mtspr(SPRN_UAMOR, 0);
> +#endif
If PPC_PKEY is disabled I think this leaves UAMOR unset, which means it
could potentially allow AMR to be used as a covert channel between
processes.
cheers
next prev parent reply other threads:[~2020-11-26 3:29 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-25 5:16 [PATCH v6 00/22] Kernel userspace access/execution prevention with hash translation Aneesh Kumar K.V
2020-11-25 5:16 ` [PATCH v6 01/22] powerpc: Add new macro to handle NESTED_IFCLR Aneesh Kumar K.V
2020-11-25 5:16 ` [PATCH v6 02/22] KVM: PPC: BOOK3S: PR: Ignore UAMOR SPR Aneesh Kumar K.V
2020-11-25 5:16 ` [PATCH v6 03/22] powerpc/book3s64/kuap/kuep: Make KUAP and KUEP a subfeature of PPC_MEM_KEYS Aneesh Kumar K.V
2020-11-25 13:30 ` Christophe Leroy
2020-11-25 14:57 ` Aneesh Kumar K.V
2020-11-26 3:25 ` Michael Ellerman
2020-11-25 5:16 ` [PATCH v6 04/22] powerpc/book3s64/kuap/kuep: Move uamor setup to pkey init Aneesh Kumar K.V
2020-11-25 13:32 ` Christophe Leroy
2020-11-26 3:28 ` Michael Ellerman [this message]
2020-11-25 5:16 ` [PATCH v6 05/22] powerpc/book3s64/kuap: Move KUAP related function outside radix Aneesh Kumar K.V
2020-11-25 5:16 ` [PATCH v6 06/22] powerpc/book3s64/kuep: Move KUEP " Aneesh Kumar K.V
2020-11-25 5:16 ` [PATCH v6 07/22] powerpc/book3s64/kuap: Rename MMU_FTR_RADIX_KUAP to MMU_FTR_KUAP Aneesh Kumar K.V
2020-11-25 13:43 ` Christophe Leroy
2020-11-25 13:52 ` Aneesh Kumar K.V
2020-11-26 3:16 ` Michael Ellerman
2020-11-25 5:16 ` [PATCH v6 08/22] powerpc/book3s64/kuap: Use Key 3 for kernel mapping with hash translation Aneesh Kumar K.V
2020-11-25 5:16 ` [PATCH v6 09/22] powerpc/exec: Set thread.regs early during exec Aneesh Kumar K.V
2020-11-25 13:47 ` Christophe Leroy
2020-11-26 7:38 ` Aneesh Kumar K.V
2020-11-26 7:43 ` Christophe Leroy
2020-11-25 5:16 ` [PATCH v6 10/22] powerpc/book3s64/pkeys: Store/restore userspace AMR/IAMR correctly on entry and exit from kernel Aneesh Kumar K.V
2020-11-25 13:52 ` Christophe Leroy
2020-11-25 13:55 ` Aneesh Kumar K.V
2020-11-25 14:16 ` Christophe Leroy
2020-11-25 5:16 ` [PATCH v6 11/22] powerpc/book3s64/pkeys: Inherit correctly on fork Aneesh Kumar K.V
2020-11-25 13:54 ` Christophe Leroy
2020-11-25 13:56 ` Aneesh Kumar K.V
2020-11-25 5:16 ` [PATCH v6 12/22] powerpc/book3s64/pkeys: Reset userspace AMR correctly on exec Aneesh Kumar K.V
2020-11-25 5:16 ` [PATCH v6 13/22] powerpc/ptrace-view: Use pt_regs values instead of thread_struct based one Aneesh Kumar K.V
2020-11-25 5:16 ` [PATCH v6 14/22] powerpc/book3s64/pkeys: Don't update SPRN_AMR when in kernel mode Aneesh Kumar K.V
2020-11-25 5:16 ` [PATCH v6 15/22] powerpc/book3s64/kuap: Restrict access to userspace based on userspace AMR Aneesh Kumar K.V
2020-11-25 5:16 ` [PATCH v6 16/22] powerpc/book3s64/kuap: Improve error reporting with KUAP Aneesh Kumar K.V
2020-11-25 14:04 ` Christophe Leroy
2020-11-26 7:44 ` Aneesh Kumar K.V
2020-11-26 9:29 ` Michael Ellerman
2020-11-26 10:39 ` Christophe Leroy
2020-11-25 5:16 ` [PATCH v6 17/22] powerpc/book3s64/kuap: Use Key 3 to implement KUAP with hash translation Aneesh Kumar K.V
2020-11-25 5:16 ` [PATCH v6 18/22] powerpc/book3s64/kuep: Use Key 3 to implement KUEP " Aneesh Kumar K.V
2020-11-25 5:16 ` [PATCH v6 19/22] powerpc/book3s64/hash/kuap: Enable kuap on hash Aneesh Kumar K.V
2021-03-15 12:06 ` Christophe Leroy
2021-03-15 12:59 ` Aneesh Kumar K.V
2021-03-15 13:02 ` Christophe Leroy
2021-10-08 9:32 ` Christophe Leroy
2021-10-11 3:28 ` Michael Ellerman
2020-11-25 5:16 ` [PATCH v6 20/22] powerpc/book3s64/hash/kuep: Enable KUEP " Aneesh Kumar K.V
2020-11-25 5:16 ` [PATCH v6 21/22] powerpc/book3s64/hash/kup: Don't hardcode kup key Aneesh Kumar K.V
2020-11-25 5:16 ` [PATCH v6 22/22] powerpc/book3s64/pkeys: Optimize FTR_KUAP and FTR_KUEP disabled case Aneesh Kumar K.V
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