From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>
Cc: "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Kees Cook <keescook@chromium.org>,
Russell Currey <ruscur@russell.cc>
Subject: Re: [PATCH v2 37/37] powerpc: Support execute-only on all powerpc
Date: Mon, 6 Nov 2023 13:23:05 +0000 [thread overview]
Message-ID: <efcfb376-5b43-4f35-e1d2-8cfce782ae3d@csgroup.eu> (raw)
In-Reply-To: <874ji4af3a.fsf@linux.ibm.com>
Le 02/11/2023 à 06:39, Aneesh Kumar K.V a écrit :
> Christophe Leroy <christophe.leroy@csgroup.eu> writes:
>
>> Introduce PAGE_EXECONLY_X macro which provides exec-only rights.
>> The _X may be seen as redundant with the EXECONLY but it helps
>> keep consistancy, all macros having the EXEC right have _X.
>>
>> And put it next to PAGE_NONE as PAGE_EXECONLY_X is
>> somehow PAGE_NONE + EXEC just like all other SOMETHING_X are
>> just SOMETHING + EXEC.
>>
>> On book3s/64 PAGE_EXECONLY becomes PAGE_READONLY_X.
>>
>> On book3s/64, as PAGE_EXECONLY is only valid for Radix add
>> VM_READ flag in vm_get_page_prot() for non-Radix.
>>
>> And update access_error() so that a non exec fault on a VM_EXEC only
>> mapping is always invalid, even when the underlying layer don't
>> always generate a fault for that.
>>
>> For 8xx, set PAGE_EXECONLY_X as _PAGE_NA | _PAGE_EXEC.
>> For others, only set it as just _PAGE_EXEC
>>
>> With that change, 8xx, e500 and 44x fully honor execute-only
>> protection.
>>
>> On 40x that is a partial implementation of execute-only. The
>> implementation won't be complete because once a TLB has been loaded
>> via the Instruction TLB miss handler, it will be possible to read
>> the page. But at least it can't be read unless it is executed first.
>>
>> On 603 MMU, TLB missed are handled by SW and there are separate
>> DTLB and ITLB. Execute-only is therefore now supported by not loading
>> DTLB when read access is not permitted.
>>
>> On hash (604) MMU it is more tricky because hash table is common to
>> load/store and execute. Nevertheless it is still possible to check
>> whether _PAGE_READ is set before loading hash table for a load/store
>> access. At least it can't be read unless it is executed first.
>>
>> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
>> Cc: Russell Currey <ruscur@russell.cc>
>> Cc: Kees Cook <keescook@chromium.org>
>> ---
>> arch/powerpc/include/asm/book3s/32/pgtable.h | 2 +-
>> arch/powerpc/include/asm/book3s/64/pgtable.h | 4 +---
>> arch/powerpc/include/asm/nohash/32/pte-8xx.h | 1 +
>> arch/powerpc/include/asm/nohash/pgtable.h | 2 +-
>> arch/powerpc/include/asm/nohash/pte-e500.h | 1 +
>> arch/powerpc/include/asm/pgtable-masks.h | 2 ++
>> arch/powerpc/mm/book3s64/pgtable.c | 10 ++++------
>> arch/powerpc/mm/fault.c | 9 +++++----
>> arch/powerpc/mm/pgtable.c | 4 ++--
>> 9 files changed, 18 insertions(+), 17 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h
>> index 244621c88510..52971ee30717 100644
>> --- a/arch/powerpc/include/asm/book3s/32/pgtable.h
>> +++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
>> @@ -425,7 +425,7 @@ static inline bool pte_access_permitted(pte_t pte, bool write)
>> {
>> /*
>> * A read-only access is controlled by _PAGE_READ bit.
>> - * We have _PAGE_READ set for WRITE and EXECUTE
>> + * We have _PAGE_READ set for WRITE
>> */
>> if (!pte_present(pte) || !pte_read(pte))
>> return false;
>>
>
> Should this now be updated to check for EXEC bit ?
I don't think so based on what I see in arm64:
https://elixir.bootlin.com/linux/v6.6/source/arch/arm64/include/asm/pgtable.h#L146
Christophe
next prev parent reply other threads:[~2023-11-06 13:24 UTC|newest]
Thread overview: 95+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-25 18:31 [PATCH v2 00/37] Implement execute-only protection on powerpc Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 01/37] powerpc/8xx: Fix pte_access_permitted() for PAGE_NONE Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 02/37] powerpc/64e: Fix wrong test in __ptep_test_and_clear_young() Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 03/37] powerpc/40x: Remove stale PTE_ATOMIC_UPDATES macro Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 04/37] powerpc: Remove pte_ERROR() Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 05/37] powerpc: Deduplicate prototypes of ptep_set_access_flags() and phys_mem_access_prot() Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 06/37] powerpc: Refactor update_mmu_cache_range() Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 07/37] powerpc: Untangle fixmap.h and pgtable.h and mmu.h Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 08/37] powerpc/nohash: Remove {pte/pmd}_protnone() Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 09/37] powerpc/nohash: Refactor declaration of {map/unmap}_kernel_page() Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 10/37] powerpc/nohash: Move 8xx version of pte_update() into pte-8xx.h Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 11/37] powerpc/nohash: Replace #ifdef CONFIG_44x by IS_ENABLED(CONFIG_44x) in pgtable.h Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 12/37] powerpc/nohash: Refactor pte_update() Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 13/37] powerpc/nohash: Refactor checking of no-change in pte_update() Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 14/37] powerpc/nohash: Deduplicate _PAGE_CHG_MASK Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 15/37] powerpc/nohash: Deduplicate pte helpers Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 16/37] powerpc/nohash: Refactor ptep_test_and_clear_young() Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 17/37] powerpc/nohash: Deduplicate ptep_set_wrprotect() and ptep_get_and_clear() Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 18/37] powerpc/nohash: Refactor pte_clear() Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 19/37] powerpc/nohash: Refactor __ptep_set_access_flags() Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 20/37] powerpc/e500: Simplify pte_mkexec() Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 21/37] powerpc: Implement and use pgprot_nx() Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 22/37] powerpc: Fail ioremap() instead of silently ignoring flags when PAGE_USER is set Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 23/37] powerpc: Remove pte_mkuser() and pte_mkpriviledged() Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 24/37] powerpc: Rely on address instead of pte_user() Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 25/37] powerpc: Refactor permission masks used for __P/__S table and kernel memory flags Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 26/37] powerpc/8xx: Use generic permission masks Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 27/37] powerpc/64s: " Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 28/37] powerpc/nohash: Add _PAGE_WRITE to supplement _PAGE_RW Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 29/37] powerpc/nohash: Replace pte_user() by pte_read() Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-10-31 10:15 ` Aneesh Kumar K.V
2023-10-31 10:15 ` Aneesh Kumar K.V
2023-11-06 13:21 ` Christophe Leroy
2023-11-07 13:34 ` Aneesh Kumar K.V
2023-11-09 18:20 ` Christophe Leroy
2023-11-13 10:23 ` Aneesh Kumar K.V
2023-11-23 15:55 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 30/37] powerpc/e500: Introduce _PAGE_READ and remove _PAGE_USER Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 31/37] powerpc/44x: " Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 32/37] powerpc/40x: " Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 33/37] powerpc/32s: Add _PAGE_WRITE to supplement _PAGE_RW Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 34/37] powerpc/32s: Introduce _PAGE_READ and remove _PAGE_USER Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 35/37] powerpc/ptdump: Display _PAGE_READ and _PAGE_WRITE Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 36/37] powerpc: Finally remove _PAGE_USER Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-09-25 18:31 ` [PATCH v2 37/37] powerpc: Support execute-only on all powerpc Christophe Leroy
2023-09-25 18:31 ` Christophe Leroy
2023-11-02 5:39 ` Aneesh Kumar K.V
2023-11-02 5:39 ` Aneesh Kumar K.V
2023-11-06 13:23 ` Christophe Leroy [this message]
2023-11-07 6:15 ` Aneesh Kumar K V
2023-11-07 6:15 ` Aneesh Kumar K V
2023-11-09 17:38 ` Christophe Leroy
2023-11-09 17:38 ` Christophe Leroy
2023-11-09 17:38 ` Christophe Leroy
2023-10-15 10:00 ` (subset) [PATCH v2 00/37] Implement execute-only protection on powerpc Michael Ellerman
2023-10-15 10:00 ` Michael Ellerman
2023-10-27 9:59 ` Michael Ellerman
2023-10-27 9:59 ` Michael Ellerman
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