From: Ram Pai <linuxram@us.ibm.com>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org,
linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org,
benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au,
khandual@linux.vnet.ibm.com, bsingharora@gmail.com,
dave.hansen@intel.com, hbabu@us.ibm.com, arnd@arndb.de,
akpm@linux-foundation.org, corbet@lwn.net, mingo@redhat.com,
mhocko@kernel.org
Subject: Re: [RFC v6 27/62] powerpc: helper to validate key-access permissions of a pte
Date: Fri, 21 Jul 2017 09:42:30 -0700 [thread overview]
Message-ID: <20170721164230.GK5487@ram.oc3035372033.ibm.com> (raw)
In-Reply-To: <87k232p9ix.fsf@skywalker.in.ibm.com>
On Fri, Jul 21, 2017 at 12:21:50PM +0530, Aneesh Kumar K.V wrote:
> Ram Pai <linuxram@us.ibm.com> writes:
>
> > On Thu, Jul 20, 2017 at 12:12:47PM +0530, Aneesh Kumar K.V wrote:
> >> Ram Pai <linuxram@us.ibm.com> writes:
> >>
> >> > helper function that checks if the read/write/execute is allowed
> >> > on the pte.
> >> >
> >> > Signed-off-by: Ram Pai <linuxram@us.ibm.com>
> >> > ---
> >> > arch/powerpc/include/asm/book3s/64/pgtable.h | 4 +++
> >> > arch/powerpc/include/asm/pkeys.h | 12 +++++++++
> >> > arch/powerpc/mm/pkeys.c | 33 ++++++++++++++++++++++++++
> >> > 3 files changed, 49 insertions(+), 0 deletions(-)
> >> >
> >> > diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
> >> > index 30d7f55..0056e58 100644
> >> > --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
> >> > +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
> >> > @@ -472,6 +472,10 @@ static inline void write_uamor(u64 value)
> >> > mtspr(SPRN_UAMOR, value);
> >> > }
> >> >
> >> > +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS
> >> > +extern bool arch_pte_access_permitted(u64 pte, bool write, bool execute);
> >> > +#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
> >> > +
> >> > #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
> >> > static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
> >> > unsigned long addr, pte_t *ptep)
> >> > diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
> >> > index bbb5d85..7a9aade 100644
> >> > --- a/arch/powerpc/include/asm/pkeys.h
> >> > +++ b/arch/powerpc/include/asm/pkeys.h
> >> > @@ -53,6 +53,18 @@ static inline u64 pte_to_hpte_pkey_bits(u64 pteflags)
> >> > ((pteflags & H_PAGE_PKEY_BIT4) ? HPTE_R_KEY_BIT4 : 0x0UL));
> >> > }
> >> >
> >> > +static inline u16 pte_to_pkey_bits(u64 pteflags)
> >> > +{
> >> > + if (!pkey_inited)
> >> > + return 0x0UL;
> >>
> >> Do we really need that above check ? We should always find it
> >> peky_inited to be set.
> >
> > Yes. there are cases where pkey_inited is not enabled.
> > a) if the MMU is radix.
> That should be be a feature check
>
> > b) if the PAGE size is 4k.
>
> That is a kernel config change
>
> > c) if the device tree says the feature is not available
> > d) if the CPU is of a older generation. P6 and older.
>
> Both feature check.
>
> how about doing something like
>
> static inline u16 pte_to_pkey_bits(u64 pteflags)
> {
> if (!(pteflags & H_PAGE_KEY_MASK))
> return 0x0UL;
This check accomplishes the same thing as the return below.
When (pteflag & H_PAGE_KEY_MASK) is 0,
the code below returns the same 0x0UL.
>
> return (((pteflags & H_PAGE_PKEY_BIT0) ? 0x10 : 0x0UL) |
> ((pteflags & H_PAGE_PKEY_BIT1) ? 0x8 : 0x0UL) |
> ((pteflags & H_PAGE_PKEY_BIT2) ? 0x4 : 0x0UL) |
> ((pteflags & H_PAGE_PKEY_BIT3) ? 0x2 : 0x0UL) |
> ((pteflags & H_PAGE_PKEY_BIT4) ? 0x1 : 0x0UL));
> }
The idea behind
if (!pkey_inited)
return 0x0UL;
was to not interpret the ptebits if we knew they were not initialized
to begin with.
--
Ram Pai
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next prev parent reply other threads:[~2017-07-21 16:42 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-16 3:56 [RFC v6 00/62] powerpc: Memory Protection Keys Ram Pai
2017-07-16 3:56 ` [RFC v6 01/62] powerpc: Free up four 64K PTE bits in 4K backed HPTE pages Ram Pai
2017-07-20 5:51 ` Aneesh Kumar K.V
2017-07-20 22:03 ` Ram Pai
2017-07-16 3:56 ` [RFC v6 02/62] powerpc: Free up four 64K PTE bits in 64K " Ram Pai
2017-07-20 5:53 ` Aneesh Kumar K.V
2017-07-16 3:56 ` [RFC v6 03/62] powerpc: introduce pte_set_hash_slot() helper Ram Pai
2017-07-20 5:56 ` Aneesh Kumar K.V
2017-07-16 3:56 ` [RFC v6 04/62] powerpc: introduce pte_get_hash_gslot() helper Ram Pai
2017-07-20 5:57 ` Aneesh Kumar K.V
2017-07-16 3:56 ` [RFC v6 05/62] powerpc: capture the PTE format changes in the dump pte report Ram Pai
2017-07-20 5:56 ` Aneesh Kumar K.V
2017-07-16 3:56 ` [RFC v6 06/62] powerpc: use helper functions in __hash_page_64K() for 64K PTE Ram Pai
2017-07-20 5:58 ` Aneesh Kumar K.V
2017-07-16 3:56 ` [RFC v6 07/62] powerpc: use helper functions in __hash_page_huge() " Ram Pai
2017-07-20 5:58 ` Aneesh Kumar K.V
2017-07-16 3:56 ` [RFC v6 08/62] powerpc: use helper functions in __hash_page_4K() " Ram Pai
2017-07-16 3:56 ` [RFC v6 09/62] powerpc: use helper functions in __hash_page_4K() for 4K PTE Ram Pai
2017-07-16 3:56 ` [RFC v6 10/62] powerpc: use helper functions in flush_hash_page() Ram Pai
2017-07-16 3:56 ` [RFC v6 11/62] powerpc: initial pkey plumbing Ram Pai
2017-07-20 6:04 ` Aneesh Kumar K.V
2017-07-20 22:11 ` Ram Pai
2017-07-16 3:56 ` [RFC v6 12/62] mm: introduce an additional vma bit for powerpc pkey Ram Pai
2017-07-16 3:56 ` [RFC v6 13/62] powerpc: track allocation status of all pkeys Ram Pai
2017-07-27 14:01 ` Thiago Jung Bauermann
2017-07-29 22:43 ` Ram Pai
2017-07-31 18:15 ` Thiago Jung Bauermann
2017-07-16 3:56 ` [RFC v6 14/62] powerpc: helper function to read,write AMR,IAMR,UAMOR registers Ram Pai
2017-07-16 3:56 ` [RFC v6 15/62] powerpc: helper functions to initialize AMR, IAMR and UMOR registers Ram Pai
2017-07-27 20:40 ` Thiago Jung Bauermann
2017-07-30 0:38 ` Ram Pai
2017-07-16 3:56 ` [RFC v6 16/62] powerpc: cleaup AMR,iAMR when a key is allocated or freed Ram Pai
2017-07-16 3:56 ` [RFC v6 17/62] powerpc: implementation for arch_set_user_pkey_access() Ram Pai
2017-07-27 14:15 ` Thiago Jung Bauermann
2017-07-29 22:59 ` Ram Pai
2017-07-16 3:56 ` [RFC v6 18/62] powerpc: sys_pkey_alloc() and sys_pkey_free() system calls Ram Pai
2017-07-16 3:56 ` [RFC v6 19/62] powerpc: ability to create execute-disabled pkeys Ram Pai
2017-07-27 14:54 ` Thiago Jung Bauermann
2017-07-27 15:34 ` Thiago Jung Bauermann
2017-07-29 23:24 ` Ram Pai
2017-07-31 12:59 ` Michael Ellerman
2017-07-16 3:56 ` [RFC v6 20/62] powerpc: store and restore the pkey state across context switches Ram Pai
2017-07-27 17:32 ` Thiago Jung Bauermann
2017-07-29 23:31 ` Ram Pai
2017-07-31 13:00 ` Michael Ellerman
2017-07-16 3:56 ` [RFC v6 21/62] powerpc: introduce execute-only pkey Ram Pai
2017-07-28 22:17 ` Thiago Jung Bauermann
2017-07-30 0:51 ` Ram Pai
2017-07-31 16:19 ` Thiago Jung Bauermann
2017-08-01 6:46 ` Michael Ellerman
2017-08-01 16:14 ` Thiago Jung Bauermann
2017-08-02 9:40 ` Michael Ellerman
[not found] ` <20170817233555.GC5427@ram.oc3035372033.ibm.com>
2017-08-17 23:42 ` Ram Pai
2017-07-16 3:56 ` [RFC v6 22/62] powerpc: ability to associate pkey to a vma Ram Pai
2017-07-16 3:56 ` [RFC v6 23/62] powerpc: implementation for arch_override_mprotect_pkey() Ram Pai
2017-07-16 3:56 ` [RFC v6 24/62] powerpc: map vma key-protection bits to pte key bits Ram Pai
2017-07-16 3:56 ` [RFC v6 25/62] powerpc: sys_pkey_mprotect() system call Ram Pai
2017-07-16 3:56 ` [RFC v6 26/62] powerpc: Program HPTE key protection bits Ram Pai
2017-07-20 6:28 ` Aneesh Kumar K.V
2017-07-16 3:56 ` [RFC v6 27/62] powerpc: helper to validate key-access permissions of a pte Ram Pai
2017-07-20 6:42 ` Aneesh Kumar K.V
2017-07-20 22:15 ` Ram Pai
2017-07-21 6:51 ` Aneesh Kumar K.V
2017-07-21 16:42 ` Ram Pai [this message]
2017-07-28 21:00 ` Thiago Jung Bauermann
2017-07-30 0:39 ` Ram Pai
2017-07-16 3:56 ` [RFC v6 28/62] powerpc: check key protection for user page access Ram Pai
2017-07-16 3:56 ` [RFC v6 29/62] powerpc: Macro the mask used for checking DSI exception Ram Pai
2017-07-16 3:56 ` [RFC v6 30/62] powerpc: implementation for arch_vma_access_permitted() Ram Pai
2017-07-16 3:56 ` [RFC v6 31/62] powerpc: Handle exceptions caused by pkey violation Ram Pai
2017-07-16 3:56 ` [RFC v6 32/62] powerpc: capture AMR register content on " Ram Pai
2017-07-16 3:56 ` [RFC v6 33/62] powerpc: introduce get_pte_pkey() helper Ram Pai
2017-07-16 3:56 ` [RFC v6 34/62] powerpc: capture the violated protection key on fault Ram Pai
2017-07-16 3:56 ` [RFC v6 35/62] powerpc: Deliver SEGV signal on pkey violation Ram Pai
2017-08-19 19:09 ` Eric W. Biederman
2017-08-22 18:06 ` Ram Pai
2017-07-16 3:56 ` [RFC v6 36/62] mm: introduce arch_pkeys_enabled() Ram Pai
2017-07-16 3:56 ` [RFC v6 37/62] x86: implementation for arch_pkeys_enabled() Ram Pai
2017-07-16 3:56 ` [RFC v6 38/62] powerpc: " Ram Pai
2017-07-16 3:56 ` [RFC v6 39/62] mm: display pkey in smaps if arch_pkeys_enabled() is true Ram Pai
2017-07-16 3:56 ` [RFC v6 40/62] x86: delete arch_show_smap() Ram Pai
2017-07-16 3:56 ` [RFC v6 41/62] selftest/x86: Move protecton key selftest to arch neutral directory Ram Pai
2017-07-16 3:56 ` [RFC v6 42/62] selftest/vm: rename all references to pkru to a generic name Ram Pai
2017-07-16 3:56 ` [RFC v6 43/62] selftest/vm: move generic definitions to header file Ram Pai
2017-07-16 3:56 ` [RFC v6 44/62] selftest/vm: typecast the pkey register Ram Pai
2017-07-16 3:56 ` [RFC v6 45/62] selftest/vm: generics function to handle shadow key register Ram Pai
2017-07-16 3:56 ` [RFC v6 46/62] selftest/vm: fix the wrong assert in pkey_disable_set() Ram Pai
2017-07-16 3:56 ` [RFC v6 47/62] selftest/vm: fixed bugs in pkey_disable_clear() Ram Pai
2017-07-16 3:56 ` [RFC v6 48/62] selftest/vm: clear the bits in shadow reg when a pkey is freed Ram Pai
2017-07-16 3:56 ` [RFC v6 49/62] selftest/vm: fix alloc_random_pkey() to make it really random Ram Pai
2017-07-16 3:56 ` [RFC v6 50/62] selftest/vm: introduce two arch independent abstraction Ram Pai
2017-07-16 3:56 ` [RFC v6 51/62] selftest/vm: pkey register should match shadow pkey Ram Pai
2017-07-16 3:56 ` [RFC v6 52/62] selftest/vm: generic cleanup Ram Pai
2017-07-16 3:56 ` [RFC v6 53/62] selftest/vm: powerpc implementation for generic abstraction Ram Pai
2017-07-16 3:56 ` [RFC v6 54/62] selftest/vm: fix an assertion in test_pkey_alloc_exhaust() Ram Pai
2017-07-16 3:56 ` [RFC v6 55/62] selftest/vm: associate key on a mapped page and detect access violation Ram Pai
2017-07-16 3:56 ` [RFC v6 56/62] selftest/vm: detect no key violation on a freed key Ram Pai
2017-07-16 3:56 ` [RFC v6 57/62] selftest/vm: associate key on a mapped page and detect write violation Ram Pai
2017-07-16 3:57 ` [RFC v6 58/62] selftest/vm: detect no write key-violation on a freed key Ram Pai
2017-07-16 3:57 ` [RFC v6 59/62] selftest/vm: detect write violation on a mapped access-denied-key page Ram Pai
2017-07-16 3:57 ` [RFC v6 60/62] selftest/vm: sub-page allocator Ram Pai
2017-07-16 3:57 ` [RFC v6 61/62] Documentation/x86: Move protecton key documentation to arch neutral directory Ram Pai
2017-07-16 3:57 ` [RFC v6 62/62] Documentation/vm: PowerPC specific updates to memory protection keys Ram Pai
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