From: Ram Pai <linuxram@us.ibm.com>
To: mpe@ellerman.id.au, mingo@redhat.com, akpm@linux-foundation.org,
corbet@lwn.net, arnd@arndb.de
Cc: linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org,
x86@kernel.org, linux-arch@vger.kernel.org,
linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-kernel@vger.kernel.org, dave.hansen@intel.com,
benh@kernel.crashing.org, paulus@samba.org,
khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com,
bsingharora@gmail.com, hbabu@us.ibm.com, mhocko@kernel.org,
bauerman@linux.vnet.ibm.com, ebiederm@xmission.com
Subject: Re: [PATCH v9 23/51] powerpc: Enable pkey subsystem
Date: Sun, 12 Nov 2017 16:54:51 -0800 [thread overview]
Message-ID: <20171113005451.GF5546@ram.oc3035372033.ibm.com> (raw)
In-Reply-To: <1509958663-18737-24-git-send-email-linuxram@us.ibm.com>
On Mon, Nov 06, 2017 at 12:57:15AM -0800, Ram Pai wrote:
> PAPR defines 'ibm,processor-storage-keys' property. It exports two
> values. The first value holds the number of data-access keys and the
> second holds the number of instruction-access keys. Due to a bug in
> the firmware, instruction-access keys is always reported as zero.
> However any key can be configured to disable data-access and/or disable
> execution-access. The inavailablity of the second value is not a
> big handicap, though it could have been used to determine if the
> platform supported disable-execution-access.
>
> Non PAPR platforms do not define this property in the device tree yet.
> Here, we hardcode CPUs that support pkey by consulting
> PowerISA3.0
>
> This patch calculates the number of keys supported by the platform.
> Alsi it determines the platform support for read/write/execution access
> support for pkeys.
>
> Signed-off-by: Ram Pai <linuxram@us.ibm.com>
> ---
>
....snip...
> +static inline bool pkey_mmu_enabled(void)
> +{
> + if (firmware_has_feature(FW_FEATURE_LPAR))
> + return pkeys_total;
> + else
> + return cpu_has_feature(CPU_FTR_PKEY);
> +}
> +
> void __init pkey_initialize(void)
> {
> int os_reserved, i;
> @@ -46,14 +54,9 @@ void __init pkey_initialize(void)
> __builtin_popcountl(ARCH_VM_PKEY_FLAGS >> VM_PKEY_SHIFT)
> != (sizeof(u64) * BITS_PER_BYTE));
>
> - /*
> - * Disable the pkey system till everything is in place. A subsequent
> - * patch will enable it.
> - */
> - static_branch_enable(&pkey_disabled);
> -
> - /* Lets assume 32 keys */
> - pkeys_total = 32;
vvvvvvvvvvvvvvvvvvvv
> + /* Let's assume 32 keys if we are not told the number of pkeys. */
> + if (!pkeys_total)
> + pkeys_total = 32;
^^^^^^^^^^^^^^^^^^^^
There is a small bug here.
On a KVM guest or a LPAR, if the device tree
does not expose pkeys, the pkey-subsystem must be disabled.
Unfortunately, the code above blindly sets the pkeys_total to 32.
This confuses pkey_mmu_enabled() into returning true. Because of this
bug the guest errorneously enables pkey-subsystem.
The fix is to delete the code marked above.
>
> /*
> * Adjust the upper limit, based on the number of bits supported by
> @@ -62,11 +65,19 @@ void __init pkey_initialize(void)
> pkeys_total = min_t(int, pkeys_total,
> (ARCH_VM_PKEY_FLAGS >> VM_PKEY_SHIFT));
>
> + if (!pkey_mmu_enabled() || radix_enabled() || !pkeys_total)
> + static_branch_enable(&pkey_disabled);
> + else
> + static_branch_disable(&pkey_disabled);
> +
RP
next prev parent reply other threads:[~2017-11-13 0:55 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-06 8:56 [PATCH v9 00/51] powerpc, mm: Memory Protection Keys Ram Pai
2017-11-06 8:56 ` [PATCH v9 01/51] mm, powerpc, x86: define VM_PKEY_BITx bits if CONFIG_ARCH_HAS_PKEYS is enabled Ram Pai
2017-11-06 8:56 ` [PATCH v9 02/51] mm, powerpc, x86: introduce an additional vma bit for powerpc pkey Ram Pai
2017-11-06 8:56 ` [PATCH v9 03/51] powerpc: initial pkey plumbing Ram Pai
2017-11-06 8:56 ` [PATCH v9 04/51] powerpc: track allocation status of all pkeys Ram Pai
2017-11-06 8:56 ` [PATCH v9 05/51] powerpc: helper function to read, write AMR, IAMR, UAMOR registers Ram Pai
2017-11-06 8:56 ` [PATCH v9 06/51] powerpc: helper functions to initialize AMR, IAMR and " Ram Pai
2017-11-06 8:56 ` [PATCH v9 07/51] powerpc: cleanup AMR, IAMR when a key is allocated or freed Ram Pai
2017-11-06 8:57 ` [PATCH v9 08/51] powerpc: implementation for arch_set_user_pkey_access() Ram Pai
2017-11-06 8:57 ` [PATCH v9 09/51] powerpc: ability to create execute-disabled pkeys Ram Pai
2017-11-06 8:57 ` [PATCH v9 10/51] powerpc: store and restore the pkey state across context switches Ram Pai
2017-11-06 8:57 ` [PATCH v9 11/51] powerpc: introduce execute-only pkey Ram Pai
2017-11-06 8:57 ` [PATCH v9 12/51] powerpc: ability to associate pkey to a vma Ram Pai
2017-11-06 8:57 ` [PATCH v9 13/51] powerpc: implementation for arch_override_mprotect_pkey() Ram Pai
2017-11-06 8:57 ` [PATCH v9 14/51] powerpc: map vma key-protection bits to pte key bits Ram Pai
2017-11-06 8:57 ` [PATCH v9 15/51] powerpc: Program HPTE key protection bits Ram Pai
2017-11-06 8:57 ` [PATCH v9 16/51] powerpc: helper to validate key-access permissions of a pte Ram Pai
2017-11-06 8:57 ` [PATCH v9 17/51] powerpc: check key protection for user page access Ram Pai
2017-11-06 8:57 ` [PATCH v9 18/51] powerpc: implementation for arch_vma_access_permitted() Ram Pai
2017-11-06 8:57 ` [PATCH v9 19/51] powerpc: Handle exceptions caused by pkey violation Ram Pai
2017-11-06 8:57 ` [PATCH v9 20/51] powerpc: introduce get_mm_addr_key() helper Ram Pai
2017-11-06 8:57 ` [PATCH v9 21/51] powerpc: Deliver SEGV signal on pkey violation Ram Pai
2017-11-06 8:57 ` [PATCH v9 22/51] powerpc/ptrace: Add memory protection key regset Ram Pai
2017-11-06 8:57 ` [PATCH v9 23/51] powerpc: Enable pkey subsystem Ram Pai
2017-11-13 0:54 ` Ram Pai [this message]
2017-11-06 8:57 ` [PATCH v9 24/51] powerpc: sys_pkey_alloc() and sys_pkey_free() system calls Ram Pai
2017-11-06 8:57 ` [PATCH v9 25/51] powerpc: sys_pkey_mprotect() system call Ram Pai
2017-11-06 8:57 ` [PATCH v9 26/51] powerpc: add sys_pkey_modify() " Ram Pai
2017-11-06 8:57 ` [PATCH v9 27/51] mm, x86 : introduce arch_pkeys_enabled() Ram Pai
2017-11-06 8:57 ` [PATCH v9 28/51] mm: display pkey in smaps if arch_pkeys_enabled() is true Ram Pai
2017-11-06 8:57 ` [PATCH v9 29/51] mm/mprotect, powerpc/mm/pkeys, x86/mm/pkeys: Add sysfs interface Ram Pai
2017-12-18 18:54 ` Dave Hansen
2017-12-18 22:18 ` Ram Pai
2017-12-18 22:28 ` Dave Hansen
2017-12-18 23:15 ` Ram Pai
2017-12-19 8:31 ` Gabriel Paubert
2017-12-19 16:22 ` Ram Pai
2017-12-19 21:34 ` Benjamin Herrenschmidt
2017-12-20 17:50 ` Ram Pai
2017-12-20 22:49 ` Benjamin Herrenschmidt
2017-12-19 10:50 ` Michael Ellerman
2017-12-19 16:32 ` Ram Pai
2017-11-06 8:57 ` [PATCH v9 30/51] Documentation/x86: Move protecton key documentation to arch neutral directory Ram Pai
2017-11-06 8:57 ` [PATCH v9 31/51] Documentation/vm: PowerPC specific updates to memory protection keys Ram Pai
2017-11-06 8:57 ` [PATCH v9 32/51] selftest/x86: Move protecton key selftest to arch neutral directory Ram Pai
2017-11-06 8:57 ` [PATCH v9 33/51] selftest/vm: rename all references to pkru to a generic name Ram Pai
2017-11-06 8:57 ` [PATCH v9 34/51] selftest/vm: move generic definitions to header file Ram Pai
2017-11-06 8:57 ` [PATCH v9 35/51] selftest/vm: typecast the pkey register Ram Pai
2017-11-06 8:57 ` [PATCH v9 36/51] selftest/vm: generic function to handle shadow key register Ram Pai
2017-11-06 8:57 ` [PATCH v9 37/51] selftest/vm: fix the wrong assert in pkey_disable_set() Ram Pai
2017-11-06 8:57 ` [PATCH v9 38/51] selftest/vm: fixed bugs in pkey_disable_clear() Ram Pai
2017-11-06 8:57 ` [PATCH v9 39/51] selftest/vm: clear the bits in shadow reg when a pkey is freed Ram Pai
2017-11-06 8:57 ` [PATCH v9 40/51] selftest/vm: fix alloc_random_pkey() to make it really random Ram Pai
2017-11-06 8:57 ` [PATCH v9 41/51] selftest/vm: introduce two arch independent abstraction Ram Pai
2017-11-06 8:57 ` [PATCH v9 42/51] selftest/vm: pkey register should match shadow pkey Ram Pai
2017-11-06 8:57 ` [PATCH v9 43/51] selftest/vm: generic cleanup Ram Pai
2017-11-06 8:57 ` [PATCH v9 44/51] selftest/vm: powerpc implementation for generic abstraction Ram Pai
2017-11-09 18:47 ` Breno Leitao
2017-11-09 23:37 ` Ram Pai
2017-11-10 11:36 ` Breno Leitao
2017-11-06 8:57 ` [PATCH v9 45/51] selftest/vm: fix an assertion in test_pkey_alloc_exhaust() Ram Pai
2017-11-06 8:57 ` [PATCH v9 46/51] selftest/vm: associate key on a mapped page and detect access violation Ram Pai
2017-11-06 8:57 ` [PATCH v9 47/51] selftest/vm: associate key on a mapped page and detect write violation Ram Pai
2017-11-06 8:57 ` [PATCH v9 48/51] selftest/vm: detect write violation on a mapped access-denied-key page Ram Pai
2017-11-06 8:57 ` [PATCH v9 49/51] selftest/vm: sub-page allocator Ram Pai
2017-11-06 8:57 ` [PATCH v9 50/51] selftests/powerpc: Add ptrace tests for Protection Key register Ram Pai
2017-11-06 8:57 ` [PATCH v9 51/51] selftests/powerpc: Add core file test " Ram Pai
2017-11-06 21:28 ` [PATCH v9 00/51] powerpc, mm: Memory Protection Keys Florian Weimer
2017-11-07 1:22 ` Ram Pai
2017-11-07 7:32 ` Florian Weimer
2017-11-07 22:39 ` Ram Pai
2017-11-07 22:47 ` Dave Hansen
2017-11-07 23:44 ` Ram Pai
2017-11-09 22:23 ` Ram Pai
2017-11-10 18:10 ` Christophe LEROY
2017-11-12 20:45 ` Ram Pai
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