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,
linuxram@us.ibm.com
Subject: [PATCH v9 11/51] powerpc: introduce execute-only pkey
Date: Mon, 6 Nov 2017 00:57:03 -0800 [thread overview]
Message-ID: <1509958663-18737-12-git-send-email-linuxram@us.ibm.com> (raw)
In-Reply-To: <1509958663-18737-1-git-send-email-linuxram@us.ibm.com>
This patch provides the implementation of execute-only pkey.
The architecture-independent layer expects the arch-dependent
layer, to support the ability to create and enable a special
key which has execute-only permission.
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
---
arch/powerpc/include/asm/book3s/64/mmu.h | 1 +
arch/powerpc/include/asm/pkeys.h | 8 ++++-
arch/powerpc/mm/pkeys.c | 56 ++++++++++++++++++++++++++++++
3 files changed, 64 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h b/arch/powerpc/include/asm/book3s/64/mmu.h
index df17fbc..44dbc91 100644
--- a/arch/powerpc/include/asm/book3s/64/mmu.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu.h
@@ -116,6 +116,7 @@ struct patb_entry {
* bit unset -> key available for allocation
*/
u32 pkey_allocation_map;
+ s16 execute_only_pkey; /* key holding execute-only protection */
#endif
} mm_context_t;
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
index 0b2d9f0..20d1f0e 100644
--- a/arch/powerpc/include/asm/pkeys.h
+++ b/arch/powerpc/include/asm/pkeys.h
@@ -128,9 +128,13 @@ static inline int mm_pkey_free(struct mm_struct *mm, int pkey)
* Try to dedicate one of the protection keys to be used as an
* execute-only protection key.
*/
+extern int __execute_only_pkey(struct mm_struct *mm);
static inline int execute_only_pkey(struct mm_struct *mm)
{
- return 0;
+ if (static_branch_likely(&pkey_disabled))
+ return -1;
+
+ return __execute_only_pkey(mm);
}
static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma,
@@ -154,6 +158,8 @@ static inline void pkey_mm_init(struct mm_struct *mm)
if (static_branch_likely(&pkey_disabled))
return;
mm_pkey_allocation_map(mm) = initial_allocation_mask;
+ /* -1 means unallocated or invalid */
+ mm->context.execute_only_pkey = -1;
}
extern void thread_pkey_regs_save(struct thread_struct *thread);
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
index 469f370..5da94fe 100644
--- a/arch/powerpc/mm/pkeys.c
+++ b/arch/powerpc/mm/pkeys.c
@@ -247,3 +247,59 @@ void thread_pkey_regs_init(struct thread_struct *thread)
write_iamr(read_iamr() & pkey_iamr_mask);
write_uamor(read_uamor() & pkey_amr_uamor_mask);
}
+
+static inline bool pkey_allows_readwrite(int pkey)
+{
+ int pkey_shift = pkeyshift(pkey);
+
+ if (!is_pkey_enabled(pkey))
+ return true;
+
+ return !(read_amr() & ((AMR_RD_BIT|AMR_WR_BIT) << pkey_shift));
+}
+
+int __execute_only_pkey(struct mm_struct *mm)
+{
+ bool need_to_set_mm_pkey = false;
+ int execute_only_pkey = mm->context.execute_only_pkey;
+ int ret;
+
+ /* Do we need to assign a pkey for mm's execute-only maps? */
+ if (execute_only_pkey == -1) {
+ /* Go allocate one to use, which might fail */
+ execute_only_pkey = mm_pkey_alloc(mm);
+ if (execute_only_pkey < 0)
+ return -1;
+ need_to_set_mm_pkey = true;
+ }
+
+ /*
+ * We do not want to go through the relatively costly dance to set AMR
+ * if we do not need to. Check it first and assume that if the
+ * execute-only pkey is readwrite-disabled than we do not have to set it
+ * ourselves.
+ */
+ if (!need_to_set_mm_pkey && !pkey_allows_readwrite(execute_only_pkey))
+ return execute_only_pkey;
+
+ /*
+ * Set up AMR so that it denies access for everything other than
+ * execution.
+ */
+ ret = __arch_set_user_pkey_access(current, execute_only_pkey,
+ PKEY_DISABLE_ACCESS |
+ PKEY_DISABLE_WRITE);
+ /*
+ * If the AMR-set operation failed somehow, just return 0 and
+ * effectively disable execute-only support.
+ */
+ if (ret) {
+ mm_pkey_free(mm, execute_only_pkey);
+ return -1;
+ }
+
+ /* We got one, store it and use it from here on out */
+ if (need_to_set_mm_pkey)
+ mm->context.execute_only_pkey = execute_only_pkey;
+ return execute_only_pkey;
+}
--
1.7.1
next prev parent reply other threads:[~2017-11-06 8:58 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 ` Ram Pai [this message]
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
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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