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 29/51] mm/mprotect, powerpc/mm/pkeys, x86/mm/pkeys: Add sysfs interface
Date: Mon, 6 Nov 2017 00:57:21 -0800 [thread overview]
Message-ID: <1509958663-18737-30-git-send-email-linuxram@us.ibm.com> (raw)
In-Reply-To: <1509958663-18737-1-git-send-email-linuxram@us.ibm.com>
From: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Expose useful information for programs using memory protection keys.
Provide implementation for powerpc and x86.
On a powerpc system with pkeys support, here is what is shown:
$ head /sys/kernel/mm/protection_keys/*
==> /sys/kernel/mm/protection_keys/disable_access_supported <==
true
==> /sys/kernel/mm/protection_keys/disable_execute_supported <==
true
==> /sys/kernel/mm/protection_keys/disable_write_supported <==
true
==> /sys/kernel/mm/protection_keys/total_keys <==
31
==> /sys/kernel/mm/protection_keys/usable_keys <==
27
And on an x86 without pkeys support:
$ head /sys/kernel/mm/protection_keys/*
==> /sys/kernel/mm/protection_keys/disable_access_supported <==
false
==> /sys/kernel/mm/protection_keys/disable_execute_supported <==
false
==> /sys/kernel/mm/protection_keys/disable_write_supported <==
false
==> /sys/kernel/mm/protection_keys/total_keys <==
1
==> /sys/kernel/mm/protection_keys/usable_keys <==
0
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/pkeys.h | 2 +
arch/powerpc/mm/pkeys.c | 24 ++++++++++
arch/x86/include/asm/mmu_context.h | 4 +-
arch/x86/include/asm/pkeys.h | 1 +
arch/x86/mm/pkeys.c | 9 ++++
include/linux/pkeys.h | 2 +-
mm/mprotect.c | 88 ++++++++++++++++++++++++++++++++++++
7 files changed, 128 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
index 333fb28..6d70b1a 100644
--- a/arch/powerpc/include/asm/pkeys.h
+++ b/arch/powerpc/include/asm/pkeys.h
@@ -237,6 +237,8 @@ static inline void pkey_mmu_values(int total_data, int total_execute)
pkeys_total = total_data;
}
+extern bool arch_supports_pkeys(int cap);
+extern unsigned int arch_usable_pkeys(void);
extern void thread_pkey_regs_save(struct thread_struct *thread);
extern void thread_pkey_regs_restore(struct thread_struct *new_thread,
struct thread_struct *old_thread);
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
index 2612f61..7e8468f 100644
--- a/arch/powerpc/mm/pkeys.c
+++ b/arch/powerpc/mm/pkeys.c
@@ -421,6 +421,30 @@ bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write,
return pkey_access_permitted(vma_pkey(vma), write, execute);
}
+unsigned int arch_usable_pkeys(void)
+{
+ unsigned int reserved;
+
+ if (static_branch_likely(&pkey_disabled))
+ return 0;
+
+ /* Reserve one more to account for the execute-only pkey. */
+ reserved = hweight32(initial_allocation_mask) + 1;
+
+ return pkeys_total > reserved ? pkeys_total - reserved : 0;
+}
+
+bool arch_supports_pkeys(int cap)
+{
+ if (static_branch_likely(&pkey_disabled))
+ return false;
+
+ if (cap & PKEY_DISABLE_EXECUTE)
+ return pkey_execute_disable_supported;
+
+ return (cap & (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE));
+}
+
long sys_pkey_modify(int pkey, unsigned long new_val)
{
bool ret;
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index 6699fc4..e3efabb 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -129,6 +129,8 @@ static inline void switch_ldt(struct mm_struct *prev, struct mm_struct *next)
void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk);
+#define PKEY_INITIAL_ALLOCATION_MAP 1
+
static inline int init_new_context(struct task_struct *tsk,
struct mm_struct *mm)
{
@@ -138,7 +140,7 @@ static inline int init_new_context(struct task_struct *tsk,
#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
if (cpu_feature_enabled(X86_FEATURE_OSPKE)) {
/* pkey 0 is the default and always allocated */
- mm->context.pkey_allocation_map = 0x1;
+ mm->context.pkey_allocation_map = PKEY_INITIAL_ALLOCATION_MAP;
/* -1 means unallocated or invalid */
mm->context.execute_only_pkey = -1;
}
diff --git a/arch/x86/include/asm/pkeys.h b/arch/x86/include/asm/pkeys.h
index f6c287b..6807288 100644
--- a/arch/x86/include/asm/pkeys.h
+++ b/arch/x86/include/asm/pkeys.h
@@ -106,5 +106,6 @@ extern int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
extern int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
unsigned long init_val);
extern void copy_init_pkru_to_fpregs(void);
+extern unsigned int arch_usable_pkeys(void);
#endif /*_ASM_X86_PKEYS_H */
diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
index d7bc0ee..3083a59 100644
--- a/arch/x86/mm/pkeys.c
+++ b/arch/x86/mm/pkeys.c
@@ -122,6 +122,15 @@ int __arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot, int pkey
return vma_pkey(vma);
}
+unsigned int arch_usable_pkeys(void)
+{
+ /* Reserve one more to account for the execute-only pkey. */
+ unsigned int reserved = (boot_cpu_has(X86_FEATURE_OSPKE) ?
+ hweight32(PKEY_INITIAL_ALLOCATION_MAP) : 0) + 1;
+
+ return arch_max_pkey() > reserved ? arch_max_pkey() - reserved : 0;
+}
+
#define PKRU_AD_KEY(pkey) (PKRU_AD_BIT << ((pkey) * PKRU_BITS_PER_PKEY))
/*
diff --git a/include/linux/pkeys.h b/include/linux/pkeys.h
index 3ca2e44..0784f20 100644
--- a/include/linux/pkeys.h
+++ b/include/linux/pkeys.h
@@ -11,6 +11,7 @@
#define arch_max_pkey() (1)
#define execute_only_pkey(mm) (0)
#define arch_override_mprotect_pkey(vma, prot, pkey) (0)
+#define arch_usable_pkeys() (0)
#define PKEY_DEDICATED_EXECUTE_ONLY 0
#define ARCH_VM_PKEY_FLAGS 0
@@ -43,7 +44,6 @@ static inline bool arch_pkeys_enabled(void)
static inline void copy_init_pkru_to_fpregs(void)
{
}
-
#endif /* ! CONFIG_ARCH_HAS_PKEYS */
#endif /* _LINUX_PKEYS_H */
diff --git a/mm/mprotect.c b/mm/mprotect.c
index ec39f73..43a4584 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -568,4 +568,92 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
return ret;
}
+#ifdef CONFIG_SYSFS
+
+#define PKEYS_ATTR_RO(_name) \
+ static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
+
+static ssize_t total_keys_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%u\n", arch_max_pkey());
+}
+PKEYS_ATTR_RO(total_keys);
+
+static ssize_t usable_keys_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%u\n", arch_usable_pkeys());
+}
+PKEYS_ATTR_RO(usable_keys);
+
+static ssize_t disable_access_supported_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ if (arch_pkeys_enabled()) {
+ strcpy(buf, "true\n");
+ return sizeof("true\n") - 1;
+ }
+
+ strcpy(buf, "false\n");
+ return sizeof("false\n") - 1;
+}
+PKEYS_ATTR_RO(disable_access_supported);
+
+static ssize_t disable_write_supported_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ if (arch_pkeys_enabled()) {
+ strcpy(buf, "true\n");
+ return sizeof("true\n") - 1;
+ }
+
+ strcpy(buf, "false\n");
+ return sizeof("false\n") - 1;
+}
+PKEYS_ATTR_RO(disable_write_supported);
+
+static ssize_t disable_execute_supported_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+#ifdef PKEY_DISABLE_EXECUTE
+ if (arch_supports_pkeys(PKEY_DISABLE_EXECUTE)) {
+ strcpy(buf, "true\n");
+ return sizeof("true\n") - 1;
+ }
+#endif
+
+ strcpy(buf, "false\n");
+ return sizeof("false\n") - 1;
+}
+PKEYS_ATTR_RO(disable_execute_supported);
+
+static struct attribute *pkeys_attrs[] = {
+ &total_keys_attr.attr,
+ &usable_keys_attr.attr,
+ &disable_access_supported_attr.attr,
+ &disable_write_supported_attr.attr,
+ &disable_execute_supported_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group pkeys_attr_group = {
+ .attrs = pkeys_attrs,
+ .name = "protection_keys",
+};
+
+static int __init pkeys_sysfs_init(void)
+{
+ int err;
+
+ err = sysfs_create_group(mm_kobj, &pkeys_attr_group);
+
+ return err;
+}
+late_initcall(pkeys_sysfs_init);
+#endif /* CONFIG_SYSFS */
+
#endif /* CONFIG_ARCH_HAS_PKEYS */
--
1.7.1
next prev parent reply other threads:[~2017-11-06 8:59 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
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 ` Ram Pai [this message]
2017-12-18 18:54 ` [PATCH v9 29/51] mm/mprotect, powerpc/mm/pkeys, x86/mm/pkeys: Add sysfs interface 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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