From: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: x86@kernel.org, linux-mm@kvack.org, Ram Pai <linuxram@us.ibm.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Anshuman Khandual <khandual@linux.vnet.ibm.com>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>,
Balbir Singh <bsingharora@gmail.com>,
Haren Myneni <hbabu@us.ibm.com>, Michal Hocko <mhocko@kernel.org>,
Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Subject: [RFC v7 26/25] mm/mprotect, powerpc/mm/pkeys, x86/mm/pkeys: Add sysfs interface
Date: Fri, 11 Aug 2017 14:34:43 -0300 [thread overview]
Message-ID: <20170811173443.6227-1-bauerman@linux.vnet.ibm.com> (raw)
In-Reply-To: <1501459946-11619-1-git-send-email-linuxram@us.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_execute_supported <==
true
==> /sys/kernel/mm/protection_keys/total_keys <==
32
==> /sys/kernel/mm/protection_keys/usable_keys <==
30
And on an x86 without pkeys support:
$ head /sys/kernel/mm/protection_keys/*
==> /sys/kernel/mm/protection_keys/disable_execute_supported <==
false
==> /sys/kernel/mm/protection_keys/total_keys <==
1
==> /sys/kernel/mm/protection_keys/usable_keys <==
0
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
---
Ram asked me to add a sysfs interface for the memory protection keys
feature. Here it is.
If you have suggestions on what should be exposed, please let me know.
arch/powerpc/include/asm/pkeys.h | 2 ++
arch/powerpc/mm/pkeys.c | 12 ++++++++
arch/x86/include/asm/mmu_context.h | 34 +++++++++++-----------
arch/x86/include/asm/pkeys.h | 1 +
arch/x86/mm/pkeys.c | 5 ++++
mm/mprotect.c | 58 ++++++++++++++++++++++++++++++++++++++
6 files changed, 96 insertions(+), 16 deletions(-)
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
index e61ed6c332db..bbc5a34cc6d6 100644
--- a/arch/powerpc/include/asm/pkeys.h
+++ b/arch/powerpc/include/asm/pkeys.h
@@ -215,6 +215,8 @@ static inline int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
return __arch_set_user_pkey_access(tsk, pkey, init_val);
}
+unsigned int arch_usable_pkeys(void);
+
static inline bool arch_pkeys_enabled(void)
{
return pkey_inited;
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
index 1424c79f45f6..54efbb133049 100644
--- a/arch/powerpc/mm/pkeys.c
+++ b/arch/powerpc/mm/pkeys.c
@@ -272,3 +272,15 @@ bool arch_vma_access_permitted(struct vm_area_struct *vma,
return pkey_access_permitted(pkey, write, execute);
}
+
+unsigned int arch_usable_pkeys(void)
+{
+ unsigned int reserved;
+
+ if (!pkey_inited)
+ return 0;
+
+ reserved = hweight32(initial_allocation_mask);
+
+ return (pkeys_total > reserved) ? pkeys_total - reserved : 0;
+}
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index 68b329d77b3a..d2eabedd583a 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -105,13 +105,30 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
#endif
}
+#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
+#define PKEY_INITIAL_ALLOCATION_MAP 1
+
+static inline int vma_pkey(struct vm_area_struct *vma)
+{
+ unsigned long vma_pkey_mask = VM_PKEY_BIT0 | VM_PKEY_BIT1 |
+ VM_PKEY_BIT2 | VM_PKEY_BIT3;
+
+ return (vma->vm_flags & vma_pkey_mask) >> VM_PKEY_SHIFT;
+}
+#else
+static inline int vma_pkey(struct vm_area_struct *vma)
+{
+ return 0;
+}
+#endif
+
static inline int init_new_context(struct task_struct *tsk,
struct mm_struct *mm)
{
#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;
}
@@ -205,21 +222,6 @@ static inline void arch_unmap(struct mm_struct *mm, struct vm_area_struct *vma,
mpx_notify_unmap(mm, vma, start, end);
}
-#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
-static inline int vma_pkey(struct vm_area_struct *vma)
-{
- unsigned long vma_pkey_mask = VM_PKEY_BIT0 | VM_PKEY_BIT1 |
- VM_PKEY_BIT2 | VM_PKEY_BIT3;
-
- return (vma->vm_flags & vma_pkey_mask) >> VM_PKEY_SHIFT;
-}
-#else
-static inline int vma_pkey(struct vm_area_struct *vma)
-{
- return 0;
-}
-#endif
-
static inline bool __pkru_allows_pkey(u16 pkey, bool write)
{
u32 pkru = read_pkru();
diff --git a/arch/x86/include/asm/pkeys.h b/arch/x86/include/asm/pkeys.h
index fa8279972ddf..e1b25aa60530 100644
--- a/arch/x86/include/asm/pkeys.h
+++ b/arch/x86/include/asm/pkeys.h
@@ -105,5 +105,6 @@ 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 2dab69a706ec..a3acca15ff83 100644
--- a/arch/x86/mm/pkeys.c
+++ b/arch/x86/mm/pkeys.c
@@ -123,6 +123,11 @@ int __arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot, int pkey
return vma_pkey(vma);
}
+unsigned int arch_usable_pkeys(void)
+{
+ return arch_max_pkey() - hweight32(PKEY_INITIAL_ALLOCATION_MAP);
+}
+
#define PKRU_AD_KEY(pkey) (PKRU_AD_BIT << ((pkey) * PKRU_BITS_PER_PKEY))
/*
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 8edd0d576254..855744b9f7d6 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -554,4 +554,62 @@ SYSCALL_DEFINE1(pkey_free, int, pkey)
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_execute_supported_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+#ifdef PKEY_DISABLE_EXECUTE
+ if (arch_pkeys_enabled()) {
+ 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_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 */
next prev parent reply other threads:[~2017-08-11 17:35 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-31 0:12 [RFC v7 00/25] powerpc: Memory Protection Keys Ram Pai
2017-07-31 0:12 ` [RFC v7 01/25] powerpc: define an additional vma bit for protection keys Ram Pai
2017-07-31 0:12 ` [RFC v7 02/25] powerpc: track allocation status of all pkeys Ram Pai
2017-08-10 20:25 ` Thiago Jung Bauermann
2017-08-11 5:39 ` Michael Ellerman
2017-08-17 16:00 ` Ram Pai
2017-08-17 15:48 ` Ram Pai
2017-08-17 20:40 ` Thiago Jung Bauermann
2017-10-18 2:42 ` Balbir Singh
2017-10-18 3:40 ` Ram Pai
2017-10-18 16:08 ` Laurent Dufour
2017-10-18 22:04 ` Ram Pai
2017-07-31 0:12 ` [RFC v7 03/25] powerpc: helper function to read, write AMR, IAMR, UAMOR registers Ram Pai
2017-07-31 0:12 ` [RFC v7 04/25] powerpc: helper functions to initialize AMR, IAMR and " Ram Pai
2017-07-31 0:12 ` [RFC v7 05/25] powerpc: cleaup AMR, iAMR when a key is allocated or freed Ram Pai
2017-07-31 0:12 ` [RFC v7 06/25] powerpc: implementation for arch_set_user_pkey_access() Ram Pai
2017-07-31 0:12 ` [RFC v7 07/25] powerpc: sys_pkey_alloc() and sys_pkey_free() system calls Ram Pai
2017-07-31 0:12 ` [RFC v7 08/25] powerpc: ability to create execute-disabled pkeys Ram Pai
2017-07-31 0:12 ` [RFC v7 09/25] powerpc: store and restore the pkey state across context switches Ram Pai
2017-08-10 20:46 ` Thiago Jung Bauermann
2017-08-11 6:34 ` Michael Ellerman
2017-08-17 16:41 ` Ram Pai
2017-07-31 0:12 ` [RFC v7 10/25] powerpc: introduce execute-only pkey Ram Pai
2017-07-31 0:12 ` [RFC v7 11/25] powerpc: ability to associate pkey to a vma Ram Pai
2017-07-31 0:12 ` [RFC v7 12/25] powerpc: implementation for arch_override_mprotect_pkey() Ram Pai
2017-10-18 15:58 ` Laurent Dufour
2017-10-18 21:37 ` Ram Pai
2017-07-31 0:12 ` [RFC v7 13/25] powerpc: map vma key-protection bits to pte key bits Ram Pai
2017-07-31 0:12 ` [RFC v7 14/25] powerpc: sys_pkey_mprotect() system call Ram Pai
2017-07-31 0:12 ` [RFC v7 15/25] powerpc: Program HPTE key protection bits Ram Pai
2017-10-18 16:15 ` Laurent Dufour
2017-10-18 22:12 ` Ram Pai
2017-10-19 5:12 ` Michael Ellerman
2017-07-31 0:12 ` [RFC v7 16/25] powerpc: helper to validate key-access permissions of a pte Ram Pai
2017-10-18 16:08 ` Laurent Dufour
2017-10-18 21:56 ` Ram Pai
2017-10-19 5:13 ` Michael Ellerman
2017-07-31 0:12 ` [RFC v7 17/25] powerpc: check key protection for user page access Ram Pai
2017-07-31 0:12 ` [RFC v7 18/25] powerpc: Macro the mask used for checking DSI exception Ram Pai
2017-07-31 0:12 ` [RFC v7 19/25] powerpc: implementation for arch_vma_access_permitted() Ram Pai
2017-07-31 0:12 ` [RFC v7 20/25] powerpc: Handle exceptions caused by pkey violation Ram Pai
2017-07-31 0:12 ` [RFC v7 21/25] powerpc: capture AMR register content on " Ram Pai
2017-07-31 0:12 ` [RFC v7 22/25] powerpc: introduce get_pte_pkey() helper Ram Pai
2017-07-31 0:12 ` [RFC v7 23/25] powerpc: capture the violated protection key on fault Ram Pai
2017-07-31 0:12 ` [RFC v7 24/25] powerpc: Deliver SEGV signal on pkey violation Ram Pai
2017-08-10 21:00 ` Thiago Jung Bauermann
2017-08-11 10:26 ` Michael Ellerman
2017-08-17 17:14 ` Ram Pai
2017-08-18 4:48 ` Michael Ellerman
2017-08-18 17:04 ` Ram Pai
2017-08-18 21:54 ` Benjamin Herrenschmidt
2017-08-18 22:36 ` Ram Pai
2017-10-18 2:25 ` Balbir Singh
2017-10-18 3:01 ` Ram Pai
2017-08-18 22:49 ` Ram Pai
2017-08-19 8:23 ` Benjamin Herrenschmidt
2017-07-31 0:12 ` [RFC v7 25/25] powerpc: Enable pkey subsystem Ram Pai
2017-08-10 21:27 ` Thiago Jung Bauermann
2017-08-17 17:40 ` Ram Pai
2017-08-17 20:30 ` Thiago Jung Bauermann
2017-08-17 23:48 ` Ram Pai
2017-08-18 5:07 ` Michael Ellerman
2017-08-18 15:26 ` Thiago Jung Bauermann
2017-08-18 16:32 ` Ram Pai
2017-08-11 17:34 ` Thiago Jung Bauermann [this message]
2017-08-18 0:25 ` [RFC v7 26/25] mm/mprotect, powerpc/mm/pkeys, x86/mm/pkeys: Add sysfs interface Ram Pai
2017-08-18 23:19 ` Thiago Jung Bauermann
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