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 v10 13/27] powerpc: implementation for arch_override_mprotect_pkey()
Date: Thu, 18 Jan 2018 17:50:34 -0800 [thread overview]
Message-ID: <1516326648-22775-14-git-send-email-linuxram@us.ibm.com> (raw)
In-Reply-To: <1516326648-22775-1-git-send-email-linuxram@us.ibm.com>
arch independent code calls arch_override_mprotect_pkey()
to return a pkey that best matches the requested protection.
This patch provides the implementation.
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
---
arch/powerpc/include/asm/mmu_context.h | 5 ++++
arch/powerpc/include/asm/pkeys.h | 21 +++++++++++++++++-
arch/powerpc/mm/pkeys.c | 36 ++++++++++++++++++++++++++++++++
3 files changed, 61 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index 4d69223..3ba571d 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -198,6 +198,11 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
#define thread_pkey_regs_save(thread)
#define thread_pkey_regs_restore(new_thread, old_thread)
#define thread_pkey_regs_init(thread)
+
+static inline int vma_pkey(struct vm_area_struct *vma)
+{
+ return 0;
+}
#endif /* CONFIG_PPC_MEM_KEYS */
#endif /* __KERNEL__ */
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
index c7cc433..0a643b8 100644
--- a/arch/powerpc/include/asm/pkeys.h
+++ b/arch/powerpc/include/asm/pkeys.h
@@ -52,6 +52,13 @@ static inline u64 pkey_to_vmflag_bits(u16 pkey)
return (((u64)pkey << VM_PKEY_SHIFT) & ARCH_VM_PKEY_FLAGS);
}
+static inline int vma_pkey(struct vm_area_struct *vma)
+{
+ if (static_branch_likely(&pkey_disabled))
+ return 0;
+ return (vma->vm_flags & ARCH_VM_PKEY_FLAGS) >> VM_PKEY_SHIFT;
+}
+
#define arch_max_pkey() pkeys_total
#define pkey_alloc_mask(pkey) (0x1 << pkey)
@@ -148,10 +155,22 @@ static inline int execute_only_pkey(struct mm_struct *mm)
return __execute_only_pkey(mm);
}
+extern int __arch_override_mprotect_pkey(struct vm_area_struct *vma,
+ int prot, int pkey);
static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma,
int prot, int pkey)
{
- return 0;
+ if (static_branch_likely(&pkey_disabled))
+ return 0;
+
+ /*
+ * Is this an mprotect_pkey() call? If so, never override the value that
+ * came from the user.
+ */
+ if (pkey != -1)
+ return pkey;
+
+ return __arch_override_mprotect_pkey(vma, prot, pkey);
}
extern int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
index ee31ab5..7630c2f 100644
--- a/arch/powerpc/mm/pkeys.c
+++ b/arch/powerpc/mm/pkeys.c
@@ -326,3 +326,39 @@ int __execute_only_pkey(struct mm_struct *mm)
mm->context.execute_only_pkey = execute_only_pkey;
return execute_only_pkey;
}
+
+static inline bool vma_is_pkey_exec_only(struct vm_area_struct *vma)
+{
+ /* Do this check first since the vm_flags should be hot */
+ if ((vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)) != VM_EXEC)
+ return false;
+
+ return (vma_pkey(vma) == vma->vm_mm->context.execute_only_pkey);
+}
+
+/*
+ * This should only be called for *plain* mprotect calls.
+ */
+int __arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot,
+ int pkey)
+{
+ /*
+ * If the currently associated pkey is execute-only, but the requested
+ * protection requires read or write, move it back to the default pkey.
+ */
+ if (vma_is_pkey_exec_only(vma) && (prot & (PROT_READ | PROT_WRITE)))
+ return 0;
+
+ /*
+ * The requested protection is execute-only. Hence let's use an
+ * execute-only pkey.
+ */
+ if (prot == PROT_EXEC) {
+ pkey = execute_only_pkey(vma->vm_mm);
+ if (pkey > 0)
+ return pkey;
+ }
+
+ /* Nothing to override. */
+ return vma_pkey(vma);
+}
--
1.7.1
next prev parent reply other threads:[~2018-01-19 1:52 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-19 1:50 [PATCH v10 00/27] powerpc, mm: Memory Protection Keys Ram Pai
2018-01-19 1:50 ` [PATCH v10 01/27] mm, powerpc, x86: define VM_PKEY_BITx bits if CONFIG_ARCH_HAS_PKEYS is enabled Ram Pai
2018-01-21 15:34 ` Aneesh Kumar K.V
2018-01-23 6:37 ` Ram Pai
2018-01-19 1:50 ` [PATCH v10 02/27] mm, powerpc, x86: introduce an additional vma bit for powerpc pkey Ram Pai
2018-01-19 1:50 ` [PATCH v10 03/27] powerpc: initial pkey plumbing Ram Pai
2018-01-22 3:34 ` [v10,03/27] " Michael Ellerman
2018-01-19 1:50 ` [PATCH v10 04/27] powerpc: track allocation status of all pkeys Ram Pai
2018-01-19 1:50 ` [PATCH v10 05/27] powerpc: helper function to read, write AMR, IAMR, UAMOR registers Ram Pai
2018-01-19 1:50 ` [PATCH v10 06/27] powerpc: helper functions to initialize AMR, IAMR and " Ram Pai
2018-01-19 1:50 ` [PATCH v10 07/27] powerpc: cleanup AMR, IAMR when a key is allocated or freed Ram Pai
2018-01-19 1:50 ` [PATCH v10 08/27] powerpc: implementation for arch_set_user_pkey_access() Ram Pai
2018-01-19 1:50 ` [PATCH v10 09/27] powerpc: ability to create execute-disabled pkeys Ram Pai
2018-01-19 1:50 ` [PATCH v10 10/27] powerpc: store and restore the pkey state across context switches Ram Pai
2018-01-19 1:50 ` [PATCH v10 11/27] powerpc: introduce execute-only pkey Ram Pai
2018-01-19 1:50 ` [PATCH v10 12/27] powerpc: ability to associate pkey to a vma Ram Pai
2018-01-19 1:50 ` Ram Pai [this message]
2018-01-19 1:50 ` [PATCH v10 14/27] powerpc: map vma key-protection bits to pte key bits Ram Pai
2018-01-19 1:50 ` [PATCH v10 15/27] powerpc: Program HPTE key protection bits Ram Pai
2018-01-19 1:50 ` [PATCH v10 16/27] powerpc: helper to validate key-access permissions of a pte Ram Pai
2018-01-19 1:50 ` [PATCH v10 17/27] powerpc: check key protection for user page access Ram Pai
2018-01-19 1:50 ` [PATCH v10 18/27] powerpc: implementation for arch_vma_access_permitted() Ram Pai
2018-01-19 1:50 ` [PATCH v10 19/27] powerpc: Handle exceptions caused by pkey violation Ram Pai
2018-01-19 1:50 ` [PATCH v10 20/27] powerpc: introduce get_mm_addr_key() helper Ram Pai
2018-01-19 1:50 ` [PATCH v10 21/27] powerpc: Deliver SEGV signal on pkey violation Ram Pai
2018-01-19 1:50 ` [PATCH v10 22/27] powerpc/ptrace: Add memory protection key regset Ram Pai
2018-01-19 1:50 ` [PATCH v10 23/27] powerpc: Enable pkey subsystem Ram Pai
2018-01-19 1:50 ` [PATCH v10 24/27] powerpc: sys_pkey_alloc() and sys_pkey_free() system calls Ram Pai
2018-01-19 1:50 ` [PATCH v10 25/27] powerpc: sys_pkey_mprotect() system call Ram Pai
2018-01-19 1:50 ` [PATCH v10 26/27] mm, x86 : introduce arch_pkeys_enabled() Ram Pai
2018-01-19 1:50 ` [PATCH v10 27/27] mm: display pkey in smaps if arch_pkeys_enabled() is true Ram Pai
2018-01-19 16:09 ` Eric W. Biederman
2018-01-19 16:50 ` Ram Pai
2018-01-19 17:04 ` Eric W. Biederman
2018-01-30 12:16 ` Michal Hocko
2018-01-30 16:28 ` Ram Pai
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