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Diffstat (limited to 'arch/powerpc/include/asm/pkeys.h')
-rw-r--r--arch/powerpc/include/asm/pkeys.h38
1 files changed, 21 insertions, 17 deletions
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
index 5ba80cffb505..20ebf153c871 100644
--- a/arch/powerpc/include/asm/pkeys.h
+++ b/arch/powerpc/include/asm/pkeys.h
@@ -13,7 +13,8 @@
DECLARE_STATIC_KEY_TRUE(pkey_disabled);
extern int pkeys_total; /* total pkeys as per device tree */
-extern u32 initial_allocation_mask; /* bits set for reserved keys */
+extern u32 initial_allocation_mask; /* bits set for the initially allocated keys */
+extern u32 reserved_allocation_mask; /* bits set for reserved keys */
#define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | \
VM_PKEY_BIT3 | VM_PKEY_BIT4)
@@ -83,19 +84,21 @@ static inline u16 pte_to_pkey_bits(u64 pteflags)
#define __mm_pkey_is_allocated(mm, pkey) \
(mm_pkey_allocation_map(mm) & pkey_alloc_mask(pkey))
-#define __mm_pkey_is_reserved(pkey) (initial_allocation_mask & \
+#define __mm_pkey_is_reserved(pkey) (reserved_allocation_mask & \
pkey_alloc_mask(pkey))
static inline bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey)
{
- /* A reserved key is never considered as 'explicitly allocated' */
- return ((pkey < arch_max_pkey()) &&
- !__mm_pkey_is_reserved(pkey) &&
- __mm_pkey_is_allocated(mm, pkey));
+ if (pkey < 0 || pkey >= arch_max_pkey())
+ return false;
+
+ /* Reserved keys are never allocated. */
+ if (__mm_pkey_is_reserved(pkey))
+ return false;
+
+ return __mm_pkey_is_allocated(mm, pkey);
}
-extern void __arch_activate_pkey(int pkey);
-extern void __arch_deactivate_pkey(int pkey);
/*
* Returns a positive, 5-bit key on success, or -1 on failure.
* Relies on the mmap_sem to protect against concurrency in mm_pkey_alloc() and
@@ -124,11 +127,6 @@ static inline int mm_pkey_alloc(struct mm_struct *mm)
ret = ffz((u32)mm_pkey_allocation_map(mm));
__mm_pkey_allocated(mm, ret);
- /*
- * Enable the key in the hardware
- */
- if (ret > 0)
- __arch_activate_pkey(ret);
return ret;
}
@@ -140,10 +138,6 @@ static inline int mm_pkey_free(struct mm_struct *mm, int pkey)
if (!mm_pkey_is_allocated(mm, pkey))
return -EINVAL;
- /*
- * Disable the key in the hardware
- */
- __arch_deactivate_pkey(pkey);
__mm_pkey_free(mm, pkey);
return 0;
@@ -187,6 +181,16 @@ static inline int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
{
if (static_branch_likely(&pkey_disabled))
return -EINVAL;
+
+ /*
+ * userspace should not change pkey-0 permissions.
+ * pkey-0 is associated with every page in the kernel.
+ * If userspace denies any permission on pkey-0, the
+ * kernel cannot operate.
+ */
+ if (pkey == 0)
+ return init_val ? -EINVAL : 0;
+
return __arch_set_user_pkey_access(tsk, pkey, init_val);
}