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Diffstat (limited to 'arch/powerpc/mm/pkeys.c')
-rw-r--r--arch/powerpc/mm/pkeys.c141
1 files changed, 46 insertions, 95 deletions
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
index e6f500fabf5e..333b1f80c435 100644
--- a/arch/powerpc/mm/pkeys.c
+++ b/arch/powerpc/mm/pkeys.c
@@ -14,9 +14,12 @@ DEFINE_STATIC_KEY_TRUE(pkey_disabled);
bool pkey_execute_disable_supported;
int pkeys_total; /* Total pkeys as per device tree */
bool pkeys_devtree_defined; /* pkey property exported by device tree */
-u32 initial_allocation_mask; /* Bits set for reserved keys */
-u64 pkey_amr_uamor_mask; /* Bits in AMR/UMOR not to be touched */
+u32 initial_allocation_mask; /* Bits set for the initially allocated keys */
+u32 reserved_allocation_mask; /* Bits set for reserved keys */
+u64 pkey_amr_mask; /* Bits in AMR not to be touched */
u64 pkey_iamr_mask; /* Bits in AMR not to be touched */
+u64 pkey_uamor_mask; /* Bits in UMOR not to be touched */
+int execute_only_key = 2;
#define AMR_BITS_PER_PKEY 2
#define AMR_RD_BIT 0x1UL
@@ -91,7 +94,7 @@ int pkey_initialize(void)
* arch-neutral code.
*/
pkeys_total = min_t(int, pkeys_total,
- (ARCH_VM_PKEY_FLAGS >> VM_PKEY_SHIFT));
+ ((ARCH_VM_PKEY_FLAGS >> VM_PKEY_SHIFT)+1));
if (!pkey_mmu_enabled() || radix_enabled() || !pkeys_total)
static_branch_enable(&pkey_disabled);
@@ -119,20 +122,39 @@ int pkey_initialize(void)
#else
os_reserved = 0;
#endif
- initial_allocation_mask = ~0x0;
- pkey_amr_uamor_mask = ~0x0ul;
+ /* Bits are in LE format. */
+ reserved_allocation_mask = (0x1 << 1) | (0x1 << execute_only_key);
+
+ /* register mask is in BE format */
+ pkey_amr_mask = ~0x0ul;
+ pkey_amr_mask &= ~(0x3ul << pkeyshift(0));
+
pkey_iamr_mask = ~0x0ul;
- /*
- * key 0, 1 are reserved.
- * key 0 is the default key, which allows read/write/execute.
- * key 1 is recommended not to be used. PowerISA(3.0) page 1015,
- * programming note.
- */
- for (i = 2; i < (pkeys_total - os_reserved); i++) {
- initial_allocation_mask &= ~(0x1 << i);
- pkey_amr_uamor_mask &= ~(0x3ul << pkeyshift(i));
- pkey_iamr_mask &= ~(0x1ul << pkeyshift(i));
+ pkey_iamr_mask &= ~(0x3ul << pkeyshift(0));
+ pkey_iamr_mask &= ~(0x3ul << pkeyshift(execute_only_key));
+
+ pkey_uamor_mask = ~0x0ul;
+ pkey_uamor_mask &= ~(0x3ul << pkeyshift(0));
+ pkey_uamor_mask &= ~(0x3ul << pkeyshift(execute_only_key));
+
+ /* mark the rest of the keys as reserved and hence unavailable */
+ for (i = (pkeys_total - os_reserved); i < pkeys_total; i++) {
+ reserved_allocation_mask |= (0x1 << i);
+ pkey_uamor_mask &= ~(0x3ul << pkeyshift(i));
+ }
+ initial_allocation_mask = reserved_allocation_mask | (0x1 << 0);
+
+ if (unlikely((pkeys_total - os_reserved) <= execute_only_key)) {
+ /*
+ * Insufficient number of keys to support
+ * execute only key. Mark it unavailable.
+ * Any AMR, UAMOR, IAMR bit set for
+ * this key is irrelevant since this key
+ * can never be allocated.
+ */
+ execute_only_key = -1;
}
+
return 0;
}
@@ -143,8 +165,7 @@ 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;
+ mm->context.execute_only_pkey = execute_only_key;
}
static inline u64 read_amr(void)
@@ -213,33 +234,6 @@ static inline void init_iamr(int pkey, u8 init_bits)
write_iamr(old_iamr | new_iamr_bits);
}
-static void pkey_status_change(int pkey, bool enable)
-{
- u64 old_uamor;
-
- /* Reset the AMR and IAMR bits for this key */
- init_amr(pkey, 0x0);
- init_iamr(pkey, 0x0);
-
- /* Enable/disable key */
- old_uamor = read_uamor();
- if (enable)
- old_uamor |= (0x3ul << pkeyshift(pkey));
- else
- old_uamor &= ~(0x3ul << pkeyshift(pkey));
- write_uamor(old_uamor);
-}
-
-void __arch_activate_pkey(int pkey)
-{
- pkey_status_change(pkey, true);
-}
-
-void __arch_deactivate_pkey(int pkey)
-{
- pkey_status_change(pkey, false);
-}
-
/*
* Set the access rights in AMR IAMR and UAMOR registers for @pkey to that
* specified in @init_val.
@@ -289,9 +283,6 @@ void thread_pkey_regs_restore(struct thread_struct *new_thread,
if (static_branch_likely(&pkey_disabled))
return;
- /*
- * TODO: Just set UAMOR to zero if @new_thread hasn't used any keys yet.
- */
if (old_thread->amr != new_thread->amr)
write_amr(new_thread->amr);
if (old_thread->iamr != new_thread->iamr)
@@ -305,9 +296,13 @@ void thread_pkey_regs_init(struct thread_struct *thread)
if (static_branch_likely(&pkey_disabled))
return;
- thread->amr = read_amr() & pkey_amr_uamor_mask;
- thread->iamr = read_iamr() & pkey_iamr_mask;
- thread->uamor = read_uamor() & pkey_amr_uamor_mask;
+ thread->amr = pkey_amr_mask;
+ thread->iamr = pkey_iamr_mask;
+ thread->uamor = pkey_uamor_mask;
+
+ write_uamor(pkey_uamor_mask);
+ write_amr(pkey_amr_mask);
+ write_iamr(pkey_iamr_mask);
}
static inline bool pkey_allows_readwrite(int pkey)
@@ -322,48 +317,7 @@ static inline bool pkey_allows_readwrite(int pkey)
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;
+ return mm->context.execute_only_pkey;
}
static inline bool vma_is_pkey_exec_only(struct vm_area_struct *vma)
@@ -407,9 +361,6 @@ static bool pkey_access_permitted(int pkey, bool write, bool execute)
int pkey_shift;
u64 amr;
- if (!pkey)
- return true;
-
if (!is_pkey_enabled(pkey))
return true;