This patch provides the detailed implementation for a user to allocate a key and enable it in the hardware.
It provides the plumbing, but it cannot be used till the system call is implemented. The next patch will do so.
Reviewed-by: Thiago Jung Bauermann bauerman@linux.vnet.ibm.com Signed-off-by: Ram Pai linuxram@us.ibm.com --- arch/powerpc/include/asm/pkeys.h | 6 ++++- arch/powerpc/mm/pkeys.c | 40 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 45 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index 9964b46..2500a90 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -139,10 +139,14 @@ static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma, return 0; }
+extern int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey, + unsigned long init_val); static inline int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, unsigned long init_val) { - return 0; + if (static_branch_likely(&pkey_disabled)) + return -EINVAL; + return __arch_set_user_pkey_access(tsk, pkey, init_val); }
extern void pkey_mm_init(struct mm_struct *mm); diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index e1dc45b..eca04cd 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -9,6 +9,7 @@ * (at your option) any later version. */
+#include <asm/mman.h> #include <linux/pkeys.h>
DEFINE_STATIC_KEY_TRUE(pkey_disabled); @@ -17,6 +18,9 @@ u32 initial_allocation_mask; /* Bits set for reserved keys */
#define AMR_BITS_PER_PKEY 2 +#define AMR_RD_BIT 0x1UL +#define AMR_WR_BIT 0x2UL +#define IAMR_EX_BIT 0x1UL #define PKEY_REG_BITS (sizeof(u64)*8) #define pkeyshift(pkey) (PKEY_REG_BITS - ((pkey+1) * AMR_BITS_PER_PKEY))
@@ -112,6 +116,20 @@ static inline void write_uamor(u64 value) mtspr(SPRN_UAMOR, value); }
+static bool is_pkey_enabled(int pkey) +{ + u64 uamor = read_uamor(); + u64 pkey_bits = 0x3ul << pkeyshift(pkey); + u64 uamor_pkey_bits = (uamor & pkey_bits); + + /* + * Both the bits in UAMOR corresponding to the key should be set or + * reset. + */ + WARN_ON(uamor_pkey_bits && (uamor_pkey_bits != pkey_bits)); + return !!(uamor_pkey_bits); +} + static inline void init_amr(int pkey, u8 init_bits) { u64 new_amr_bits = (((u64)init_bits & 0x3UL) << pkeyshift(pkey)); @@ -154,3 +172,25 @@ 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. + */ +int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey, + unsigned long init_val) +{ + u64 new_amr_bits = 0x0ul; + + if (!is_pkey_enabled(pkey)) + return -EINVAL; + + /* Set the bits we need in AMR: */ + if (init_val & PKEY_DISABLE_ACCESS) + new_amr_bits |= AMR_RD_BIT | AMR_WR_BIT; + else if (init_val & PKEY_DISABLE_WRITE) + new_amr_bits |= AMR_WR_BIT; + + init_amr(pkey, new_amr_bits); + return 0; +}