summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorRam Pai <linuxram@us.ibm.com>2018-01-18 17:50:30 -0800
committerMichael Ellerman <mpe@ellerman.id.au>2018-01-20 22:59:00 +1100
commitdcf872956d444bbbd46f601024ea989ced03f8a7 (patch)
tree84daad698cac49a0595b8940e6888bf01cc83796
parent2ddc53f3a7516b3e2c4ab9c36854a227641a4fde (diff)
powerpc: ability to create execute-disabled pkeys
powerpc has hardware support to disable execute on a pkey. This patch enables the ability to create execute-disabled keys. Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
-rw-r--r--arch/powerpc/include/uapi/asm/mman.h6
-rw-r--r--arch/powerpc/mm/pkeys.c16
2 files changed, 22 insertions, 0 deletions
diff --git a/arch/powerpc/include/uapi/asm/mman.h b/arch/powerpc/include/uapi/asm/mman.h
index e63bc37e33af..65065ce32814 100644
--- a/arch/powerpc/include/uapi/asm/mman.h
+++ b/arch/powerpc/include/uapi/asm/mman.h
@@ -30,4 +30,10 @@
#define MAP_STACK 0x20000 /* give out an address that is best suited for process/thread stacks */
#define MAP_HUGETLB 0x40000 /* create a huge page mapping */
+/* Override any generic PKEY permission defines */
+#define PKEY_DISABLE_EXECUTE 0x4
+#undef PKEY_ACCESS_MASK
+#define PKEY_ACCESS_MASK (PKEY_DISABLE_ACCESS |\
+ PKEY_DISABLE_WRITE |\
+ PKEY_DISABLE_EXECUTE)
#endif /* _UAPI_ASM_POWERPC_MMAN_H */
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
index b01238bd88c1..e61bea4a3606 100644
--- a/arch/powerpc/mm/pkeys.c
+++ b/arch/powerpc/mm/pkeys.c
@@ -25,6 +25,14 @@ int pkey_initialize(void)
int os_reserved, i;
/*
+ * We define PKEY_DISABLE_EXECUTE in addition to the arch-neutral
+ * generic defines for PKEY_DISABLE_ACCESS and PKEY_DISABLE_WRITE.
+ * Ensure that the bits a distinct.
+ */
+ BUILD_BUG_ON(PKEY_DISABLE_EXECUTE &
+ (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE));
+
+ /*
* Disable the pkey system till everything is in place. A subsequent
* patch will enable it.
*/
@@ -177,10 +185,18 @@ int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
unsigned long init_val)
{
u64 new_amr_bits = 0x0ul;
+ u64 new_iamr_bits = 0x0ul;
if (!is_pkey_enabled(pkey))
return -EINVAL;
+ if (init_val & PKEY_DISABLE_EXECUTE) {
+ if (!pkey_execute_disable_supported)
+ return -EINVAL;
+ new_iamr_bits |= IAMR_EX_BIT;
+ }
+ init_iamr(pkey, new_iamr_bits);
+
/* Set the bits we need in AMR: */
if (init_val & PKEY_DISABLE_ACCESS)
new_amr_bits |= AMR_RD_BIT | AMR_WR_BIT;