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@xxxxxxxxxx>
---
arch/powerpc/include/asm/pkeys.h | 12 ++++++++++++
arch/powerpc/mm/pkeys.c | 5 +++++
2 files changed, 17 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
index aec3f49..9d59619 100644
--- a/arch/powerpc/include/asm/pkeys.h
+++ b/arch/powerpc/include/asm/pkeys.h
@@ -22,6 +22,18 @@
#define VM_PKEY_BIT4 VM_HIGH_ARCH_4
#endif
+/* override any generic PKEY Permission defines */
+#undef PKEY_DISABLE_ACCESS
+#define PKEY_DISABLE_ACCESS 0x1
+#undef PKEY_DISABLE_WRITE
+#define PKEY_DISABLE_WRITE 0x2
+#undef PKEY_DISABLE_EXECUTE
+#define PKEY_DISABLE_EXECUTE 0x4
+#undef PKEY_ACCESS_MASK
+#define PKEY_ACCESS_MASK (PKEY_DISABLE_ACCESS |\
+ PKEY_DISABLE_WRITE |\
+ PKEY_DISABLE_EXECUTE)
+
#define arch_max_pkey() pkeys_total
#define AMR_RD_BIT 0x1UL
#define AMR_WR_BIT 0x2UL
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
index 5b3531e..c1c40c3 100644
--- a/arch/powerpc/mm/pkeys.c
+++ b/arch/powerpc/mm/pkeys.c
@@ -78,6 +78,7 @@ 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;
@@ -90,5 +91,9 @@ int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
init_amr(pkey, new_amr_bits);
+ if ((init_val & PKEY_DISABLE_EXECUTE))
+ new_iamr_bits |= IAMR_EX_BIT;
+
+ init_iamr(pkey, new_iamr_bits);
return 0;
}
--
1.7.1
--
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