[PATCH] powerpc/mm: Invalidate subpage_prot() system call on radix platforms

[Anshuman Khandual]

Radix enabled platforms don't support subpage_prot() system calls. But
at present the system calls goes through without an error and fails
later on while validating expected subpage accesses. Lets not allow
the system call on powerpc radix platforms to begin with to prevent
this confusion in user space.

Signed-off-by: Anshuman Khandual <khandual at linux.vnet.ibm.com>
---
 arch/powerpc/mm/subpage-prot.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/powerpc/mm/subpage-prot.c b/arch/powerpc/mm/subpage-prot.c
index 781532d..4005468 100644
--- a/arch/powerpc/mm/subpage-prot.c
+++ b/arch/powerpc/mm/subpage-prot.c
@@ -195,6 +195,9 @@ long sys_subpage_prot(unsigned long addr, unsigned long len, u32 __user *map)
 	unsigned long next, limit;
 	int err;
 
+	if (radix_enabled())
+		return -ENOSYS;
+
 	/* Check parameters */
 	if ((addr & ~PAGE_MASK) || (len & ~PAGE_MASK) ||
 	    addr >= mm->task_size || len >= mm->task_size ||
-- 
1.8.5.2