[powerpc v4 2/3] Detect instruction fetch denied and report

[Balbir Singh]

ISA 3 allows for prevention of instruction fetch and execution
of user mode pages. If such an error occurs, SRR1 bit 35
reports the error. We catch and report the error in do_page_fault()

Signed-off-by: Balbir Singh <bsingharora at gmail.com>
---
 arch/powerpc/mm/fault.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index d0b137d..1e7ff7b 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -404,6 +404,10 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
 		    (cpu_has_feature(CPU_FTR_NOEXECUTE) ||
 		     !(vma->vm_flags & (VM_READ | VM_WRITE))))
 			goto bad_area;
+
+		if (regs->msr & SRR1_ISI_N_OR_G)
+			goto bad_area;
+
 #ifdef CONFIG_PPC_STD_MMU
 		/*
 		 * protfault should only happen due to us
-- 
2.5.5