powerpc/mm: Fix reporting of kernel execute faults on the 8xx

[ Upstream commit ffca395b11c4a5a6df6d6345f794b0e3d578e2d0 ]

On the 8xx, no-execute is set via PPP bits in the PTE. Therefore
a no-exec fault generates DSISR_PROTFAULT error bits,
not DSISR_NOEXEC_OR_G.

This patch adds DSISR_PROTFAULT in the test mask.

Fixes: d3ca587404b3 ("powerpc/mm: Fix reporting of kernel execute faults")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 6e1e390..52863de 100644 (file)
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -215,7 +215,9 @@ static int mm_fault_error(struct pt_regs *regs, unsigned long addr, int fault)
 static bool bad_kernel_fault(bool is_exec, unsigned long error_code,
                             unsigned long address)
 {
-       if (is_exec && (error_code & (DSISR_NOEXEC_OR_G | DSISR_KEYFAULT))) {
+       /* NX faults set DSISR_PROTFAULT on the 8xx, DSISR_NOEXEC_OR_G on others */
+       if (is_exec && (error_code & (DSISR_NOEXEC_OR_G | DSISR_KEYFAULT |
+                                     DSISR_PROTFAULT))) {
                printk_ratelimited(KERN_CRIT "kernel tried to execute"
                                   " exec-protected page (%lx) -"
                                   "exploit attempt? (uid: %d)\n",