ppc64: add paranoid warnings for unexpected DSISR_PROTFAULT

[cascardo/linux.git] / arch / powerpc / mm / fault.c

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 6154b0a..b396868 100644 (file)
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -389,19 +389,6 @@ good_area:
 #endif /* CONFIG_8xx */
 
        if (is_exec) {
-#ifdef CONFIG_PPC_STD_MMU
-               /* Protection fault on exec go straight to failure on
-                * Hash based MMUs as they either don't support per-page
-                * execute permission, or if they do, it's handled already
-                * at the hash level. This test would probably have to
-                * be removed if we change the way this works to make hash
-                * processors use the same I/D cache coherency mechanism
-                * as embedded.
-                */
-               if (error_code & DSISR_PROTFAULT)
-                       goto bad_area;
-#endif /* CONFIG_PPC_STD_MMU */
-
                /*
                 * Allow execution from readable areas if the MMU does not
                 * provide separate controls over reading and executing.
@@ -416,6 +403,14 @@ good_area:
                    (cpu_has_feature(CPU_FTR_NOEXECUTE) ||
                     !(vma->vm_flags & (VM_READ | VM_WRITE))))
                        goto bad_area;
+#ifdef CONFIG_PPC_STD_MMU
+               /*
+                * protfault should only happen due to us
+                * mapping a region readonly temporarily. PROT_NONE
+                * is also covered by the VMA check above.
+                */
+               WARN_ON_ONCE(error_code & DSISR_PROTFAULT);
+#endif /* CONFIG_PPC_STD_MMU */
        /* a write */
        } else if (is_write) {
                if (!(vma->vm_flags & VM_WRITE))
@@ -423,11 +418,9 @@ good_area:
                flags |= FAULT_FLAG_WRITE;
        /* a read */
        } else {
-               /* protection fault */
-               if (error_code & 0x08000000)
-                       goto bad_area;
                if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
                        goto bad_area;
+               WARN_ON_ONCE(error_code & DSISR_PROTFAULT);
        }
 
        /*