[PATCH] powerpc/mm: tell if a bad page fault on data is read or write.

[Christophe Leroy]

DSISR has a bit to tell if the fault is due to a read or a write.

Display it.

Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr>
---
 arch/powerpc/mm/fault.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 8432c281de92..b5047f9b5dec 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -645,6 +645,7 @@ NOKPROBE_SYMBOL(do_page_fault);
 void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
 {
        const struct exception_table_entry *entry;
+       int is_write = page_fault_is_write(regs->dsisr);
 
        /* Are we prepared to handle this fault?  */
        if ((entry = search_exception_tables(regs->nip)) != NULL) {
@@ -658,9 +659,10 @@ void bad_page_fault(struct pt_regs *regs, unsigned long 
address, int sig)
        case 0x300:
        case 0x380:
        case 0xe00:
-               pr_alert("BUG: %s at 0x%08lx\n",
+               pr_alert("BUG: %s on %s at 0x%08lx\n",
                         regs->dar < PAGE_SIZE ? "Kernel NULL pointer 
dereference" :
-                        "Unable to handle kernel data access", regs->dar);
+                        "Unable to handle kernel data access",
+                        is_write ? "write" : "read", regs->dar);
                break;
        case 0x400:
        case 0x480:
-- 
2.13.3