powerpc: Fill in si_addr_lsb siginfo field

Fill in the si_addr_lsb siginfo field so the hwpoison code can
pass to userspace the length of memory that has been corrupted.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 588b6ccc0569..24b3f4949df4 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -33,6 +33,7 @@
 #include <linux/magic.h>
 #include <linux/ratelimit.h>
 #include <linux/context_tracking.h>
+#include <linux/hugetlb.h>
 
 #include <asm/firmware.h>
 #include <asm/page.h>
@@ -118,6 +119,7 @@ static int do_sigbus(struct pt_regs *regs, unsigned long address,
                      unsigned int fault)
 {
         siginfo_t info;
+        unsigned int lsb = 0;
 
         up_read(&current->mm->mmap_sem);
 
@@ -135,7 +137,13 @@ static int do_sigbus(struct pt_regs *regs, unsigned long address,
                         current->comm, current->pid, address);
                 info.si_code = BUS_MCEERR_AR;
         }
+
+        if (fault & VM_FAULT_HWPOISON_LARGE)
+                lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault));
+        if (fault & VM_FAULT_HWPOISON)
+                lsb = PAGE_SHIFT;
 #endif
+        info.si_addr_lsb = lsb;
         force_sig_info(SIGBUS, &info, current);
         return MM_FAULT_RETURN;
 }