[PATCH] powerpc: Implement PR_[GS]ET_UNALIGN prctls for powerpc

This gives the ability to control whether alignment exceptions get
fixed up or reported to the process as a SIGBUS, using the existing
PR_SET_UNALIGN and PR_GET_UNALIGN prctls.  We do not implement the
option of logging a message on alignment exceptions.

Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 03def5715494..91a6e04d9741 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -805,9 +805,11 @@ void __kprobes program_check_exception(struct pt_regs *regs)
 
 void alignment_exception(struct pt_regs *regs)
 {
-        int fixed;
+        int fixed = 0;
 
-        fixed = fix_alignment(regs);
+        /* we don't implement logging of alignment exceptions */
+        if (!(current->thread.align_ctl & PR_UNALIGN_SIGBUS))
+                fixed = fix_alignment(regs);
 
         if (fixed == 1) {
                 regs->nip += 4; /* skip over emulated instruction */