signal/openrisc: Fix do_unaligned_access to send the proper signal

commit 500d58300571b6602341b041f97c082a461ef994 upstream.

While reviewing the signal sending on openrisc the do_unaligned_access
function stood out because it is obviously wrong.  A comment about an
si_code set above when actually si_code is never set.  Leading to a
random si_code being sent to userspace in the event of an unaligned
access.

Looking further SIGBUS BUS_ADRALN is the proper pair of signal and
si_code to send for an unaligned access. That is what other
architectures do and what is required by posix.

Given that do_unaligned_access is broken in a way that no one can be
relying on it on openrisc fix the code to just do the right thing.

Fixes: 769a8a96229e ("OpenRISC: Traps")
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: openrisc@lists.librecores.org
Acked-by: Stafford Horne <shorne@gmail.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/openrisc/kernel/traps.c b/arch/openrisc/kernel/traps.c
index 3d3f606..605a284 100644 (file)
--- a/arch/openrisc/kernel/traps.c
+++ b/arch/openrisc/kernel/traps.c
@@ -302,12 +302,12 @@ asmlinkage void do_unaligned_access(struct pt_regs *regs, unsigned long address)
        siginfo_t info;
 
        if (user_mode(regs)) {
-               /* Send a SIGSEGV */
-               info.si_signo = SIGSEGV;
+               /* Send a SIGBUS */
+               info.si_signo = SIGBUS;
                info.si_errno = 0;
-               /* info.si_code has been set above */
-               info.si_addr = (void *)address;
-               force_sig_info(SIGSEGV, &info, current);
+               info.si_code = BUS_ADRALN;
+               info.si_addr = (void __user *)address;
+               force_sig_info(SIGBUS, &info, current);
        } else {
                printk("KERNEL: Unaligned Access 0x%.8lx\n", address);
                show_registers(regs);