[PATCH 5.4 223/320] parisc: Avoid calling faulthandler_disabled() twice

Greg Kroah-Hartman
2022-01-24T19:40:58Z

From: John David Anglin <dave.anglin@bell.net>

[ Upstream commit 9e9d4b460f23bab61672eae397417d03917d116c ]

In handle_interruption(), we call faulthandler_disabled() to check whether the
fault handler is not disabled. If the fault handler is disabled, we immediately
call do_page_fault(). It then calls faulthandler_disabled(). If disabled,
do_page_fault() attempts to fixup the exception by jumping to no_context:

no_context:

if (!user_mode(regs) && fixup_exception(regs)) {
return;
}

parisc_terminate("Bad Address (null pointer deref?)", regs, code, address);

Apart from the error messages, the two blocks of code perform the same
function.

We can avoid two calls to faulthandler_disabled() by a simple revision
to the code in handle_interruption().

Note: I didn't try to fix the formatting of this code block.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/parisc/kernel/traps.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
index 82fc011894889..2a1060d747a5d 100644
--- a/arch/parisc/kernel/traps.c
+++ b/arch/parisc/kernel/traps.c
@@ -783,7 +783,7 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
* unless pagefault_disable() was called before.
*/

- if (fault_space == 0 && !faulthandler_disabled())
+ if (faulthandler_disabled() || fault_space == 0)
{
/* Clean up and return if in exception table. */
if (fixup_exception(regs))
--
2.34.1