Date:   Sat, 29 Aug 2020 18:36:31 +0200
From:   Helge Deller <deller@gmx.de>
To:     linux-parisc@vger.kernel.org,
        James Bottomley <James.Bottomley@hansenpartnership.com>,
        John David Anglin <dave.anglin@bell.net>
Subject: [RFC][PATCH] parisc: Drop parisc special case for __sighandler_t
Message-ID: <20200829163631.GA7483@ls3530.fritz.box>
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Sender: linux-parisc-owner@vger.kernel.org
Precedence: bulk

I believe we can and *should* drop this parisc-specific typedef for
__sighandler_t when compiling a 64-bit kernel. The reasons:

1. We don't have a 64-bit userspace yet, so nothing (on userspace side)
can break.

2. Inside the Linux kernel, this is only used in kernel/signal.c, in
function kernel_sigaction() where the signal handler is compared against
SIG_IGN.  SIG_IGN is defined as (__sighandler_t)1), so only the pointers
are compared.

3. Even when a 64-bit userspace gets added at some point, I think
__sighandler_t should be defined what it is: a function pointer struct.

I compiled kernel/signal.c with and without the patch, and the produced co=
de
is identical in both cases.

Opinions?
Do I miss something?
If we want to change it, we should do it before this patch gets applied:
https://patchwork.kernel.org/patch/11730893/

Signed-off-by: Helge Deller <deller@gmx.de>

diff --git a/arch/parisc/include/uapi/asm/signal.h b/arch/parisc/include/u=
api/asm/signal.h
index e605197b462c..d9c51769851a 100644
=2D-- a/arch/parisc/include/uapi/asm/signal.h
+++ b/arch/parisc/include/uapi/asm/signal.h
@@ -85,16 +85,8 @@
 struct siginfo;

 /* Type of a signal handler.  */
-#if defined(__LP64__)
-/* function pointers on 64-bit parisc are pointers to little structs and =
the
- * compiler doesn't support code which changes or tests the address of
- * the function in the little struct.  This is really ugly -PB
- */
-typedef char __user *__sighandler_t;
-#else
 typedef void __signalfn_t(int);
 typedef __signalfn_t __user *__sighandler_t;
-#endif

 typedef struct sigaltstack {
 	void __user *ss_sp;