commit a54f1655be4cb103a6729adcc9ca914c5fdf1ca0
author Al Viro <viro@zeniv.linux.org.uk> Tue Apr 24 01:46:23 2012 -0400
committer Al Viro <viro@zeniv.linux.org.uk> Mon May 21 23:59:47 2012 -0400
tree a54cfff27d2fb3b9d04daa3490a7e601df586c18
parent 899dfaa7e7dd825f8366c2a6b38067db43644dc6

m68k: add TIF_NOTIFY_RESUME and handle it.

TIF_NOTIFY_RESUME added (as bit 5).  That way nommu glue needs no changes at
all; mmu one needs just to replace jmi do_signal_return to jne do_signal_return
There we have flags shifted up, until bit 6 (SIGPENDING) is in MSBit; instead
of checking that MSBit is set (jmi) we check that MSBit or something below it
is set (jne); bits 0..4 are never set, so that's precisely "bit 6 or bit 5 is
set".

Usual handling of NOTIFY_RESUME/SIGPENDING is done in do_notify_resume(); glue
calls it instead of do_signal().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/m68k/kernel/entry_mm.S

diff --git a/arch/m68k/kernel/entry_mm.S b/arch/m68k/kernel/entry_mm.S
index 675a854..f29e73c 100644
--- a/arch/m68k/kernel/entry_mm.S
+++ b/arch/m68k/kernel/entry_mm.S
@@ -148,7 +148,7 @@
 	jcs	do_trace_exit
 	jmi	do_delayed_trace
 	lslw	#8,%d0
-	jmi	do_signal_return
+	jne	do_signal_return
 	pea	resume_userspace
 	jra	schedule
 
@@ -172,7 +172,7 @@
 	| save top of frame
 	movel	%sp,%curptr@(TASK_THREAD+THREAD_ESP0)
 	lslb	#1,%d0
-	jmi	do_signal_return
+	jne	do_signal_return
 	pea	resume_userspace
 	jra	schedule
 
@@ -182,7 +182,7 @@
 	subql	#4,%sp			| dummy return address
 	SAVE_SWITCH_STACK
 	pea	%sp@(SWITCH_STACK_SIZE)
-	bsrl	do_signal
+	bsrl	do_notify_resume
 	addql	#4,%sp
 	RESTORE_SWITCH_STACK
 	addql	#4,%sp

arch/m68k/kernel/signal.c

diff --git a/arch/m68k/kernel/signal.c b/arch/m68k/kernel/signal.c
index d8f6960..d9f3d19 100644
--- a/arch/m68k/kernel/signal.c
+++ b/arch/m68k/kernel/signal.c
@@ -43,6 +43,7 @@
 #include <linux/tty.h>
 #include <linux/binfmts.h>
 #include <linux/module.h>
+#include <linux/tracehook.h>
 
 #include <asm/setup.h>
 #include <asm/uaccess.h>
@@ -1154,7 +1155,7 @@
  * want to handle. Thus you cannot kill init even with a SIGKILL even by
  * mistake.
  */
-asmlinkage void do_signal(struct pt_regs *regs)
+static void do_signal(struct pt_regs *regs)
 {
 	siginfo_t info;
 	struct k_sigaction ka;
@@ -1186,3 +1187,15 @@
 		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 	}
 }
+
+void do_notify_resume(struct pt_regs *regs)
+{
+	if (test_thread_flag(TIF_SIGPENDING))
+		do_signal(regs);
+
+	if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) {
+		tracehook_notify_resume(regs);
+		if (current->replacement_session_keyring)
+			key_replace_session_keyring();
+	}
+}