From c065eadb535347661079b93ef4b77739ec40a064 Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@felloff.net>
Date: Thu, 6 Feb 2014 22:43:33 +0100
Subject: [PATCH] pc64: fix note handling

---
 sys/src/9/kw/syscall.c |  2 +-
 sys/src/9/omap4/trap.c |  2 +-
 sys/src/9/pc/trap.c    |  2 +-
 sys/src/9/pc64/fns.h   |  1 +
 sys/src/9/pc64/l.s     |  5 +++++
 sys/src/9/pc64/trap.c  | 17 ++++++++++++++---
 6 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/sys/src/9/kw/syscall.c b/sys/src/9/kw/syscall.c
index fc148dee9..8ef7a0edf 100644
--- a/sys/src/9/kw/syscall.c
+++ b/sys/src/9/kw/syscall.c
@@ -261,7 +261,7 @@ syscall(Ureg* ureg)
 	up->psstate = 0;
 
 	if(scallnr == NOTED)
-		noted(ureg, up->s.args[0]);
+		noted(ureg, *((ulong*)up->s.args));
 
 	splhi();
 	if(scallnr != RFORK && (up->procctl || up->nnote))
diff --git a/sys/src/9/omap4/trap.c b/sys/src/9/omap4/trap.c
index 26de7ac8d..50450855a 100644
--- a/sys/src/9/omap4/trap.c
+++ b/sys/src/9/omap4/trap.c
@@ -370,7 +370,7 @@ syscall(Ureg *ureg)
 	up->psstate = nil;
 
 	if(scall == NOTED)
-		noted(ureg, up->s.args[0]);
+		noted(ureg, *((ulong*)up->s.args));
 	if(scall != RFORK && (up->procctl || up->nnote)){
 		splhi();
 		notify(ureg);
diff --git a/sys/src/9/pc/trap.c b/sys/src/9/pc/trap.c
index cf85bcad6..fbc6aef2c 100644
--- a/sys/src/9/pc/trap.c
+++ b/sys/src/9/pc/trap.c
@@ -799,7 +799,7 @@ syscall(Ureg* ureg)
 	up->psstate = 0;
 
 	if(scallnr == NOTED)
-		noted(ureg, up->s.args[0]);
+		noted(ureg, *((ulong*)up->s.args));
 
 	if(scallnr!=RFORK && (up->procctl || up->nnote)){
 		splhi();
diff --git a/sys/src/9/pc64/fns.h b/sys/src/9/pc64/fns.h
index 5586d1aa5..47c3acf7a 100644
--- a/sys/src/9/pc64/fns.h
+++ b/sys/src/9/pc64/fns.h
@@ -104,6 +104,7 @@ uintptr	*mmuwalk(uintptr*, uintptr, int, int);
 int	mtrr(uvlong, uvlong, char *);
 void	mtrrclock(void);
 int	mtrrprint(char *, long);
+void	noteret(void);
 uchar	nvramread(int);
 void	nvramwrite(int, uchar);
 void	outb(int, int);
diff --git a/sys/src/9/pc64/l.s b/sys/src/9/pc64/l.s
index e1eb310b1..e0038a1d6 100644
--- a/sys/src/9/pc64/l.s
+++ b/sys/src/9/pc64/l.s
@@ -737,6 +737,10 @@ TEXT forkret(SB), 1, $-4
 
 	BYTE $0x48; SYSRET			/* SYSRETQ */
 
+TEXT noteret(SB), 1, $-4
+	CLI
+	JMP _intrestore
+
 /*
  * Interrupt/exception handling.
  */
@@ -786,6 +790,7 @@ _intrnested:
 	PUSHQ	SP
 	CALL	trap(SB)
 
+_intrestore:
 	POPQ	AX
 
 	POPQ	AX
diff --git a/sys/src/9/pc64/trap.c b/sys/src/9/pc64/trap.c
index a83fe2f3f..41a8c4978 100644
--- a/sys/src/9/pc64/trap.c
+++ b/sys/src/9/pc64/trap.c
@@ -758,8 +758,19 @@ syscall(Ureg* ureg)
 	up->insyscall = 0;
 	up->psstate = 0;
 
-	if(scallnr == NOTED)
-		noted(ureg, up->s.args[0]);
+	if(scallnr == NOTED){
+		noted(ureg, *((ulong*)up->s.args));
+
+		/*
+		 * normally, syscall() returns to forkret()
+		 * not restoring general registers when going
+		 * to userspace. to completely restore the
+		 * interrupted context, we have to return thru
+		 * noteret(). we override return pc to jump to
+		 * to it when returning form syscall()
+		 */
+		((void**)&ureg)[-1] = (void*)noteret;
+	}
 
 	if(scallnr!=RFORK && (up->procctl || up->nnote)){
 		splhi();
@@ -904,7 +915,7 @@ if(0) print("%s %lud: noted %#p %#p\n",
 			pprint("suicide: trap in noted\n");
 			pexit("Suicide", 0);
 		}
-		up->ureg = (Ureg*)(*(ulong*)(oureg-BY2WD));
+		up->ureg = (Ureg*)(*(uintptr*)(oureg-BY2WD));
 		qunlock(&up->debug);
 		break;
 
-- 
2.44.0