From 6620a6fb459531921b1730d9a67f54c692e424c7 Mon Sep 17 00:00:00 2001
From: guenther <guenther@openbsd.org>
Date: Sat, 18 Apr 2015 05:14:05 +0000
Subject: [PATCH] i386 and amd64 have only one syscall entry point now, so
 simply the EIP/RIP adjustment for ERESTART

ok mlarkin@
---
 sys/arch/amd64/amd64/locore.S |  4 ++--
 sys/arch/amd64/amd64/trap.c   | 10 +++-------
 sys/arch/i386/i386/locore.s   |  4 ++--
 sys/arch/i386/i386/trap.c     | 13 ++++---------
 4 files changed, 11 insertions(+), 20 deletions(-)

diff --git a/sys/arch/amd64/amd64/locore.S b/sys/arch/amd64/amd64/locore.S
index c4d9cee4d6a..d3f9cffcfb0 100644
--- a/sys/arch/amd64/amd64/locore.S
+++ b/sys/arch/amd64/amd64/locore.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: locore.S,v 1.63 2015/03/22 05:55:39 guenther Exp $	*/
+/*	$OpenBSD: locore.S,v 1.64 2015/04/18 05:14:05 guenther Exp $	*/
 /*	$NetBSD: locore.S,v 1.13 2004/03/25 18:33:17 drochner Exp $	*/
 
 /*
@@ -1024,7 +1024,7 @@ IDTVEC(syscall)
 	movq	%r11, TF_RFLAGS(%rsp)	/* old rflags from syscall insn */
 	movq	$(GSEL(GUCODE_SEL, SEL_UPL)), TF_CS(%rsp)
 	movq	%rcx,TF_RIP(%rsp)
-	movq	$2,TF_ERR(%rsp)
+	movq	$2,TF_ERR(%rsp)		/* ignored */
 	movq	$T_ASTFLT, TF_TRAPNO(%rsp)
 
 	movq	CPUVAR(CURPROC),%r14
diff --git a/sys/arch/amd64/amd64/trap.c b/sys/arch/amd64/amd64/trap.c
index 473273c3262..3c452797354 100644
--- a/sys/arch/amd64/amd64/trap.c
+++ b/sys/arch/amd64/amd64/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.44 2015/03/14 03:38:46 jsg Exp $	*/
+/*	$OpenBSD: trap.c,v 1.45 2015/04/18 05:14:05 guenther Exp $	*/
 /*	$NetBSD: trap.c,v 1.2 2003/05/04 23:51:56 fvdl Exp $	*/
 
 /*-
@@ -562,12 +562,8 @@ syscall(struct trapframe *frame)
 		frame->tf_rflags &= ~PSL_C;	/* carry bit */
 		break;
 	case ERESTART:
-		/*
-		 * The offset to adjust the PC by depends on whether we entered
-		 * the kernel through the trap or call gate.  We pushed the
-		 * size of the instruction into tf_err on entry.
-		 */
-		frame->tf_rip -= frame->tf_err;
+		/* Back up over the syscall instruction (2 bytes) */
+		frame->tf_rip -= 2;
 		break;
 	case EJUSTRETURN:
 		/* nothing to do */
diff --git a/sys/arch/i386/i386/locore.s b/sys/arch/i386/i386/locore.s
index ed000829dc7..81e61c70cdb 100644
--- a/sys/arch/i386/i386/locore.s
+++ b/sys/arch/i386/i386/locore.s
@@ -1,4 +1,4 @@
-/*	$OpenBSD: locore.s,v 1.152 2015/04/12 18:37:53 mlarkin Exp $	*/
+/*	$OpenBSD: locore.s,v 1.153 2015/04/18 05:14:05 guenther Exp $	*/
 /*	$NetBSD: locore.s,v 1.145 1996/05/03 19:41:19 christos Exp $	*/
 
 /*-
@@ -1491,7 +1491,7 @@ calltrap:
  * Trap gate entry for syscall
  */
 IDTVEC(syscall)
-	pushl	$2		# size of instruction for restart
+	pushl	$2		# ignored
 	pushl	$T_ASTFLT	# trap # for doing ASTs
 	INTRENTRY
 	pushl	%esp
diff --git a/sys/arch/i386/i386/trap.c b/sys/arch/i386/i386/trap.c
index 5119002090d..e277cdf1940 100644
--- a/sys/arch/i386/i386/trap.c
+++ b/sys/arch/i386/i386/trap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: trap.c,v 1.120 2015/01/11 19:34:52 guenther Exp $	*/
+/*	$OpenBSD: trap.c,v 1.121 2015/04/18 05:14:05 guenther Exp $	*/
 /*	$NetBSD: trap.c,v 1.95 1996/05/05 06:50:02 mycroft Exp $	*/
 
 /*-
@@ -531,7 +531,7 @@ syscall(struct trapframe *frame)
 	caddr_t params;
 	struct sysent *callp;
 	struct proc *p;
-	int error, opc, nsys;
+	int error, nsys;
 	register_t code, args[8], rval[2];
 #ifdef DIAGNOSTIC
 	int ocpl = lapic_tpr;
@@ -545,7 +545,6 @@ syscall(struct trapframe *frame)
 #endif
 	p = curproc;
 	p->p_md.md_regs = frame;
-	opc = frame->tf_eip;
 	code = frame->tf_eax;
 
 	nsys = p->p_p->ps_emul->e_nsysent;
@@ -640,12 +639,8 @@ syscall(struct trapframe *frame)
 		frame->tf_eflags &= ~PSL_C;	/* carry bit */
 		break;
 	case ERESTART:
-		/*
-		 * The offset to adjust the PC by depends on whether we entered
-		 * the kernel through the trap or call gate.  We pushed the
-		 * size of the instruction into tf_err on entry.
-		 */
-		frame->tf_eip = opc - frame->tf_err;
+		/* Back up over the int$80 (2 bytes) that made the syscall */
+		frame->tf_eip -= 2;
 		break;
 	case EJUSTRETURN:
 		/* nothing to do */
-- 
2.20.1