From: kettenis <kettenis@openbsd.org>
Date: Thu, 13 May 2021 06:44:11 +0000 (+0000)
Subject: When doing AST processing:
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=0f6296b86303a33577b09ef08e0a0e23296d6b0c;p=openbsd

When doing AST processing:
1) block interrupts, then check for ASTs
2) if no ASTs, return with interrupts blocked, so they can be re-enabled
   ATOMICALLY in the return to userspace
3) if an AST happened, then re-enable interrupts, call ast(), then goto 1

ok jsg@
---

diff --git a/sys/arch/riscv64/riscv64/exception.S b/sys/arch/riscv64/riscv64/exception.S
index 316447f99aa..719f9ab9c8b 100644
--- a/sys/arch/riscv64/riscv64/exception.S
+++ b/sys/arch/riscv64/riscv64/exception.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: exception.S,v 1.3 2021/05/10 05:58:20 jsg Exp $	*/
+/*	$OpenBSD: exception.S,v 1.4 2021/05/13 06:44:11 kettenis Exp $	*/
 
 /*-
  * Copyright (c) 2015-2018 Ruslan Bukin <br@bsdpad.com>
@@ -183,9 +183,8 @@
 .endm
 
 .macro	do_ast
-	/* Disable interrupts */
-	csrr	a4, sstatus
 1:
+	/* Disable interrupts */
 	csrci	sstatus, (SSTATUS_SIE)
 
 	/* Check for astpending */
@@ -196,8 +195,8 @@
 
 	sw	x0, P_ASTPENDING(a1)
 
-	/* Restore interrupts */
-	csrw	sstatus, a4
+	/* Enable interrupts */
+	csrsi	sstatus, (SSTATUS_SIE)
 
 	/* handle the ast */
 	mv	a0, sp