From: kettenis <kettenis@openbsd.org>
Date: Mon, 28 Jun 2021 09:35:09 +0000 (+0000)
Subject: Implement copyin32().
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=53fc5f58d1241148f56fc2fc6066d2a9eedb175c;p=openbsd

Implement copyin32().

ok deraadt@
---

diff --git a/sys/arch/riscv64/riscv64/copy.S b/sys/arch/riscv64/riscv64/copy.S
index 54ab2d2f783..96a4fa87c1a 100644
--- a/sys/arch/riscv64/riscv64/copy.S
+++ b/sys/arch/riscv64/riscv64/copy.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: copy.S,v 1.4 2021/05/15 20:14:05 deraadt Exp $	*/
+/*	$OpenBSD: copy.S,v 1.5 2021/06/28 09:35:09 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2020 Brian Bamsch <bbamsch@google.com>
@@ -62,7 +62,7 @@ ENTRY(copyin)
 	EXIT_USER_ACCESS(a4)
 	SET_FAULT_HANDLER(a3, a4)
 .Lcopyiodone:
-	mv	a0, x0
+	mv	a0, zero
 	RETGUARD_CHECK(copyio, a6)
 	ret
 
@@ -76,6 +76,33 @@ ENTRY(copyin)
 	ret
 END(copyin)
 
+/*
+ * a0 = user space address
+ * a1 = kernel space address
+ *
+ * Atomically copies a 32-bit word from user space to kernel space
+ */
+ENTRY(copyin32)
+	RETGUARD_SETUP(copyio, a6)
+	/* Check source alignment. */
+	andi	a2, a0, 3
+	bnez	a2, .Lcopyiofault_nopcb
+	/* Check that source is in userspace. */
+	li	a4, VM_MAXUSER_ADDRESS
+	bgeu	a0, a4, .Lcopyiofault_nopcb
+
+	la	a3, .Lcopyiofault_user
+	SWAP_FAULT_HANDLER(a3, a4, a5)
+	ENTER_USER_ACCESS(a4)
+
+	lw	a2, 0(a0)
+	sw	a2, 0(a1)
+
+	EXIT_USER_ACCESS(a4)
+	SET_FAULT_HANDLER(a3, a4)
+	j	.Lcopyiodone
+END(copyin)
+
 /*
  * a0 = kernel space address
  * a1 = user space address