Module Name:    src
Committed By:   msaitoh
Date:           Tue Oct  1 18:44:24 UTC 2019

Modified Files:
        src/sys/external/bsd/drm2/dist/drm/i915: i915_gem_stolen.c

Log Message:
 Avoid undefined behavior in g4x_get_stolen_reserved().
The change is the same as newer i915_gem_stolen.c.


To generate a diff of this commit:
cvs rdiff -u -r1.11 -r1.12 \
    src/sys/external/bsd/drm2/dist/drm/i915/i915_gem_stolen.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

Modified files:

Index: src/sys/external/bsd/drm2/dist/drm/i915/i915_gem_stolen.c
diff -u src/sys/external/bsd/drm2/dist/drm/i915/i915_gem_stolen.c:1.11 src/sys/external/bsd/drm2/dist/drm/i915/i915_gem_stolen.c:1.12
--- src/sys/external/bsd/drm2/dist/drm/i915/i915_gem_stolen.c:1.11	Thu Sep 13 08:25:55 2018
+++ src/sys/external/bsd/drm2/dist/drm/i915/i915_gem_stolen.c	Tue Oct  1 18:44:24 2019
@@ -1,4 +1,4 @@
-/*	$NetBSD: i915_gem_stolen.c,v 1.11 2018/09/13 08:25:55 mrg Exp $	*/
+/*	$NetBSD: i915_gem_stolen.c,v 1.12 2019/10/01 18:44:24 msaitoh Exp $	*/
 
 /*
  * Copyright © 2008-2012 Intel Corporation
@@ -29,7 +29,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: i915_gem_stolen.c,v 1.11 2018/09/13 08:25:55 mrg Exp $");
+__KERNEL_RCSID(0, "$NetBSD: i915_gem_stolen.c,v 1.12 2019/10/01 18:44:24 msaitoh Exp $");
 
 #include <linux/printk.h>
 #include <linux/err.h>
@@ -308,18 +308,13 @@ static void g4x_get_stolen_reserved(stru
 	unsigned long stolen_top = dev_priv->mm.stolen_base +
 		dev_priv->gtt.stolen_size;
 
-	*base = (reg_val & G4X_STOLEN_RESERVED_ADDR2_MASK) << 16;
+	if (!(reg_val & G4X_STOLEN_RESERVED_ADDR2_MASK))
+		return;
 
+	*base = (reg_val & G4X_STOLEN_RESERVED_ADDR2_MASK) << 16;
 	WARN_ON((reg_val & G4X_STOLEN_RESERVED_ADDR1_MASK) < *base);
 
-	/* On these platforms, the register doesn't have a size field, so the
-	 * size is the distance between the base and the top of the stolen
-	 * memory. We also have the genuine case where base is zero and there's
-	 * nothing reserved. */
-	if (*base == 0)
-		*size = 0;
-	else
-		*size = stolen_top - *base;
+	*size = stolen_top - *base;
 }
 
 static void gen6_get_stolen_reserved(struct drm_i915_private *dev_priv,

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