From 2d7514152b1c82c81a363f8a171237567ebb7e66 Mon Sep 17 00:00:00 2001
From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Date: Fri, 3 Nov 2017 09:05:38 +0000
Subject: [PATCH] drm/i915: Warn in debug builds of incorrect usages of ptr_pack_bits
Git-commit: 2d7514152b1c82c81a363f8a171237567ebb7e66
Patch-mainline: v4.16-rc1
References: FATE#322643 bsc#1055900
GEM_BUG_ON if the packed bits do not fit into the specified width.
V2: Avoid using the macro argument twice.
V3: Drop unnecessary braces. (Joonas)
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (v1)
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171103090538.14474-1-tvrtko.ursulin@linux.intel.com
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/gpu/drm/i915/i915_utils.h | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/i915/i915_utils.h
+++ b/drivers/gpu/drm/i915/i915_utils.h
@@ -83,8 +83,11 @@
(typeof(ptr))(__v & -BIT(n)); \
})
-#define ptr_pack_bits(ptr, bits, n) \
- ((typeof(ptr))((unsigned long)(ptr) | (bits)))
+#define ptr_pack_bits(ptr, bits, n) ({ \
+ unsigned long __bits = (bits); \
+ GEM_BUG_ON(__bits & -BIT(n)); \
+ ((typeof(ptr))((unsigned long)(ptr) | __bits)); \
+})
#define page_mask_bits(ptr) ptr_mask_bits(ptr, PAGE_SHIFT)
#define page_unmask_bits(ptr) ptr_unmask_bits(ptr, PAGE_SHIFT)