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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Johannes Berg <johannes.berg@intel.com>,
        Richard Weinberger <richard@nod.at>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 282/846] lib/logic_iomem: Fix operation on 32-bit
Date:   Mon, 24 Jan 2022 19:36:39 +0100
Message-Id: <20220124184110.654106787@linuxfoundation.org>
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From: Johannes Berg <johannes.berg@intel.com>

[ Upstream commit 4e8a5edac5010820e7c5303fc96f5a262e096bb6 ]

On 32-bit, the first entry might be at 0/NULL, but that's
strange and leads to issues, e.g. where we check "if (ret)".
Use a IOREMAP_BIAS/IOREMAP_MASK of 0x80000000UL to avoid
this. This then requires reducing the number of areas (via
MAX_AREAS), but we still have 128 areas, which is enough.

Fixes: ca2e334232b6 ("lib: add iomem emulation (logic_iomem)")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 lib/logic_iomem.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/logic_iomem.c b/lib/logic_iomem.c
index 54fa601f3300b..549b22d4bcde1 100644
--- a/lib/logic_iomem.c
+++ b/lib/logic_iomem.c
@@ -21,15 +21,15 @@ struct logic_iomem_area {
 
 #define AREA_SHIFT	24
 #define MAX_AREA_SIZE	(1 << AREA_SHIFT)
-#define MAX_AREAS	((1ULL<<32) / MAX_AREA_SIZE)
+#define MAX_AREAS	((1U << 31) / MAX_AREA_SIZE)
 #define AREA_BITS	((MAX_AREAS - 1) << AREA_SHIFT)
 #define AREA_MASK	(MAX_AREA_SIZE - 1)
 #ifdef CONFIG_64BIT
 #define IOREMAP_BIAS	0xDEAD000000000000UL
 #define IOREMAP_MASK	0xFFFFFFFF00000000UL
 #else
-#define IOREMAP_BIAS	0
-#define IOREMAP_MASK	0
+#define IOREMAP_BIAS	0x80000000UL
+#define IOREMAP_MASK	0x80000000UL
 #endif
 
 static DEFINE_MUTEX(regions_mtx);
-- 
2.34.1