linux-kernel - [PATCH] iommu/vt-d: Fix linker error on 32-bit

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Date:   Thu, 10 Jun 2021 10:31:20 +0200
From:   Joerg Roedel <joro@...tes.org>
To:     Joerg Roedel <joro@...tes.org>,
        Lu Baolu <baolu.lu@...ux.intel.com>,
        Will Deacon <will@...nel.org>
Cc:     David Woodhouse <dwmw2@...radead.org>,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        Joerg Roedel <jroedel@...e.de>
Subject: [PATCH] iommu/vt-d: Fix linker error on 32-bit

From: Joerg Roedel <jroedel@...e.de>

A recent commit broke the build on 32-bit x86. The linker throws these
messages:

	ld: drivers/iommu/intel/perf.o: in function `dmar_latency_snapshot':
	perf.c:(.text+0x40c): undefined reference to `__udivdi3'
	ld: perf.c:(.text+0x458): undefined reference to `__udivdi3'

The reason are the 64-bit divides in dmar_latency_snapshot(). Use the
div_u64() helper function for those.

Fixes: 55ee5e67a59a ("iommu/vt-d: Add common code for dmar latency performance monitors")
Signed-off-by: Joerg Roedel <jroedel@...e.de>
---
 drivers/iommu/intel/perf.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/intel/perf.c b/drivers/iommu/intel/perf.c
index faaa96dda437..73b7ec705552 100644
--- a/drivers/iommu/intel/perf.c
+++ b/drivers/iommu/intel/perf.c
@@ -141,14 +141,14 @@ int dmar_latency_snapshot(struct intel_iommu *iommu, char *str, size_t size)
 				if (val == UINT_MAX)
 					val = 0;
 				else
-					val /= 1000;
+					val = div_u64(val, 1000);
 				break;
 			case COUNTS_MAX:
-				val /= 1000;
+				val = div_u64(val, 1000);
 				break;
 			case COUNTS_SUM:
 				if (lstat[i].samples)
-					val /= (lstat[i].samples * 1000);
+					val = div_u64(val, (lstat[i].samples * 1000));
 				else
 					val = 0;
 				break;
-- 
2.31.1