From b19aeeb91e3c548a7f42828f4d474e23ae6b59b8 Mon Sep 17 00:00:00 2001
From: Laszlo Ersek <lersek@redhat.com>
Date: Sun, 10 Sep 2017 00:23:42 +0200
Subject: [PATCH] MdeModulePkg/PartitionDxe: don't divide 64-bit values with C
 operators

In edk2, the division and shifting of 64-bit values are forbidden with
C-language operators, because the compiler may generate intrinsic calls
for them.

For example, clang-3.8 emits a call to "__umoddi3" for

  UDF_LOGICAL_SECTOR_SIZE % Media->BlockSize

in PartitionInstallUdfChildHandles(), if PartitionDxe is built for IA32,
which then fails to link.

UDF_LOGICAL_SECTOR_SIZE has type UINT64, while
EFI_BLOCK_IO_MEDIA.BlockSize has type UINT32(). Replace the % operator
with a DivU64x32Remainder() call.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Paulo Alcantara <pcacjr@zytor.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Paulo Alcantara <pcacjr@zytor.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 MdeModulePkg/Universal/Disk/PartitionDxe/Udf.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/MdeModulePkg/Universal/Disk/PartitionDxe/Udf.c b/MdeModulePkg/Universal/Disk/PartitionDxe/Udf.c
index 3174ab2b4b..e46cf1d4f4 100644
--- a/MdeModulePkg/Universal/Disk/PartitionDxe/Udf.c
+++ b/MdeModulePkg/Universal/Disk/PartitionDxe/Udf.c
@@ -243,6 +243,7 @@ PartitionInstallUdfChildHandles (
   IN  EFI_DEVICE_PATH_PROTOCOL     *DevicePath
   )
 {
+  UINT32                       RemainderByMediaBlockSize;
   EFI_STATUS                   Status;
   EFI_BLOCK_IO_MEDIA           *Media;
   EFI_DEVICE_PATH_PROTOCOL     *DevicePathNode;
@@ -255,7 +256,12 @@ PartitionInstallUdfChildHandles (
   //
   // Check if UDF logical block size is multiple of underlying device block size
   //
-  if ((UDF_LOGICAL_SECTOR_SIZE % Media->BlockSize) != 0 ||
+  DivU64x32Remainder (
+    UDF_LOGICAL_SECTOR_SIZE,   // Dividend
+    Media->BlockSize,          // Divisor
+    &RemainderByMediaBlockSize // Remainder
+    );
+  if (RemainderByMediaBlockSize != 0 ||
       Media->BlockSize > UDF_LOGICAL_SECTOR_SIZE) {
     return EFI_NOT_FOUND;
   }