# git rev-parse -q --verify f74fc58f295a45c29b565a898d869034099ca9a1^{commit}
f74fc58f295a45c29b565a898d869034099ca9a1
already have revision, skipping fetch
# git checkout -q -f -B kisskb f74fc58f295a45c29b565a898d869034099ca9a1
# git clean -qxdf
# < git log -1
# commit f74fc58f295a45c29b565a898d869034099ca9a1
# Author: Alexey Kardashevskiy <aik@ozlabs.ru>
# Date:   Thu Jul 18 15:11:39 2019 +1000
# 
#     powerpc/powernv/ioda2: Create bigger default window with 64k IOMMU pages
#     
#     At the moment we create a small window only for 32bit devices, the window
#     maps 0..2GB of the PCI space only. For other devices we either use
#     a sketchy bypass or hardware bypass but the former can only work if
#     the amount of RAM is no bigger than the device's DMA mask and the latter
#     requires devices to support at least 59bit DMA.
#     
#     This extends the default DMA window to the maximum size possible to allow
#     a wider DMA mask than just 32bit. The default window size is now limited
#     by the the iommu_table::it_map allocation bitmap which is a contiguous
#     array, 1 bit per an IOMMU page.
#     
#     This increases the default IOMMU page size from hard coded 4K to
#     the system page size to allow wider DMA masks.
#     
#     This increases the level number to not exceed the max order allocation
#     limit per TCE level. By the same time, this keeps minimal levels number
#     as 2 in order to save memory.
#     
#     As the extended window now overlaps the 32bit MMIO region, this adds
#     an area reservation to iommu_init_table().
#     
#     After this change the default window size is 0x80000000000==1<<43 so
#     devices limited to DMA mask smaller than the amount of system RAM can
#     still use more than just 2GB of memory for DMA.
#     
#     This is an optimization and not a bug fix for DMA API usage.
#     
#     With the on-demand allocation of indirect TCE table levels enabled and
#     2 levels, the first TCE level size is just
#     1<<ceil((log2(0x7ffffffffff+1)-16)/2)=16384 TCEs or 2 system pages.
#     
#     Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20190718051139.74787-5-aik@ozlabs.ru
# < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version
# < git log --format=%s --max-count=1 f74fc58f295a45c29b565a898d869034099ca9a1
# < make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-next_44x_arches_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  44x/arches_defconfig
# make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-next_44x_arches_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  
<stdin>:1511:2: warning: #warning syscall clone3 not implemented [-Wcpp]
Completed OK
# rm -rf /kisskb/build/powerpc-next_44x_arches_defconfig_powerpc-gcc5
# Build took: 0:00:39.373266