# git rev-parse -q --verify 2542f2f17eb335c13f525e523319ba59f2fd82a0^{commit}
2542f2f17eb335c13f525e523319ba59f2fd82a0
already have revision, skipping fetch
# git checkout -q -f -B kisskb 2542f2f17eb335c13f525e523319ba59f2fd82a0
# git clean -qxdf
# < git log -1
# commit 2542f2f17eb335c13f525e523319ba59f2fd82a0
# Author: Frederic Barrat <fbarrat@linux.ibm.com>
# Date:   Wed Jan 9 16:13:42 2019 +0100
# 
#     powerpc/powernv/npu: Fix oops in pnv_try_setup_npu_table_group()
#     
#     With a recent change around IOMMU group, a system with an opencapi
#     adapter is no longer booting and we get a kernel oops:
#     
#       BUG: Kernel NULL pointer dereference at 0x00000028
#       Faulting instruction address: 0xc0000000000aa38c
#       ...
#       NIP pnv_try_setup_npu_table_group+0x1c/0x1a0
#       LR  pnv_pci_ioda_fixup+0x1f8/0x660
#       Call Trace:
#         pnv_try_setup_npu_table_group+0x60/0x
#         pnv_pci_ioda_fixup+0x20c/0x660
#         pcibios_resource_survey+0x2c8/0x31c
#         pcibios_init+0xb0/0xe4
#         do_one_initcall+0x64/0x264
#         kernel_init_freeable+0x36c/0x468
#         kernel_init+0x2c/0x148
#         ret_from_kernel_thread+0x5c/0x68
#     
#     An opencapi device is using a device PE, so the current code breaks
#     because pe->pbus is not defined.
#     
#     More generally, there's no need to define an IOMMU group for opencapi,
#     as the device sends real addresses directly (admittedly, the
#     virtualization story is yet to be written). So let's fix it by
#     skipping the IOMMU group setup for opencapi PHBs.
#     
#     Fixes: 0bd971676e68 ("powerpc/powernv/npu: Add compound IOMMU groups")
#     Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com>
#     Reviewed-by: Greg Kurz <groug@kaod.org>
#     Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-gcc --version
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-ld --version
# < git log --format=%s --max-count=1 2542f2f17eb335c13f525e523319ba59f2fd82a0
# < make -s -j 120 ARCH=x86 O=/kisskb/build/powerpc-fixes_x86_64_defconfig_x86_64-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-  x86_64_defconfig
# make -s -j 120 ARCH=x86 O=/kisskb/build/powerpc-fixes_x86_64_defconfig_x86_64-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-  
You are building kernel with non-retpoline compiler.
Please update your compiler.
make[1]: *** [arch/x86/Makefile:300: checkbin] Error 1
make[1]: *** Waiting for unfinished jobs....
make: *** [Makefile:152: sub-make] Error 2
Command 'make -s -j 120 ARCH=x86 O=/kisskb/build/powerpc-fixes_x86_64_defconfig_x86_64-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-  ' returned non-zero exit status 2
# rm -rf /kisskb/build/powerpc-fixes_x86_64_defconfig_x86_64-gcc4.6
# Build took: 0:00:03.636787