# git rev-parse -q --verify 36e826b568e412f61d68fedc02a67b4d8b7583cc^{commit}
36e826b568e412f61d68fedc02a67b4d8b7583cc
already have revision, skipping fetch
# git checkout -q -f -B kisskb 36e826b568e412f61d68fedc02a67b4d8b7583cc
# git clean -qxdf
# < git log -1
# commit 36e826b568e412f61d68fedc02a67b4d8b7583cc
# Author: Aditya Gupta <adityag@linux.ibm.com>
# Date:   Mon Oct 23 12:56:12 2023 +0530
# 
#     powerpc/vmcore: Add MMU information to vmcoreinfo
#     
#     Since below commit, address mapping for vmemmap has changed for Radix
#     MMU, where address mapping is stored in kernel page table itself,
#     instead of earlier used 'vmemmap_list'.
#     
#         commit 368a0590d954 ("powerpc/book3s64/vmemmap: switch radix to use
#         a different vmemmap handling function")
#     
#     Hence with upstream kernel, in case of Radix MMU, makedumpfile fails
#     to do address translation for vmemmap addresses, as it depended on
#     vmemmap_list, which can now be empty.
#     
#     While fixing the address translation in makedumpfile, it was identified
#     that currently makedumpfile cannot distinguish between Hash MMU and
#     Radix MMU, unless VMLINUX is passed with -x flag to makedumpfile. And
#     hence fails to assign offsets and shifts correctly (such as in L4 to
#     PGDIR offset calculation in makedumpfile).
#     
#     For getting the MMU, makedumpfile uses `cur_cpu_spec.mmu_features`.
#     
#     Add `cur_cpu_spec` symbol and offset of `mmu_features` in the `cpu_spec`
#     struct, to VMCOREINFO, so that makedumpfile can assign the offsets
#     correctly, without needing a VMLINUX.
#     
#     Also, even along with `cur_cpu_spec->mmu_features` makedumpfile has to
#     depend on the 'MMU_FTR_TYPE_RADIX' flag in mmu_features, implying kernel
#     developers need to be cautious of changes to 'MMU_FTR_*' defines.
#     
#     A more stable approach was suggested in the below thread by contributors:
#      https://lore.kernel.org/linuxppc-dev/20230920105706.853626-1-adityag@linux.ibm.com/
#     
#     The suggestion was to add whether 'RADIX_MMU' is enabled in vmcoreinfo
#     
#     This patch also implements the suggestion, by adding 'RADIX_MMU' in
#     vmcoreinfo, which makedumpfile can use to get whether the crashed system
#     had RADIX MMU (in which case 'NUMBER(RADIX_MMU)=1') or not (in which
#     case 'NUMBER(RADIX_MMU)=0')
#     
#     Fixes: 368a0590d954 ("powerpc/book3s64/vmemmap: switch radix to use a different vmemmap handling function")
#     Reported-by: Sachin Sant <sachinp@linux.ibm.com>
#     Signed-off-by: Aditya Gupta <adityag@linux.ibm.com>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://msgid.link/20231023072612.50874-1-adityag@linux.ibm.com
# < /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 36e826b568e412f61d68fedc02a67b4d8b7583cc
# make -s -j 160 ARCH=powerpc O=/kisskb/build/powerpc-next_40x_walnut_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  40x/walnut_defconfig
# < make -s -j 160 ARCH=powerpc O=/kisskb/build/powerpc-next_40x_walnut_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  help
# make -s -j 160 ARCH=powerpc O=/kisskb/build/powerpc-next_40x_walnut_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  olddefconfig
# make -s -j 160 ARCH=powerpc O=/kisskb/build/powerpc-next_40x_walnut_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  
Completed OK
# rm -rf /kisskb/build/powerpc-next_40x_walnut_defconfig_powerpc-gcc5
# Build took: 0:01:03.995997