# git rev-parse -q --verify c14cbef0319d21339a76247c3061230ae2950a7c^{commit}
c14cbef0319d21339a76247c3061230ae2950a7c
already have revision, skipping fetch
# git checkout -q -f -B kisskb c14cbef0319d21339a76247c3061230ae2950a7c
# git clean -qxdf
# < git log -1
# commit c14cbef0319d21339a76247c3061230ae2950a7c
# Author: Christophe Leroy <christophe.leroy@c-s.fr>
# Date:   Mon Jun 3 08:20:28 2019 +0000
# 
#     powerpc: fix kexec failure on book3s/32
#     
#     In the old days, _PAGE_EXEC didn't exist on 6xx aka book3s/32.
#     Therefore, allthough __mapin_ram_chunk() was already mapping kernel
#     text with PAGE_KERNEL_TEXT and the rest with PAGE_KERNEL, the entire
#     memory was executable. Part of the memory (first 512kbytes) was
#     mapped with BATs instead of page table, but it was also entirely
#     mapped as executable.
#     
#     In commit 385e89d5b20f ("powerpc/mm: add exec protection on
#     powerpc 603"), we started adding exec protection to some 6xx, namely
#     the 603, for pages mapped via pagetables.
#     
#     Then, in commit 63b2bc619565 ("powerpc/mm/32s: Use BATs for
#     STRICT_KERNEL_RWX"), the exec protection was extended to BAT mapped
#     memory, so that really only the kernel text could be executed.
#     
#     The problem here is that kexec is based on copying some code into
#     upper part of memory then executing it from there in order to install
#     a fresh new kernel at its definitive location.
#     
#     However, the code is position independant and first part of it is
#     just there to deactivate the MMU and jump to the second part. So it
#     is possible to run this first part inplace instead of running the
#     copy. Once the MMU is off, there is no protection anymore and the
#     second part of the code will just run as before.
#     
#     Reported-by: Aaro Koskinen <aaro.koskinen@iki.fi>
#     Fixes: 63b2bc619565 ("powerpc/mm/32s: Use BATs for STRICT_KERNEL_RWX")
#     Cc: stable@vger.kernel.org
#     Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
#     Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/sh4-linux/bin/sh4-linux-gcc --version
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/sh4-linux/bin/sh4-linux-ld --version
# < git log --format=%s --max-count=1 c14cbef0319d21339a76247c3061230ae2950a7c
# < make -s -j 80 ARCH=sh O=/kisskb/build/powerpc-fixes_sh-defconfig_sh4 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/sh4-linux/bin/sh4-linux-  defconfig
# make -s -j 80 ARCH=sh O=/kisskb/build/powerpc-fixes_sh-defconfig_sh4 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/sh4-linux/bin/sh4-linux-  
  Generating include/generated/machtypes.h
/kisskb/src/arch/sh/kernel/cpu/sh4/../sh3/../../entry-common.S: Assembler messages:
/kisskb/src/arch/sh/kernel/cpu/sh4/../sh3/../../entry-common.S:385: Warning: overflow in branch to syscall_exit_work; converted into longer instruction sequence
/kisskb/src/arch/sh/kernel/cpu/sh4/../sh3/../../entry-common.S:388: Warning: overflow in branch to syscall_exit_work; converted into longer instruction sequence
/kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl':
/kisskb/src/kernel/printk/printk.c:194:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/proc/inode.c: In function 'proc_reg_open':
/kisskb/src/include/linux/list.h:65:12: warning: 'pdeo' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/proc/inode.c:331:21: note: 'pdeo' was declared here
/kisskb/src/kernel/rcu/srcutree.c: In function 'init_srcu_struct_fields':
/kisskb/src/kernel/rcu/srcutree.c:140:32: warning: 'levelspread[<U7640>]' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/kernel/rcu/srcutree.c:88:6: note: 'levelspread[<U7640>]' was declared here
/kisskb/src/drivers/base/regmap/regmap.c: In function 'regmap_raw_read':
/kisskb/src/drivers/base/regmap/regmap.c:2589:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/base/regmap/regmap.c: In function '_regmap_raw_write':
/kisskb/src/drivers/base/regmap/regmap.c:1850:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/net/ipv6/ip6_output.c: In function '__ip6_append_data.isra.16':
/kisskb/src/include/linux/skbuff.h:1406:6: warning: 'extra_uref' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/net/ipv6/ip6_output.c:1278:14: note: 'extra_uref' was declared here
/kisskb/src/mm/vmstat.c: In function 'sysctl_vm_numa_stat_handler':
/kisskb/src/mm/vmstat.c:90:5: warning: 'oldval' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/net/ipv4/ip_output.c: In function '__ip_append_data':
/kisskb/src/include/linux/skbuff.h:1406:6: warning: 'extra_uref' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/net/ipv4/ip_output.c:881:14: note: 'extra_uref' was declared here
/kisskb/src/fs/ext4/readpage.c: In function 'ext4_mpage_readpages':
/kisskb/src/fs/ext4/readpage.c:295:1: warning: the frame size of 1200 bytes is larger than 1024 bytes [-Wframe-larger-than=]
/kisskb/src/drivers/sh/clk/cpg.c: In function 'r8':
/kisskb/src/drivers/sh/clk/cpg.c:41:2: warning: passing argument 1 of 'ioread8' discards 'const' qualifier from pointer target type [enabled by default]
/kisskb/src/include/asm-generic/iomap.h:29:21: note: expected 'void *' but argument is of type 'const void *'
/kisskb/src/drivers/sh/clk/cpg.c: In function 'r16':
/kisskb/src/drivers/sh/clk/cpg.c:46:2: warning: passing argument 1 of 'ioread16' discards 'const' qualifier from pointer target type [enabled by default]
/kisskb/src/include/asm-generic/iomap.h:30:21: note: expected 'void *' but argument is of type 'const void *'
/kisskb/src/drivers/sh/clk/cpg.c: In function 'r32':
/kisskb/src/drivers/sh/clk/cpg.c:51:2: warning: passing argument 1 of 'ioread32' discards 'const' qualifier from pointer target type [enabled by default]
/kisskb/src/include/asm-generic/iomap.h:32:21: note: expected 'void *' but argument is of type 'const void *'
/kisskb/src/net/ipv4/fib_semantics.c: In function 'fib_create_info':
/kisskb/src/net/ipv4/fib_semantics.c:1027:12: warning: 'err' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/net/ipv4/fib_semantics.c:971:6: note: 'err' was declared here
/kisskb/src/mm/hugetlb.c: In function 'alloc_pool_huge_page':
/kisskb/src/mm/hugetlb.c:1465:5: warning: 'page' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/mpage.c: In function 'do_mpage_readpage':
/kisskb/src/fs/mpage.c:338:1: warning: the frame size of 1108 bytes is larger than 1024 bytes [-Wframe-larger-than=]
/kisskb/src/fs/mpage.c: In function '__mpage_writepage':
/kisskb/src/fs/mpage.c:690:1: warning: the frame size of 1148 bytes is larger than 1024 bytes [-Wframe-larger-than=]
  Kernel: arch/sh/boot/zImage is ready
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_sh-defconfig_sh4
# Build took: 0:00:44.727793