# git rev-parse -q --verify b3258f133d72af0bb463e198610d47ae57498b00^{commit}
b3258f133d72af0bb463e198610d47ae57498b00
already have revision, skipping fetch
# git checkout -q -f -B kisskb b3258f133d72af0bb463e198610d47ae57498b00
# git clean -qxdf
# < git log -1
# commit b3258f133d72af0bb463e198610d47ae57498b00
# Author: Michael Ellerman <mpe@ellerman.id.au>
# Date:   Fri Mar 20 14:21:16 2020 +1100
# 
#     powerpc/64: Prevent stack protection in early boot
#     
#     The previous commit reduced the amount of code that is run before we
#     setup a paca. However there are still a few remaining functions that
#     run with no paca, or worse, with an arbitrary value in r13 that will
#     be used as a paca pointer.
#     
#     In particular the stack protector canary is stored in the paca, so if
#     stack protector is activated for any of these functions we will read
#     the stack canary from wherever r13 points. If r13 happens to point
#     outside of memory we will get a machine check / checkstop.
#     
#     For example if we modify initialise_paca() to trigger stack
#     protection, and then boot in the mambo simulator with r13 poisoned in
#     skiboot before calling the kernel:
#     
#       DEBUG: 19952232: (19952232): INSTRUCTION: PC=0xC0000000191FC1E8: [0x3C4C006D]: addis   r2,r12,0x6D [fetch]
#       DEBUG: 19952236: (19952236): INSTRUCTION: PC=0xC00000001807EAD8: [0x7D8802A6]: mflr    r12 [fetch]
#       FATAL ERROR: 19952276: (19952276): Check Stop for 0:0: Machine Check with ME bit of MSR off
#       DEBUG: 19952276: (19952276): INSTRUCTION: PC=0xC0000000191FCA7C: [0xE90D0CF8]: ld      r8,0xCF8(r13) [Instruction Failed]
#       INFO: 19952276: (19952277): ** Execution stopped: Mambo Error, Machine Check Stop,  **
#       systemsim % bt
#       pc:                             0xC0000000191FCA7C      initialise_paca+0x54
#       lr:                             0xC0000000191FC22C      early_setup+0x44
#       stack:0x00000000198CBED0        0x0     +0x0
#       stack:0x00000000198CBF00        0xC0000000191FC22C      early_setup+0x44
#       stack:0x00000000198CBF90        0x1801C968      +0x1801C968
#     
#     So annotate the relevant functions to ensure stack protection is never
#     enabled for them.
#     
#     Fixes: 06ec27aea9fc ("powerpc/64: add stack protector support")
#     Cc: stable@vger.kernel.org # v4.20+
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20200320032116.1024773-2-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 b3258f133d72af0bb463e198610d47ae57498b00
# < make -s -j 48 ARCH=sh O=/kisskb/build/powerpc-next_sh-defconfig_sh4-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/sh4-linux/bin/sh4-linux-  defconfig
# < make -s -j 48 ARCH=sh O=/kisskb/build/powerpc-next_sh-defconfig_sh4-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/sh4-linux/bin/sh4-linux-  help
# make -s -j 48 ARCH=sh O=/kisskb/build/powerpc-next_sh-defconfig_sh4-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/sh4-linux/bin/sh4-linux-  olddefconfig
# make -s -j 48 ARCH=sh O=/kisskb/build/powerpc-next_sh-defconfig_sh4-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/sh4-linux/bin/sh4-linux-  
  Generating include/generated/machtypes.h
<stdin>:1511:2: warning: #warning syscall clone3 not implemented [-Wcpp]
/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/fs/proc/inode.c: In function 'proc_reg_open':
/kisskb/src/include/linux/list.h:72:12: warning: 'pdeo' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/proc/inode.c:338:21: note: 'pdeo' was declared here
/kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl':
/kisskb/src/kernel/printk/printk.c:204:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized]
/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/kernel/trace/trace_events.c: In function 'event_create_dir':
/kisskb/src/kernel/trace/trace_events.c:2040:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/ext4/extents.c: In function 'ext4_convert_unwritten_io_end_vec':
/kisskb/src/fs/ext4/extents.c:5009:23: warning: 'ret' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/ext4/readpage.c: In function 'ext4_mpage_readpages':
/kisskb/src/fs/ext4/readpage.c:416:1: warning: the frame size of 1180 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=]
/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/mm/hugetlb.c: In function 'alloc_pool_huge_page':
/kisskb/src/mm/hugetlb.c:1426:5: warning: 'page' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/usb/core/devio.c: In function 'async_completed':
/kisskb/src/drivers/usb/core/devio.c:625:23: warning: 'errno' may be used uninitialized in this function [-Wuninitialized]
/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 *'
  Kernel: arch/sh/boot/zImage is ready
Completed OK
# rm -rf /kisskb/build/powerpc-next_sh-defconfig_sh4-gcc4.6
# Build took: 0:00:41.869966