# 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 # 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 # Link: https://lore.kernel.org/r/20200320032116.1024773-2-mpe@ellerman.id.au # < /opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version # < git log --format=%s --max-count=1 b3258f133d72af0bb463e198610d47ae57498b00 # < make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-next_ppc6xx_defconfig_powerpc-gcc9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux- ppc6xx_defconfig # < make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-next_ppc6xx_defconfig_powerpc-gcc9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux- help # make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-next_ppc6xx_defconfig_powerpc-gcc9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux- olddefconfig # make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-next_ppc6xx_defconfig_powerpc-gcc9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-9.2.0-nolibc/powerpc64-linux/bin/powerpc64-linux- In file included from /kisskb/src/sound/ppc/pmac.h:12, from /kisskb/src/sound/ppc/awacs.c:16: /kisskb/src/sound/ppc/awacs.c: In function 'snd_pmac_awacs_init': /kisskb/src/include/sound/control.h:218:9: warning: 'speaker_vol' may be used uninitialized in this function [-Wmaybe-uninitialized] 218 | return _snd_ctl_add_slave(master, slave, 0); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /kisskb/src/sound/ppc/awacs.c:873:36: note: 'speaker_vol' was declared here 873 | struct snd_kcontrol *master_vol, *speaker_vol; | ^~~~~~~~~~~ INFO: Uncompressed kernel (size 0xbf26a4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf26a4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf26a4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf26a4) overlaps the address of the wrapper(0x400000) INFO: Uncompressed kernel (size 0xbf26a4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf26a4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf26a4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf26a4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf26a4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbf26a4) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbe1fbc) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) INFO: Uncompressed kernel (size 0xbe1fbc) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xc00000) Image Name: Linux-5.6.0-rc2+ Created: Fri Mar 20 21:33:26 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5574904 Bytes = 5444.24 KiB = 5.32 MiB Load Address: 00000000 Entry Point: 00000000 Image Name: Linux-5.6.0-rc2+ Created: Fri Mar 20 21:33:27 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5610597 Bytes = 5479.10 KiB = 5.35 MiB Load Address: 00c00000 Entry Point: 00c0090c Image Name: Linux-5.6.0-rc2+ Created: Fri Mar 20 21:33:27 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5610371 Bytes = 5478.88 KiB = 5.35 MiB Load Address: 00c00000 Entry Point: 00c002ac Image Name: Linux-5.6.0-rc2+ Created: Fri Mar 20 21:33:28 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5609135 Bytes = 5477.67 KiB = 5.35 MiB Load Address: 00c00000 Entry Point: 00c002ac Image Name: Linux-5.6.0-rc2+ Created: Fri Mar 20 21:33:28 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5610870 Bytes = 5479.37 KiB = 5.35 MiB Load Address: 00c00000 Entry Point: 00c0090c Image Name: Linux-5.6.0-rc2+ Created: Fri Mar 20 21:33:28 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5610042 Bytes = 5478.56 KiB = 5.35 MiB Load Address: 00c00000 Entry Point: 00c002ac Image Name: Linux-5.6.0-rc2+ Created: Fri Mar 20 21:33:28 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5609913 Bytes = 5478.43 KiB = 5.35 MiB Load Address: 00c00000 Entry Point: 00c002ac Image Name: Linux-5.6.0-rc2+ Created: Fri Mar 20 21:33:28 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5610128 Bytes = 5478.64 KiB = 5.35 MiB Load Address: 00c00000 Entry Point: 00c002ac Image Name: Linux-5.6.0-rc2+ Created: Fri Mar 20 21:33:28 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5609266 Bytes = 5477.80 KiB = 5.35 MiB Load Address: 00c00000 Entry Point: 00c002ac Completed OK # rm -rf /kisskb/build/powerpc-next_ppc6xx_defconfig_powerpc-gcc9 # Build took: 0:04:14.423273