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  1. 31 Jan, 2023 1 commit
  3. 30 Jan, 2023 2 commits
  5. 17 Jan, 2023 1 commit
    • Heiko Carstens's avatar
      s390: workaround invalid gcc-11 out of bounds read warning · 41e19926
      Heiko Carstens authored 
      GCC 11.1.0 and 11.2.0 generate a wrong warning when compiling the
kernel e.g. with allmodconfig:

arch/s390/kernel/setup.c: In function ‘setup_lowcore_dat_on’:
./include/linux/fortify-string.h:57:33: error: ‘__builtin_memcpy’ reading 128 bytes from a region of size 0 [-Werror=stringop-overread]
...
arch/s390/kernel/setup.c:526:9: note: in expansion of macro ‘memcpy’
  526 |         memcpy(abs_lc->cregs_save_area, S390_lowcore.cregs_save_area,
      |         ^~~~~~

This could be addressed by using absolute_pointer() with the
S390_lowcore macro, but this is not a good idea since this generates
worse code for performance critical paths.

Therefore simply use a for loop to copy the array in question and get
rid of the warning.
Reported-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
      41e19926
  7. 11 Jan, 2023 4 commits
  9. 10 Jan, 2023 1 commit
    • Alexander Egorenkov's avatar
      s390/kexec: fix ipl report address for kdump · c2337a40
      Alexander Egorenkov authored 
      This commit addresses the following erroneous situation with file-based
kdump executed on a system with a valid IPL report.

On s390, a kdump kernel, its initrd and IPL report if present are loaded
into a special and reserved on boot memory region - crashkernel. When
a system crashes and kdump was activated before, the purgatory code
is entered first which swaps the crashkernel and [0 - crashkernel size]
memory regions. Only after that the kdump kernel is entered. For this
reason, the pointer to an IPL report in lowcore must point to the IPL report
after the swap and not to the address of the IPL report that was located in
crashkernel memory region before the swap. Failing to do so, makes the
kdump's decompressor try to read memory from the crashkernel memory region
which already contains the production's kernel memory.

The situation described above caused spontaneous kdump failures/hangs
on systems where the Secure IPL is activated because on such systems
an IPL report is always present. In that case kdump's decompressor tried
to parse an IPL report which frequently lead to illegal memory accesses
because an IPL report contains addresses to various data.

Cc: <stable@vger.kernel.org>
Fixes: 99feaa71 ("s390/kexec_file: Create ipl report and pass to next kernel")
Reviewed-by: default avatarVasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarAlexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
      c2337a40
  11. 09 Jan, 2023 1 commit
  13. 06 Jan, 2023 3 commits
    • Masahiro Yamada's avatar
      s390: define RUNTIME_DISCARD_EXIT to fix link error with GNU ld < 2.36 · a494398b
      Masahiro Yamada authored 
      Nathan Chancellor reports that the s390 vmlinux fails to link with
GNU ld < 2.36 since commit 99cb0d91 ("arch: fix broken BuildID
for arm64 and riscv").

It happens for defconfig, or more specifically for CONFIG_EXPOLINE=y.

  $ s390x-linux-gnu-ld --version | head -n1
  GNU ld (GNU Binutils for Debian) 2.35.2
  $ make -s ARCH=s390 CROSS_COMPILE=s390x-linux-gnu- allnoconfig
  $ ./scripts/config -e CONFIG_EXPOLINE
  $ make -s ARCH=s390 CROSS_COMPILE=s390x-linux-gnu- olddefconfig
  $ make -s ARCH=s390 CROSS_COMPILE=s390x-linux-gnu-
  `.exit.text' referenced in section `.s390_return_reg' of drivers/base/dd.o: defined in discarded section `.exit.text' of drivers/base/dd.o
  make[1]: *** [scripts/Makefile.vmlinux:34: vmlinux] Error 1
  make: *** [Makefile:1252: vmlinux] Error 2

arch/s390/kernel/vmlinux.lds.S wants to keep EXIT_TEXT:

        .exit.text : {
                EXIT_TEXT
        }

But, at the same time, EXIT_TEXT is thrown away by DISCARD because
s390 does not define RUNTIME_DISCARD_EXIT.

I still do not understand why the latter wins after 99cb0d91,
but defining RUNTIME_DISCARD_EXIT seems correct because the comment
line in arch/s390/kernel/vmlinux.lds.S says:

        /*
         * .exit.text is discarded at runtime, not link time,
         * to deal with references from __bug_table
         */

Nathan also found that binutils commit 21401fc7bf67 ("Duplicate output
sections in scripts") cured this issue, so we cannot reproduce it with
binutils 2.36+, but it is better to not rely on it.

Fixes: 99cb0d91 ("arch: fix broken BuildID for arm64 and riscv")
Link: https://lore.kernel.org/all/Y7Jal56f6UBh1abE@dev-arch.thelio-3990X/Reported-by: default avatarNathan Chancellor <nathan@kernel.org>
Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20230105031306.1455409-1-masahiroy@kernel.orgSigned-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
      a494398b
    • Alexander Gordeev's avatar
      s390: expicitly align _edata and _end symbols on page boundary · 45d619bd
      Alexander Gordeev authored 
      Symbols _edata and _end in the linker script are the
only unaligned expicitly on page boundary. Although
_end is aligned implicitly by BSS_SECTION macro that
is still inconsistent and could lead to a bug if a tool
or function would assume that _edata is as aligned as
others.

For example, vmem_map_init() function does not align
symbols _etext, _einittext etc. Should these symbols
be unaligned as well, the size of ranges to update
were short on one page.

Instead of fixing every occurrence of this kind in the
code and external tools just force the alignment on
these two symbols.
Reviewed-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
      45d619bd
    • Niklas Schnelle's avatar
      s390/debug: add _ASM_S390_ prefix to header guard · 0d4d5236
      Niklas Schnelle authored 
      Using DEBUG_H without a prefix is very generic and inconsistent with
other header guards in arch/s390/include/asm. In fact it collides with
the same name in the ath9k wireless driver though that depends on !S390
via disabled wireless support. Let's just use a consistent header guard
name and prevent possible future trouble.
Signed-off-by: default avatarNiklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
      0d4d5236
  15. 01 Jan, 2023 6 commits
  17. 31 Dec, 2022 2 commits
  19. 30 Dec, 2022 19 commits
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