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| author |   Ilya Leoshkevich <iii@linux.ibm.com> | 2025-05-15 17:52:13 +0200 |
|---|---|---|
| committer |   Andrew Morton <akpm@linux-foundation.org> | 2025-05-21 10:48:25 -0700 |
| commit | c164679bed3a5f0d235723c2395d9a5122b151c4 (patch) | |
| tree | 5f303dc271388538125e35916af8bd07d17feb6f | |
| parent | scripts/gdb/symbols: factor out pagination_off() (diff) | |
| download | linux-rng-c164679bed3a5f0d235723c2395d9a5122b151c4.tar.xz linux-rng-c164679bed3a5f0d235723c2395d9a5122b151c4.zip | |
scripts/gdb/symbols: determine KASLR offset on s390 during early boot
Using lx-symbols during s390 early boot fails with:
Error occurred in Python: 'utf-8' codec can't decode byte 0xcb in position 0: invalid continuation byte
The reason is that s390 decompressor's startup_kernel() does not create
vmcoreinfo note, and sets vmcore_info to kernel's physical base. This
confuses get_vmcore_s390().
Fix by handling this special case. Extract vm_layout.kaslr_offset from
the kernel image in physical memory, which is placed there by the
decompressor using the __bootdata_preserved mechanism, and generate a
synthetic vmcoreinfo note from it.
Link: https://lkml.kernel.org/r/20250515155811.114392-4-iii@linux.ibm.com
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | scripts/gdb/linux/symbols.py | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/scripts/gdb/linux/symbols.py b/scripts/gdb/linux/symbols.py index 0c7af712c44c..2332bd8eddf1 100644 --- a/scripts/gdb/linux/symbols.py +++ b/scripts/gdb/linux/symbols.py @@ -54,6 +54,18 @@ def get_vmcore_s390(): vmcore_info = 0x0e0c paddr_vmcoreinfo_note = gdb.parse_and_eval("*(unsigned long long *)" + hex(vmcore_info)) + if paddr_vmcoreinfo_note == 0 or paddr_vmcoreinfo_note & 1: + # In the early boot case, extract vm_layout.kaslr_offset from the + # vmlinux image in physical memory. + if paddr_vmcoreinfo_note == 0: + kaslr_offset_phys = 0 + else: + kaslr_offset_phys = paddr_vmcoreinfo_note - 1 + with utils.pagination_off(): + gdb.execute("symbol-file {0} -o {1}".format( + utils.get_vmlinux(), hex(kaslr_offset_phys))) + kaslr_offset = gdb.parse_and_eval("vm_layout.kaslr_offset") + return "KERNELOFFSET=" + hex(kaslr_offset)[2:] inferior = gdb.selected_inferior() elf_note = inferior.read_memory(paddr_vmcoreinfo_note, 12) n_namesz, n_descsz, n_type = struct.unpack(">III", elf_note) |