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| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2012-10-04 14:46:12 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2012-10-09 14:16:58 +0200 |
| commit | e76e82d772522b05ed93228478d2a4460754b6a4 (patch) | |
| tree | ea31d76fc3103518c1802d135e71266feabd70f1 /arch/s390/Kconfig.debug | |
| parent | s390: add support to start the kernel in 64 bit mode. (diff) | |
| download | linux-e76e82d772522b05ed93228478d2a4460754b6a4.tar.xz linux-e76e82d772522b05ed93228478d2a4460754b6a4.zip | |
s390/mm: add page table dumper
This is more or less the same as the x86 page table dumper which was
merged four years ago: 926e5392 "x86: add code to dump the (kernel)
page tables for visual inspection by kernel developers".
We add a file at /sys/kernel/debug/kernel_page_tables for debugging
purposes so it's quite easy to see the kernel page table layout and
possible odd mappings:
---[ Identity Mapping ]---
0x0000000000000000-0x0000000000100000 1M PTE RW
---[ Kernel Image Start ]---
0x0000000000100000-0x0000000000800000 7M PMD RO
0x0000000000800000-0x00000000008a9000 676K PTE RO
0x00000000008a9000-0x0000000000900000 348K PTE RW
0x0000000000900000-0x0000000001500000 12M PMD RW
---[ Kernel Image End ]---
0x0000000001500000-0x0000000280000000 10219M PMD RW
0x0000000280000000-0x000003d280000000 3904G PUD I
---[ vmemmap Area ]---
0x000003d280000000-0x000003d288c00000 140M PTE RW
0x000003d288c00000-0x000003d300000000 1908M PMD I
0x000003d300000000-0x000003e000000000 52G PUD I
---[ vmalloc Area ]---
0x000003e000000000-0x000003e000009000 36K PTE RW
0x000003e000009000-0x000003e0000ee000 916K PTE I
0x000003e0000ee000-0x000003e000146000 352K PTE RW
0x000003e000146000-0x000003e000200000 744K PTE I
0x000003e000200000-0x000003e080000000 2046M PMD I
0x000003e080000000-0x0000040000000000 126G PUD I
This usually makes only sense for kernel developers. The output
with CONFIG_DEBUG_PAGEALLOC is not very helpful, because of the
huge number of mapped out pages, however I decided for the time
being to not add a !DEBUG_PAGEALLOC dependency.
Maybe it's helpful for somebody even with that option.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/Kconfig.debug')
| -rw-r--r-- | arch/s390/Kconfig.debug | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/s390/Kconfig.debug b/arch/s390/Kconfig.debug index d76cef3fef37..fc32a2df4974 100644 --- a/arch/s390/Kconfig.debug +++ b/arch/s390/Kconfig.debug @@ -31,6 +31,18 @@ config DEBUG_STRICT_USER_COPY_CHECKS If unsure, or if you run an older (pre 4.4) gcc, say N. +config S390_PTDUMP + bool "Export kernel pagetable layout to userspace via debugfs" + depends on DEBUG_KERNEL + select DEBUG_FS + ---help--- + Say Y here if you want to show the kernel pagetable layout in a + debugfs file. This information is only useful for kernel developers + who are working in architecture specific areas of the kernel. + It is probably not a good idea to enable this feature in a production + kernel. + If in doubt, say "N" + config DEBUG_SET_MODULE_RONX def_bool y depends on MODULES |