path: root/sys/amd64/include/minidump.h
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* Sparsify the vm_page_dump bitmapD Scott Phillips2020-09-211-1/+2
| | | | | | | | | | | | | | | | | | | On Ampere Altra systems, the sparse population of RAM within the physical address space causes the vm_page_dump bitmap to be much larger than necessary, increasing the size from ~8 Mib to > 2 Gib (and overflowing `int` for the size). Changing the page dump bitmap also changes the minidump file format, so changes are also necessary in libkvm. Reviewed by: jhb Approved by: scottl (implicit) MFC after: 1 week Sponsored by: Ampere Computing, Inc. Differential Revision: https://reviews.freebsd.org/D26131 Notes: svn path=/head/; revision=365978
* sys/amd64: further adoption of SPDX licensing ID tags.Pedro F. Giffuni2017-11-271-0/+2
| | | | | | | | | | | | | | | Mainly focus on files that use BSD 2-Clause license, however the tool I was using misidentified many licenses so this was mostly a manual - error prone - task. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts. Notes: svn path=/head/; revision=326257
* amd64: introduce minidump version 2Andriy Gapon2010-11-111-2/+2
| | | | | | | | | | | | | | | | | | | | | After KVA space was increased to 512GB on amd64 it became impractical to use PTEs as entries in the minidump map of dumped pages, because size of that map alone would already be 1GB. Instead, we now use PDEs as page map entries and employ two stage lookup in libkvm: virtual address -> PDE -> PTE -> physical address. PTEs are now dumped as regular pages. Fixed page map size now is 2MB. libkvm keeps support for accessing amd64 minidumps of version 1. Support for 1GB pages is added. Many thanks to Alan Cox for his guidance, numerous reviews, suggestions, enhancments and corrections. Reviewed by: alc [kernel part] MFC after: 15 days Notes: svn path=/head/; revision=215133
* Introduce minidumps. Full physical memory crash dumps are still availablePeter Wemm2006-04-211-0/+46
via the debug.minidump sysctl and tunable. Traditional dumps store all physical memory. This was once a good thing when machines had a maximum of 64M of ram and 1GB of kvm. These days, machines often have many gigabytes of ram and a smaller amount of kvm. libkvm+kgdb don't have a way to access physical ram that is not mapped into kvm at the time of the crash dump, so the extra ram being dumped is mostly wasted. Minidumps invert the process. Instead of dumping physical memory in in order to guarantee that all of kvm's backing is dumped, minidumps instead dump only memory that is actively mapped into kvm. amd64 has a direct map region that things like UMA use. Obviously we cannot dump all of the direct map region because that is effectively an old style all-physical-memory dump. Instead, introduce a bitmap and two helper routines (dump_add_page(pa) and dump_drop_page(pa)) that allow certain critical direct map pages to be included in the dump. uma_machdep.c's allocator is the intended consumer. Dumps are a custom format. At the very beginning of the file is a header, then a copy of the message buffer, then the bitmap of pages present in the dump, then the final level of the kvm page table trees (2MB mappings are expanded into a 4K page mappings), then the sparse physical pages according to the bitmap. libkvm can now conveniently access the kvm page table entries. Booting my test 8GB machine, forcing it into ddb and forcing a dump leads to a 48MB minidump. While this is a best case, I expect minidumps to be in the 100MB-500MB range. Obviously, never larger than physical memory of course. minidumps are on by default. It would want be necessary to turn them off if it was necessary to debug corrupt kernel page table management as that would mess up minidumps as well. Both minidumps and regular dumps are supported on the same machine. Notes: svn path=/head/; revision=157908