mainlining shenanigans
e9d0e6330e
If trampoline code would need to switch between 4- and 5-level paging modes, we have to use a page table in trampoline memory. Having it in trampoline memory guarantees that it's below 4G and we can point CR3 to it from 32-bit trampoline code. We only use the page table if the desired paging mode doesn't match the mode we are in. Otherwise the page table is unused and trampoline code wouldn't touch CR3. For 4- to 5-level paging transition, we set up current (4-level paging) CR3 as the first and the only entry in a new top-level page table. For 5- to 4-level paging transition, copy page table pointed by first entry in the current top-level page table as our new top-level page table. If the page table is used by trampoline we would need to copy it to new page table outside trampoline and update CR3 before restoring trampoline memory. Tested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Eric Biederman <ebiederm@xmission.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Juergen Gross <jgross@suse.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180226180451.86788-6-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.