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Konrad Rzeszutek Wilk
0d35756e4c
As compared to x86 the va of the hypervisor .text is locked down - we cannot modify the running pagetables to have the .ro flag unset. We borrow the same idea that alternative patching has - which is to vmap the entire .text region and use the alternative virtual address for patching. Since we are doing vmap we may fail, hence the arch_livepatch_quiesce was changed (see "x86,arm: Change arch_livepatch_quiesce() declaration") to return an error value which will be bubbled in payload->rc and provided to the user (along with messages in the ring buffer). The livepatch virtual address space (where the new functions are) needs to be close to the hypervisor virtual address so that the trampoline can reach it. As such we re-use the BOOT_RELOC_VIRT_START which is not used after bootup (alternatively we can also use the space after the _end to FIXMAP_ADDR(0), but that may be too small). The ELF relocation engine at the start was coded from the "ELF for the ARM 64-bit Architecture (AArch64)" (http://infocenter.arm.com/help/topic/com.arm.doc.ihi0056b/IHI0056B_aaelf64.pdf) but after a while of trying to write the correct bit shifting and masking from scratch I ended up borrowing from Linux, the 'reloc_insn_imm' (Linux v4.7 arch/arm64/kernel/module.c function. See 257cb251925f854da435cbf79b140984413871ac "arm64: Loadable modules") And while at it - we also utilize code from Linux to construct the right branch instruction (see "arm64/insn: introduce aarch64_insn_gen_{nop|branch_imm}() helper functions"). In the livepatch payload loading code we tweak the #ifdef to only exclude ARM_32. The exceptions are not part of ARM 32/64 hence they are still behind the #ifdef. We also expand the MAINTAINERS file to include the arm64 and arm32 platform specific livepatch file. Acked-by: Julien Grall <julien.grall@arm.com> Acked-by: Jan Beulich <jbeulich@suse.com> [non-arm parts] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-bugtool =========== The xen-bugtool command line application will collate the Xen dmesg output, details of the hardware configuration of your machine, information about the build of Xen that you are using, plus, if you allow it, various logs. The information collated can either be posted to a Xen Bugzilla bug (this bug must already exist in the system, and you must be a registered user there), or it can be saved as a .tar.bz2 for sending or archiving. The collated logs may contain private information, and if you are at all worried about that, you should not use this tool, or you should explicitly exclude those logs from the archive. xen-bugtool is wholly interactive, so simply run it, and answer the questions.