src/sys/compat/linux/linux_vdso.c, branch release/13.2.0

Drop "All rights reserved" from my copyright statements.

2022-06-17T19:33:09Z

Add email and fixup years while here. Reviewed by: imp Differential Revision: https://reviews.freebsd.org/D30912 MFC after: 2 weeks (cherry picked from commit 1ca6b15bbdcebd6a0726dae2e9b72f383139d16c)

linux(4); Almost complete the vDSO.

2022-06-17T19:33:07Z

The vDSO (virtual dynamic shared object) is a small shared library that the kernel maps R/O into the address space of all Linux processes on image activation. The vDSO is a fully formed ELF image, shared by all processes with the same ABI, has no process private data. The primary purpose of the vDSO: - non-executable stack, signal trampolines not copied to the stack; - signal trampolines unwind, mandatory for the NPTL; - to avoid contex-switch overhead frequently used system calls can be implemented in the vDSO: for now gettimeofday, clock_gettime. The first two have been implemented, so add the implementation of system calls. System calls implemenation based on a native timekeeping code with some limitations: - ifunc can't be used, as vDSO r/o mapped to the process VA and rtld can't relocate symbols; - reading HPET memory is not implemented for now (TODO). In case on any error vDSO system calls fallback to the kernel system calls. For unimplemented vDSO system calls added prototypes which call corresponding kernel system call. Relnotes: yes Tested by: trasz (arm64) Differential revision: https://reviews.freebsd.org/D30900 MFC after: 2 weeks (cherry picked from commit 9931033bbfbe56a037723638cf3712366c6d943f)

amd64: wrap 64bit sigtramp into vdso

2022-01-02T16:43:01Z

(cherry picked from commit ab4524b3d7fba872a143b03c9346cb04c3670efa)

linux: Unmap the VDSO page when unloading

2021-02-23T01:29:55Z

linux_shared_page_init() creates an object and grabs and maps a single page to back the VDSO. When destroying the VDSO object, we failed to destroy the mapping and free KVA. Fix this. Reviewed by: kib Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D28696 (cherry picked from commit 0fc8a796722846d0d676548aa0f5cc660199db73)

compat: clean up empty lines in .c and .h files

2020-09-01T21:24:33Z

Fix the last few cases that grab without busy or valid. The grab functions must

2019-12-02T22:38:25Z

return the page in some held state for consistency elsewhere. Reviewed by: alc, kib, markj Differential Revision: https://reviews.freebsd.org/D22610

Avoid using [LINUX_]SHAREDPAGE constant directly in the vdso code.

2017-07-30T21:24:20Z

This is needed for https://reviews.freebsd.org/D11780. Reported by: kib@

Fix usage of the same 'i' variable in the external and nested loops.

2017-03-14T18:29:23Z

Submitted by: Svyatoslav Sponsored by: PVS-Studio MFC after: 1 week

Add 64 bit support to the vdso.

2015-05-24T15:45:36Z

Differential Revision: https://reviews.freebsd.org/D1069 Reviewed by: trasz

Implement vdso - virtual dynamic shared object. Through vdso Linux

2015-05-24T15:28:17Z

exposes functions from kernel with proper DWARF CFI information so that it becomes easier to unwind through them. Using vdso is a mandatory for a thread cancelation && cleanup on a modern glibc. Differential Revision: https://reviews.freebsd.org/D1060