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.
Tested by: trasz (arm64)
Differential revision: https://reviews.freebsd.org/D30900
MFC after: 2 weeks
These ABIs do not use umtx at all, so there is nothing to clean.
Cloudabi references to umtx keys do not require any cleanups anyway.
Requested by: dchagin
Reviewed by: dchagin, markj
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D30987
This makes prctl(2) support PR_SET_NO_NEW_PRIVS, by mapping it
to the native PROC_NO_NEW_PRIVS_CTL procctl(2).
Sponsored By: EPSRC
Differential Revision: https://reviews.freebsd.org/D30973
Implement dumping core for Linux binaries on amd64, for both
32- and 64-bit executables. Some bits are still missing.
This is based on a prototype by chuck@.
Reviewed By: kib
Sponsored By: EPSRC
Differential Revision: https://reviews.freebsd.org/D30019
Assuming we can't run on i486, i586 class cpu, retire linux_kplatform var
and use hardcoded 'machine' value in linux_newuname().
I have added linux_kplatform for consistency with linux_platform which is
placed in to vdso to avoid excess copyout it on stack for AT_PLATFORM at
exec time.
This is the first stage of Linuxulator's vdso revision.
Reviewed by: trasz, imp
Differential Revision: https://reviews.freebsd.org/D30774
MFC after: 2 weeks
For now the Linux emulation layer uses in kernel ppoll(2) without
conversion of user supplied fd 'events', and does not convert the
kernel supplied fd 'revents'.
At least POLLRDHUP is handled by FreeBSD differently than by
Linux. Seems that Linux silencly ignores POLLRDHUP on non socket fd's
unlike FreeBSD, which does more strictly check and fails.
Rework the Linux ppoll, using kern_poll and converting 'events'
and 'revents' values.
While here, move poll events defines to the MI part of code as they
mostly identical on all arches except arm.
Differential Revision: https://reviews.freebsd.org/D30716
MFC after: 2 weeks
Filter out the flags we do support; previously we would print
out the flag value verbatim.
Reviewed By: dchagin
Sponsored By: EPSRC
Differential Revision: https://reviews.freebsd.org/D30693
This fixes a number of AppImages; tested with
scribus-1.5.6.1-linux-x86_64.AppImage.
Reported By: @probonopd
Reviewed By: asomers, emaste
Sponsored By: EPSRC
Differential Revision: https://reviews.freebsd.org/D30606
Retire ksiginfo_to_lsiginfo function, use siginfo_to_lsiginfo instead.
Convert rt_sigtimedwait siginfo variables to well known names.
MFC after: 2 weeks
The second 'linuxcommon' line was added by c66f5b079d
but Linuxulator's modules dependend on 'linux_common'.
To avoid such mistakes in the future rename moduledata name and module
name to 'linux_common' and retire 'linuxcommon' line.
Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D30409
MFC after: 2 weeks
Remove all the 'entry' and 'return' probes; they clutter up the source
and are redundant to FBT.
Reviewed By: dchagin
Sponsored By: EPSRC
Differential Revision: https://reviews.freebsd.org/D30040
This is required for the current Arch Linux binaries to work.
PR: 254112
Reviewed By: emaste
Sponsored By: EPSRC
Differential Revision: https://reviews.freebsd.org/D29218
Without it, Qt5 apps from Focal fail to start, being unable to load
their plugins. It's also necessary for glibc 2.33, as found in recent
Arch snapshots.
PR: 254112
Reviewed By: kib
Sponsored by: The FreeBSD Foundation, EPSRC
Differential Revision: https://reviews.freebsd.org/D28192
This should be a no-op; the purpose of this is to reduce
a spurious difference between Linuxulator and Linux, to make
debugging core dumps slightly easier.
Note that AT_HWCAP2 we pass to Linux binaries is always 0,
instead of being equal to 'cpu_feature2'. This matches what
I've observed under Ubuntu Focal VM.
Reviewed By: chuck, dchagin
Sponsored By: EPSRC
Differential Revision: https://reviews.freebsd.org/D29609
For native FreeBSD binaries, the return value from __getcwd(2)
doesn't really matter, as the libc wrapper takes over and returns
the proper errno.
PR: kern/254120
Reported By: Alex S <iwtcex@gmail.com>
Reviewed By: kib
Sponsored By: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D29217
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
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D28696
