Commit Graph

5 Commits

Author SHA1 Message Date
Ed Schouten
ab83575070 Make CloudABI's way of doing TLS more friendly to userspace emulators.
We're currently seeing how hard it would be to run CloudABI binaries on
operating systems cannot be modified easily (Windows, Mac OS X). The
idea is that we want to just run them without any sandboxing. Now
that CloudABI executables are PIE, this is already a bit easier, but TLS
is still problematic:

- CloudABI executables want to write to the %fs, which typically
  requires extra system calls by the emulator every time it needs to
  switch between CloudABI's and its own TLS.

- If CloudABI executables overwrite the %fs base unconditionally, it
  also becomes harder for the emulator to store a backup of the old
  value of %fs. To solve this, let's no longer overwrite %fs, but just
  %fs:0.

As CloudABI's C library does not use a TCB, this space can now be used
by an emulator to keep track of its internal state. The executable can
now safely overwrite %fs:0, as long as it makes sure that the TCB is
copied over to the new TLS area.

Ensure that there is an initial TLS area set up when the process starts,
only containing a bogus TCB. We don't really care about its contents on
FreeBSD.

Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D5836
2016-04-06 11:11:31 +00:00
Ed Schouten
4a8b3b18cc Make Position Independent Executables work for CloudABI.
- Set BI_CAN_EXEC_DYN, so we can execute ET_DYN ELF files in addition to
  regular ET_EXECs.
- Provide an AT_BASE entry in the auxiliary vector, so the executable
  knows at which address it got loaded and can apply relocations.
2016-03-31 18:52:00 +00:00
John Baldwin
6fc8053f1a Fix reporting of the CloudABI ABI in kdump.
- Advertise the word size for CloudABI ABIs via the SV_LP64 flag.  All of
  the other ABIs include either SV_ILP32 or SV_LP64.
- Fix kdump to not assume a 32-bit ABI if the ABI flags field is non-zero
  but SV_LP64 isn't set.  Instead, only assume a 32-bit ABI if SV_ILP32 is
  set and fallback to the unknown value of "00" if neither SV_LP64 nor
  SV_ILP32 is set.

Reviewed by:	kib, ed
Differential Revision:	https://reviews.freebsd.org/D5560
2016-03-09 18:38:30 +00:00
Svatopluk Kraus
a1e1814d76 As <machine/pmap.h> is included from <vm/pmap.h>, there is no need to
include it explicitly when <vm/pmap.h> is already included.

Reviewed by:	alc, kib
Differential Revision:	https://reviews.freebsd.org/D5373
2016-02-22 09:02:20 +00:00
Ed Schouten
2ff069a7bc Add support for CloudABI on ARM64.
It turns out that it is pretty easy to make CloudABI work on ARM64. We
essentially only need to copy over the sysvec from AMD64 and ensure that
we use ARM64 specific registers.

As there is an overlap between function argument and return registers,
we do need to extend cloudabi64_schedtail() to only set its values if
we're actually forking. Not when we're creating a new thread.

Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D3917
2015-10-22 11:09:25 +00:00