struct thread.
For all architectures, the syscall trap handlers have to allocate the
structure on the stack. The structure takes 88 bytes on 64bit arches
which is not negligible. Also, it cannot be easily found by other
code, which e.g. caused duplication of some members of the structure
to struct thread already. The change removes td_dbg_sc_code and
td_dbg_sc_nargs which were directly copied from syscall_args.
The structure is put into the copied on fork part of the struct thread
to make the syscall arguments information correct in the child after
fork.
This move will also allow several more uses shortly.
Reviewed by: jhb (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 3 weeks
X-Differential revision: https://reviews.freebsd.org/D11080
matches static binaries.
Interpretation of the 'static' there is that the binary must not
specify an interpreter. In particular, shared objects are matched by
the brand if BI_CAN_EXEC_DYN is also set.
This improves precision of the brand matching, which should eliminate
surprises due to brand ordering.
Revert r315701.
Discussed with and tested by: ed (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
CloudABI executables are statically linked and don't have an
interpreter. Setting the interpreter path to NULL used to work
previously, but r314851 introduced code that checks the string
unconditionally. Running CloudABI executables now causes a null pointer
dereference.
Looking at the rest of imgact_elf.c, it seems various other codepaths
already leaned on the fact that the interpreter path is set. Let's just
go ahead and pick an obviously incorrect interpreter path to appease
imgact_elf.c.
MFC after: 1 week
In order to make CloudABI work on ARMv6, start off by copying over the
sysvec for ARM64 and adjust it to use 32-bit registers. Also add code
for fetching arguments from the stack if needed, as there are fewer
register than on ARM64.
Also import the vDSO that is needed to invoke system calls. This vDSO
uses the intra procedure call register (ip) to store the system call
number. This is a bit simpler than what native FreeBSD does, as FreeBSD
uses r7, while preserving the original r7 into ip.
This sysvec seems to be complete enough to start CloudABI processes.
These processes are capable of linking in the vDSO and are therefore
capable of executing (most?) system calls successfully. Unfortunately,
the biggest show stopper is still that TLS is completely broken:
- The linker used by CloudABI, LLD, still has troubles with some of the
relocations needed for TLS. See LLVM bug 30218 for more details.
- Whereas FreeBSD uses the tpidruro register for TLS, for CloudABI I
want to make use of tpidrurw, so that userspace can modify the base
address directly. This is needed for efficient emulation.
Unfortunately, this register doesn't seem to be preserved across
context switches yet.
Obtained from: https://github.com/NuxiNL/cloudabi (the vDSO)
