With clang 15, the following -Werror warnings are produced:
sys/x86/linux/linux_vdso_selector_x86.c:44:28: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
linux_vdso_tsc_selector_idx()
^
void
sys/x86/linux/linux_vdso_selector_x86.c:62:28: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
linux_vdso_cpu_selector_idx()
^
void
This is because linux_vdso_tsc_selector_idx() and
linux_vdso_cpu_selector_idx are declared with (void) argument lists, but
defined with empty argument lists. Make the definitions match the
declarations.
MFC after: 3 days
Replace sigframe sf_extramask by native sigset_t and use it to
store/restore the thread signal mask without conversion to/from
Linux signal mask.
Pointy hat to: dchagin
MFC after: 2 weeks
The signal trampoine-related definitions are used only in the MD part
of code, wherefore moved from everywhere used linux.h to separate MD
headers.
MFC after: 2 weeks
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
