In particular, when the syscall number is too large, or when syscall is
dynamic. For that, add nosys_sysent structure to pass fake sysent to
syscall top code.
Reviewed by: dchagin, markj
Discussed with: jhb
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D41976
The lr register is cleared at the beginning of the _dl_start and _start,
so there is no need to initialize it.
Gnu libc _start takes an rtld_fini pointer in x0 which is set by ld.so
for __libc_start_main, the kernel does not register any atexit pointers.
While here fix whitespaces.
MFC after: 1 week
To help porting the Linux emulation layer to a new platforms start using
Linux names for conditional builds instead of architecture-specific ifdefs.
MFC after: 1 week
Adding a writev syscall wrapper is needed due to Linux family of write
syscalls doesn't distinguish between in kernel blocking operations
and always returns EAGAIN while FreeBSD can return ENOBUFS.
MFC after: 1 month
Adding a write syscall wrapper is needed due to Linux family of write
syscalls doesn't distinguish between in kernel blocking operations
and always returns EAGAIN while FreeBSD can return ENOBUFS.
MFC after: 1 month
Adding a write syscall wrapper is needed due to Linux family of write
syscalls doesn't distinguish between in kernel blocking operations
and always returns EAGAIN while FreeBSD can return ENOBUFS.
MFC after: 1 month
To avoid clobbering of any registers by the trampoline code use Linux
way to call signal handlers. I.e., we are out from the kernel right into
the signal handler, put return address from the signal handler into the
link register.
The mysterious NOP is required for some unwinders (e.g. libc++) that
unconditionally subtract one from the result of _Unwind_GetIP() in order
to identify the calling function.
MFC after: 1 week
To allow unwinders to go througth a previous to sigreturn frame we should
properly emulate the trampoline frame record which should points to the
previous frame and set the trampoline frame pointer to the emulated frame
before calling signal handler.
MFC after: 1 week
An Aarch64 sigreturn trampoline frame can't currently be described in
a DWARF .eh_frame section, because Aarch64 does not define a register
number for PC and provide no direct way to encode PC of the previous
frame. Instead, unwinders (libgcc, gdb, libunwind) detect the sigreturn
frame by looking for the sigreturn instruction. If a sigreturn frame is
detected, unwinders restores all the gprs, SP and PC by assuming that
sp points to an rt_sigframe Linux kernel struct
When entering the kernel, the link register (lr) contains the return
address of the previous frame, the exception link register (elr) contains
the address of the next instruction after the one which generated the
exception, i.e., PC.
MFC after: 1 week
The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.
Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix
As of version 2.6.0 of the Linux kernel, dev_t is a 32-bit unsigned integer
on all platforms. Prior the 2.6 kernel dev_t type was an unsigned short.
However, since the firs commit of the Linuxulator, mknod syscall get int dev
argument.
Also, there is some confusion here, while the kernel declares a dev_t type
as a 32-bit sized, the user-space dev_t type can be size of 64 bits, e.g.,
in the Glibc library.
To avoid confusion and to help porting of the Linuxulator to other platforms
use explicit l_dev_t for dev argument of mknod syscalls.
Export default MINSIGSTKSZ value for the x86 until we do not preserve AVX
registers in the signal context.
Differential Revision: https://reviews.freebsd.org/D39644
MFC after: 1 month
Have more accruate comments. While #if, #else, etc are copied to the
header files, lines that don't start with # are not. And #include files
are only output to sysinc (which winds up at the front of init_sysent.c
which seems a bit odd). This is all radically undocumented, and likely
has drifted somewhat from 4.4BSD and what other systems do (they've
drifted too, fwiw).
Sponsored by: Netflix
To avoid confusing people, rename linux_timer.h to linux_time.h,
as linux_timer.c is the implementation of timer syscalls only,
while linux_time.c contains implementation of all stuff declared
in linux_time.h.
MFC after: 2 weeks
