Uses the build system's ability for generating source files from AWK
programs. This simplifies the library's `Makefile.uk` and the re-
generation is properly triggered on dependency changes.
Because generated header files are stored in a different destination
path, the same change cannot be performed for these files, at the
moment.

Signed-off-by: Simon Kuenzer <[email protected]>
Reviewed-by: Dragos Iulian Argint <[email protected]>
Reviewed-by: Adina Smeu <[email protected]>
Reviewed-by: Cezar Craciunoiu <[email protected]>
Reviewed-by: Razvan Deaconescu <[email protected]>
Approved-by: Razvan Deaconescu <[email protected]>
Tested-by: Unikraft CI <[email protected]>
GitHub-Closes: #565

Compiles the binary system call handler code as ISR-safe. Additionally,
the extended context is saved and restored of the system call caller on
each binary system call. The reason is that extended register sets maybe
used by the system call implementations and the Linux system call
calling convention assumes that caller programs do not have to save the
state themselves.

Signed-off-by: Simon Kuenzer <[email protected]>
Reviewed-by: Dragos Iulian Argint <[email protected]>
Reviewed-by: Adina Smeu <[email protected]>
Reviewed-by: Cezar Craciunoiu <[email protected]>
Reviewed-by: Razvan Deaconescu <[email protected]>
Approved-by: Razvan Deaconescu <[email protected]>
Tested-by: Unikraft CI <[email protected]>
GitHub-Closes: #565

Introduces an option to save & restore the TLS pointer on binary system
calls. Unikraft's internal TLS pointer is loaded before the system call
is handled. This option allows the usage of different TLS pointers
within the system caller program. We name such programs, userland
programs.

Signed-off-by: Simon Kuenzer <[email protected]>
Reviewed-by: Dragos Iulian Argint <[email protected]>
Reviewed-by: Adina Smeu <[email protected]>
Reviewed-by: Cezar Craciunoiu <[email protected]>
Reviewed-by: Razvan Deaconescu <[email protected]>
Approved-by: Razvan Deaconescu <[email protected]>
Tested-by: Unikraft CI <[email protected]>
GitHub-Closes: #565

Instead of initializing the default set of file descriptors with a
constructor function, we initialize them during early init. At this
point of boot time, the heap, scheduling, and TLS are initialized.
Because `vfscore` uses the `dup` system call, we introduce this commit
in preparation for the fact that a TLS may be required to perform a
system call.

Signed-off-by: Simon Kuenzer <[email protected]>
Reviewed-by: Dragos Iulian Argint <[email protected]>
Reviewed-by: Adina Smeu <[email protected]>
Reviewed-by: Cezar Craciunoiu <[email protected]>
Reviewed-by: Razvan Deaconescu <[email protected]>
Approved-by: Razvan Deaconescu <[email protected]>
Tested-by: Unikraft CI <[email protected]>
GitHub-Closes: #565

This commit introduces system call return address tracking, which
is needed by some system call implementations (like `SYS_CLONE`). Such
implementations can query the return address with
`uk_syscall_return_addr()`.

Checkpatch-Ignore: MULTISTATEMENT_MACRO_USE_DO_WHILE
Signed-off-by: Simon Kuenzer <[email protected]>
Reviewed-by: Dragos Iulian Argint <[email protected]>
Reviewed-by: Adina Smeu <[email protected]>
Reviewed-by: Cezar Craciunoiu <[email protected]>
Reviewed-by: Razvan Deaconescu <[email protected]>
Approved-by: Razvan Deaconescu <[email protected]>
Tested-by: Unikraft CI <[email protected]>
GitHub-Closes: #565

Variadic system calls are system calls with a variable number of
arguments. Some of them become optional or are only needed depending on
a given flag or a command number.
This commit introduces the support for statically mapping such
system calls at compile time. For this purpose, the
`uk_syscall_(r_)static()` macros are evaluating the number of given
arguments and will automatically auto-complete missing arguments with
zeros or remove additional arguments that aren't handled by the
particular system call implementation.

Signed-off-by: Simon Kuenzer <[email protected]>
Reviewed-by: Dragos Iulian Argint <[email protected]>
Reviewed-by: Adina Smeu <[email protected]>
Reviewed-by: Cezar Craciunoiu <[email protected]>
Reviewed-by: Razvan Deaconescu <[email protected]>
Approved-by: Razvan Deaconescu <[email protected]>
Tested-by: Unikraft CI <[email protected]>
GitHub-Closes: #565

If `CONFIG_LIBSYSCALL_SHIM_HANDLER_ULTLS` is configured, system call
handlers can retrieve the caller's TLS pointer with
`uk_syscall_ultlsp()` if the system call was called by a binary system
call.
Please note that only if the system call was called by a binary system
call and the TLS pointer of the caller is different to the Unikraft-TLS
pointer, this function will return the caller's TLS pointer.

Signed-off-by: Simon Kuenzer <[email protected]>
Reviewed-by: Dragos Iulian Argint <[email protected]>
Reviewed-by: Adina Smeu <[email protected]>
Reviewed-by: Cezar Craciunoiu <[email protected]>
Reviewed-by: Razvan Deaconescu <[email protected]>
Approved-by: Razvan Deaconescu <[email protected]>
Tested-by: Unikraft CI <[email protected]>
GitHub-Closes: #565

The (internal) symbol declarations of `_uk_vprintd()` and `_uk_printd()`
are always provided. This allows rare cases where libraries have their
own decision logics when and which debug message to compile in.

Signed-off-by: Simon Kuenzer <[email protected]>
Reviewed-by: Dragos Iulian Argint <[email protected]>
Reviewed-by: Adina Smeu <[email protected]>
Reviewed-by: Cezar Craciunoiu <[email protected]>
Reviewed-by: Razvan Deaconescu <[email protected]>
Approved-by: Razvan Deaconescu <[email protected]>
Tested-by: Unikraft CI <[email protected]>
GitHub-Closes: #565

This commit introduces two options for printing a debug message 1) when
a system call handler is invoked and 2) when a binary system call is
handled.

Signed-off-by: Simon Kuenzer <[email protected]>
Reviewed-by: Dragos Iulian Argint <[email protected]>
Reviewed-by: Adina Smeu <[email protected]>
Reviewed-by: Cezar Craciunoiu <[email protected]>
Reviewed-by: Razvan Deaconescu <[email protected]>
Approved-by: Razvan Deaconescu <[email protected]>
Tested-by: Unikraft CI <[email protected]>
GitHub-Closes: #565