I am getting this error while trying to compile some files.
Error-[NYI-NS] Not Yet Implemented
The following feature is not yet supported: Replacing interface cell in
logical library not yet supported
My files:
monitor_interface.sv
interface monitor_if(
input logic a,
input logic b
);
endinterface
bind TB monitor_if
mon_if1(
...
);
File 2 (which has "`include monitor_interface.sv")
virtual monitor_if if1;
//passes this interface to another module.
I don't understand what is going on. Any pointers will be much appreciated.
[Edit]
top.sv
virtual monitor_interface monitor_if;
initial begin
...
end
monitor mon1(monitor_if);
monitor.sv:
module monitor (monitor_if);
A "Not Yet Implemented" message usually means the tool recognizes what you are trying to do, but does not support it, most likely related to the bind construct. You should have gotten a line number pointing to the exact spot.
Is the bind statement inside another module? or outside of any construct.
The problem could also be you made a mistake somewhere and the compiler did the best it could do understand, but it is giving you an unrelated error. where is the `include statement?
Related
Is it possible to tail call eBPF codes that use different modes?
For example, if I coded a code that printk("hello world") using kprobe,
would I be able to tail call a XDP code afterwards or vice versa?
I programmed something on eBPF that uses a socket buffer and seems like when I try to tail call another code that uses kprobe, it doesn't load the program.
I wanted to tail call a code that uses XDP_PASS after using a BPF.SOCKET_FILTER mode but seems like tail call isn't working.
I've been trying to figure this out but I can't find any documentations regarding tail calling codes that use different modes :P
Thanks in advance!
No, it is not.
Have a look at kernel commit 04fd61ab36ec, which introduced tail calls: the comment in the first piece of code (in internal kernel header bpf.h), defining the struct bpf_array, sets a owner_prog_type member, and explains the following in a comment:
/* 'ownership' of prog_array is claimed by the first program that
* is going to use this map or by the first program which FD is stored
* in the map to make sure that all callers and callees have the same
* prog_type and JITed flag
*/
So once the program type associated with a BPF program array, used for tail calls, has been defined, it is not possible to use it with other program types. Which makes sense, since different program types work with different context (packet data VS traced function context VS ...), can use different helpers, have return functions with different meanings, necessitate different checks from the verifier, ... So it's hard to see how jumping from one type to another would work. How could you start with processing a network packet, and all of a sudden jump to a piece of code that is supposed to trace some internals of the kernel? :)
Note that it is also impossible to mix JIT-ed and non-JIT-ed programs, as indicated by the owner_jited of the struct.
I am going through the book by Galvin on OS . There is a section at the end of chapter 2 where the author writes about "adding a system call " to the kernel.
He describes how using asmlinkage we can create a file containing a function and make it qualify as a system call . But in the next part about how to call the system call he writes the following :
" Unfortunately, these are low-level operations that cannot be performed using C language statements and instead require assembly instructions. Fortunately, Linux provides macros for instantiating wrapper functions that contain the appropriate assembly instructions. For instance, the following C program uses the _syscallO() macro to invoke the newly defined system call:
Basically , I want to understand how syscall() function generally works . Now , what I understand by Macros is a system for text substitution .
(Please correct me If I am wrong)
How does a macro call an assembly language instruction ?
Is it so that syscallO() when compiled is translated into the address(op code) of the instruction to execute a trap ?(But this somehow doesn't fit with concept or definition of macros that I have )
What exactly are the wrapper functions that are contained inside and are they also written in assembly language ?
Suppose , I want to create a function of my own which performs the system call then what are the things that I need to do . Do , I need to compile it to generate the machine code for performing Trap instructions ?
Man, you have to pay $156 dollars to by the thing, then you actually have to read it. You could probably get an VMS Internals and Data Structures book for under $30.
That said, let me try to translate that gibberish into English.
System calls do not use the same kind of linkage (i.e. method of passing parameters and calling functions) that other functions use.
Rather than executing a call instruction of some kind, to execute a system service, you trigger an exception (which in Intel is bizarrely called an interrupt).
The CPU expects the operating system to create a DISPATCH TABLE and store its location and size in a special hardware register(s). The dispatch table is an array of pointers to handlers for exceptions and interrupts.
Exceptions and interrupts have numbers so, when exception or interrupt number #1 occurs, the CPU invokes the 2d exception handler (not #0, but #1) in the dispatch table in kernel mode.
What exactly are the wrapper functions that are contained inside and are they also written in assembly language ?
The operating system devotes usually one (but sometimes more) exceptions to system services. You need to do some thing like this in assembly language to invoke a system service:
INT $80 ; Explicitly trigger exception 80h
Because you have to execute a specific instruction, this has to be one in assembly language. Maybe your C compiler can do assembly language in line to call system service like that. But even if it could, it would be a royal PITA to have to do it each time you wanted to call a system service.
Plus I have not filled in all the details here (only the actual call to the system service). Normally, when you call functions in C (or whatever), the arguments are pushed on the program stack. Because the stack usually changes when you enter kernel mode, arguments to system calls need to be stored in registers.
PLUS you need to identify what system service you want to execute. Usually, system services have numbers. The number of the system service is loaded into the first register (e.g., R0 or AX).
The full process when you need to invoke a system service is:
Save the registers you are going to overwrite on the stack.
Load the arguments you want to pass to the system service into hardware registers.
Load the number of the system service into the lowest register.
Trigger the exception to enter kernel mode.
Unload the arguments returned by the system service from registers
Possibly do some error checking
Restore the registers you saved before.
Instead of doing this each time you call a system service, operating systems provide wrapper functions for high level languages to use. You call the wrapper as you would normally call a function. The wrapper (in assembly language) does the steps above for you.
Because these wrappers are pretty much the same (usually the only difference is the result of different numbers of arguments), wrappers can be created using macros. Some assemblers have powerful macro facilities that allow a single macro to define all wrappers, even with different numbers of arguments.
Linux provides multiple _syscall C macros that create wrappers. There is one for each number of arguments. Note that these macros are just for operating system developers. Once the wrapper is there, everyone can use it.
How does a macro call an assembly language instruction ?
These _syscall macros have to generate in line assembly code.
Finally, note that these wrappers do not define the actual system service. That has to be set up in the dispatch table and the system service exception handler.
in UVM e Reference document is written:
You can call read_reg_field or write_reg_field for registers whose fields
are defined as single_field_access (see “vr_ad_port_unit Syntax and Examples”).
...
For example:
write_reg_fields tx_mode_reg {.resv = 4; .dest = 2};
But there is no example for using read_reg_field...
Could you please explain how should it be used?
(I've tried the next code, but it gives compilation error:
some_var = read_reg_field my_reg_file.my_reg {.my_reg_field} )
Thank you for your help.
As far as I know there is no read_reg_fieds macro. If you want to do a read to a register and then save the value of a certain field, do this:
read_reg my_reg;
value = my_reg.my_reg_field;
Normally, when you read register, you read them completely. Reading only individual fields makes sense if your bus protocol allows narrow transfers (i.e. your data width is 32 bits, but you can do 16 bit transfers on it). I haven't seen such a thing implemented in vr_ad (could be there and I just don't know of it), but UVM RAL (the SystemVerilog register package) supports it.
Long story short, if you just care about getting your data from your DUT, using read_reg is enough.
When the Design Under Test is implemented in verilog or vhdl - you can read the register as a whole, you cannot "read just some of its fields".
A register is at a specific address, reading this register -> read from this address.
The quote of the spec about fields access is when the DUT is a SystemC model.
Connecting to SC models is done using ports. If the model defines a port for each field - you can read a field.
I'm trying to create a custom message level 'alert' (between warn and error) in Perl, but consistently get the error message:
create_custom_level must be called before init or first get_logger() call at /usr/share/perl5/Log/Log4perl/Logger.pm line 705.
My declaration of the custom level looks like this:
use Log::Log4perl qw(get_logger);
use Log::Log4perl::Level;
Log::Log4perl::Logger::create_custom_level("ALERT", "ERROR");
As far as I can tell from the documentation putting this at the top of any file which intends to use the custom level should be enough. So I can't tell what I'm doing wrong. Looking in the file Logger.pm where the error is thrown from shows that logger is being initialized before the custom level is being declared. Does anyone know how this could be happening?
P.S. I assure you creating a custom level is the right choice here, even if it's frowned upon.
EDIT: Question Answered! The top answer was more a guide to debugging, so I wanted to copy my solution from the comment section so that future readers would be more likely to see it.
I found that there were two steps to fixing my problem:
I needed to put create_custom_level in a BEGIN { ... } statement so that it would run at compile time, since it was apparently being beaten by a logger initialization that was being called at compile time.
I realized that putting the same create_custom_level line in both the main script (.pl) and its modules (.pm) is redundant and caused part of my problems. Depending on the order in which you've put your statements that execute at compile time (like 'use' and 'BEGIN'), calling create_custom_level in multiple files could lead to the sequence: 'create custom level', 'initialize logger', 'create custom level', across multiple files. I didn't figure out where the logger was being initialized early, but I was able to circumvent that by just creating my custom level as early as possible (for other inexperienced coders, using the perl debugger can be key in understanding the order in which lines and files are executed). Best to put create_custom_level in the original script or the first module it uses.
Hope this helps someone else!
The code you provided doesn't produce an error.
Perhaps you have some other code later in your script that is evaluated at compile time -- a module loaded in a use statement or some code in a BEGIN { ... } block -- that initializes a Logger.
If it's not obvious where this might be happening, you can use the Perl debugger to find out where the Logger call could be coming from. First, put this line in your file right after the use Log::Log4perl; and use Log::Log4perl::Level; statements:
BEGIN { $DB::single=1 }
This statement will get the debugger to stop at this line during the compile time phase, and allow you to stop at breakpoints during the rest of the compile phase. Then fire up a debugger
$ perl -d the_script.pl
set breakpoints on the critical Log::Log4perl functions
DB<1> b Log::Log4perl::init
DB<2> b Log::Log4perl::get_logger
begin executing the code
DB<3> c
and when the code stops, get a stack trace
Log::Log4perl::get_logger(/usr/local/lib/perl5/site_perl/5.18.1/Log/Log4perl.pm:371):
371: my $category;
DB<4> T
I want to organize a working bus functional model and push commonly used procedures (which look like CPU subroutines) out into a package and get them out of the main cpu model, but I'm stuck.
The procedures don't have access to the hardware bits when they're pushed out in a package.
In Verilog, I would put commonly used procedures out into an include file and link them into the CPU model as required for a given test suite.
More details:
I have a working bus functional model of a CPU, for simulation test benching.
At the "user interface" level I have a process called "main" running inside the CPU model which calls my predefined "instruction set" like this:
cpu_read(address, read_result);
cpu_write(address, write_data);
etc.
I bundle groups of those calls up into higher level procedures like
configure_communication_bus;
clear_all_packet_counters;
etc.
At the next layer these generic functions call a more hardware specific version which knows the interface timing for the design,
and those procedures then use an input record and output record to connect to the hardware module ports and waggle the cpu bus signals as required.
cpu_read calls hardware_cpu_read(cpu_input_record, cpu_output_record, address);
Something like this:
procedure cpu_read (address : in std_logic_vector(15 downto 0);
read_result : out std_logic_vector(31 downto 0));
begin
hardware_cpu_read(cpu_input_record, cpu_output_record, address, read_result);
end procedure;
The cpu_input_record and cpu_output_record are declared as signals of type nnn_record in the cpu model vhdl file.
So this is all working, but every single one of these procedures is all stored in the cpu VHDL module file, and all in the procedure declaration section so that they are all in the same scope.
If I share the model with team members they will need to add their own testing subroutines, and those also are all in the same location in the file, as well, their simulation test code has to go into the "main" process along with mine.
I'd rather link in various tests from outside the model, and only keep model specific procedures in the model file..
Ironically I can push the lowest level hardware procedure out to a package, and call those procedures from within the "main" process, but the higher level processes can't be put out into that package or any other packages because they don't have access to the cpu_read_record and cpu_write_record.
I feel like there must be a simple way to clean up this code and make it modular, and I'm just missing something obvious.
I don't really think making a command interpreter and loading my test code into a behavioral ROM is the right way to go by the way. Nor is fighting with the simulator interface to connect up a C program, but I may break down and try this..
Quick sketch of an answer (to the question I think you are asking! :-) though I may be off-beam...
To move the BFM subprograms into a reusable package, they need to be independent of the execution scope - that usually means a long parameter list for each of them. So using them in a testbench quickly gets tedious compared with the parameterless (or parameter-lite) versions you have now..
The usual workaround is to implement the BFM in a package, with long parameter lists.
Then write parameter-lite local equivalents (wrappers) in the execution scope, which simply call the package versions supplying all the parameters explicitly.
This is just boilerplate - not pretty but it does allow you to move the BFM into a package. These wrappers can be local to the testbench, to a process within it, or even to a subprogram within that process.
(The parameter types can be records for tidiness : these are probably declared in a third package, shared between BFM. TB, and synthesisable device under test...)
Thanks to overloading, there is no ambiguity between the local and BFM package versions, so the actual testbench remains as simple as possible.
Example wrapper function :
function cpu_read(address : unsigned) return slv_32 is
begin
return BFM_pack.cpu_read (
address => address,
rd_data_bus => tb_rd_data_bus,
wait => tb_wait_signal,
oe => tb_mem_oe,
-- ditto for all the signals constants variables it needs from the tb_ scope
);
end cpu_read;
Currently your test procedures require two extra signals on them, cpu_input_record and cpu_output_record. This is not so bad. It is not uncommon to just have these on all procedures that interact with the cpu and be done with it. So use hardware_cpu_read and not cpu_read. Add cpu_input_record, cpu_output_record to your configure_communication_bus and clear_all_packet_counters procedures and be done. Perhaps choose shorter names.
I do a similar approach, except I use only one record with resolved elements. To make this work, you need to initialize the record so that all elements are non-driving (ie: 'Z' for std_logic). To make this more flexible, I have created resolution functions for integer, time, and real. However, this only saves you one signal. Not a real huge win. Perhaps half way to where you think you want to be. But it is more work than what you are doing.
For VHDL-201X, we are working on syntax to allow parameters/ports automatically map to a identically named signal. This will get you to where you want to be with any of the approaches (yours, mine, or Brian's without the extra wrapper subprogram). It is posted here: http://www.eda.org/twiki/bin/view.cgi/P1076/ImplicitConnections. Given this, I would add the two records to your procedures and call it good enough for now.
Once you get by this problem, you seem to also be asking is how do I write separate tests using the same testbench. For this I use multiple architectures - I like to think of these as a Factory Class for concurrent code. To make this feasible, I separate the stimulus generation code from the rest of the testbench (typically: netlist connections and clock). My presentation, "VHDL Testbench Techniques that Leapfrog SystemVerilog", has an overview of this architecture along with a number of other goodies. It is available at: http://www.synthworks.com/papers/index.htm
You're definitely on the right track, in fact I have a variant like this (what you describe).
The catch is, now I build up a whole subroutine using the "parameter light" procedures, and those are what I want to put in a package to share and reuse. The problem is that any procedure pushed out to a package can't call to the parameter light procedures in the main vhdl file..
So what happens is we have one main vhdl file with all the common CPU hardware setup routines, and every designer's test code all in the same vhdl file..
Long story short, putting our test subroutines into separate files is really what I was hoping for..