Hi, Thomas
> > Hi Zhangjin,
> >
> > some general comments for the whole series.
> >
> > On 2023-06-21 20:52:30+0800, Zhangjin Wu wrote:
> > > Hi, Willy
> > >
> > > This patchset mainly allows speed up the nolibc test with a minimal
> > > kernel config.
> > >
> (snip)
> > >
> > > * selftests/nolibc: fix up kernel parameters support
> > >
> > > kernel cmdline allows pass two types of parameters, one is without
> > > '=', another is with '=', the first one is passed as init arguments,
> > > the sencond one is passed as init environment variables.
> > >
> > > Our nolibc-test prefer arguments to environment variables, this not
> > > work when users add such parameters in the kernel cmdline:
> > >
> > > noapic NOLIBC_TEST=syscall
> > >
> > > So, this patch will verify the setting from arguments at first, if it
> > > is no valid, will try the environment variables instead.
> >
> > This would be much simpler as:
> >
> > test = getenv("NOLIBC_TEST");
> > if (!test)
> > test = argv[1];
> >
> > It changes the semantics a bit, but it doesn't seem to be an issue.
> > (Maybe gated behind getpid() == 1).
>
> Cool suggestion, it looks really better:
>
> if (getpid() == 1) {
> prepare();
>
> /* kernel cmdline may pass: "noapic NOLIBC_TEST=syscall",
> * to init program:
> *
> * "noapic" as arguments,
> * "NOLIBC_TEST=syscall" as environment variables,
> *
> * to avoid getting null test in this case, parsing
> * environment variables at first.
> */
> test = getenv("NOLIBC_TEST");
> if (!test)
> test = argv[1];
> } else {
> /* for normal nolibc-test program, prefer arguments */
> test = argv[1];
> if (!test)
> test = getenv("NOLIBC_TEST");
> }
>
Test shows, when no NOLIBC_TEST environment variable passed to kernel cmdline,
it will still branch to this code:
test = argv[1]; /* nopaic ... */
And therefore report the whole test is ignored and no test will be run:
Ignoring unknown test name 'noapic'
So, we may still need to verify it like my originally proposed method, but
let's further verify the one from NOLIBC_TEST=, we should tune the code a
litle.
Thanks,
Zhangjin
