On 13/03/2025 1:52 pm, Jan Beulich wrote:
> ... before making changes to the involved logic.
>
> Signed-off-by: Jan Beulich <jbeul...@suse.com>
> ---
> With this FAST_SYMBOL_LOOKUP may make sense to permit enabling even
> when LIVEPATCH=n. Thoughts? (In this case "symbols: centralize and re-
> arrange $(all_symbols) calculation" would want pulling ahead.)
>
> --- a/xen/common/symbols.c
> +++ b/xen/common/symbols.c
> @@ -260,6 +260,41 @@ unsigned long symbols_lookup_by_name(con
> return 0;
> }
>
> +#ifdef CONFIG_SELF_TESTS
> +
> +static void __init test_lookup(unsigned long addr, const char *expected)
> +{
> + char buf[KSYM_NAME_LEN + 1];
> + const char *name, *symname;
> + unsigned long size, offs;
> +
> + name = symbols_lookup(addr, &size, &offs, buf);
> + if ( !name )
> + panic("%s: address not found\n", expected);
> + if ( offs )
> + panic("%s: non-zero offset (%#lx) unexpected\n", expected, offs);
> +
> + /* Cope with static symbols, where varying file names/paths may be used.
> */
> + symname = strchr(name, '#');
> + symname = symname ? symname + 1 : name;
> + if ( strcmp(symname, expected) )
> + panic("%s: unexpected symbol name: '%s'\n", expected, symname);
> +
> + offs = symbols_lookup_by_name(name);
> + if ( offs != addr )
> + panic("%s: address %#lx unexpected; wanted %#lx\n",
> + expected, offs, addr);
> +}
> +
> +static void __init __constructor test_symbols(void)
> +{
> + /* Be sure to only try this for cf_check functions. */
I'm very happy to see the take-up of SELF_TESTs. Although I probably
ought to tie it into a Kconfig option to make the errors non-fatal,
which I've been meaning to do for a bit.
One question though. cf_check is an x86-ism, even if it leaks out into
common code.
I think you mean "functions emitted into the final image"? If so, I
don't think this is relevant then, because ...
> + test_lookup((unsigned long)dump_execstate, "dump_execstate");
> + test_lookup((unsigned long)test_symbols, __func__);
... taking the function address here forces it to be emitted even if it
would otherwise have been inlined.
~Andrew
