event: Remove obsolete comment and __used attributes

Now that we have both resolved the problem on sandbox that lead to a comment
about linker list entries being omitted as well as made linker lists
never list themselves as unused, we can update the event header file.
Remove the now obsolete comment and "__used" attribute marker.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@konsulko.com>

diff --git a/include/event.h b/include/event.h
index 3ce5f992b04e649ff84743afd851ad915bcf9c0d..450281f666a8762148c9bceb1c6ec139ede03e1a 100644 (file)
--- a/include/event.h
+++ b/include/event.h
@@ -308,44 +308,13 @@ static inline const char *event_spy_id(struct evspy_info *spy)
 #endif
 }
 
-/*
- * It seems that LTO will drop list entries if it decides they are not used,
- * although the conditions that cause this are unclear.
- *
- * The example found is the following:
- *
- * static int sandbox_misc_init_f(void *ctx, struct event *event)
- * {
- *    return sandbox_early_getopt_check();
- * }
- * EVENT_SPY_FULL(EVT_MISC_INIT_F, sandbox_misc_init_f);
- *
- * where EVENT_SPY_FULL uses ll_entry_declare()
- *
- * In this case, LTO decides to drop the sandbox_misc_init_f() function
- * (which is fine) but then drops the linker-list entry too. This means
- * that the code no longer works, in this case sandbox no-longer checks its
- * command-line arguments properly.
- *
- * Without LTO, the KEEP() command in the .lds file is enough to keep the
- * entry around. But with LTO it seems that the entry has already been
- * dropped before the link script is considered.
- *
- * The only solution I can think of is to mark linker-list entries as 'used'
- * using an attribute. This should be safe, since we don't actually want to drop
- * any of these. However this does slightly limit LTO's optimisation choices.
- *
- * Another issue has come up, only with clang: using 'static' makes it throw
- * away the linker-list entry sometimes, e.g. with the EVT_FT_FIXUP entry in
- * vbe_simple.c - so for now, make it global.
- */
 #define EVENT_SPY_FULL(_type, _func) \
-       __used ll_entry_declare(struct evspy_info, _type ## _3_ ## _func, \
+       ll_entry_declare(struct evspy_info, _type ## _3_ ## _func, \
                evspy_info) = _ESPY_REC(_type, _func)
 
 /* Simple spy with no function arguments */
 #define EVENT_SPY_SIMPLE(_type, _func) \
-       __used ll_entry_declare(struct evspy_info_simple, \
+       ll_entry_declare(struct evspy_info_simple, \
                _type ## _3_ ## _func, \
                evspy_info) = _ESPY_REC_SIMPLE(_type, _func)