From 50128aeb0f8bb5a2d820e4c7a6ac0bb745809fc1 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Fri, 28 Oct 2022 13:50:54 +0200 Subject: [PATCH] cyclic: get rid of cyclic_init() Currently, we must call cyclic_init() at some point before cyclic_register() becomes possible. That turns out to be somewhat awkward, especially with SPL, and has resulted in a watchdog callback not being registered, thus causing the board to prematurely reset. We already rely on gd->cyclic reliably being set to NULL by the asm code that clears all of gd. Now that the cyclic list is a hlist, and thus an empty list is represented by a NULL head pointer, and struct cyclic_drv has no other members, we can just as well drop a level of indirection and put the hlist_head directly in struct global_data. This doesn't increase the size of struct global_data, gets rid of an early malloc(), and generates slightly smaller code. But primarily, this avoids having to call cyclic_init() early; the cyclic infrastructure is simply ready to register callbacks as soon as we enter C code. We can still end up with schedule() being called from asm very early, so we still need to check that gd itself has been properly initialized [*], but once it has, gd->cyclic_list is perfectly fine to access, and will just be an empty list. As for cyclic_uninit(), it was never really the opposite of cyclic_init() since it didn't free the struct cyclic_drv nor set gd->cyclic to NULL. Rename it to cyclic_unregister_all() and use that in test/, and also insert a call at the end of the board_init_f sequence so that gd->cyclic_list is a fresh empty list before we enter board_init_r(). A small piece of ugliness is that I had to add a cast in cyclic_get_list() to silence a "discards 'volatile' qualifier" warning, but that is completely equivalent to the existing handling of the uclass_root_s list_head member. [*] I'm not really sure where we guarantee that the register used for gd contains 0 until it gets explicitly initialized, but that must be the case, otherwise testing gd for being NULL would not make much sense. Signed-off-by: Rasmus Villemoes Reviewed-by: Stefan Roese Tested-by: Stefan Roese Tested-by: Tim Harvey # imx8mm-venice-* --- common/board_f.c | 11 ++++++++++- common/board_r.c | 1 - common/cyclic.c | 32 +++++++------------------------- include/asm-generic/global_data.h | 4 ++-- include/cyclic.h | 27 +++------------------------ test/test-main.c | 3 +-- 6 files changed, 23 insertions(+), 55 deletions(-) diff --git a/common/board_f.c b/common/board_f.c index faa0964..7c26e23 100644 --- a/common/board_f.c +++ b/common/board_f.c @@ -839,7 +839,6 @@ static const init_fnc_t init_sequence_f[] = { initf_malloc, log_init, initf_bootstage, /* uses its own timer, so does not need DM */ - cyclic_init, event_init, #ifdef CONFIG_BLOBLIST bloblist_init, @@ -957,6 +956,16 @@ static const init_fnc_t init_sequence_f[] = { do_elf_reloc_fixups, #endif clear_bss, + /* + * Deregister all cyclic functions before relocation, so that + * gd->cyclic_list does not contain any references to pre-relocation + * devices. Drivers will register their cyclic functions anew when the + * devices are probed again. + * + * This should happen as late as possible so that the window where a + * watchdog device is not serviced is as small as possible. + */ + cyclic_unregister_all, #if !defined(CONFIG_ARM) && !defined(CONFIG_SANDBOX) && \ !CONFIG_IS_ENABLED(X86_64) jump_to_copy, diff --git a/common/board_r.c b/common/board_r.c index 828ad44..db9cfb3 100644 --- a/common/board_r.c +++ b/common/board_r.c @@ -617,7 +617,6 @@ static init_fnc_t init_sequence_r[] = { #endif initr_barrier, initr_malloc, - cyclic_init, log_init, initr_bootstage, /* Needs malloc() but has its own timer */ #if defined(CONFIG_CONSOLE_RECORD) diff --git a/common/cyclic.c b/common/cyclic.c index 32d9bf0..a49bfc8 100644 --- a/common/cyclic.c +++ b/common/cyclic.c @@ -22,7 +22,8 @@ void hw_watchdog_reset(void); struct hlist_head *cyclic_get_list(void) { - return &gd->cyclic->cyclic_list; + /* Silence "discards 'volatile' qualifier" warning. */ + return (struct hlist_head *)&gd->cyclic_list; } struct cyclic_info *cyclic_register(cyclic_func_t func, uint64_t delay_us, @@ -30,11 +31,6 @@ struct cyclic_info *cyclic_register(cyclic_func_t func, uint64_t delay_us, { struct cyclic_info *cyclic; - if (!gd->cyclic) { - pr_debug("Cyclic IF not ready yet\n"); - return NULL; - } - cyclic = calloc(1, sizeof(struct cyclic_info)); if (!cyclic) { pr_debug("Memory allocation error\n"); @@ -47,7 +43,7 @@ struct cyclic_info *cyclic_register(cyclic_func_t func, uint64_t delay_us, cyclic->name = strdup(name); cyclic->delay_us = delay_us; cyclic->start_time_us = timer_get_us(); - hlist_add_head(&cyclic->list, &gd->cyclic->cyclic_list); + hlist_add_head(&cyclic->list, cyclic_get_list()); return cyclic; } @@ -71,7 +67,7 @@ void cyclic_run(void) return; gd->flags |= GD_FLG_CYCLIC_RUNNING; - hlist_for_each_entry_safe(cyclic, tmp, &gd->cyclic->cyclic_list, list) { + hlist_for_each_entry_safe(cyclic, tmp, cyclic_get_list(), list) { /* * Check if this cyclic function needs to get called, e.g. * do not call the cyclic func too often @@ -113,31 +109,17 @@ void schedule(void) * schedule() might get called very early before the cyclic IF is * ready. Make sure to only call cyclic_run() when it's initalized. */ - if (gd && gd->cyclic) + if (gd) cyclic_run(); } -int cyclic_uninit(void) +int cyclic_unregister_all(void) { struct cyclic_info *cyclic; struct hlist_node *tmp; - hlist_for_each_entry_safe(cyclic, tmp, &gd->cyclic->cyclic_list, list) + hlist_for_each_entry_safe(cyclic, tmp, cyclic_get_list(), list) cyclic_unregister(cyclic); return 0; } - -int cyclic_init(void) -{ - int size = sizeof(struct cyclic_drv); - - gd->cyclic = (struct cyclic_drv *)malloc(size); - if (!gd->cyclic) - return -ENOMEM; - - memset(gd->cyclic, '\0', size); - INIT_HLIST_HEAD(&gd->cyclic->cyclic_list); - - return 0; -} diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h index 8d348b0..02ad8ca 100644 --- a/include/asm-generic/global_data.h +++ b/include/asm-generic/global_data.h @@ -481,9 +481,9 @@ struct global_data { #endif #ifdef CONFIG_CYCLIC /** - * @cyclic: cyclic driver data + * @cyclic_list: list of registered cyclic functions */ - struct cyclic_drv *cyclic; + struct hlist_head cyclic_list; #endif /** * @dmtag_list: List of DM tags diff --git a/include/cyclic.h b/include/cyclic.h index 4a11f9b..44ad3cb 100644 --- a/include/cyclic.h +++ b/include/cyclic.h @@ -15,15 +15,6 @@ #include /** - * struct cyclic_drv - Cyclic driver internal data - * - * @cyclic_list: Cylic list node - */ -struct cyclic_drv { - struct hlist_head cyclic_list; -}; - -/** * struct cyclic_info - Information about cyclic execution function * * @func: Function to call periodically @@ -75,18 +66,11 @@ struct cyclic_info *cyclic_register(cyclic_func_t func, uint64_t delay_us, int cyclic_unregister(struct cyclic_info *cyclic); /** - * cyclic_init() - Set up cyclic functions - * - * Init a list of cyclic functions, so that these can be added as needed - */ -int cyclic_init(void); - -/** - * cyclic_uninit() - Clean up cyclic functions + * cyclic_unregister_all() - Clean up cyclic functions * * This removes all cyclic functions */ -int cyclic_uninit(void); +int cyclic_unregister_all(void); /** * cyclic_get_list() - Get cyclic list pointer @@ -134,12 +118,7 @@ static inline void schedule(void) { } -static inline int cyclic_init(void) -{ - return 0; -} - -static inline int cyclic_uninit(void) +static inline int cyclic_unregister_all(void) { return 0; } diff --git a/test/test-main.c b/test/test-main.c index ddfd89c..fe3ef6d 100644 --- a/test/test-main.c +++ b/test/test-main.c @@ -287,7 +287,6 @@ static int dm_test_restore(struct device_node *of_root) static int test_pre_run(struct unit_test_state *uts, struct unit_test *test) { ut_assertok(event_init()); - ut_assertok(cyclic_init()); if (test->flags & UT_TESTF_DM) ut_assertok(dm_test_pre_run(uts)); @@ -347,7 +346,7 @@ static int test_post_run(struct unit_test_state *uts, struct unit_test *test) ut_unsilence_console(uts); if (test->flags & UT_TESTF_DM) ut_assertok(dm_test_post_run(uts)); - ut_assertok(cyclic_uninit()); + ut_assertok(cyclic_unregister_all()); ut_assertok(event_uninit()); free(uts->of_other); -- 2.7.4