From 1b47b80e2fa777b37a9486512f4636d7e6aaa353 Mon Sep 17 00:00:00 2001 From: Thomas Weißschuh Date: Fri, 17 Feb 2023 03:14:41 +0000 Subject: livepatch: Make kobj_type structures constant MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Since commit ee6d3dd4ed48 ("driver core: make kobj_type constant.") the driver core allows the usage of const struct kobj_type. Take advantage of this to constify the structure definitions to prevent modification at runtime. Signed-off-by: Thomas Weißschuh Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20230217-kobj_type-livepatch-v1-1-06ded292e897@weissschuh.net --- kernel/livepatch/core.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel/livepatch/core.c') diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index 4bd2d5e10f20..feaf90c5e537 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -596,7 +596,7 @@ static void klp_kobj_release_patch(struct kobject *kobj) complete(&patch->finish); } -static struct kobj_type klp_ktype_patch = { +static const struct kobj_type klp_ktype_patch = { .release = klp_kobj_release_patch, .sysfs_ops = &kobj_sysfs_ops, .default_groups = klp_patch_groups, @@ -612,7 +612,7 @@ static void klp_kobj_release_object(struct kobject *kobj) klp_free_object_dynamic(obj); } -static struct kobj_type klp_ktype_object = { +static const struct kobj_type klp_ktype_object = { .release = klp_kobj_release_object, .sysfs_ops = &kobj_sysfs_ops, .default_groups = klp_object_groups, @@ -628,7 +628,7 @@ static void klp_kobj_release_func(struct kobject *kobj) klp_free_func_nop(func); } -static struct kobj_type klp_ktype_func = { +static const struct kobj_type klp_ktype_func = { .release = klp_kobj_release_func, .sysfs_ops = &kobj_sysfs_ops, }; -- cgit From 3703bd54cd37e7875f51ece8df8c85c184e40bba Mon Sep 17 00:00:00 2001 From: Zhen Lei Date: Wed, 8 Mar 2023 15:38:46 +0800 Subject: kallsyms: Delete an unused parameter related to {module_}kallsyms_on_each_symbol() The parameter 'struct module *' in the hook function associated with {module_}kallsyms_on_each_symbol() is no longer used. Delete it. Suggested-by: Petr Mladek Signed-off-by: Zhen Lei Reviewed-by: Vincenzo Palazzo Acked-by: Jiri Olsa Acked-by: Steven Rostedt (Google) Signed-off-by: Luis Chamberlain --- include/linux/kallsyms.h | 7 +++---- include/linux/module.h | 6 ++---- kernel/kallsyms.c | 5 ++--- kernel/kallsyms_selftest.c | 6 +++--- kernel/livepatch/core.c | 3 +-- kernel/module/kallsyms.c | 5 ++--- kernel/trace/ftrace.c | 3 +-- 7 files changed, 14 insertions(+), 21 deletions(-) (limited to 'kernel/livepatch/core.c') diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h index 0065209cc004..fe3c9993b5bf 100644 --- a/include/linux/kallsyms.h +++ b/include/linux/kallsyms.h @@ -67,8 +67,7 @@ static inline void *dereference_symbol_descriptor(void *ptr) #ifdef CONFIG_KALLSYMS unsigned long kallsyms_sym_address(int idx); -int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *, - unsigned long), +int kallsyms_on_each_symbol(int (*fn)(void *, const char *, unsigned long), void *data); int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long), const char *name, void *data); @@ -166,8 +165,8 @@ static inline bool kallsyms_show_value(const struct cred *cred) return false; } -static inline int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *, - unsigned long), void *data) +static inline int kallsyms_on_each_symbol(int (*fn)(void *, const char *, unsigned long), + void *data) { return -EOPNOTSUPP; } diff --git a/include/linux/module.h b/include/linux/module.h index c3b357196470..d2d900077bde 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -965,13 +965,11 @@ static inline bool module_sig_ok(struct module *module) #if defined(CONFIG_MODULES) && defined(CONFIG_KALLSYMS) int module_kallsyms_on_each_symbol(const char *modname, - int (*fn)(void *, const char *, - struct module *, unsigned long), + int (*fn)(void *, const char *, unsigned long), void *data); #else static inline int module_kallsyms_on_each_symbol(const char *modname, - int (*fn)(void *, const char *, - struct module *, unsigned long), + int (*fn)(void *, const char *, unsigned long), void *data) { return -EOPNOTSUPP; diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 83f499182c9a..77747391f49b 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -288,8 +288,7 @@ unsigned long kallsyms_lookup_name(const char *name) * Iterate over all symbols in vmlinux. For symbols from modules use * module_kallsyms_on_each_symbol instead. */ -int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *, - unsigned long), +int kallsyms_on_each_symbol(int (*fn)(void *, const char *, unsigned long), void *data) { char namebuf[KSYM_NAME_LEN]; @@ -299,7 +298,7 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *, for (i = 0, off = 0; i < kallsyms_num_syms; i++) { off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf)); - ret = fn(data, namebuf, NULL, kallsyms_sym_address(i)); + ret = fn(data, namebuf, kallsyms_sym_address(i)); if (ret != 0) return ret; cond_resched(); diff --git a/kernel/kallsyms_selftest.c b/kernel/kallsyms_selftest.c index bfbc12da3326..a2e3745d15c4 100644 --- a/kernel/kallsyms_selftest.c +++ b/kernel/kallsyms_selftest.c @@ -95,7 +95,7 @@ static struct test_item test_items[] = { static char stub_name[KSYM_NAME_LEN]; -static int stat_symbol_len(void *data, const char *name, struct module *mod, unsigned long addr) +static int stat_symbol_len(void *data, const char *name, unsigned long addr) { *(u32 *)data += strlen(name); @@ -154,7 +154,7 @@ static void test_kallsyms_compression_ratio(void) pr_info(" ---------------------------------------------------------\n"); } -static int lookup_name(void *data, const char *name, struct module *mod, unsigned long addr) +static int lookup_name(void *data, const char *name, unsigned long addr) { u64 t0, t1, t; struct test_stat *stat = (struct test_stat *)data; @@ -207,7 +207,7 @@ static bool match_cleanup_name(const char *s, const char *name) return !strncmp(s, name, len); } -static int find_symbol(void *data, const char *name, struct module *mod, unsigned long addr) +static int find_symbol(void *data, const char *name, unsigned long addr) { struct test_stat *stat = (struct test_stat *)data; diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index 4bd2d5e10f20..1de2c40cc378 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -142,8 +142,7 @@ static int klp_match_callback(void *data, unsigned long addr) return 0; } -static int klp_find_callback(void *data, const char *name, - struct module *mod, unsigned long addr) +static int klp_find_callback(void *data, const char *name, unsigned long addr) { struct klp_find_arg *args = data; diff --git a/kernel/module/kallsyms.c b/kernel/module/kallsyms.c index 8e89f459ffdd..3320586584f1 100644 --- a/kernel/module/kallsyms.c +++ b/kernel/module/kallsyms.c @@ -503,8 +503,7 @@ unsigned long module_kallsyms_lookup_name(const char *name) } int module_kallsyms_on_each_symbol(const char *modname, - int (*fn)(void *, const char *, - struct module *, unsigned long), + int (*fn)(void *, const char *, unsigned long), void *data) { struct module *mod; @@ -533,7 +532,7 @@ int module_kallsyms_on_each_symbol(const char *modname, continue; ret = fn(data, kallsyms_symbol_name(kallsyms, i), - mod, kallsyms_symbol_value(sym)); + kallsyms_symbol_value(sym)); if (ret != 0) goto out; } diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 29baa97d0d53..76caca8f496a 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -8391,8 +8391,7 @@ struct kallsyms_data { * and returns 1 in case we resolved all the requested symbols, * 0 otherwise. */ -static int kallsyms_callback(void *data, const char *name, - struct module *mod, unsigned long addr) +static int kallsyms_callback(void *data, const char *name, unsigned long addr) { struct kallsyms_data *args = data; const char **sym; -- cgit From e3ff7c609f39671d1aaff4fb4a8594e14f3e03f8 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Fri, 24 Feb 2023 08:50:00 -0800 Subject: livepatch,sched: Add livepatch task switching to cond_resched() There have been reports [1][2] of live patches failing to complete within a reasonable amount of time due to CPU-bound kthreads. Fix it by patching tasks in cond_resched(). There are four different flavors of cond_resched(), depending on the kernel configuration. Hook into all of them. A more elegant solution might be to use a preempt notifier. However, non-ORC unwinders can't unwind a preempted task reliably. [1] https://lore.kernel.org/lkml/20220507174628.2086373-1-song@kernel.org/ [2] https://lkml.kernel.org/lkml/20230120-vhost-klp-switching-v1-0-7c2b65519c43@kernel.org Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Petr Mladek Tested-by: Seth Forshee (DigitalOcean) Link: https://lore.kernel.org/r/4ae981466b7814ec221014fc2554b2f86f3fb70b.1677257135.git.jpoimboe@kernel.org --- include/linux/livepatch.h | 1 + include/linux/livepatch_sched.h | 29 +++++++++++ include/linux/sched.h | 20 ++++++-- kernel/livepatch/core.c | 1 + kernel/livepatch/transition.c | 107 ++++++++++++++++++++++++++++++++++------ kernel/sched/core.c | 64 +++++++++++++++++++++--- 6 files changed, 194 insertions(+), 28 deletions(-) create mode 100644 include/linux/livepatch_sched.h (limited to 'kernel/livepatch/core.c') diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h index 293e29960c6e..9b9b38e89563 100644 --- a/include/linux/livepatch.h +++ b/include/linux/livepatch.h @@ -13,6 +13,7 @@ #include #include #include +#include #if IS_ENABLED(CONFIG_LIVEPATCH) diff --git a/include/linux/livepatch_sched.h b/include/linux/livepatch_sched.h new file mode 100644 index 000000000000..013794fb5da0 --- /dev/null +++ b/include/linux/livepatch_sched.h @@ -0,0 +1,29 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef _LINUX_LIVEPATCH_SCHED_H_ +#define _LINUX_LIVEPATCH_SCHED_H_ + +#include +#include + +#ifdef CONFIG_LIVEPATCH + +void __klp_sched_try_switch(void); + +#if !defined(CONFIG_PREEMPT_DYNAMIC) || !defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) + +DECLARE_STATIC_KEY_FALSE(klp_sched_try_switch_key); + +static __always_inline void klp_sched_try_switch(void) +{ + if (static_branch_unlikely(&klp_sched_try_switch_key)) + __klp_sched_try_switch(); +} + +#endif /* !CONFIG_PREEMPT_DYNAMIC || !CONFIG_HAVE_PREEMPT_DYNAMIC_CALL */ + +#else /* !CONFIG_LIVEPATCH */ +static inline void klp_sched_try_switch(void) {} +static inline void __klp_sched_try_switch(void) {} +#endif /* CONFIG_LIVEPATCH */ + +#endif /* _LINUX_LIVEPATCH_SCHED_H_ */ diff --git a/include/linux/sched.h b/include/linux/sched.h index 63d242164b1a..6d654eb4cabd 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -36,6 +36,7 @@ #include #include #include +#include #include /* task_struct member predeclarations (sorted alphabetically): */ @@ -2070,6 +2071,9 @@ extern int __cond_resched(void); #if defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) +void sched_dynamic_klp_enable(void); +void sched_dynamic_klp_disable(void); + DECLARE_STATIC_CALL(cond_resched, __cond_resched); static __always_inline int _cond_resched(void) @@ -2078,6 +2082,7 @@ static __always_inline int _cond_resched(void) } #elif defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY) + extern int dynamic_cond_resched(void); static __always_inline int _cond_resched(void) @@ -2085,20 +2090,25 @@ static __always_inline int _cond_resched(void) return dynamic_cond_resched(); } -#else +#else /* !CONFIG_PREEMPTION */ static inline int _cond_resched(void) { + klp_sched_try_switch(); return __cond_resched(); } -#endif /* CONFIG_PREEMPT_DYNAMIC */ +#endif /* PREEMPT_DYNAMIC && CONFIG_HAVE_PREEMPT_DYNAMIC_CALL */ -#else +#else /* CONFIG_PREEMPTION && !CONFIG_PREEMPT_DYNAMIC */ -static inline int _cond_resched(void) { return 0; } +static inline int _cond_resched(void) +{ + klp_sched_try_switch(); + return 0; +} -#endif /* !defined(CONFIG_PREEMPTION) || defined(CONFIG_PREEMPT_DYNAMIC) */ +#endif /* !CONFIG_PREEMPTION || CONFIG_PREEMPT_DYNAMIC */ #define cond_resched() ({ \ __might_resched(__FILE__, __LINE__, 0); \ diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index 4bd2d5e10f20..eea7c8ec6e05 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -33,6 +33,7 @@ * * - klp_ftrace_handler() * - klp_update_patch_state() + * - __klp_sched_try_switch() */ DEFINE_MUTEX(klp_mutex); diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c index 824e2e3f07dd..e9fd83a02228 100644 --- a/kernel/livepatch/transition.c +++ b/kernel/livepatch/transition.c @@ -9,6 +9,7 @@ #include #include +#include #include "core.h" #include "patch.h" #include "transition.h" @@ -26,6 +27,25 @@ static int klp_target_state = KLP_UNDEFINED; static unsigned int klp_signals_cnt; +/* + * When a livepatch is in progress, enable klp stack checking in + * cond_resched(). This helps CPU-bound kthreads get patched. + */ +#if defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) + +#define klp_cond_resched_enable() sched_dynamic_klp_enable() +#define klp_cond_resched_disable() sched_dynamic_klp_disable() + +#else /* !CONFIG_PREEMPT_DYNAMIC || !CONFIG_HAVE_PREEMPT_DYNAMIC_CALL */ + +DEFINE_STATIC_KEY_FALSE(klp_sched_try_switch_key); +EXPORT_SYMBOL(klp_sched_try_switch_key); + +#define klp_cond_resched_enable() static_branch_enable(&klp_sched_try_switch_key) +#define klp_cond_resched_disable() static_branch_disable(&klp_sched_try_switch_key) + +#endif /* CONFIG_PREEMPT_DYNAMIC && CONFIG_HAVE_PREEMPT_DYNAMIC_CALL */ + /* * This work can be performed periodically to finish patching or unpatching any * "straggler" tasks which failed to transition in the first attempt. @@ -174,8 +194,8 @@ void klp_update_patch_state(struct task_struct *task) * barrier (smp_rmb) for two cases: * * 1) Enforce the order of the TIF_PATCH_PENDING read and the - * klp_target_state read. The corresponding write barrier is in - * klp_init_transition(). + * klp_target_state read. The corresponding write barriers are in + * klp_init_transition() and klp_reverse_transition(). * * 2) Enforce the order of the TIF_PATCH_PENDING read and a future read * of func->transition, if klp_ftrace_handler() is called later on @@ -343,6 +363,44 @@ static bool klp_try_switch_task(struct task_struct *task) return !ret; } +void __klp_sched_try_switch(void) +{ + if (likely(!klp_patch_pending(current))) + return; + + /* + * This function is called from cond_resched() which is called in many + * places throughout the kernel. Using the klp_mutex here might + * deadlock. + * + * Instead, disable preemption to prevent racing with other callers of + * klp_try_switch_task(). Thanks to task_call_func() they won't be + * able to switch this task while it's running. + */ + preempt_disable(); + + /* + * Make sure current didn't get patched between the above check and + * preempt_disable(). + */ + if (unlikely(!klp_patch_pending(current))) + goto out; + + /* + * Enforce the order of the TIF_PATCH_PENDING read above and the + * klp_target_state read in klp_try_switch_task(). The corresponding + * write barriers are in klp_init_transition() and + * klp_reverse_transition(). + */ + smp_rmb(); + + klp_try_switch_task(current); + +out: + preempt_enable(); +} +EXPORT_SYMBOL(__klp_sched_try_switch); + /* * Sends a fake signal to all non-kthread tasks with TIF_PATCH_PENDING set. * Kthreads with TIF_PATCH_PENDING set are woken up. @@ -449,7 +507,8 @@ void klp_try_complete_transition(void) return; } - /* we're done, now cleanup the data structures */ + /* Done! Now cleanup the data structures. */ + klp_cond_resched_disable(); patch = klp_transition_patch; klp_complete_transition(); @@ -501,6 +560,8 @@ void klp_start_transition(void) set_tsk_thread_flag(task, TIF_PATCH_PENDING); } + klp_cond_resched_enable(); + klp_signals_cnt = 0; } @@ -556,8 +617,9 @@ void klp_init_transition(struct klp_patch *patch, int state) * see a func in transition with a task->patch_state of KLP_UNDEFINED. * * Also enforce the order of the klp_target_state write and future - * TIF_PATCH_PENDING writes to ensure klp_update_patch_state() doesn't - * set a task->patch_state to KLP_UNDEFINED. + * TIF_PATCH_PENDING writes to ensure klp_update_patch_state() and + * __klp_sched_try_switch() don't set a task->patch_state to + * KLP_UNDEFINED. */ smp_wmb(); @@ -593,14 +655,10 @@ void klp_reverse_transition(void) klp_target_state == KLP_PATCHED ? "patching to unpatching" : "unpatching to patching"); - klp_transition_patch->enabled = !klp_transition_patch->enabled; - - klp_target_state = !klp_target_state; - /* * Clear all TIF_PATCH_PENDING flags to prevent races caused by - * klp_update_patch_state() running in parallel with - * klp_start_transition(). + * klp_update_patch_state() or __klp_sched_try_switch() running in + * parallel with the reverse transition. */ read_lock(&tasklist_lock); for_each_process_thread(g, task) @@ -610,9 +668,28 @@ void klp_reverse_transition(void) for_each_possible_cpu(cpu) clear_tsk_thread_flag(idle_task(cpu), TIF_PATCH_PENDING); - /* Let any remaining calls to klp_update_patch_state() complete */ + /* + * Make sure all existing invocations of klp_update_patch_state() and + * __klp_sched_try_switch() see the cleared TIF_PATCH_PENDING before + * starting the reverse transition. + */ klp_synchronize_transition(); + /* + * All patching has stopped, now re-initialize the global variables to + * prepare for the reverse transition. + */ + klp_transition_patch->enabled = !klp_transition_patch->enabled; + klp_target_state = !klp_target_state; + + /* + * Enforce the order of the klp_target_state write and the + * TIF_PATCH_PENDING writes in klp_start_transition() to ensure + * klp_update_patch_state() and __klp_sched_try_switch() don't set + * task->patch_state to the wrong value. + */ + smp_wmb(); + klp_start_transition(); } @@ -626,9 +703,9 @@ void klp_copy_process(struct task_struct *child) * the task flag up to date with the parent here. * * The operation is serialized against all klp_*_transition() - * operations by the tasklist_lock. The only exception is - * klp_update_patch_state(current), but we cannot race with - * that because we are current. + * operations by the tasklist_lock. The only exceptions are + * klp_update_patch_state(current) and __klp_sched_try_switch(), but we + * cannot race with them because we are current. */ if (test_tsk_thread_flag(current, TIF_PATCH_PENDING)) set_tsk_thread_flag(child, TIF_PATCH_PENDING); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 5ddd9610be56..b9616f153946 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8525,6 +8525,7 @@ EXPORT_STATIC_CALL_TRAMP(might_resched); static DEFINE_STATIC_KEY_FALSE(sk_dynamic_cond_resched); int __sched dynamic_cond_resched(void) { + klp_sched_try_switch(); if (!static_branch_unlikely(&sk_dynamic_cond_resched)) return 0; return __cond_resched(); @@ -8673,13 +8674,17 @@ int sched_dynamic_mode(const char *str) #error "Unsupported PREEMPT_DYNAMIC mechanism" #endif -void sched_dynamic_update(int mode) +DEFINE_MUTEX(sched_dynamic_mutex); +static bool klp_override; + +static void __sched_dynamic_update(int mode) { /* * Avoid {NONE,VOLUNTARY} -> FULL transitions from ever ending up in * the ZERO state, which is invalid. */ - preempt_dynamic_enable(cond_resched); + if (!klp_override) + preempt_dynamic_enable(cond_resched); preempt_dynamic_enable(might_resched); preempt_dynamic_enable(preempt_schedule); preempt_dynamic_enable(preempt_schedule_notrace); @@ -8687,36 +8692,79 @@ void sched_dynamic_update(int mode) switch (mode) { case preempt_dynamic_none: - preempt_dynamic_enable(cond_resched); + if (!klp_override) + preempt_dynamic_enable(cond_resched); preempt_dynamic_disable(might_resched); preempt_dynamic_disable(preempt_schedule); preempt_dynamic_disable(preempt_schedule_notrace); preempt_dynamic_disable(irqentry_exit_cond_resched); - pr_info("Dynamic Preempt: none\n"); + if (mode != preempt_dynamic_mode) + pr_info("Dynamic Preempt: none\n"); break; case preempt_dynamic_voluntary: - preempt_dynamic_enable(cond_resched); + if (!klp_override) + preempt_dynamic_enable(cond_resched); preempt_dynamic_enable(might_resched); preempt_dynamic_disable(preempt_schedule); preempt_dynamic_disable(preempt_schedule_notrace); preempt_dynamic_disable(irqentry_exit_cond_resched); - pr_info("Dynamic Preempt: voluntary\n"); + if (mode != preempt_dynamic_mode) + pr_info("Dynamic Preempt: voluntary\n"); break; case preempt_dynamic_full: - preempt_dynamic_disable(cond_resched); + if (!klp_override) + preempt_dynamic_disable(cond_resched); preempt_dynamic_disable(might_resched); preempt_dynamic_enable(preempt_schedule); preempt_dynamic_enable(preempt_schedule_notrace); preempt_dynamic_enable(irqentry_exit_cond_resched); - pr_info("Dynamic Preempt: full\n"); + if (mode != preempt_dynamic_mode) + pr_info("Dynamic Preempt: full\n"); break; } preempt_dynamic_mode = mode; } +void sched_dynamic_update(int mode) +{ + mutex_lock(&sched_dynamic_mutex); + __sched_dynamic_update(mode); + mutex_unlock(&sched_dynamic_mutex); +} + +#ifdef CONFIG_HAVE_PREEMPT_DYNAMIC_CALL + +static int klp_cond_resched(void) +{ + __klp_sched_try_switch(); + return __cond_resched(); +} + +void sched_dynamic_klp_enable(void) +{ + mutex_lock(&sched_dynamic_mutex); + + klp_override = true; + static_call_update(cond_resched, klp_cond_resched); + + mutex_unlock(&sched_dynamic_mutex); +} + +void sched_dynamic_klp_disable(void) +{ + mutex_lock(&sched_dynamic_mutex); + + klp_override = false; + __sched_dynamic_update(preempt_dynamic_mode); + + mutex_unlock(&sched_dynamic_mutex); +} + +#endif /* CONFIG_HAVE_PREEMPT_DYNAMIC_CALL */ + static int __init setup_preempt_mode(char *str) { int mode = sched_dynamic_mode(str); -- cgit