From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756200Ab1KBAcd (ORCPT ); Tue, 1 Nov 2011 20:32:33 -0400 Received: from claw.goop.org ([74.207.240.146]:40967 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751889Ab1KBAc2 (ORCPT ); Tue, 1 Nov 2011 20:32:28 -0400 Message-ID: <4EB0748E.1070601@goop.org> Date: Tue, 01 Nov 2011 15:37:02 -0700 From: Jeremy Fitzhardinge User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:7.0.1) Gecko/20110930 Thunderbird/7.0.1 MIME-Version: 1.0 To: Steven Rostedt , Jason Baron , Peter Zijlstra , Ingo Molnar CC: Linux Kernel Mailing List , the arch/x86 maintainers , Linus Torvalds Subject: [GIT PULL] make Jump Labels work early X-Enigmail-Version: 1.3.2 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi all, This is the series which makes jump labels work early. Does someone want to pick this up, or should I just send it to Linus directly? [ I see Linus has already picked up the stop-machine patch from -mm. ] Thanks, J The following changes since commit a102a9ece5489e1718cd7543aa079082450ac3a2: Linux 3.1-rc8 (2011-09-27 15:48:34 -0700) are available in the git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git upstream/jump-label-noearly Jeremy Fitzhardinge (9): jump_label: use proper atomic_t initializer stop_machine: make stop_machine safe and efficient to call early jump_label: if a key has already been initialized, don't nop it out x86/jump_label: drop arch_jump_label_text_poke_early() sparc/jump_label: drop arch_jump_label_text_poke_early() jump_label: add arch_jump_label_transform_static() to optimise non-live code updates s390/jump-label: add arch_jump_label_transform_static() x86/jump_label: add arch_jump_label_transform_static() jump-label: initialize jump-label subsystem much earlier arch/s390/kernel/jump_label.c | 51 ++++++++++++++++++++++++--------------- arch/sparc/kernel/jump_label.c | 8 ------ arch/x86/kernel/jump_label.c | 20 +++++++++++---- include/linux/jump_label.h | 23 +++++++++++------- init/main.c | 3 ++ kernel/jump_label.c | 37 ++++++++++++++++------------ kernel/stop_machine.c | 22 +++++++++++++++++ 7 files changed, 105 insertions(+), 59 deletions(-) diff --git a/arch/s390/kernel/jump_label.c b/arch/s390/kernel/jump_label.c index 44cc06b..b987ab2 100644 --- a/arch/s390/kernel/jump_label.c +++ b/arch/s390/kernel/jump_label.c @@ -18,26 +18,15 @@ struct insn { } __packed; struct insn_args { - unsigned long *target; - struct insn *insn; - ssize_t size; + struct jump_entry *entry; + enum jump_label_type type; }; -static int __arch_jump_label_transform(void *data) +static void __jump_label_transform(struct jump_entry *entry, + enum jump_label_type type) { - struct insn_args *args = data; - int rc; - - rc = probe_kernel_write(args->target, args->insn, args->size); - WARN_ON_ONCE(rc < 0); - return 0; -} - -void arch_jump_label_transform(struct jump_entry *entry, - enum jump_label_type type) -{ - struct insn_args args; struct insn insn; + int rc; if (type == JUMP_LABEL_ENABLE) { /* brcl 15,offset */ @@ -49,11 +38,33 @@ void arch_jump_label_transform(struct jump_entry *entry, insn.offset = 0; } - args.target = (void *) entry->code; - args.insn = &insn; - args.size = JUMP_LABEL_NOP_SIZE; + rc = probe_kernel_write((void *)entry->code, &insn, JUMP_LABEL_NOP_SIZE); + WARN_ON_ONCE(rc < 0); +} - stop_machine(__arch_jump_label_transform, &args, NULL); +static int __sm_arch_jump_label_transform(void *data) +{ + struct insn_args *args = data; + + __jump_label_transform(args->entry, args->type); + return 0; +} + +void arch_jump_label_transform(struct jump_entry *entry, + enum jump_label_type type) +{ + struct insn_args args; + + args.entry = entry; + args.type = type; + + stop_machine(__sm_arch_jump_label_transform, &args, NULL); +} + +void arch_jump_label_transform_static(struct jump_entry *entry, + enum jump_label_type type) +{ + __jump_label_transform(entry, type); } #endif diff --git a/arch/sparc/kernel/jump_label.c b/arch/sparc/kernel/jump_label.c index ea2dafc..971fd43 100644 --- a/arch/sparc/kernel/jump_label.c +++ b/arch/sparc/kernel/jump_label.c @@ -36,12 +36,4 @@ void arch_jump_label_transform(struct jump_entry *entry, put_online_cpus(); } -void arch_jump_label_text_poke_early(jump_label_t addr) -{ - u32 *insn_p = (u32 *) (unsigned long) addr; - - *insn_p = 0x01000000; - flushi(insn_p); -} - #endif diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c index 3fee346..ea9d5f2f 100644 --- a/arch/x86/kernel/jump_label.c +++ b/arch/x86/kernel/jump_label.c @@ -24,8 +24,9 @@ union jump_code_union { } __attribute__((packed)); }; -void arch_jump_label_transform(struct jump_entry *entry, - enum jump_label_type type) +static void __jump_label_transform(struct jump_entry *entry, + enum jump_label_type type, + void *(*poker)(void *, const void *, size_t)) { union jump_code_union code; @@ -35,17 +36,24 @@ void arch_jump_label_transform(struct jump_entry *entry, (entry->code + JUMP_LABEL_NOP_SIZE); } else memcpy(&code, ideal_nops[NOP_ATOMIC5], JUMP_LABEL_NOP_SIZE); + + (*poker)((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE); +} + +void arch_jump_label_transform(struct jump_entry *entry, + enum jump_label_type type) +{ get_online_cpus(); mutex_lock(&text_mutex); - text_poke_smp((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE); + __jump_label_transform(entry, type, text_poke_smp); mutex_unlock(&text_mutex); put_online_cpus(); } -void arch_jump_label_text_poke_early(jump_label_t addr) +void arch_jump_label_transform_static(struct jump_entry *entry, + enum jump_label_type type) { - text_poke_early((void *)addr, ideal_nops[NOP_ATOMIC5], - JUMP_LABEL_NOP_SIZE); + __jump_label_transform(entry, type, text_poke_early); } #endif diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h index 66f23dc..388b0d4 100644 --- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -16,7 +16,7 @@ struct jump_label_key { # include # define HAVE_JUMP_LABEL -#endif +#endif /* CC_HAVE_ASM_GOTO && CONFIG_JUMP_LABEL */ enum jump_label_type { JUMP_LABEL_DISABLE = 0, @@ -28,9 +28,9 @@ struct module; #ifdef HAVE_JUMP_LABEL #ifdef CONFIG_MODULES -#define JUMP_LABEL_INIT {{ 0 }, NULL, NULL} +#define JUMP_LABEL_INIT {ATOMIC_INIT(0), NULL, NULL} #else -#define JUMP_LABEL_INIT {{ 0 }, NULL} +#define JUMP_LABEL_INIT {ATOMIC_INIT(0), NULL} #endif static __always_inline bool static_branch(struct jump_label_key *key) @@ -41,18 +41,20 @@ static __always_inline bool static_branch(struct jump_label_key *key) extern struct jump_entry __start___jump_table[]; extern struct jump_entry __stop___jump_table[]; +extern void jump_label_init(void); extern void jump_label_lock(void); extern void jump_label_unlock(void); extern void arch_jump_label_transform(struct jump_entry *entry, - enum jump_label_type type); -extern void arch_jump_label_text_poke_early(jump_label_t addr); + enum jump_label_type type); +extern void arch_jump_label_transform_static(struct jump_entry *entry, + enum jump_label_type type); extern int jump_label_text_reserved(void *start, void *end); extern void jump_label_inc(struct jump_label_key *key); extern void jump_label_dec(struct jump_label_key *key); extern bool jump_label_enabled(struct jump_label_key *key); extern void jump_label_apply_nops(struct module *mod); -#else +#else /* !HAVE_JUMP_LABEL */ #include @@ -62,6 +64,10 @@ struct jump_label_key { atomic_t enabled; }; +static __always_inline void jump_label_init(void) +{ +} + static __always_inline bool static_branch(struct jump_label_key *key) { if (unlikely(atomic_read(&key->enabled))) @@ -96,7 +102,6 @@ static inline int jump_label_apply_nops(struct module *mod) { return 0; } +#endif /* HAVE_JUMP_LABEL */ -#endif - -#endif +#endif /* _LINUX_JUMP_LABEL_H */ diff --git a/init/main.c b/init/main.c index 2a9b88a..29d8d84 100644 --- a/init/main.c +++ b/init/main.c @@ -515,6 +515,9 @@ asmlinkage void __init start_kernel(void) parse_args("Booting kernel", static_command_line, __start___param, __stop___param - __start___param, &unknown_bootoption); + + jump_label_init(); + /* * These use large bootmem allocations and must precede * kmem_cache_init() diff --git a/kernel/jump_label.c b/kernel/jump_label.c index a8ce450..bbdfe2a 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -104,6 +104,18 @@ static int __jump_label_text_reserved(struct jump_entry *iter_start, return 0; } +/* + * Update code which is definitely not currently executing. + * Architectures which need heavyweight synchronization to modify + * running code can override this to make the non-live update case + * cheaper. + */ +void __weak arch_jump_label_transform_static(struct jump_entry *entry, + enum jump_label_type type) +{ + arch_jump_label_transform(entry, type); +} + static void __jump_label_update(struct jump_label_key *key, struct jump_entry *entry, struct jump_entry *stop, int enable) @@ -121,14 +133,7 @@ static void __jump_label_update(struct jump_label_key *key, } } -/* - * Not all archs need this. - */ -void __weak arch_jump_label_text_poke_early(jump_label_t addr) -{ -} - -static __init int jump_label_init(void) +void __init jump_label_init(void) { struct jump_entry *iter_start = __start___jump_table; struct jump_entry *iter_stop = __stop___jump_table; @@ -139,22 +144,22 @@ static __init int jump_label_init(void) jump_label_sort_entries(iter_start, iter_stop); for (iter = iter_start; iter < iter_stop; iter++) { - arch_jump_label_text_poke_early(iter->code); - if (iter->key == (jump_label_t)(unsigned long)key) + struct jump_label_key *iterk; + + iterk = (struct jump_label_key *)(unsigned long)iter->key; + arch_jump_label_transform_static(iter, jump_label_enabled(iterk) ? + JUMP_LABEL_ENABLE : JUMP_LABEL_DISABLE); + if (iterk == key) continue; - key = (struct jump_label_key *)(unsigned long)iter->key; - atomic_set(&key->enabled, 0); + key = iterk; key->entries = iter; #ifdef CONFIG_MODULES key->next = NULL; #endif } jump_label_unlock(); - - return 0; } -early_initcall(jump_label_init); #ifdef CONFIG_MODULES @@ -212,7 +217,7 @@ void jump_label_apply_nops(struct module *mod) return; for (iter = iter_start; iter < iter_stop; iter++) - arch_jump_label_text_poke_early(iter->code); + arch_jump_label_transform_static(iter, JUMP_LABEL_DISABLE); } static int jump_label_add_module(struct module *mod) diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index ba5070c..d3f960a 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -41,6 +41,7 @@ struct cpu_stopper { }; static DEFINE_PER_CPU(struct cpu_stopper, cpu_stopper); +static bool stop_machine_initialized = false; static void cpu_stop_init_done(struct cpu_stop_done *done, unsigned int nr_todo) { @@ -386,6 +387,8 @@ static int __init cpu_stop_init(void) cpu_stop_cpu_callback(&cpu_stop_cpu_notifier, CPU_ONLINE, bcpu); register_cpu_notifier(&cpu_stop_cpu_notifier); + stop_machine_initialized = true; + return 0; } early_initcall(cpu_stop_init); @@ -485,6 +488,25 @@ int __stop_machine(int (*fn)(void *), void *data, const struct cpumask *cpus) .num_threads = num_online_cpus(), .active_cpus = cpus }; + if (!stop_machine_initialized) { + /* + * Handle the case where stop_machine() is called + * early in boot before stop_machine() has been + * initialized. + */ + unsigned long flags; + int ret; + + WARN_ON_ONCE(smdata.num_threads != 1); + + local_irq_save(flags); + hard_irq_disable(); + ret = (*fn)(data); + local_irq_restore(flags); + + return ret; + } + /* Set the initial state and stop all online cpus. */ set_state(&smdata, STOPMACHINE_PREPARE); return stop_cpus(cpu_online_mask, stop_machine_cpu_stop, &smdata);