From 6d723736e472f7a0cd5b62c84152fceead241328 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 10 Apr 2009 14:53:50 -0400 Subject: tracing/events: add support for modules to TRACE_EVENT Impact: allow modules to add TRACE_EVENTS on load This patch adds the final hooks to allow modules to use the TRACE_EVENT macro. A notifier and a data structure are used to link the TRACE_EVENTs defined in the module to connect them with the ftrace event tracing system. It also adds the necessary automated clean ups to the trace events when a module is removed. Cc: Rusty Russell Signed-off-by: Steven Rostedt --- include/linux/module.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/module.h') diff --git a/include/linux/module.h b/include/linux/module.h index 627ac082e2a..6155fa44168 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -337,6 +337,10 @@ struct module const char **trace_bprintk_fmt_start; unsigned int num_trace_bprintk_fmt; #endif +#ifdef CONFIG_EVENT_TRACING + struct ftrace_event_call *trace_events; + unsigned int num_trace_events; +#endif #ifdef CONFIG_MODULE_UNLOAD /* What modules depend on me? */ -- cgit v1.2.3-70-g09d2 From 93eb677d74a4f7d3edfb678c94f6c0544d9fbad2 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 15 Apr 2009 13:24:06 -0400 Subject: ftrace: use module notifier for function tracer The hooks in the module code for the function tracer must be called before any of that module code runs. The function tracer hooks modify the module (replacing calls to mcount to nops). If the code is executed while the change occurs, then the CPU can take a GPF. To handle the above with a bit of paranoia, I originally implemented the hooks as calls directly from the module code. After examining the notifier calls, it looks as though the start up notify is called before any of the module's code is executed. This makes the use of the notify safe with ftrace. Only the startup notify is required to be "safe". The shutdown simply removes the entries from the ftrace function list, and does not modify any code. This change has another benefit. It removes a issue with a reverse dependency in the mutexes of ftrace_lock and module_mutex. [ Impact: fix lock dependency bug, cleanup ] Cc: Rusty Russell Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 7 ---- include/linux/module.h | 4 +++ kernel/module.c | 19 ++++------- kernel/trace/ftrace.c | 90 +++++++++++++++++++++++++++++++++++--------------- 4 files changed, 75 insertions(+), 45 deletions(-) (limited to 'include/linux/module.h') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 53869bef610..97c83e1bc58 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -233,8 +233,6 @@ extern int ftrace_arch_read_dyn_info(char *buf, int size); extern int skip_trace(unsigned long ip); -extern void ftrace_release(void *start, unsigned long size); - extern void ftrace_disable_daemon(void); extern void ftrace_enable_daemon(void); #else @@ -325,13 +323,8 @@ static inline void __ftrace_enabled_restore(int enabled) #ifdef CONFIG_FTRACE_MCOUNT_RECORD extern void ftrace_init(void); -extern void ftrace_init_module(struct module *mod, - unsigned long *start, unsigned long *end); #else static inline void ftrace_init(void) { } -static inline void -ftrace_init_module(struct module *mod, - unsigned long *start, unsigned long *end) { } #endif /* diff --git a/include/linux/module.h b/include/linux/module.h index 6155fa44168..a8f2c0aa4c3 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -341,6 +341,10 @@ struct module struct ftrace_event_call *trace_events; unsigned int num_trace_events; #endif +#ifdef CONFIG_FTRACE_MCOUNT_RECORD + unsigned long *ftrace_callsites; + unsigned int num_ftrace_callsites; +#endif #ifdef CONFIG_MODULE_UNLOAD /* What modules depend on me? */ diff --git a/kernel/module.c b/kernel/module.c index a0394706f10..2383e60fcf3 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1490,9 +1490,6 @@ static void free_module(struct module *mod) /* Free any allocated parameters. */ destroy_params(mod->kp, mod->num_kp); - /* release any pointers to mcount in this module */ - ftrace_release(mod->module_core, mod->core_size); - /* This may be NULL, but that's OK */ module_free(mod, mod->module_init); kfree(mod->args); @@ -1893,11 +1890,9 @@ static noinline struct module *load_module(void __user *umod, unsigned int symindex = 0; unsigned int strindex = 0; unsigned int modindex, versindex, infoindex, pcpuindex; - unsigned int num_mcount; struct module *mod; long err = 0; void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */ - unsigned long *mseg; mm_segment_t old_fs; DEBUGP("load_module: umod=%p, len=%lu, uargs=%p\n", @@ -2179,7 +2174,13 @@ static noinline struct module *load_module(void __user *umod, sizeof(*mod->trace_events), &mod->num_trace_events); #endif - +#ifdef CONFIG_FTRACE_MCOUNT_RECORD + /* sechdrs[0].sh_size is always zero */ + mod->ftrace_callsites = section_objs(hdr, sechdrs, secstrings, + "__mcount_loc", + sizeof(*mod->ftrace_callsites), + &mod->num_ftrace_callsites); +#endif #ifdef CONFIG_MODVERSIONS if ((mod->num_syms && !mod->crcs) || (mod->num_gpl_syms && !mod->gpl_crcs) @@ -2244,11 +2245,6 @@ static noinline struct module *load_module(void __user *umod, dynamic_debug_setup(debug, num_debug); } - /* sechdrs[0].sh_size is always zero */ - mseg = section_objs(hdr, sechdrs, secstrings, "__mcount_loc", - sizeof(*mseg), &num_mcount); - ftrace_init_module(mod, mseg, mseg + num_mcount); - err = module_finalize(hdr, sechdrs, mod); if (err < 0) goto cleanup; @@ -2309,7 +2305,6 @@ static noinline struct module *load_module(void __user *umod, cleanup: kobject_del(&mod->mkobj.kobj); kobject_put(&mod->mkobj.kobj); - ftrace_release(mod->module_core, mod->core_size); free_unload: module_unload_free(mod); #if defined(CONFIG_MODULE_UNLOAD) && defined(CONFIG_SMP) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index a2348898858..5b606f45b6c 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -916,30 +916,6 @@ static void ftrace_free_rec(struct dyn_ftrace *rec) rec->flags |= FTRACE_FL_FREE; } -void ftrace_release(void *start, unsigned long size) -{ - struct dyn_ftrace *rec; - struct ftrace_page *pg; - unsigned long s = (unsigned long)start; - unsigned long e = s + size; - - if (ftrace_disabled || !start) - return; - - mutex_lock(&ftrace_lock); - do_for_each_ftrace_rec(pg, rec) { - if ((rec->ip >= s) && (rec->ip < e)) { - /* - * rec->ip is changed in ftrace_free_rec() - * It should not between s and e if record was freed. - */ - FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE); - ftrace_free_rec(rec); - } - } while_for_each_ftrace_rec(); - mutex_unlock(&ftrace_lock); -} - static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip) { struct dyn_ftrace *rec; @@ -2752,14 +2728,72 @@ static int ftrace_convert_nops(struct module *mod, return 0; } -void ftrace_init_module(struct module *mod, - unsigned long *start, unsigned long *end) +#ifdef CONFIG_MODULES +void ftrace_release(void *start, void *end) +{ + struct dyn_ftrace *rec; + struct ftrace_page *pg; + unsigned long s = (unsigned long)start; + unsigned long e = (unsigned long)end; + + if (ftrace_disabled || !start || start == end) + return; + + mutex_lock(&ftrace_lock); + do_for_each_ftrace_rec(pg, rec) { + if ((rec->ip >= s) && (rec->ip < e)) { + /* + * rec->ip is changed in ftrace_free_rec() + * It should not between s and e if record was freed. + */ + FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE); + ftrace_free_rec(rec); + } + } while_for_each_ftrace_rec(); + mutex_unlock(&ftrace_lock); +} + +static void ftrace_init_module(struct module *mod, + unsigned long *start, unsigned long *end) { if (ftrace_disabled || start == end) return; ftrace_convert_nops(mod, start, end); } +static int ftrace_module_notify(struct notifier_block *self, + unsigned long val, void *data) +{ + struct module *mod = data; + + switch (val) { + case MODULE_STATE_COMING: + ftrace_init_module(mod, mod->ftrace_callsites, + mod->ftrace_callsites + + mod->num_ftrace_callsites); + break; + case MODULE_STATE_GOING: + ftrace_release(mod->ftrace_callsites, + mod->ftrace_callsites + + mod->num_ftrace_callsites); + break; + } + + return 0; +} +#else +static int ftrace_module_notify(struct notifier_block *self, + unsigned long val, void *data) +{ + return 0; +} +#endif /* CONFIG_MODULES */ + +struct notifier_block ftrace_module_nb = { + .notifier_call = ftrace_module_notify, + .priority = 0, +}; + extern unsigned long __start_mcount_loc[]; extern unsigned long __stop_mcount_loc[]; @@ -2791,6 +2825,10 @@ void __init ftrace_init(void) __start_mcount_loc, __stop_mcount_loc); + ret = register_module_notifier(&ftrace_module_nb); + if (!ret) + pr_warning("Failed to register trace ftrace module notifier\n"); + return; failed: ftrace_disabled = 1; -- cgit v1.2.3-70-g09d2 From ad6561dffa17f17bb68d7207d422c26c381c4313 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Fri, 12 Jun 2009 21:47:03 -0600 Subject: module: trim exception table on init free. It's theoretically possible that there are exception table entries which point into the (freed) init text of modules. These could cause future problems if other modules get loaded into that memory and cause an exception as we'd see the wrong fixup. The only case I know of is kvm-intel.ko (when CONFIG_CC_OPTIMIZE_FOR_SIZE=n). Amerigo fixed this long-standing FIXME in the x86 version, but this patch is more general. This implements trim_init_extable(); most archs are simple since they use the standard lib/extable.c sort code. Alpha and IA64 use relative addresses in their fixups, so thier trimming is a slight variation. Sparc32 is unique; it doesn't seem to define ARCH_HAS_SORT_EXTABLE, yet it defines its own sort_extable() which overrides the one in lib. It doesn't sort, so we have to mark deleted entries instead of actually trimming them. Inspired-by: Amerigo Wang Signed-off-by: Rusty Russell Cc: linux-alpha@vger.kernel.org Cc: sparclinux@vger.kernel.org Cc: linux-ia64@vger.kernel.org --- arch/alpha/mm/extable.c | 21 +++++++++++++++++++++ arch/ia64/mm/extable.c | 26 ++++++++++++++++++++++++++ arch/sparc/include/asm/uaccess_32.h | 3 +++ arch/sparc/mm/extable.c | 29 +++++++++++++++++++++++++++++ include/linux/module.h | 1 + kernel/module.c | 1 + lib/extable.c | 21 ++++++++++++++++++++- 7 files changed, 101 insertions(+), 1 deletion(-) (limited to 'include/linux/module.h') diff --git a/arch/alpha/mm/extable.c b/arch/alpha/mm/extable.c index 62dc379d301..813c9b63c0e 100644 --- a/arch/alpha/mm/extable.c +++ b/arch/alpha/mm/extable.c @@ -48,6 +48,27 @@ void sort_extable(struct exception_table_entry *start, cmp_ex, swap_ex); } +#ifdef CONFIG_MODULES +/* + * Any entry referring to the module init will be at the beginning or + * the end. + */ +void trim_init_extable(struct module *m) +{ + /*trim the beginning*/ + while (m->num_exentries && + within_module_init(ex_to_addr(&m->extable[0]), m)) { + m->extable++; + m->num_exentries--; + } + /*trim the end*/ + while (m->num_exentries && + within_module_init(ex_to_addr(&m->extable[m->num_exentries-1]), + m)) + m->num_exentries--; +} +#endif /* CONFIG_MODULES */ + const struct exception_table_entry * search_extable(const struct exception_table_entry *first, const struct exception_table_entry *last, diff --git a/arch/ia64/mm/extable.c b/arch/ia64/mm/extable.c index 71c50dd8f87..e95d5ad9285 100644 --- a/arch/ia64/mm/extable.c +++ b/arch/ia64/mm/extable.c @@ -53,6 +53,32 @@ void sort_extable (struct exception_table_entry *start, cmp_ex, swap_ex); } +static inline unsigned long ex_to_addr(const struct exception_table_entry *x) +{ + return (unsigned long)&x->insn + x->insn; +} + +#ifdef CONFIG_MODULES +/* + * Any entry referring to the module init will be at the beginning or + * the end. + */ +void trim_init_extable(struct module *m) +{ + /*trim the beginning*/ + while (m->num_exentries && + within_module_init(ex_to_addr(&m->extable[0]), m)) { + m->extable++; + m->num_exentries--; + } + /*trim the end*/ + while (m->num_exentries && + within_module_init(ex_to_addr(&m->extable[m->num_exentries-1]), + m)) + m->num_exentries--; +} +#endif /* CONFIG_MODULES */ + const struct exception_table_entry * search_extable (const struct exception_table_entry *first, const struct exception_table_entry *last, diff --git a/arch/sparc/include/asm/uaccess_32.h b/arch/sparc/include/asm/uaccess_32.h index 47d5619d43f..8303ac48103 100644 --- a/arch/sparc/include/asm/uaccess_32.h +++ b/arch/sparc/include/asm/uaccess_32.h @@ -17,6 +17,9 @@ #ifndef __ASSEMBLY__ +#define ARCH_HAS_SORT_EXTABLE +#define ARCH_HAS_SEARCH_EXTABLE + /* Sparc is not segmented, however we need to be able to fool access_ok() * when doing system calls from kernel mode legitimately. * diff --git a/arch/sparc/mm/extable.c b/arch/sparc/mm/extable.c index 16cc28935e3..a61c349448e 100644 --- a/arch/sparc/mm/extable.c +++ b/arch/sparc/mm/extable.c @@ -28,6 +28,10 @@ search_extable(const struct exception_table_entry *start, * word 3: last insn address + 4 bytes * word 4: fixup code address * + * Deleted entries are encoded as: + * word 1: unused + * word 2: -1 + * * See asm/uaccess.h for more details. */ @@ -39,6 +43,10 @@ search_extable(const struct exception_table_entry *start, continue; } + /* A deleted entry; see trim_init_extable */ + if (walk->fixup == -1) + continue; + if (walk->insn == value) return walk; } @@ -57,6 +65,27 @@ search_extable(const struct exception_table_entry *start, return NULL; } +#ifdef CONFIG_MODULES +/* We could memmove them around; easier to mark the trimmed ones. */ +void trim_init_extable(struct module *m) +{ + unsigned int i; + bool range; + + for (i = 0; i < m->num_exentries; i += range ? 2 : 1) { + range = m->extable[i].fixup == 0; + + if (within_module_init(m->extable[i].insn, m)) { + m->extable[i].fixup = -1; + if (range) + m->extable[i+1].fixup = -1; + } + if (range) + i++; + } +} +#endif /* CONFIG_MODULES */ + /* Special extable search, which handles ranges. Returns fixup */ unsigned long search_extables_range(unsigned long addr, unsigned long *g2) { diff --git a/include/linux/module.h b/include/linux/module.h index a8f2c0aa4c3..a7bc6e7b43a 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -77,6 +77,7 @@ search_extable(const struct exception_table_entry *first, void sort_extable(struct exception_table_entry *start, struct exception_table_entry *finish); void sort_main_extable(void); +void trim_init_extable(struct module *m); #ifdef MODULE #define MODULE_GENERIC_TABLE(gtype,name) \ diff --git a/kernel/module.c b/kernel/module.c index 35f7de00bf0..e4ab36ce767 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2455,6 +2455,7 @@ SYSCALL_DEFINE3(init_module, void __user *, umod, mutex_lock(&module_mutex); /* Drop initial reference. */ module_put(mod); + trim_init_extable(mod); module_free(mod, mod->module_init); mod->module_init = NULL; mod->init_size = 0; diff --git a/lib/extable.c b/lib/extable.c index 179c0874559..4cac81ec225 100644 --- a/lib/extable.c +++ b/lib/extable.c @@ -39,7 +39,26 @@ void sort_extable(struct exception_table_entry *start, sort(start, finish - start, sizeof(struct exception_table_entry), cmp_ex, NULL); } -#endif + +#ifdef CONFIG_MODULES +/* + * If the exception table is sorted, any referring to the module init + * will be at the beginning or the end. + */ +void trim_init_extable(struct module *m) +{ + /*trim the beginning*/ + while (m->num_exentries && within_module_init(m->extable[0].insn, m)) { + m->extable++; + m->num_exentries--; + } + /*trim the end*/ + while (m->num_exentries && + within_module_init(m->extable[m->num_exentries-1].insn, m)) + m->num_exentries--; +} +#endif /* CONFIG_MODULES */ +#endif /* !ARCH_HAS_SORT_EXTABLE */ #ifndef ARCH_HAS_SEARCH_EXTABLE /* -- cgit v1.2.3-70-g09d2 From 0d9c25dde878a636ee9a9b53923569171bf9a55b Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Tue, 16 Jun 2009 15:33:37 -0700 Subject: headers: move module_bug_finalize()/module_bug_cleanup() definitions into module.h They're in linux/bug.h at present, which causes include order tangles. In particular, linux/bug.h cannot be used by linux/atomic.h because, according to Nikanth: linux/bug.h pulls in linux/module.h => linux/spinlock.h => asm/spinlock.h (which uses atomic_inc) => asm/atomic.h. bug.h is a pretty low-level thing and module.h is a higher-level thing, IMO. Cc: Nikanth Karthikesan Cc: Rusty Russell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/bug.h | 12 ------------ include/linux/module.h | 17 +++++++++++++++++ 2 files changed, 17 insertions(+), 12 deletions(-) (limited to 'include/linux/module.h') diff --git a/include/linux/bug.h b/include/linux/bug.h index 54398d2c6d8..d276b5510c8 100644 --- a/include/linux/bug.h +++ b/include/linux/bug.h @@ -1,7 +1,6 @@ #ifndef _LINUX_BUG_H #define _LINUX_BUG_H -#include #include enum bug_trap_type { @@ -24,10 +23,6 @@ const struct bug_entry *find_bug(unsigned long bugaddr); enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs); -int module_bug_finalize(const Elf_Ehdr *, const Elf_Shdr *, - struct module *); -void module_bug_cleanup(struct module *); - /* These are defined by the architecture */ int is_valid_bugaddr(unsigned long addr); @@ -38,13 +33,6 @@ static inline enum bug_trap_type report_bug(unsigned long bug_addr, { return BUG_TRAP_TYPE_BUG; } -static inline int module_bug_finalize(const Elf_Ehdr *hdr, - const Elf_Shdr *sechdrs, - struct module *mod) -{ - return 0; -} -static inline void module_bug_cleanup(struct module *mod) {} #endif /* CONFIG_GENERIC_BUG */ #endif /* _LINUX_BUG_H */ diff --git a/include/linux/module.h b/include/linux/module.h index a7bc6e7b43a..505f20dcc1c 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -697,4 +697,21 @@ static inline void module_remove_modinfo_attrs(struct module *mod) #define __MODULE_STRING(x) __stringify(x) + +#ifdef CONFIG_GENERIC_BUG +int module_bug_finalize(const Elf_Ehdr *, const Elf_Shdr *, + struct module *); +void module_bug_cleanup(struct module *); + +#else /* !CONFIG_GENERIC_BUG */ + +static inline int module_bug_finalize(const Elf_Ehdr *hdr, + const Elf_Shdr *sechdrs, + struct module *mod) +{ + return 0; +} +static inline void module_bug_cleanup(struct module *mod) {} +#endif /* CONFIG_GENERIC_BUG */ + #endif /* _LINUX_MODULE_H */ -- cgit v1.2.3-70-g09d2 From b99b87f70c7785ab1e253c6220f4b0b57ce3a7f7 Mon Sep 17 00:00:00 2001 From: Peter Oberparleiter Date: Wed, 17 Jun 2009 16:28:03 -0700 Subject: kernel: constructor support Call constructors (gcc-generated initcall-like functions) during kernel start and module load. Constructors are e.g. used for gcov data initialization. Disable constructor support for usermode Linux to prevent conflicts with host glibc. Signed-off-by: Peter Oberparleiter Acked-by: Rusty Russell Acked-by: WANG Cong Cc: Sam Ravnborg Cc: Jeff Dike Cc: Andi Kleen Cc: Huang Ying Cc: Li Wei Cc: Michael Ellerman Cc: Ingo Molnar Cc: Heiko Carstens Cc: Martin Schwidefsky Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-generic/sections.h | 3 +++ include/asm-generic/vmlinux.lds.h | 9 +++++++++ include/linux/init.h | 3 +++ include/linux/module.h | 6 ++++++ init/Kconfig | 5 +++++ init/main.c | 12 ++++++++++++ kernel/module.c | 16 ++++++++++++++++ 7 files changed, 54 insertions(+) (limited to 'include/linux/module.h') diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h index 4ce48e87853..d083561337f 100644 --- a/include/asm-generic/sections.h +++ b/include/asm-generic/sections.h @@ -14,6 +14,9 @@ extern char __kprobes_text_start[], __kprobes_text_end[]; extern char __initdata_begin[], __initdata_end[]; extern char __start_rodata[], __end_rodata[]; +/* Start and end of .ctors section - used for constructor calls. */ +extern char __ctors_start[], __ctors_end[]; + /* function descriptor handling (if any). Override * in asm/sections.h */ #ifndef dereference_function_descriptor diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 6bdba10fef4..55413e568f0 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -440,12 +440,21 @@ INIT_TASK \ } +#ifdef CONFIG_CONSTRUCTORS +#define KERNEL_CTORS() VMLINUX_SYMBOL(__ctors_start) = .; \ + *(.ctors) \ + VMLINUX_SYMBOL(__ctors_end) = .; +#else +#define KERNEL_CTORS() +#endif + /* init and exit section handling */ #define INIT_DATA \ *(.init.data) \ DEV_DISCARD(init.data) \ CPU_DISCARD(init.data) \ MEM_DISCARD(init.data) \ + KERNEL_CTORS() \ *(.init.rodata) \ DEV_DISCARD(init.rodata) \ CPU_DISCARD(init.rodata) \ diff --git a/include/linux/init.h b/include/linux/init.h index 8c2c9989626..13b633ed695 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -134,6 +134,9 @@ typedef void (*exitcall_t)(void); extern initcall_t __con_initcall_start[], __con_initcall_end[]; extern initcall_t __security_initcall_start[], __security_initcall_end[]; +/* Used for contructor calls. */ +typedef void (*ctor_fn_t)(void); + /* Defined in init/main.c */ extern int do_one_initcall(initcall_t fn); extern char __initdata boot_command_line[]; diff --git a/include/linux/module.h b/include/linux/module.h index 505f20dcc1c..098bdb7bfac 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -363,6 +363,12 @@ struct module local_t ref; #endif #endif + +#ifdef CONFIG_CONSTRUCTORS + /* Constructor functions. */ + ctor_fn_t *ctors; + unsigned int num_ctors; +#endif }; #ifndef MODULE_ARCH_INIT #define MODULE_ARCH_INIT {} diff --git a/init/Kconfig b/init/Kconfig index c4b3c6d51a7..1ce05a4cb5f 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -16,6 +16,11 @@ config DEFCONFIG_LIST default "$ARCH_DEFCONFIG" default "arch/$ARCH/defconfig" +config CONSTRUCTORS + bool + depends on !UML + default y + menu "General setup" config EXPERIMENTAL diff --git a/init/main.c b/init/main.c index 0e7aedeaa05..1a65fdd0631 100644 --- a/init/main.c +++ b/init/main.c @@ -720,6 +720,17 @@ asmlinkage void __init start_kernel(void) rest_init(); } +/* Call all constructor functions linked into the kernel. */ +static void __init do_ctors(void) +{ +#ifdef CONFIG_CONSTRUCTORS + ctor_fn_t *call = (ctor_fn_t *) __ctors_start; + + for (; call < (ctor_fn_t *) __ctors_end; call++) + (*call)(); +#endif +} + int initcall_debug; core_param(initcall_debug, initcall_debug, bool, 0644); @@ -800,6 +811,7 @@ static void __init do_basic_setup(void) usermodehelper_init(); driver_init(); init_irq_proc(); + do_ctors(); do_initcalls(); } diff --git a/kernel/module.c b/kernel/module.c index 215aaab09e9..38928fcaff2 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2216,6 +2216,10 @@ static noinline struct module *load_module(void __user *umod, mod->unused_gpl_crcs = section_addr(hdr, sechdrs, secstrings, "__kcrctab_unused_gpl"); #endif +#ifdef CONFIG_CONSTRUCTORS + mod->ctors = section_objs(hdr, sechdrs, secstrings, ".ctors", + sizeof(*mod->ctors), &mod->num_ctors); +#endif #ifdef CONFIG_MARKERS mod->markers = section_objs(hdr, sechdrs, secstrings, "__markers", @@ -2389,6 +2393,17 @@ static noinline struct module *load_module(void __user *umod, goto free_hdr; } +/* Call module constructors. */ +static void do_mod_ctors(struct module *mod) +{ +#ifdef CONFIG_CONSTRUCTORS + unsigned long i; + + for (i = 0; i < mod->num_ctors; i++) + mod->ctors[i](); +#endif +} + /* This is where the real work happens */ SYSCALL_DEFINE3(init_module, void __user *, umod, unsigned long, len, const char __user *, uargs) @@ -2417,6 +2432,7 @@ SYSCALL_DEFINE3(init_module, void __user *, umod, blocking_notifier_call_chain(&module_notify_list, MODULE_STATE_COMING, mod); + do_mod_ctors(mod); /* Start the module */ if (mod->init != NULL) ret = do_one_initcall(mod->init); -- cgit v1.2.3-70-g09d2