From: Peter Oberparleiter Call constructors during kernel init and module load. Required by the gcov profiling infrastructure: gcc's profiling code uses constructors to register profiling data structures. Signed-off-by: Peter Oberparleiter Cc: Sam Ravnborg Cc: Rusty Russell Signed-off-by: Andrew Morton --- arch/powerpc/kernel/vmlinux.lds.S | 3 +++ include/asm-generic/sections.h | 1 + include/asm-generic/vmlinux.lds.h | 5 +++++ include/linux/init.h | 2 ++ include/linux/module.h | 4 +++- init/main.c | 10 ++++++++++ kernel/module.c | 13 +++++++++++++ 7 files changed, 37 insertions(+), 1 deletion(-) diff -puN arch/powerpc/kernel/vmlinux.lds.S~kernel-call-constructors arch/powerpc/kernel/vmlinux.lds.S --- a/arch/powerpc/kernel/vmlinux.lds.S~kernel-call-constructors +++ a/arch/powerpc/kernel/vmlinux.lds.S @@ -191,6 +191,9 @@ SECTIONS *(.toc) } #endif + .data.gcov : { + CONSTRUCTORS + } . = ALIGN(PAGE_SIZE); _edata = .; diff -puN include/asm-generic/sections.h~kernel-call-constructors include/asm-generic/sections.h --- a/include/asm-generic/sections.h~kernel-call-constructors +++ a/include/asm-generic/sections.h @@ -23,5 +23,6 @@ extern char __per_cpu_start[], __per_cpu extern char __kprobes_text_start[], __kprobes_text_end[]; extern char __initdata_begin[], __initdata_end[]; extern char __start_rodata[], __end_rodata[]; +extern char __ctor_start[], __ctor_end[]; #endif /* _ASM_GENERIC_SECTIONS_H_ */ diff -puN include/asm-generic/vmlinux.lds.h~kernel-call-constructors include/asm-generic/vmlinux.lds.h --- a/include/asm-generic/vmlinux.lds.h~kernel-call-constructors +++ a/include/asm-generic/vmlinux.lds.h @@ -406,3 +406,8 @@ } \ __per_cpu_end = .; #endif + +#define CONSTRUCTORS \ + VMLINUX_SYMBOL(__ctor_start) = .; \ + *(.ctors) \ + VMLINUX_SYMBOL(__ctor_end) = .; diff -puN include/linux/init.h~kernel-call-constructors include/linux/init.h --- a/include/linux/init.h~kernel-call-constructors +++ a/include/linux/init.h @@ -138,6 +138,8 @@ typedef void (*exitcall_t)(void); extern initcall_t __con_initcall_start[], __con_initcall_end[]; extern initcall_t __security_initcall_start[], __security_initcall_end[]; +typedef void (*ctorcall_t)(void); + /* Defined in init/main.c */ extern char __initdata boot_command_line[]; extern char *saved_command_line; diff -puN include/linux/module.h~kernel-call-constructors include/linux/module.h --- a/include/linux/module.h~kernel-call-constructors +++ a/include/linux/module.h @@ -345,7 +345,9 @@ struct module /* Reference counts */ struct module_ref ref[NR_CPUS]; #endif - + /* Constructor calls. */ + ctorcall_t *ctors; + unsigned long num_ctors; }; #ifndef MODULE_ARCH_INIT #define MODULE_ARCH_INIT {} diff -puN init/main.c~kernel-call-constructors init/main.c --- a/init/main.c~kernel-call-constructors +++ a/init/main.c @@ -690,6 +690,15 @@ asmlinkage void __init start_kernel(void rest_init(); } +static void __init do_ctors(void) +{ + ctorcall_t *call; + + for (call = (ctorcall_t *) __ctor_start; + call < (ctorcall_t *) __ctor_end; call++) + (*call)(); +} + static int __initdata initcall_debug; static int __init initcall_debug_setup(char *str) @@ -770,6 +779,7 @@ static void __init do_basic_setup(void) usermodehelper_init(); driver_init(); init_irq_proc(); + do_ctors(); do_initcalls(); } diff -puN kernel/module.c~kernel-call-constructors kernel/module.c --- a/kernel/module.c~kernel-call-constructors +++ a/kernel/module.c @@ -1807,6 +1807,7 @@ static struct module *load_module(void _ #endif unsigned int markersindex; unsigned int markersstringsindex; + unsigned int ctorsindex; struct module *mod; long err = 0; void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */ @@ -1905,6 +1906,7 @@ static struct module *load_module(void _ #ifdef ARCH_UNWIND_SECTION_NAME unwindex = find_sec(hdr, sechdrs, secstrings, ARCH_UNWIND_SECTION_NAME); #endif + ctorsindex = find_sec(hdr, sechdrs, secstrings, ".ctors"); /* Don't keep modinfo and version sections. */ sechdrs[infoindex].sh_flags &= ~(unsigned long)SHF_ALLOC; @@ -2120,6 +2122,8 @@ static struct module *load_module(void _ mod->num_markers = sechdrs[markersindex].sh_size / sizeof(*mod->markers); #endif + mod->ctors = (void *) sechdrs[ctorsindex].sh_addr; + mod->num_ctors = sechdrs[ctorsindex].sh_size / sizeof(*mod->ctors); /* Find duplicate symbols */ err = verify_export_symbols(mod); @@ -2232,6 +2236,14 @@ static struct module *load_module(void _ goto free_hdr; } +static void do_mod_ctors(struct module *mod) +{ + unsigned long i; + + for (i = 0; i < mod->num_ctors; i++) + mod->ctors[i](); +} + /* This is where the real work happens */ asmlinkage long sys_init_module(void __user *umod, @@ -2262,6 +2274,7 @@ sys_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 = mod->init(); _