Messages in this thread Patch in this message | | | Date | Mon, 21 Apr 2008 14:34:12 +0200 | From | Peter Oberparleiter <> | Subject | [RFC PATCH 1/8] kernel: call constructors |
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From: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
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 <peter.oberparleiter@de.ibm.com> --- arch/powerpc/kernel/vmlinux.lds.S | 3 +++ include/asm-generic/sections.h | 1 + include/asm-generic/vmlinux.lds.h | 8 ++++++++ include/linux/module.h | 5 +++++ init/main.c | 10 ++++++++++ kernel/module.c | 13 +++++++++++++ 6 files changed, 40 insertions(+)
Index: linux-2.6.25/include/asm-generic/vmlinux.lds.h =================================================================== --- linux-2.6.25.orig/include/asm-generic/vmlinux.lds.h +++ linux-2.6.25/include/asm-generic/vmlinux.lds.h @@ -352,3 +352,11 @@ *(.data.percpu.shared_aligned) \ } \ __per_cpu_end = .; + +#define CONSTRUCTORS \ + __CTOR_LIST__ = .; \ + *(.ctors) \ + __CTOR_END__ = .; \ + __DTOR_LIST__ = .; \ + *(.dtors) \ + __DTOR_END__ = .; Index: linux-2.6.25/arch/powerpc/kernel/vmlinux.lds.S =================================================================== --- linux-2.6.25.orig/arch/powerpc/kernel/vmlinux.lds.S +++ linux-2.6.25/arch/powerpc/kernel/vmlinux.lds.S @@ -196,6 +196,9 @@ SECTIONS *(.toc) } #endif + .data.gcov : { + CONSTRUCTORS + } . = ALIGN(PAGE_SIZE); _edata = .; Index: linux-2.6.25/include/asm-generic/sections.h =================================================================== --- linux-2.6.25.orig/include/asm-generic/sections.h +++ linux-2.6.25/include/asm-generic/sections.h @@ -13,5 +13,6 @@ 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_LIST__[], __CTOR_END__[]; #endif /* _ASM_GENERIC_SECTIONS_H_ */ Index: linux-2.6.25/include/linux/module.h =================================================================== --- linux-2.6.25.orig/include/linux/module.h +++ linux-2.6.25/include/linux/module.h @@ -246,6 +246,8 @@ struct module_sect_attrs struct module_param_attrs; +typedef void (*ctorcall_t)(void); + struct module { enum module_state state; @@ -359,6 +361,9 @@ struct module struct marker *markers; unsigned int num_markers; #endif + /* Constructor calls. */ + ctorcall_t *ctors; + unsigned long num_ctors; }; #ifndef MODULE_ARCH_INIT #define MODULE_ARCH_INIT {} Index: linux-2.6.25/kernel/module.c =================================================================== --- linux-2.6.25.orig/kernel/module.c +++ linux-2.6.25/kernel/module.c @@ -1718,6 +1718,7 @@ static struct module *load_module(void _ unsigned int unusedgplcrcindex; unsigned int markersindex; unsigned int markersstringsindex; + unsigned int ctorsindex; struct module *mod; long err = 0; void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */ @@ -1814,6 +1815,7 @@ 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 section */ sechdrs[infoindex].sh_flags &= ~(unsigned long)SHF_ALLOC; @@ -2021,6 +2023,8 @@ 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); @@ -2133,6 +2137,14 @@ 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, @@ -2163,6 +2175,7 @@ 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(); Index: linux-2.6.25/init/main.c =================================================================== --- linux-2.6.25.orig/init/main.c +++ linux-2.6.25/init/main.c @@ -650,6 +650,15 @@ asmlinkage void __init start_kernel(void rest_init(); } +static void __init do_ctors(void) +{ + ctorcall_t *call; + + for (call = (ctorcall_t *) __CTOR_LIST__; + call < (ctorcall_t *) __CTOR_END__; call++) + (*call)(); +} + static int __initdata initcall_debug; static int __init initcall_debug_setup(char *str) @@ -735,6 +744,7 @@ static void __init do_basic_setup(void) usermodehelper_init(); driver_init(); init_irq_proc(); + do_ctors(); do_initcalls(); }
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