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Gitweb: http://git.kernel.org/linus/b99b87f70c7785ab1e253c6220f4b0b57ce3a7f7 Commit: b99b87f70c7785ab1e253c6220f4b0b57ce3a7f7 Parent: e24aca672ff06aff0e6a1045efab86043ea5f735 Author: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> AuthorDate: Wed Jun 17 16:28:03 2009 -0700 Committer: Linus Torvalds <torvalds@linux-foundation.org> CommitDate: Thu Jun 18 13:03:57 2009 -0700 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 <oberpar@linux.vnet.ibm.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: WANG Cong <xiyou.wangcong@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Huang Ying <ying.huang@intel.com> Cc: Li Wei <W.Li@Sun.COM> Cc: Michael Ellerman <michaele@au1.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Heiko Carstens <heicars2@linux.vnet.ibm.com> Cc: Martin Schwidefsky <mschwid2@linux.vnet.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> --- 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(+), 0 deletions(-) diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h index 4ce48e8..d083561 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 6bdba10..55413e5 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 8c2c998..13b633e 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 505f20d..098bdb7 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 c4b3c6d..1ce05a4 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 0e7aede..1a65fdd 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 215aaab..38928fc 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); -- To unsubscribe from this list: send the line "unsubscribe git-commits-head" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html