diff options
| -rw-r--r-- | Documentation/feature-removal-schedule.txt | 10 | ||||
| -rw-r--r-- | include/asm-generic/vmlinux.lds.h | 28 | ||||
| -rw-r--r-- | include/linux/module.h | 20 | ||||
| -rw-r--r-- | kernel/module.c | 78 | ||||
| -rw-r--r-- | lib/Kconfig.debug | 16 |
5 files changed, 150 insertions, 2 deletions
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 027285d0c26c..033ac91da07a 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -177,6 +177,16 @@ Who: Jean Delvare <khali@linux-fr.org> --------------------------- +What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports + (temporary transition config option provided until then) + The transition config option will also be removed at the same time. +When: before 2.6.19 +Why: Unused symbols are both increasing the size of the kernel binary + and are often a sign of "wrong API" +Who: Arjan van de Ven <arjan@linux.intel.com> + +--------------------------- + What: remove EXPORT_SYMBOL(tasklist_lock) When: August 2006 Files: kernel/fork.c diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 9d11550b4818..db5a3732f106 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -58,6 +58,20 @@ VMLINUX_SYMBOL(__stop___ksymtab_gpl) = .; \ } \ \ + /* Kernel symbol table: Normal unused symbols */ \ + __ksymtab_unused : AT(ADDR(__ksymtab_unused) - LOAD_OFFSET) { \ + VMLINUX_SYMBOL(__start___ksymtab_unused) = .; \ + *(__ksymtab_unused) \ + VMLINUX_SYMBOL(__stop___ksymtab_unused) = .; \ + } \ + \ + /* Kernel symbol table: GPL-only unused symbols */ \ + __ksymtab_unused_gpl : AT(ADDR(__ksymtab_unused_gpl) - LOAD_OFFSET) { \ + VMLINUX_SYMBOL(__start___ksymtab_unused_gpl) = .; \ + *(__ksymtab_unused_gpl) \ + VMLINUX_SYMBOL(__stop___ksymtab_unused_gpl) = .; \ + } \ + \ /* Kernel symbol table: GPL-future-only symbols */ \ __ksymtab_gpl_future : AT(ADDR(__ksymtab_gpl_future) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start___ksymtab_gpl_future) = .; \ @@ -79,6 +93,20 @@ VMLINUX_SYMBOL(__stop___kcrctab_gpl) = .; \ } \ \ + /* Kernel symbol table: Normal unused symbols */ \ + __kcrctab_unused : AT(ADDR(__kcrctab_unused) - LOAD_OFFSET) { \ + VMLINUX_SYMBOL(__start___kcrctab_unused) = .; \ + *(__kcrctab_unused) \ + VMLINUX_SYMBOL(__stop___kcrctab_unused) = .; \ + } \ + \ + /* Kernel symbol table: GPL-only unused symbols */ \ + __kcrctab_unused_gpl : AT(ADDR(__kcrctab_unused_gpl) - LOAD_OFFSET) { \ + VMLINUX_SYMBOL(__start___kcrctab_unused_gpl) = .; \ + *(__kcrctab_unused_gpl) \ + VMLINUX_SYMBOL(__stop___kcrctab_unused_gpl) = .; \ + } \ + \ /* Kernel symbol table: GPL-future-only symbols */ \ __kcrctab_gpl_future : AT(ADDR(__kcrctab_gpl_future) - LOAD_OFFSET) { \ VMLINUX_SYMBOL(__start___kcrctab_gpl_future) = .; \ diff --git a/include/linux/module.h b/include/linux/module.h index 9ebbb74b7b72..9e9dc7c24d95 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -203,6 +203,15 @@ void *__symbol_get_gpl(const char *symbol); #define EXPORT_SYMBOL_GPL_FUTURE(sym) \ __EXPORT_SYMBOL(sym, "_gpl_future") + +#ifdef CONFIG_UNUSED_SYMBOLS +#define EXPORT_UNUSED_SYMBOL(sym) __EXPORT_SYMBOL(sym, "_unused") +#define EXPORT_UNUSED_SYMBOL_GPL(sym) __EXPORT_SYMBOL(sym, "_unused_gpl") +#else +#define EXPORT_UNUSED_SYMBOL(sym) +#define EXPORT_UNUSED_SYMBOL_GPL(sym) +#endif + #endif struct module_ref @@ -261,6 +270,15 @@ struct module unsigned int num_gpl_syms; const unsigned long *gpl_crcs; + /* unused exported symbols. */ + const struct kernel_symbol *unused_syms; + unsigned int num_unused_syms; + const unsigned long *unused_crcs; + /* GPL-only, unused exported symbols. */ + const struct kernel_symbol *unused_gpl_syms; + unsigned int num_unused_gpl_syms; + const unsigned long *unused_gpl_crcs; + /* symbols that will be GPL-only in the near future. */ const struct kernel_symbol *gpl_future_syms; unsigned int num_gpl_future_syms; @@ -456,6 +474,8 @@ void module_remove_driver(struct device_driver *); #define EXPORT_SYMBOL(sym) #define EXPORT_SYMBOL_GPL(sym) #define EXPORT_SYMBOL_GPL_FUTURE(sym) +#define EXPORT_UNUSED_SYMBOL(sym) +#define EXPORT_UNUSED_SYMBOL_GPL(sym) /* Given an address, look for it in the exception tables. */ static inline const struct exception_table_entry * diff --git a/kernel/module.c b/kernel/module.c index 10e5b872adf6..03b738172a8c 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1,4 +1,4 @@ -/* Rewritten by Rusty Russell, on the backs of many others... +/* Copyright (C) 2002 Richard Henderson Copyright (C) 2001 Rusty Russell, 2002 Rusty Russell IBM. @@ -122,9 +122,17 @@ extern const struct kernel_symbol __start___ksymtab_gpl[]; extern const struct kernel_symbol __stop___ksymtab_gpl[]; extern const struct kernel_symbol __start___ksymtab_gpl_future[]; extern const struct kernel_symbol __stop___ksymtab_gpl_future[]; +extern const struct kernel_symbol __start___ksymtab_unused[]; +extern const struct kernel_symbol __stop___ksymtab_unused[]; +extern const struct kernel_symbol __start___ksymtab_unused_gpl[]; +extern const struct kernel_symbol __stop___ksymtab_unused_gpl[]; +extern const struct kernel_symbol __start___ksymtab_gpl_future[]; +extern const struct kernel_symbol __stop___ksymtab_gpl_future[]; extern const unsigned long __start___kcrctab[]; extern const unsigned long __start___kcrctab_gpl[]; extern const unsigned long __start___kcrctab_gpl_future[]; +extern const unsigned long __start___kcrctab_unused[]; +extern const unsigned long __start___kcrctab_unused_gpl[]; #ifndef CONFIG_MODVERSIONS #define symversion(base, idx) NULL @@ -144,6 +152,17 @@ static const struct kernel_symbol *lookup_symbol(const char *name, return NULL; } +static void printk_unused_warning(const char *name) +{ + printk(KERN_WARNING "Symbol %s is marked as UNUSED, " + "however this module is using it.\n", name); + printk(KERN_WARNING "This symbol will go away in the future.\n"); + printk(KERN_WARNING "Please evalute if this is the right api to use, " + "and if it really is, submit a report the linux kernel " + "mailinglist together with submitting your code for " + "inclusion.\n"); +} + /* Find a symbol, return value, crc and module which owns it */ static unsigned long __find_symbol(const char *name, struct module **owner, @@ -186,6 +205,25 @@ static unsigned long __find_symbol(const char *name, return ks->value; } + ks = lookup_symbol(name, __start___ksymtab_unused, + __stop___ksymtab_unused); + if (ks) { + printk_unused_warning(name); + *crc = symversion(__start___kcrctab_unused, + (ks - __start___ksymtab_unused)); + return ks->value; + } + + if (gplok) + ks = lookup_symbol(name, __start___ksymtab_unused_gpl, + __stop___ksymtab_unused_gpl); + if (ks) { + printk_unused_warning(name); + *crc = symversion(__start___kcrctab_unused_gpl, + (ks - __start___ksymtab_unused_gpl)); + return ks->value; + } + /* Now try modules. */ list_for_each_entry(mod, &modules, list) { *owner = mod; @@ -204,6 +242,23 @@ static unsigned long __find_symbol(const char *name, return ks->value; } } + ks = lookup_symbol(name, mod->unused_syms, mod->unused_syms + mod->num_unused_syms); + if (ks) { + printk_unused_warning(name); + *crc = symversion(mod->unused_crcs, (ks - mod->unused_syms)); + return ks->value; + } + + if (gplok) { + ks = lookup_symbol(name, mod->unused_gpl_syms, + mod->unused_gpl_syms + mod->num_unused_gpl_syms); + if (ks) { + printk_unused_warning(name); + *crc = symversion(mod->unused_gpl_crcs, + (ks - mod->unused_gpl_syms)); + return ks->value; + } + } ks = lookup_symbol(name, mod->gpl_future_syms, (mod->gpl_future_syms + mod->num_gpl_future_syms)); @@ -1407,6 +1462,8 @@ static struct module *load_module(void __user *umod, exportindex, modindex, obsparmindex, infoindex, gplindex, crcindex, gplcrcindex, versindex, pcpuindex, gplfutureindex, gplfuturecrcindex, unwindex = 0; + unsigned int unusedindex, unusedcrcindex, unusedgplindex, + unusedgplcrcindex; struct module *mod; long err = 0; void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */ @@ -1487,9 +1544,13 @@ static struct module *load_module(void __user *umod, exportindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab"); gplindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_gpl"); gplfutureindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_gpl_future"); + unusedindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_unused"); + unusedgplindex = find_sec(hdr, sechdrs, secstrings, "__ksymtab_unused_gpl"); crcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab"); gplcrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_gpl"); gplfuturecrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_gpl_future"); + unusedcrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_unused"); + unusedgplcrcindex = find_sec(hdr, sechdrs, secstrings, "__kcrctab_unused_gpl"); setupindex = find_sec(hdr, sechdrs, secstrings, "__param"); exindex = find_sec(hdr, sechdrs, secstrings, "__ex_table"); obsparmindex = find_sec(hdr, sechdrs, secstrings, "__obsparm"); @@ -1638,14 +1699,27 @@ static struct module *load_module(void __user *umod, mod->gpl_crcs = (void *)sechdrs[gplcrcindex].sh_addr; mod->num_gpl_future_syms = sechdrs[gplfutureindex].sh_size / sizeof(*mod->gpl_future_syms); + mod->num_unused_syms = sechdrs[unusedindex].sh_size / + sizeof(*mod->unused_syms); + mod->num_unused_gpl_syms = sechdrs[unusedgplindex].sh_size / + sizeof(*mod->unused_gpl_syms); mod->gpl_future_syms = (void *)sechdrs[gplfutureindex].sh_addr; if (gplfuturecrcindex) mod->gpl_future_crcs = (void *)sechdrs[gplfuturecrcindex].sh_addr; + mod->unused_syms = (void *)sechdrs[unusedindex].sh_addr; + if (unusedcrcindex) + mod->unused_crcs = (void *)sechdrs[unusedcrcindex].sh_addr; + mod->unused_gpl_syms = (void *)sechdrs[unusedgplindex].sh_addr; + if (unusedgplcrcindex) + mod->unused_crcs = (void *)sechdrs[unusedgplcrcindex].sh_addr; + #ifdef CONFIG_MODVERSIONS if ((mod->num_syms && !crcindex) || (mod->num_gpl_syms && !gplcrcindex) || - (mod->num_gpl_future_syms && !gplfuturecrcindex)) { + (mod->num_gpl_future_syms && !gplfuturecrcindex) || + (mod->num_unused_syms && !unusedcrcindex) || + (mod->num_unused_gpl_syms && !unusedgplcrcindex)) { printk(KERN_WARNING "%s: No versions for exported symbols." " Tainting kernel.\n", mod->name); add_taint(TAINT_FORCED_MODULE); diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 5330911ebd30..e4fcbd12cf6e 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -23,6 +23,22 @@ config MAGIC_SYSRQ keys are documented in <file:Documentation/sysrq.txt>. Don't say Y unless you really know what this hack does. +config UNUSED_SYMBOLS + bool "Enable unused/obsolete exported symbols" + default y if X86 + help + Unused but exported symbols make the kernel needlessly bigger. For + that reason most of these unused exports will soon be removed. This + option is provided temporarily to provide a transition period in case + some external kernel module needs one of these symbols anyway. If you + encounter such a case in your module, consider if you are actually + using the right API. (rationale: since nobody in the kernel is using + this in a module, there is a pretty good chance it's actually the + wrong interface to use). If you really need the symbol, please send a + mail to the linux kernel mailing list mentioning the symbol and why + you really need it, and what the merge plan to the mainline kernel for + your module is. + config DEBUG_KERNEL bool "Kernel debugging" help |