From patchwork Thu Mar 14 04:00:40 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rusty Russell X-Patchwork-Id: 227444 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:4978:20e::2]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 87ACD2C0097 for ; Thu, 14 Mar 2013 17:46:45 +1100 (EST) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UG1uq-0007jG-9v; Thu, 14 Mar 2013 06:45:28 +0000 Received: from ozlabs.org ([2402:b800:7003:1:1::1]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UG1um-0007im-5w for linux-mtd@lists.infradead.org; Thu, 14 Mar 2013 06:45:26 +0000 Received: by ozlabs.org (Postfix, from userid 1011) id 776CD2C007B; Thu, 14 Mar 2013 17:45:18 +1100 (EST) From: Rusty Russell To: Sam Ravnborg Subject: Re: [RFC -next] linux/linkage.h: fix symbol prefix handling In-Reply-To: <20130313063157.GB19681@merkur.ravnborg.org> References: <1362656642-2693-1-git-send-email-james.hogan@imgtec.com> <87sj46wyf2.fsf@rustcorp.com.au> <5139AC39.90805@imgtec.com> <874ngiwije.fsf@rustcorp.com.au> <20130311230731.0c610d86569d09f6e23b8e61@canb.auug.org.au> <87ppz5usts.fsf@rustcorp.com.au> <20130312233300.9d86d47bb5369923ad520a21@canb.auug.org.au> <87ehfkuq27.fsf@rustcorp.com.au> <20130313063157.GB19681@merkur.ravnborg.org> User-Agent: Notmuch/0.14 (http://notmuchmail.org) Emacs/23.4.1 (i686-pc-linux-gnu) Date: Thu, 14 Mar 2013 14:30:40 +1030 Message-ID: <87zjy6tytz.fsf@rustcorp.com.au> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130314_024524_936895_18DCE3FD X-CRM114-Status: GOOD ( 27.19 ) X-Spam-Score: -4.3 (----) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-4.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.4 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Michal Marek , Stephen Rothwell , James Hogan , Mike Frysinger , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, Paul Gortmaker , linux-next@vger.kernel.org, linux-mtd@lists.infradead.org, Al Viro , Jean Delvare , uclinux-dist-devel@blackfin.uclinux.org, Andrew Morton , Guenter Roeck X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-mtd" Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org Sam Ravnborg writes: >> actually, y'know, proof-read it. > Hmm.. >> + $(KERNELRELEASE) "$(patsubst y,_,$(CONFIG_HAVE_SYMBOL_PREFIX_UNDERSCORE))" >> >> +config HAVE_UNDERSCORE_SYMBOL_PREFIX > > HAVE_UNDERSCORE_... or HAVE_SYMBOL_... confusion. > I prefer the HAVE_SYMBOL_... variant but no strong feelings.. Thanks, fixed. (HAVE_UNDERSCORE_ won by grep majority vote, but I don't really care either). >> + * >> + * If you think the above arrogance just encourages more people to add >> + * random crap to this file, you're not alone. > Kill this. ?? It went in without my Ack, and it's a particularly offensive turd. I can replace it with a civilized comment, instead of being snarky though... >> /* Some toolchains use a `_' prefix for all user symbols. */ >> -#ifdef CONFIG_SYMBOL_PREFIX >> -#define MODULE_SYMBOL_PREFIX CONFIG_SYMBOL_PREFIX >> +#ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX >> +#define __VMLINUX_SYMBOL(x) _##x >> +#define __VMLINUX_SYMBOL_STR(x) "_" #x >> +#define VMLINUX_SYMBOL_PREFIX_STR "_" >> #else >> -#define MODULE_SYMBOL_PREFIX "" >> +#define __VMLINUX_SYMBOL(x) x >> +#define __VMLINUX_SYMBOL_STR(x) #x >> +#define VMLINUX_SYMBOL_PREFIX_STR "" >> #endif > > We know the prefix is an underscore. No benefits from defining > VMLINUX_SYMBOL_PREFIX_STR. The config name even syas so. > Skipping the above give us only one way to check > for the prefix - today we mix the two. After testing, I think you're right. The two users are both slightly clearer after this (though mtd is a tiny bit less optimal). Note: James, your patch hunk now looks like this: - buf_printf(b, "\t{ %#8x, \"%s\" },\n", s->crc, s->name); + buf_printf(b, "\t{ %#8x, VMLINUX_SYMBOL_STR(%s) },\n", + s->crc, s->name); Here's version 3: From: Rusty Russell Subject: CONFIG_SYMBOL_PREFIX: cleanup. We have CONFIG_SYMBOL_PREFIX, which three archs define to the string "_". But Al Viro broke this in "consolidate cond_syscall and SYSCALL_ALIAS declarations" (in linux-next), and he's not the first to do so. Using CONFIG_SYMBOL_PREFIX is awkward, since we usually just want to prefix it so something. So various places define helpers which are defined to nothing if CONFIG_SYMBOL_PREFIX isn't set: 1) include/asm-generic/unistd.h defines __SYMBOL_PREFIX. 2) include/asm-generic/vmlinux.lds.h defines VMLINUX_SYMBOL(sym) 3) include/linux/export.h defines MODULE_SYMBOL_PREFIX. 4) include/linux/kernel.h defines SYMBOL_PREFIX (which differs from #7) 5) kernel/modsign_certificate.S defines ASM_SYMBOL(sym) 6) scripts/modpost.c defines MODULE_SYMBOL_PREFIX 7) scripts/Makefile.lib defines SYMBOL_PREFIX on the commandline if CONFIG_SYMBOL_PREFIX is set, so that we have a non-string version for pasting. (arch/h8300/include/asm/linkage.h defines SYMBOL_NAME(), too). Let's solve this properly: 1) No more generic prefix, just CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX. 2) Make linux/export.h usable from asm. 3) Define VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR(). 4) Make everyone use them. Signed-off-by: Rusty Russell diff --git a/Makefile b/Makefile index a05ea42..0b09ba5 100644 --- a/Makefile +++ b/Makefile @@ -1398,7 +1398,7 @@ quiet_cmd_rmfiles = $(if $(wildcard $(rm-files)),CLEAN $(wildcard $(rm-files)) # Run depmod only if we have System.map and depmod is executable quiet_cmd_depmod = DEPMOD $(KERNELRELEASE) cmd_depmod = $(CONFIG_SHELL) $(srctree)/scripts/depmod.sh $(DEPMOD) \ - $(KERNELRELEASE) "$(patsubst "%",%,$(CONFIG_SYMBOL_PREFIX))" + $(KERNELRELEASE) "$(patsubst y,_,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX))" # Create temporary dir for module support files # clean it up only when building all modules diff --git a/arch/Kconfig b/arch/Kconfig index 1455579..7b433a4 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -384,6 +384,12 @@ config MODULES_USE_ELF_REL Modules only use ELF REL relocations. Modules with ELF RELA relocations will give an error. +config HAVE_UNDERSCORE_SYMBOL_PREFIX + bool + help + Some architectures generate an _ in front of C symbols; things like + module loading and assembly files need to know about this. + # # ABI hall of shame # diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig index c3f2e0b..453ebe4 100644 --- a/arch/blackfin/Kconfig +++ b/arch/blackfin/Kconfig @@ -1,7 +1,3 @@ -config SYMBOL_PREFIX - string - default "_" - config MMU def_bool n @@ -33,6 +29,7 @@ config BLACKFIN select ARCH_HAVE_CUSTOM_GPIO_H select ARCH_WANT_OPTIONAL_GPIOLIB select HAVE_UID16 + select HAVE_UNDERSCORE_SYMBOL_PREFIX select VIRT_TO_BUS select ARCH_WANT_IPC_PARSE_VERSION select HAVE_GENERIC_HARDIRQS diff --git a/arch/h8300/Kconfig b/arch/h8300/Kconfig index 79250de..303e4f9 100644 --- a/arch/h8300/Kconfig +++ b/arch/h8300/Kconfig @@ -12,10 +12,7 @@ config H8300 select MODULES_USE_ELF_RELA select OLD_SIGSUSPEND3 select OLD_SIGACTION - -config SYMBOL_PREFIX - string - default "_" + select HAVE_UNDERSCORE_SYMBOL_PREFIX config MMU bool diff --git a/arch/metag/Kconfig b/arch/metag/Kconfig index afc8973..2099617 100644 --- a/arch/metag/Kconfig +++ b/arch/metag/Kconfig @@ -1,7 +1,3 @@ -config SYMBOL_PREFIX - string - default "_" - config METAG def_bool y select EMBEDDED @@ -27,6 +23,7 @@ config METAG select HAVE_MOD_ARCH_SPECIFIC select HAVE_PERF_EVENTS select HAVE_SYSCALL_TRACEPOINTS + select HAVE_UNDERSCORE_SYMBOL_PREFIX select IRQ_DOMAIN select MODULES_USE_ELF_RELA select OF diff --git a/drivers/mtd/chips/gen_probe.c b/drivers/mtd/chips/gen_probe.c index 3b9a284..74dbb6b 100644 --- a/drivers/mtd/chips/gen_probe.c +++ b/drivers/mtd/chips/gen_probe.c @@ -204,14 +204,16 @@ static inline struct mtd_info *cfi_cmdset_unknown(struct map_info *map, struct cfi_private *cfi = map->fldrv_priv; __u16 type = primary?cfi->cfiq->P_ID:cfi->cfiq->A_ID; #ifdef CONFIG_MODULES - char probename[16+sizeof(MODULE_SYMBOL_PREFIX)]; + char probename[sizeof(VMLINUX_SYMBOL_STR(cfi_cmdset_%4.4X))]; cfi_cmdset_fn_t *probe_function; - sprintf(probename, MODULE_SYMBOL_PREFIX "cfi_cmdset_%4.4X", type); + sprintf(probename, VMLINUX_SYMBOL_STR(cfi_cmdset_%4.4X), type); probe_function = __symbol_get(probename); if (!probe_function) { - request_module(probename + sizeof(MODULE_SYMBOL_PREFIX) - 1); + char modname[sizeof("cfi_cmdset_%4.4X")]; + sprintf(modname, "cfi_cmdset_%4.4X", type); + request_module(modname); probe_function = __symbol_get(probename); } diff --git a/include/asm-generic/unistd.h b/include/asm-generic/unistd.h index 4077b5d..15c0598 100644 --- a/include/asm-generic/unistd.h +++ b/include/asm-generic/unistd.h @@ -1,4 +1,5 @@ #include +#include /* * These are required system calls, we should @@ -17,12 +18,7 @@ * but it doesn't work on all toolchains, so we just do it by hand */ #ifndef cond_syscall -#ifdef CONFIG_SYMBOL_PREFIX -#define __SYMBOL_PREFIX CONFIG_SYMBOL_PREFIX -#else -#define __SYMBOL_PREFIX -#endif -#define cond_syscall(x) asm(".weak\t" __SYMBOL_PREFIX #x "\n\t" \ - ".set\t" __SYMBOL_PREFIX #x "," \ - __SYMBOL_PREFIX "sys_ni_syscall") +#define cond_syscall(x) asm(".weak\t" VMLINUX_SYMBOL_STR(x) "\n\t" \ + ".set\t" VMLINUX_SYMBOL_STR(x) "," \ + VMLINUX_SYMBOL_STR(sys_ni_syscall)) #endif diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index afa12c7..eb58d2d 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -52,13 +52,7 @@ #define LOAD_OFFSET 0 #endif -#ifndef SYMBOL_PREFIX -#define VMLINUX_SYMBOL(sym) sym -#else -#define PASTE2(x,y) x##y -#define PASTE(x,y) PASTE2(x,y) -#define VMLINUX_SYMBOL(sym) PASTE(SYMBOL_PREFIX, sym) -#endif +#include /* Align . to a 8 byte boundary equals to maximum function alignment. */ #define ALIGN_FUNCTION() . = ALIGN(8) diff --git a/include/linux/export.h b/include/linux/export.h index 696c0f4..412cd50 100644 --- a/include/linux/export.h +++ b/include/linux/export.h @@ -5,17 +5,24 @@ * to reduce the amount of pointless cruft we feed to gcc when only * exporting a simple symbol or two. * - * If you feel the need to add #include to this file - * then you are doing something wrong and should go away silently. + * Try not to add #includes here. It slows compilation and makes kernel + * hackers place grumpy comments in header files. */ /* Some toolchains use a `_' prefix for all user symbols. */ -#ifdef CONFIG_SYMBOL_PREFIX -#define MODULE_SYMBOL_PREFIX CONFIG_SYMBOL_PREFIX +#ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX +#define __VMLINUX_SYMBOL(x) _##x +#define __VMLINUX_SYMBOL_STR(x) "_" #x #else -#define MODULE_SYMBOL_PREFIX "" +#define __VMLINUX_SYMBOL(x) x +#define __VMLINUX_SYMBOL_STR(x) #x #endif +/* Indirect, so macros are expanded before pasting. */ +#define VMLINUX_SYMBOL(x) __VMLINUX_SYMBOL(x) +#define VMLINUX_SYMBOL_STR(x) __VMLINUX_SYMBOL_STR(x) + +#ifndef __ASSEMBLY__ struct kernel_symbol { unsigned long value; @@ -51,7 +58,7 @@ extern struct module __this_module; __CRC_SYMBOL(sym, sec) \ static const char __kstrtab_##sym[] \ __attribute__((section("__ksymtab_strings"), aligned(1))) \ - = MODULE_SYMBOL_PREFIX #sym; \ + = VMLINUX_SYMBOL_STR(sym); \ static const struct kernel_symbol __ksymtab_##sym \ __used \ __attribute__((section("___ksymtab" sec "+" #sym), unused)) \ @@ -85,5 +92,6 @@ extern struct module __this_module; #define EXPORT_UNUSED_SYMBOL_GPL(sym) #endif /* CONFIG_MODULES */ +#endif /* !__ASSEMBLY__ */ #endif /* _LINUX_EXPORT_H */ diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 80d3687..e13e992 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -723,13 +723,6 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } /* Trap pasters of __FUNCTION__ at compile-time */ #define __FUNCTION__ (__func__) -/* This helps us to avoid #ifdef CONFIG_SYMBOL_PREFIX */ -#ifdef CONFIG_SYMBOL_PREFIX -#define SYMBOL_PREFIX CONFIG_SYMBOL_PREFIX -#else -#define SYMBOL_PREFIX "" -#endif - /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */ #ifdef CONFIG_FTRACE_MCOUNT_RECORD # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD diff --git a/include/linux/module.h b/include/linux/module.h index ead1b57..46f1ea0 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -190,7 +190,7 @@ extern int modules_disabled; /* for sysctl */ /* Get/put a kernel symbol (calls must be symmetric) */ void *__symbol_get(const char *symbol); void *__symbol_get_gpl(const char *symbol); -#define symbol_get(x) ((typeof(&x))(__symbol_get(MODULE_SYMBOL_PREFIX #x))) +#define symbol_get(x) ((typeof(&x))(__symbol_get(VMLINUX_SYMBOL_STR(x)))) /* modules using other modules: kdb wants to see this. */ struct module_use { @@ -453,7 +453,7 @@ extern void __module_put_and_exit(struct module *mod, long code) #ifdef CONFIG_MODULE_UNLOAD unsigned long module_refcount(struct module *mod); void __symbol_put(const char *symbol); -#define symbol_put(x) __symbol_put(MODULE_SYMBOL_PREFIX #x) +#define symbol_put(x) __symbol_put(VMLINUX_SYMBOL_STR(x)) void symbol_put_addr(void *addr); /* Sometimes we know we already have a refcount, and it's easier not diff --git a/kernel/modsign_certificate.S b/kernel/modsign_certificate.S index 246b4c6..4a9a86d 100644 --- a/kernel/modsign_certificate.S +++ b/kernel/modsign_certificate.S @@ -1,15 +1,8 @@ -/* SYMBOL_PREFIX defined on commandline from CONFIG_SYMBOL_PREFIX */ -#ifndef SYMBOL_PREFIX -#define ASM_SYMBOL(sym) sym -#else -#define PASTE2(x,y) x##y -#define PASTE(x,y) PASTE2(x,y) -#define ASM_SYMBOL(sym) PASTE(SYMBOL_PREFIX, sym) -#endif +#include #define GLOBAL(name) \ - .globl ASM_SYMBOL(name); \ - ASM_SYMBOL(name): + .globl VMLINUX_SYMBOL(name); \ + VMLINUX_SYMBOL(name): .section ".init.data","aw" diff --git a/kernel/module.c b/kernel/module.c index 0925c9a..cfd4a3f 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1209,7 +1209,7 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs, /* Since this should be found in kernel (which can't be removed), * no locking is necessary. */ - if (!find_symbol(MODULE_SYMBOL_PREFIX "module_layout", NULL, + if (!find_symbol(VMLINUX_SYMBOL_STR(module_layout), NULL, &crc, true, false)) BUG(); return check_version(sechdrs, versindex, "module_layout", mod, crc, diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 07125e6..a373a1f 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -119,13 +119,6 @@ _c_flags += $(if $(patsubst n%,, \ $(CFLAGS_GCOV)) endif -ifdef CONFIG_SYMBOL_PREFIX -_sym_flags = -DSYMBOL_PREFIX=$(patsubst "%",%,$(CONFIG_SYMBOL_PREFIX)) -_cpp_flags += $(_sym_flags) -_a_flags += $(_sym_flags) -endif - - # If building the kernel in a separate objtree expand all occurrences # of -Idir to -I$(srctree)/dir except for absolute paths (starting with '/'). diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 3d569d6..0149949 100644 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -74,9 +74,8 @@ kallsyms() info KSYM ${2} local kallsymopt; - if [ -n "${CONFIG_SYMBOL_PREFIX}" ]; then - kallsymopt="${kallsymopt} \ - --symbol-prefix=${CONFIG_SYMBOL_PREFIX}" + if [ -n "${CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX}" ]; then + kallsymopt="${kallsymopt} --symbol-prefix=_" fi if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 78b30c1..282decf 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -18,14 +18,7 @@ #include "modpost.h" #include "../../include/generated/autoconf.h" #include "../../include/linux/license.h" - -/* Some toolchains use a `_' prefix for all user symbols. */ -#ifdef CONFIG_SYMBOL_PREFIX -#define MODULE_SYMBOL_PREFIX CONFIG_SYMBOL_PREFIX -#else -#define MODULE_SYMBOL_PREFIX "" -#endif - +#include "../../include/linux/export.h" /* Are we using CONFIG_MODVERSIONS? */ int modversions = 0; @@ -562,7 +555,7 @@ static void parse_elf_finish(struct elf_info *info) static int ignore_undef_symbol(struct elf_info *info, const char *symname) { /* ignore __this_module, it will be resolved shortly */ - if (strcmp(symname, MODULE_SYMBOL_PREFIX "__this_module") == 0) + if (strcmp(symname, VMLINUX_SYMBOL_STR(__this_module)) == 0) return 1; /* ignore global offset table */ if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0) @@ -583,8 +576,8 @@ static int ignore_undef_symbol(struct elf_info *info, const char *symname) return 0; } -#define CRC_PFX MODULE_SYMBOL_PREFIX "__crc_" -#define KSYMTAB_PFX MODULE_SYMBOL_PREFIX "__ksymtab_" +#define CRC_PFX VMLINUX_SYMBOL_STR(__crc_) +#define KSYMTAB_PFX VMLINUX_SYMBOL_STR(__ksymtab_) static void handle_modversions(struct module *mod, struct elf_info *info, Elf_Sym *sym, const char *symname) @@ -637,14 +630,15 @@ static void handle_modversions(struct module *mod, struct elf_info *info, } #endif - if (memcmp(symname, MODULE_SYMBOL_PREFIX, - strlen(MODULE_SYMBOL_PREFIX)) == 0) { - mod->unres = - alloc_symbol(symname + - strlen(MODULE_SYMBOL_PREFIX), - ELF_ST_BIND(sym->st_info) == STB_WEAK, - mod->unres); - } +#ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX + if (symname[0] != '_') + break; + else + symname++; +#endif + mod->unres = alloc_symbol(symname, + ELF_ST_BIND(sym->st_info) == STB_WEAK, + mod->unres); break; default: /* All exported symbols */ @@ -652,9 +646,9 @@ static void handle_modversions(struct module *mod, struct elf_info *info, sym_add_exported(symname + strlen(KSYMTAB_PFX), mod, export); } - if (strcmp(symname, MODULE_SYMBOL_PREFIX "init_module") == 0) + if (strcmp(symname, VMLINUX_SYMBOL_STR(init_module)) == 0) mod->has_init = 1; - if (strcmp(symname, MODULE_SYMBOL_PREFIX "cleanup_module") == 0) + if (strcmp(symname, VMLINUX_SYMBOL_STR(cleanup_module)) == 0) mod->has_cleanup = 1; break; }