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 <rusty@rustcorp.com.au>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Tested-by: James Hogan <james.hogan@imgtec.com> (metag)

diff --git a/Makefile b/Makefile
index a05ea42c5f185d66692be18747e9e90b9633cd20..0b09ba5e492ad85d259092880048a7e8e976ec71 100644 (file)
--- 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 1455579791ec02514a5d616a4b6749cbec3185b0..7b433a4bcc285c7127618a8467d738e041709975 100644 (file)
--- 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 c3f2e0bc644aed0b64e86b7a801424d5cb239b9a..453ebe46b065d01d0afa272528220f9e73aede52 100644 (file)
--- 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 79250de1b12a434f7b0d945cb6b4b42559a9d101..303e4f9a79d19998452760a913828a64c5773345 100644 (file)
--- 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 afc8973d14883ee340ba9531c7c82b1585f9c9cd..2099617e3ec0de7161dd224002e623848c6c66f9 100644 (file)
--- 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 3b9a2843c5f8f6da0610b22920918854e70db49f..74dbb6bcf4883a8a0461685ea0f180de7ad3da0d 100644 (file)
--- 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 4077b5d9ff8184f6a4446273b8fcaed792206dc0..15c0598e110938cf34b90df983f746efc27ceb94 100644 (file)
--- a/include/asm-generic/unistd.h
+++ b/include/asm-generic/unistd.h
@@ -1,4 +1,5 @@
 #include <uapi/asm-generic/unistd.h>
+#include <linux/export.h>
 
 /*
  * 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 afa12c7a025c4ea72dac8a0d6eb12b9c593536b1..eb58d2d7d9718d0c220387b3c60febf30f324e71 100644 (file)
--- 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 <linux/export.h>
 
 /* 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 696c0f48afc71716f00477ac5a0412804845a66e..412cd509effe0ca3b73e5524e121921457296681 100644 (file)
--- 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 <linux/foo.h> 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 80d36874689b40da26a3107ba509a8ca10dc74da..e13e992eae8a41e19a8af549ca2cd7a81788dda1 100644 (file)
--- 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 ead1b5719a12cbe5ca58ae4e31057add2ba289d5..46f1ea01e6f62161db550b13be8a2ed85246219a 100644 (file)
--- 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 246b4c6e613505740a86b5640af6ff544cbc9a35..4a9a86d12c8b0711efa1420b8c1c80094ee95e17 100644 (file)
--- 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 <linux/export.h>
 
 #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 0925c9a719753f19085ee267edfc643205c752aa..cfd4a3f68d7d7f2758b3f73ebd741d70e820f711 100644 (file)
--- 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 07125e697d7a980efdb0f9136ee5741fe8cf0473..a373a1f660236c16232756cf5b8db42cb9f960e6 100644 (file)
--- 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 3d569d6022c296c7bc5ba4e0162279f4c9dc832c..014994936b1c2152c82f793ce646342159d78eb5 100644 (file)
--- 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 78b30c1548e9d19f5827f4ad26f0715be4b040b0..282decfa29ae33c9e73599f48b5d6ce42d0f94c9 100644 (file)
--- 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;
        }