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CONFIG_SYMBOL_PREFIX: cleanup.

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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)
This commit is contained in:
Rusty Russell 2013-03-15 15:04:17 +10:30
parent 4febd95a8a
commit b92021b09d
16 changed files with 57 additions and 88 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Makefile
View File

@ -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

6
arch/Kconfig
View File

@ -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
#

5
arch/blackfin/Kconfig
View File

@ -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

5
arch/h8300/Kconfig
View File

@ -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

5
arch/metag/Kconfig
View File

@ -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

8
drivers/mtd/chips/gen_probe.c
View File

@ -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);
}

12
include/asm-generic/unistd.h
View File

@ -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

8
include/asm-generic/vmlinux.lds.h
View File

@ -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)

20
include/linux/export.h
View File

@ -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 */

7
include/linux/kernel.h
View File

@ -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

4
include/linux/module.h
View File

@ -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

13
kernel/modsign_certificate.S
View File

@ -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"

2
kernel/module.c
View File

@ -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,

7
scripts/Makefile.lib
View File

@ -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 '/').

5
scripts/link-vmlinux.sh
View File

@ -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

36
scripts/mod/modpost.c
View File

@ -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;
}