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)

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/Kconfig b/arch/Kconfig
index 1455579791ec..7b433a4bcc28 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
 #