module: make MODULE_SYMBOL_PREFIX into a CONFIG option

The next commit will require the use of MODULE_SYMBOL_PREFIX in
.tmp_exports-asm.S.  Currently it is mixed in with C structure
definitions in "asm/module.h".  Move the definition of this arch option
into Kconfig, so it can be easily accessed by any code.

This also lets modpost.c use the same definition.  Previously modpost
relied on a hardcoded list of architectures in mk_elfconfig.c.

A build test for blackfin, one of the two MODULE_SYMBOL_PREFIX archs,
showed the generated code was unchanged.  vmlinux was identical save
for build ids, and an apparently randomized suffix on a single "__key"
symbol in the kallsyms data).

Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Acked-by: Mike Frysinger <vapier@gentoo.org> (blackfin)
CC: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

2 files changed, 10 insertions, 4 deletions

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index b6e818f4b247..67e652068e0e 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -52,8 +52,12 @@
 #define LOAD_OFFSET 0
 #endif
 
-#ifndef VMLINUX_SYMBOL
-#define VMLINUX_SYMBOL(_sym_) _sym_
+#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
 
 /* Align . to a 8 byte boundary equals to maximum function alignment. */
diff --git a/include/linux/module.h b/include/linux/module.h
index 482efc865acf..6cb1a3cab5d3 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -25,8 +25,10 @@
 /* Not Yet Implemented */
 #define MODULE_SUPPORTED_DEVICE(name)
 
-/* some toolchains uses a `_' prefix for all user symbols */
-#ifndef MODULE_SYMBOL_PREFIX
+/* 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