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Message-ID: <5141AB3A.2060705@imgtec.com>
Date: Thu, 14 Mar 2013 10:49:30 +0000
From: James Hogan <james.hogan@...tec.com>
To: Rusty Russell <rusty@...tcorp.com.au>
CC: Sam Ravnborg <sam@...nborg.org>,
Stephen Rothwell <sfr@...b.auug.org.au>,
Al Viro <viro@...iv.linux.org.uk>,
Michal Marek <mmarek@...e.cz>,
"Andrew Morton" <akpm@...ux-foundation.org>,
Guenter Roeck <linux@...ck-us.net>,
Jean Delvare <khali@...ux-fr.org>,
<linux-kbuild@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
Mike Frysinger <vapier@...too.org>,
<uclinux-dist-devel@...ckfin.uclinux.org>,
<linux-next@...r.kernel.org>,
Paul Gortmaker <paul.gortmaker@...driver.com>,
<linux-mtd@...ts.infradead.org>
Subject: Re: [RFC -next] linux/linkage.h: fix symbol prefix handling
On 14/03/13 04:00, Rusty Russell wrote:
> From: Rusty Russell <rusty@...tcorp.com.au>
> 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 <rusty@...tcorp.com.au>
Reviewed-by: James Hogan <james.hogan@...tec.com>
Tested-by: James Hogan <james.hogan@...tec.com> (metag)
The only other special case of symbol prefixing I'm aware of is in
scripts/genksyms/genksyms.c. It makes the decision at runtime based
on the --arch=$ARCH argument, and is the only use of the arch argument:
> if ((strcmp(arch, "h8300") == 0) || (strcmp(arch, "blackfin") == 0) ||
> (strcmp(arch, "metag") == 0))
> mod_prefix = "_";
Does the patch below look reasonable in addition to your patch?
(Note: I'm not sure if genksyms is only used internally or whether
it's API should be kept stable?).
Thanks
James
Subject: [PATCH] genksyms: pass symbol-prefix instead of arch
Pass symbol-prefix to genksyms instead of arch, so that the decision
what symbol prefix to use is kept in one place.
Basically genksyms used to take a -a $ARCH argument and it used that to
determine whether to add an underscore symbol prefix. It's now changed
to take a -s $SYMBOL_PREFIX argument so that the caller decides whether
a symbol prefix is required. The build system then uses
CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX to determine whether to pass the
argument.
Signed-off-by: James Hogan <james.hogan@...tec.com>
---
scripts/Makefile.build | 3 ++-
scripts/genksyms/genksyms.c | 18 +++++++-----------
2 files changed, 9 insertions(+), 12 deletions(-)
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 0e801c3..d5d859c 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -211,7 +211,8 @@ $(obj)/%.i: $(src)/%.c FORCE
cmd_gensymtypes = \
$(CPP) -D__GENKSYMS__ $(c_flags) $< | \
- $(GENKSYMS) $(if $(1), -T $(2)) -a $(ARCH) \
+ $(GENKSYMS) $(if $(1), -T $(2)) \
+ $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \
$(if $(KBUILD_PRESERVE),-p) \
-r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
diff --git a/scripts/genksyms/genksyms.c b/scripts/genksyms/genksyms.c
index d25e4a1..88632df 100644
--- a/scripts/genksyms/genksyms.c
+++ b/scripts/genksyms/genksyms.c
@@ -45,7 +45,6 @@ int in_source_file;
static int flag_debug, flag_dump_defs, flag_reference, flag_dump_types,
flag_preserve, flag_warnings;
-static const char *arch = "";
static const char *mod_prefix = "";
static int errors;
@@ -731,7 +730,7 @@ static void genksyms_usage(void)
{
fputs("Usage:\n" "genksyms [-adDTwqhV] > /path/to/.tmp_obj.ver\n" "\n"
#ifdef __GNU_LIBRARY__
- " -a, --arch Select architecture\n"
+ " -s, --symbol-prefix Select symbol prefix\n"
" -d, --debug Increment the debug level (repeatable)\n"
" -D, --dump Dump expanded symbol defs (for debugging only)\n"
" -r, --reference file Read reference symbols from a file\n"
@@ -742,7 +741,7 @@ static void genksyms_usage(void)
" -h, --help Print this message\n"
" -V, --version Print the release version\n"
#else /* __GNU_LIBRARY__ */
- " -a Select architecture\n"
+ " -s Select symbol prefix\n"
" -d Increment the debug level (repeatable)\n"
" -D Dump expanded symbol defs (for debugging only)\n"
" -r file Read reference symbols from a file\n"
@@ -763,7 +762,7 @@ int main(int argc, char **argv)
#ifdef __GNU_LIBRARY__
struct option long_opts[] = {
- {"arch", 1, 0, 'a'},
+ {"symbol-prefix", 1, 0, 's'},
{"debug", 0, 0, 'd'},
{"warnings", 0, 0, 'w'},
{"quiet", 0, 0, 'q'},
@@ -776,14 +775,14 @@ int main(int argc, char **argv)
{0, 0, 0, 0}
};
- while ((o = getopt_long(argc, argv, "a:dwqVDr:T:ph",
+ while ((o = getopt_long(argc, argv, "s:dwqVDr:T:ph",
&long_opts[0], NULL)) != EOF)
#else /* __GNU_LIBRARY__ */
- while ((o = getopt(argc, argv, "a:dwqVDr:T:ph")) != EOF)
+ while ((o = getopt(argc, argv, "s:dwqVDr:T:ph")) != EOF)
#endif /* __GNU_LIBRARY__ */
switch (o) {
- case 'a':
- arch = optarg;
+ case 's':
+ mod_prefix = optarg;
break;
case 'd':
flag_debug++;
@@ -826,9 +825,6 @@ int main(int argc, char **argv)
genksyms_usage();
return 1;
}
- if ((strcmp(arch, "h8300") == 0) || (strcmp(arch, "blackfin") == 0) ||
- (strcmp(arch, "metag") == 0))
- mod_prefix = "_";
{
extern int yydebug;
extern int yy_flex_debug;
--
1.8.1.2
--
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