From: Michal Marek <mmarek@suse.cz>
To: Takashi Iwai <tiwai@suse.de>
Cc: Rusty Russell <rusty@ozlabs.org>,
David Howells <dhowells@redhat.com>,
linux-kernel@vger.kernel.org,
James Hogan <james.hogan@imgtec.com>
Subject: Re: [PATCH 2/3] MODSIGN: Avoid using .incbin in C source
Date: Wed, 5 Dec 2012 10:50:57 +0100 [thread overview]
Message-ID: <20121205095057.GA26543@sepie.suse.cz> (raw)
In-Reply-To: <s5hobi9aqxs.wl%tiwai@suse.de>
On Wed, Dec 05, 2012 at 08:39:11AM +0100, Takashi Iwai wrote:
> At Wed, 05 Dec 2012 10:28:48 +1030,
> Rusty Russell wrote:
> >
> > David Howells <dhowells@redhat.com> writes:
> >
> > > Michal Marek <mmarek@suse.cz> wrote:
> > >
> > >> Using the asm .incbin statement in C sources breaks any gcc wrapper which
> > >> assumes that preprocessed C source is self-contained. Use a separate .S
> > >> file to include the siging key and certificate.
> > >
> > > I was trying to avoid that as .S files generally don't crop up in generic
> > > code and the format of the assembly varies with the arch. However, you don't
> > > seem to have anything that should cause a problem - so:
> > >
> > > Acked-by: David Howells <dhowells@redhat.com>
> >
> > GLOBAL() is defined in x86 only, AFAICT.
Sorry for that, the Tested-by actually meant Tested-on-x86_64-by :/
> How about the revised patch below?
[...]
> diff --git a/kernel/modsign_certificate.S b/kernel/modsign_certificate.S
> new file mode 100644
> index 0000000..695d4e3
> --- /dev/null
> +++ b/kernel/modsign_certificate.S
> @@ -0,0 +1,18 @@
> +#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
It looks good, but looking at your patch, I just noticed that we have two
versions of the SYMBOL_PREFIX macro in the kernel now:
scripts/Makefile.lib has had since some time
ifdef CONFIG_SYMBOL_PREFIX
_sym_flags = -DSYMBOL_PREFIX=$(patsubst "%",%,$(CONFIG_SYMBOL_PREFIX))
_cpp_flags += $(_sym_flags)
_a_flags += $(_sym_flags)
endif
while include/linux/kernel.h now has
/* This helps us to avoid #ifdef CONFIG_SYMBOL_PREFIX */
#ifdef CONFIG_SYMBOL_PREFIX
#define SYMBOL_PREFIX CONFIG_SYMBOL_PREFIX
#else
#define SYMBOL_PREFIX ""
#endif
So depending on whether you include <linux/kernel.h> or not,
SYMBOL_PREFIX expands to either a string or a token. James, Rusty, how
about the patch below? If Takashi's patch is applied first, then
obviously the modsign_pubkey.c part should be dropped and the ASM_SYMBOL
definition in modsign_certificate.S can be simplified instead.
Michal
>From df545c46fb89c085387f4d98c7a4fb06a7f678a9 Mon Sep 17 00:00:00 2001
From: Michal Marek <mmarek@suse.cz>
Date: Wed, 5 Dec 2012 10:03:15 +0100
Subject: [PATCH] linux/kernel.h: Avoid conflicting SYMBOL_PREFIX definition
scripts/Makefile.lib already defines SYMBOL_PREFIX to the token _ if
CONFIG_SYMBOL_PREFIX is defined. Drop the string definition in
linux/kernel.h and change scripts/Makefile.lib to define SYMBOL_PREFIX
on all architectures.
Signed-off-by: Michal Marek <mmarek@suse.cz>
---
include/asm-generic/vmlinux.lds.h | 4 ----
include/linux/kernel.h | 7 -------
kernel/modsign_pubkey.c | 5 +++--
scripts/Makefile.lib | 5 ++---
4 files changed, 5 insertions(+), 16 deletions(-)
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index d1ea7ce..7756a0c 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -52,13 +52,9 @@
#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
/* Align . to a 8 byte boundary equals to maximum function alignment. */
#define ALIGN_FUNCTION() . = ALIGN(8)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index d140e8f..9a6bccb 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -717,13 +717,6 @@ 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/kernel/modsign_pubkey.c b/kernel/modsign_pubkey.c
index 767e559..93ce84b 100644
--- a/kernel/modsign_pubkey.c
+++ b/kernel/modsign_pubkey.c
@@ -9,6 +9,7 @@
* 2 of the Licence, or (at your option) any later version.
*/
+#include <linux/stringify.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/cred.h>
@@ -21,10 +22,10 @@ struct key *modsign_keyring;
extern __initdata const u8 modsign_certificate_list[];
extern __initdata const u8 modsign_certificate_list_end[];
asm(".section .init.data,\"aw\"\n"
- SYMBOL_PREFIX "modsign_certificate_list:\n"
+ __stringify(SYMBOL_PREFIX) "modsign_certificate_list:\n"
".incbin \"signing_key.x509\"\n"
".incbin \"extra_certificates\"\n"
- SYMBOL_PREFIX "modsign_certificate_list_end:"
+ __stringify(SYMBOL_PREFIX) "modsign_certificate_list_end:"
);
/*
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index bdf42fd..1138e77 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -119,11 +119,10 @@ _c_flags += $(if $(patsubst n%,, \
$(CFLAGS_GCOV))
endif
-ifdef CONFIG_SYMBOL_PREFIX
_sym_flags = -DSYMBOL_PREFIX=$(patsubst "%",%,$(CONFIG_SYMBOL_PREFIX))
-_cpp_flags += $(_sym_flags)
+_c_flags += $(_sym_flags)
_a_flags += $(_sym_flags)
-endif
+_cpp_flags += $(_sym_flags)
# If building the kernel in a separate objtree expand all occurrences
--
1.7.10.4
next prev parent reply other threads:[~2012-12-05 9:51 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-04 10:18 [PATCH 1/3] MODSIGN: Fix comparison erros in scripts/sign-file Michal Marek
2012-12-04 10:18 ` [PATCH 2/3] MODSIGN: Avoid using .incbin in C source Michal Marek
2012-12-04 10:18 ` [PATCH 3/3] MODSIGN: Drop ccache hack Michal Marek
2012-12-04 18:15 ` [PATCH 1/3] MODSIGN: Fix comparison erros in scripts/sign-file David Howells
2012-12-04 18:17 ` [PATCH 2/3] MODSIGN: Avoid using .incbin in C source David Howells
2012-12-04 23:58 ` Rusty Russell
2012-12-05 7:39 ` Takashi Iwai
2012-12-05 9:50 ` Michal Marek [this message]
2012-12-05 10:06 ` Takashi Iwai
2012-12-05 10:30 ` James Hogan
2012-12-05 11:05 ` Michal Marek
2012-12-05 11:16 ` James Hogan
2012-12-07 4:40 ` Rusty Russell
2012-12-10 10:12 ` James Hogan
2012-12-05 10:30 ` David Howells
2012-12-05 10:54 ` Michal Marek
2012-12-05 12:35 ` David Howells
2012-12-05 7:46 ` Takashi Iwai
2012-12-04 18:29 ` [PATCH 3/3] MODSIGN: Drop ccache hack David Howells
2012-12-04 23:44 ` [PATCH 1/3] MODSIGN: Fix comparison erros in scripts/sign-file Rusty Russell
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