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Date: Thu, 8 Mar 2007 20:22:08 +0100
From: Sam Ravnborg <sam@...nborg.org>
To: LKML <linux-kernel@...r.kernel.org>, Andrew Morton <akpm@...l.org>
Subject: kbuild fixes for section mismatch warnings
The following series of patches gets rid of some false positives
for the section mismatch warnings.
It also enables proper check of section mismatch warnings
when a module is built-in.
So expect a few new warnings to pop up..
The most controversial ones are the patch that ignores
the warning when a function marked __init is exported. Greg KH
says it is OK. And the one allowing the logo references.
Comments are welcome!
kbuild: silence section mismatch warnings for exported functions
kbuild: whitelist logo references from .text to .init.data
kbuild: fix segmentation fault in modpost
kbuild: fix warnings from .pci_fixup section
kbuild: whitelist section mismatch in init/main.c
kbuild: fix section mismatch check for vmlinux
During the last release a great number of section mismatch fixes
has been included and the plan is to make a section mismatch
an error on line with any normal linking errors when all the
non-drivers warnings are fixed.
The diffstat:
b/Makefile | 1
b/init/main.c | 6 +-
b/scripts/Makefile.modpost | 8 +--
b/scripts/mod/modpost.c | 34 +++++++++------
scripts/mod/modpost.c | 98 ++++++++++++++++++++++++++++++++-------------
5 files changed, 100 insertions(+), 47 deletions(-)
The changes to init/main.c is a simple function rename.
The full list of changes are included below.
The changes are present in kbuild.git at:
git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild.git
I do not plan to push these until next merge window since this
is not critical changes.
PS. I have a backlog of three months of kbuild mails that I
need to walk through. Andrew have applied quite a lot in main
absence period but I have a few remaining patches.
They will be pushed when I get to them.
Sam
>From 5a1ed6a563f5a198d3d7164abf7a5708af20e7ce Mon Sep 17 00:00:00 2001
From: Sam Ravnborg <sam@...nborg.org>
Date: Mon, 26 Feb 2007 15:33:52 +0100
Subject: kbuild: fix section mismatch check for vmlinux
vmlinux does not contain relocation entries which is
used by the section mismatch checks.
Reported by: Atsushi Nemoto <anemo@....ocn.ne.jp>
Use the individual objects as inputs to overcome
this limitation.
In modpost check the .o files and skip non-ELF files.
Signed-off-by: Sam Ravnborg <sam@...nborg.org>
---
Makefile | 1 +
scripts/Makefile.modpost | 8 ++++----
scripts/mod/modpost.c | 33 +++++++++++++++++++++------------
3 files changed, 26 insertions(+), 16 deletions(-)
diff --git a/Makefile b/Makefile
index 30b66e2..fa32fde 100644
--- a/Makefile
+++ b/Makefile
@@ -603,6 +603,7 @@ vmlinux-init := $(head-y) $(init-y)
vmlinux-main := $(core-y) $(libs-y) $(drivers-y) $(net-y)
vmlinux-all := $(vmlinux-init) $(vmlinux-main)
vmlinux-lds := arch/$(ARCH)/kernel/vmlinux.lds
+export KBUILD_VMLINUX_OBJS := $(vmlinux-all)
# Rule to link vmlinux - also used during CONFIG_KALLSYMS
# May be overridden by arch/$(ARCH)/Makefile
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 65e0a79..d5bbbcc 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -63,16 +63,16 @@ quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules
$(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile) \
$(if $(KBUILD_EXTMOD),-I $(modulesymfile)) \
$(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \
- $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w) \
- $(wildcard vmlinux) $(filter-out FORCE,$^)
+ $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w)
PHONY += __modpost
__modpost: $(modules:.ko=.o) FORCE
- $(call cmd,modpost)
+ $(call cmd,modpost) $(wildcard vmlinux) $(filter-out FORCE,$^)
quiet_cmd_kernel-mod = MODPOST $@
- cmd_kernel-mod = $(cmd_modpost)
+ cmd_kernel-mod = $(cmd_modpost) $(KBUILD_VMLINUX_OBJS)
+PHONY += vmlinux
vmlinux: FORCE
$(call cmd,kernel-mod)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index c4b5398..ecf5dff 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -333,10 +333,10 @@ void release_file(void *file, unsigned long size)
munmap(file, size);
}
-static void parse_elf(struct elf_info *info, const char *filename)
+static int parse_elf(struct elf_info *info, const char *filename)
{
unsigned int i;
- Elf_Ehdr *hdr = info->hdr;
+ Elf_Ehdr *hdr;
Elf_Shdr *sechdrs;
Elf_Sym *sym;
@@ -346,9 +346,18 @@ static void parse_elf(struct elf_info *info, const char *filename)
exit(1);
}
info->hdr = hdr;
- if (info->size < sizeof(*hdr))
- goto truncated;
-
+ if (info->size < sizeof(*hdr)) {
+ /* file too small, assume this is an empty .o file */
+ return 0;
+ }
+ /* Is this a valid ELF file? */
+ if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
+ (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
+ (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
+ (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
+ /* Not an ELF file - silently ignore it */
+ return 0;
+ }
/* Fix endianness in ELF header */
hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
@@ -371,8 +380,10 @@ static void parse_elf(struct elf_info *info, const char *filename)
= (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
const char *secname;
- if (sechdrs[i].sh_offset > info->size)
- goto truncated;
+ if (sechdrs[i].sh_offset > info->size) {
+ fatal("%s is truncated. sechdrs[i].sh_offset=%u > sizeof(*hrd)=%ul\n", filename, (unsigned int)sechdrs[i].sh_offset, sizeof(*hdr));
+ return 0;
+ }
secname = secstrings + sechdrs[i].sh_name;
if (strcmp(secname, ".modinfo") == 0) {
info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
@@ -407,10 +418,7 @@ static void parse_elf(struct elf_info *info, const char *filename)
sym->st_value = TO_NATIVE(sym->st_value);
sym->st_size = TO_NATIVE(sym->st_size);
}
- return;
-
- truncated:
- fatal("%s is truncated.\n", filename);
+ return 1;
}
static void parse_elf_finish(struct elf_info *info)
@@ -1088,7 +1096,8 @@ static void read_symbols(char *modname)
struct elf_info info = { };
Elf_Sym *sym;
- parse_elf(&info, modname);
+ if (!parse_elf(&info, modname))
+ return;
mod = new_module(modname);
--
1.4.4.2
>From e7ac21ad1e50a1ab3a73a3869649cea952acc101 Mon Sep 17 00:00:00 2001
From: Sam Ravnborg <sam@...nborg.org>
Date: Mon, 26 Feb 2007 16:45:41 +0100
Subject: kbuild: whitelist section mismatch in init/main.c
In init/main.c we have a reference from rest_init() to .init.text
which is intentional.
Rename the function 'init' to 'kernel_init' to make it a
kernel wide unique symbol and whitelist the reference.
Signed-off-by: Sam Ravnborg <sam@...nborg.org>
---
init/main.c | 6 +++---
scripts/mod/modpost.c | 15 ++++++++++++++-
2 files changed, 17 insertions(+), 4 deletions(-)
diff --git a/init/main.c b/init/main.c
index a92989e..7a92b4c 100644
--- a/init/main.c
+++ b/init/main.c
@@ -82,7 +82,7 @@
#warning gcc-4.1.0 is known to miscompile the kernel. A different compiler version is recommended.
#endif
-static int init(void *);
+static int kernel_init(void *);
extern void init_IRQ(void);
extern void fork_init(unsigned long);
@@ -435,7 +435,7 @@ static void __init setup_command_line(char *command_line)
static void noinline rest_init(void)
__releases(kernel_lock)
{
- kernel_thread(init, NULL, CLONE_FS | CLONE_SIGHAND);
+ kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
numa_default_policy();
unlock_kernel();
@@ -772,7 +772,7 @@ static int noinline init_post(void)
panic("No init found. Try passing init= option to kernel.");
}
-static int __init init(void * unused)
+static int __init kernel_init(void * unused)
{
lock_kernel();
/*
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index ecf5dff..1c076bf 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -589,7 +589,7 @@ static int strrcmp(const char *s, const char *sub)
* the pattern is identified by:
* tosec = .init.text | .exit.text | .init.data
* fromsec = .data
- * atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one
+ * atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one, *_console
*
* Pattern 3:
* Some symbols belong to init section but still it is ok to reference
@@ -599,6 +599,14 @@ static int strrcmp(const char *s, const char *sub)
* For ex. symbols marking the init section boundaries.
* This pattern is identified by
* refsymname = __init_begin, _sinittext, _einittext
+ * Pattern 4:
+ * During the early init phase we have references from .init.text to
+ * .text we have an intended section mismatch - do not warn about it.
+ * See kernel_init() in init/main.c
+ * tosec = .init.text
+ * fromsec = .text
+ * atsym = kernel_init
+ * Some symbols belong to init section but still it is ok to reference
**/
static int secref_whitelist(const char *modname, const char *tosec,
const char *fromsec, const char *atsym,
@@ -668,6 +676,11 @@ static int secref_whitelist(const char *modname, const char *tosec,
if (strcmp(refsymname, *s) == 0)
return 1;
}
+ /* Check for pattern 4 */
+ if ((strcmp(tosec, ".init.text") == 0) &&
+ (strcmp(fromsec, ".text") == 0) &&
+ (strcmp(refsymname, "kernel_init") == 0))
+ return 1;
return 0;
}
--
1.4.4.2
>From 297eb8e1e0df56efd25ab32647d6f43715a06f6c Mon Sep 17 00:00:00 2001
From: Sam Ravnborg <sam@...nborg.org>
Date: Mon, 26 Feb 2007 17:49:06 +0100
Subject: kbuild: fix warnings from .pci_fixup section
Now where we do not pass vmlinux to modpost we started
to see section mismatch warnings from .pci_fixup.
Refactored code a little to include these in the
whitelist again.
Signed-off-by: Sam Ravnborg <sam@...nborg.org>
---
scripts/mod/modpost.c | 44 +++++++++++++++++++++++++-------------------
1 files changed, 25 insertions(+), 19 deletions(-)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 1c076bf..2b3b066 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -592,6 +592,14 @@ static int strrcmp(const char *s, const char *sub)
* atsym = *driver, *_template, *_sht, *_ops, *_probe, *probe_one, *_console
*
* Pattern 3:
+ * Whitelist all references from .pci_fixup* section to .init.text
+ * This is part of the PCI init when built-in
+ *
+ * Pattern 4:
+ * Whitelist all refereces from .text.head to .init.data
+ * Whitelist all refereces from .text.head to .init.text
+ *
+ * Pattern 5:
* Some symbols belong to init section but still it is ok to reference
* these from non-init sections as these symbols don't have any memory
* allocated for them and symbol address and value are same. So even
@@ -599,7 +607,8 @@ static int strrcmp(const char *s, const char *sub)
* For ex. symbols marking the init section boundaries.
* This pattern is identified by
* refsymname = __init_begin, _sinittext, _einittext
- * Pattern 4:
+ *
+ * Pattern 6:
* During the early init phase we have references from .init.text to
* .text we have an intended section mismatch - do not warn about it.
* See kernel_init() in init/main.c
@@ -657,26 +666,23 @@ static int secref_whitelist(const char *modname, const char *tosec,
if (f1 && f2)
return 1;
- /* Whitelist all references from .pci_fixup section if vmlinux
- * Whitelist all refereces from .text.head to .init.data if vmlinux
- * Whitelist all refereces from .text.head to .init.text if vmlinux
- */
- if (is_vmlinux(modname)) {
- if ((strcmp(fromsec, ".pci_fixup") == 0) &&
- (strcmp(tosec, ".init.text") == 0))
- return 1;
-
- if ((strcmp(fromsec, ".text.head") == 0) &&
- ((strcmp(tosec, ".init.data") == 0) ||
- (strcmp(tosec, ".init.text") == 0)))
- return 1;
+ /* Check for pattern 3 */
+ if ((strncmp(fromsec, ".pci_fixup", strlen(".pci_fixup")) == 0) &&
+ (strcmp(tosec, ".init.text") == 0))
+ return 1;
- /* Check for pattern 3 */
- for (s = pat3refsym; *s; s++)
- if (strcmp(refsymname, *s) == 0)
- return 1;
- }
/* Check for pattern 4 */
+ if ((strcmp(fromsec, ".text.head") == 0) &&
+ ((strcmp(tosec, ".init.data") == 0) ||
+ (strcmp(tosec, ".init.text") == 0)))
+ return 1;
+
+ /* Check for pattern 5 */
+ for (s = pat3refsym; *s; s++)
+ if (strcmp(refsymname, *s) == 0)
+ return 1;
+
+ /* Check for pattern 6 */
if ((strcmp(tosec, ".init.text") == 0) &&
(strcmp(fromsec, ".text") == 0) &&
(strcmp(refsymname, "kernel_init") == 0))
--
1.4.4.2
>From 3201d6a1c1336ee37b701c6117a4694a4bbbc88c Mon Sep 17 00:00:00 2001
From: Sam Ravnborg <sam@...nborg.org>
Date: Mon, 26 Feb 2007 19:46:52 +0100
Subject: kbuild: fix segmentation fault in modpost
If modpost was called manually with filenames without '/'
then modpost would segfault.
Signed-off-by: Sam Ravnborg <sam@...nborg.org>
---
scripts/mod/modpost.c | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 2b3b066..15d69c4 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1344,6 +1344,7 @@ static void add_depends(struct buffer *b, struct module *mod,
buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
buf_printf(b, "\"depends=");
for (s = mod->unres; s; s = s->next) {
+ const char *p;
if (!s->module)
continue;
@@ -1351,8 +1352,11 @@ static void add_depends(struct buffer *b, struct module *mod,
continue;
s->module->seen = 1;
- buf_printf(b, "%s%s", first ? "" : ",",
- strrchr(s->module->name, '/') + 1);
+ if ((p = strrchr(s->module->name, '/')) != NULL)
+ p++;
+ else
+ p = s->module->name;
+ buf_printf(b, "%s%s", first ? "" : ",", p);
first = 0;
}
buf_printf(b, "\";\n");
--
1.4.4.2
>From b8c477af29397acf3b9f1458d4df79d267a1d3d7 Mon Sep 17 00:00:00 2001
From: Sam Ravnborg <sam@...nborg.org>
Date: Tue, 27 Feb 2007 09:14:58 +0100
Subject: kbuild: whitelist logo references from .text to .init.data
drivers/video/logo has references from .text to .init.data
but function is only used during early init.
So reference is OK and we do not want to warn about them =>
whitelist the reference.
Signed-off-by: Sam Ravnborg <sam@...nborg.org>
---
scripts/mod/modpost.c | 15 +++++++++++++++
1 files changed, 15 insertions(+), 0 deletions(-)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 15d69c4..9042039 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -616,6 +616,15 @@ static int strrcmp(const char *s, const char *sub)
* fromsec = .text
* atsym = kernel_init
* Some symbols belong to init section but still it is ok to reference
+ *
+ * Pattern 7:
+ * Logos used in drivers/video/logo reside in __initdata but the
+ * funtion that references them are EXPORT_SYMBOL() so cannot be
+ * marker __init. So we whitelist them here.
+ * The pattern is:
+ * tosec = .init.data
+ * fromsec = .text*
+ * refsymname = logo_
**/
static int secref_whitelist(const char *modname, const char *tosec,
const char *fromsec, const char *atsym,
@@ -687,6 +696,12 @@ static int secref_whitelist(const char *modname, const char *tosec,
(strcmp(fromsec, ".text") == 0) &&
(strcmp(refsymname, "kernel_init") == 0))
return 1;
+
+ /* Check for pattern 7 */
+ if ((strcmp(tosec, ".init.data") == 0) &&
+ (strncmp(fromsec, ".text", strlen(".text")) == 0) &&
+ (strncmp(refsymname, "logo_", strlen("logo_")) == 0))
+ return 1;
return 0;
}
--
1.4.4.2
>From 79eb05acd2864302b359bd3e690f0a72643bba0d Mon Sep 17 00:00:00 2001
From: Sam Ravnborg <sam@...nborg.org>
Date: Sat, 3 Mar 2007 19:34:23 +0100
Subject: kbuild: silence section mismatch warnings for exported functions
There are legitime cases of exported functions which
is marked __init. Some examples are in drivers/pci/
where the pci subsystem export symbols to be used by other
__init functions.
So ignore references from ksymtab* to .init.text
Signed-off-by: Sam Ravnborg <sam@...nborg.org>
---
scripts/mod/modpost.c | 11 +++++++++++
1 files changed, 11 insertions(+), 0 deletions(-)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 9042039..9e80dc5 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -625,6 +625,13 @@ static int strrcmp(const char *s, const char *sub)
* tosec = .init.data
* fromsec = .text*
* refsymname = logo_
+ *
+ * Pattern 8:
+ * Symbols exported may be marked __init because we need to
+ * export functions that are only used by init function.
+ * The pattern is:
+ * tosec = .init.text
+ * fromsec = __ksymtab*
**/
static int secref_whitelist(const char *modname, const char *tosec,
const char *fromsec, const char *atsym,
@@ -702,6 +709,10 @@ static int secref_whitelist(const char *modname, const char *tosec,
(strncmp(fromsec, ".text", strlen(".text")) == 0) &&
(strncmp(refsymname, "logo_", strlen("logo_")) == 0))
return 1;
+ /* Check for pattern 8 */
+ if ((strcmp(tosec, ".init.text") == 0) &&
+ (strncmp(fromsec, "__ksymtab", strlen("__ksymtab")) == 0))
+ return 1;
return 0;
}
--
1.4.4.2
-
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