[PATCH 9/12] kallsyms: Generate relocatable symbols

Vivek Goyal
2006-10-03T17:31:35Z

Print the addresses of non-absolute symbols relative to _text
so that ld will generate relocations. Allowing a relocatable
kernel to relocate them. We can't actually use the symbol names
because kallsyms includes static symbols that are not exported
from their object files.

Add the _text symbol definitions to the architectures which don't
define it otherwise linker will fail.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
---

arch/h8300/kernel/vmlinux.lds.S | 1 +
arch/m68knommu/kernel/vmlinux.lds.S | 1 +
arch/powerpc/kernel/vmlinux.lds.S | 1 +
arch/ppc/kernel/vmlinux.lds.S | 1 +
arch/sparc/kernel/vmlinux.lds.S | 1 +
arch/sparc64/kernel/vmlinux.lds.S | 1 +
arch/v850/kernel/vmlinux.lds.S | 1 +
scripts/kallsyms.c | 20 +++++++++++++++++---
8 files changed, 24 insertions(+), 3 deletions(-)

diff -puN scripts/kallsyms.c~kallsyms.c-Generate-relocatable-symbols scripts/kallsyms.c
--- linux-2.6.18-git17/scripts/kallsyms.c~kallsyms.c-Generate-relocatable-symbols 2006-10-02 13:17:59.000000000 -0400
+++ linux-2.6.18-git17-root/scripts/kallsyms.c 2006-10-02 13:17:59.000000000 -0400
@@ -43,7 +43,7 @@ struct sym_entry {

static struct sym_entry *table;
static unsigned int table_size, table_cnt;
-static unsigned long long _stext, _etext, _sinittext, _einittext, _sextratext, _eextratext;
+static unsigned long long _text, _stext, _etext, _sinittext, _einittext, _sextratext, _eextratext;
static int all_symbols = 0;
static char symbol_prefix_char = '\0';

@@ -91,7 +91,9 @@ static int read_symbol(FILE *in, struct
sym++;

/* Ignore most absolute/undefined (?) symbols. */
- if (strcmp(sym, "_stext") == 0)
+ if (strcmp(sym, "_text") == 0)
+ _text = s->addr;
+ else if (strcmp(sym, "_stext") == 0)
_stext = s->addr;
else if (strcmp(sym, "_etext") == 0)
_etext = s->addr;
@@ -265,9 +267,21 @@ static void write_src(void)

printf(".data\n");

+ /* Provide proper symbols relocatability by their '_text'
+ * relativeness. The symbol names cannot be used to construct
+ * normal symbol references as the list of symbols contains
+ * symbols that are declared static and are private to their
+ * .o files. This prevents .tmp_kallsyms.o or any other
+ * object from referencing them.
+ */
output_label("kallsyms_addresses");
for (i = 0; i < table_cnt; i++) {
- printf("\tPTR\t%#llx\n", table[i].addr);
+ if (toupper(table[i].sym[0]) != 'A') {
+ printf("\tPTR\t_text + %#llx\n",
+ table[i].addr - _text);
+ } else {
+ printf("\tPTR\t%#llx\n", table[i].addr);
+ }
}
printf("\n");

diff -puN arch/h8300/kernel/vmlinux.lds.S~kallsyms.c-Generate-relocatable-symbols arch/h8300/kernel/vmlinux.lds.S
--- linux-2.6.18-git17/arch/h8300/kernel/vmlinux.lds.S~kallsyms.c-Generate-relocatable-symbols 2006-10-02 13:17:59.000000000 -0400
+++ linux-2.6.18-git17-root/arch/h8300/kernel/vmlinux.lds.S 2006-10-02 13:17:59.000000000 -0400
@@ -70,6 +70,7 @@ SECTIONS
#endif
.text :
{
+ _text = .;
#if defined(CONFIG_ROMKERNEL)
*(.int_redirect)
#endif
diff -puN arch/m68knommu/kernel/vmlinux.lds.S~kallsyms.c-Generate-relocatable-symbols arch/m68knommu/kernel/vmlinux.lds.S
--- linux-2.6.18-git17/arch/m68knommu/kernel/vmlinux.lds.S~kallsyms.c-Generate-relocatable-symbols 2006-10-02 13:17:59.000000000 -0400
+++ linux-2.6.18-git17-root/arch/m68knommu/kernel/vmlinux.lds.S 2006-10-02 13:17:59.000000000 -0400
@@ -60,6 +60,7 @@ SECTIONS {
#endif

.text : {
+ _text = .;
_stext = . ;
*(.text)
SCHED_TEXT
diff -puN arch/powerpc/kernel/vmlinux.lds.S~kallsyms.c-Generate-relocatable-symbols arch/powerpc/kernel/vmlinux.lds.S
--- linux-2.6.18-git17/arch/powerpc/kernel/vmlinux.lds.S~kallsyms.c-Generate-relocatable-symbols 2006-10-02 13:17:59.000000000 -0400
+++ linux-2.6.18-git17-root/arch/powerpc/kernel/vmlinux.lds.S 2006-10-02 13:17:59.000000000 -0400
@@ -33,6 +33,7 @@ SECTIONS

/* Text and gots */
.text : {
+ _text = .;
*(.text .text.*)
SCHED_TEXT
LOCK_TEXT
diff -puN arch/ppc/kernel/vmlinux.lds.S~kallsyms.c-Generate-relocatable-symbols arch/ppc/kernel/vmlinux.lds.S
--- linux-2.6.18-git17/arch/ppc/kernel/vmlinux.lds.S~kallsyms.c-Generate-relocatable-symbols 2006-10-02 13:17:59.000000000 -0400
+++ linux-2.6.18-git17-root/arch/ppc/kernel/vmlinux.lds.S 2006-10-02 13:17:59.000000000 -0400
@@ -31,6 +31,7 @@ SECTIONS
.plt : { *(.plt) }
.text :
{
+ _text = .;
*(.text)
SCHED_TEXT
LOCK_TEXT
diff -puN arch/sparc64/kernel/vmlinux.lds.S~kallsyms.c-Generate-relocatable-symbols arch/sparc64/kernel/vmlinux.lds.S
--- linux-2.6.18-git17/arch/sparc64/kernel/vmlinux.lds.S~kallsyms.c-Generate-relocatable-symbols 2006-10-02 13:17:59.000000000 -0400
+++ linux-2.6.18-git17-root/arch/sparc64/kernel/vmlinux.lds.S 2006-10-02 13:17:59.000000000 -0400
@@ -13,6 +13,7 @@ SECTIONS
. = 0x4000;
.text 0x0000000000404000 :
{
+ _text = .;
*(.text)
SCHED_TEXT
LOCK_TEXT
diff -puN arch/sparc/kernel/vmlinux.lds.S~kallsyms.c-Generate-relocatable-symbols arch/sparc/kernel/vmlinux.lds.S
--- linux-2.6.18-git17/arch/sparc/kernel/vmlinux.lds.S~kallsyms.c-Generate-relocatable-symbols 2006-10-02 13:17:59.000000000 -0400
+++ linux-2.6.18-git17-root/arch/sparc/kernel/vmlinux.lds.S 2006-10-02 13:17:59.000000000 -0400
@@ -11,6 +11,7 @@ SECTIONS
. = 0x10000 + SIZEOF_HEADERS;
.text 0xf0004000 :
{
+ _text = .;
*(.text)
SCHED_TEXT
LOCK_TEXT
diff -puN arch/v850/kernel/vmlinux.lds.S~kallsyms.c-Generate-relocatable-symbols arch/v850/kernel/vmlinux.lds.S
--- linux-2.6.18-git17/arch/v850/kernel/vmlinux.lds.S~kallsyms.c-Generate-relocatable-symbols 2006-10-02 13:17:59.000000000 -0400
+++ linux-2.6.18-git17-root/arch/v850/kernel/vmlinux.lds.S 2006-10-02 13:17:59.000000000 -0400
@@ -90,6 +90,7 @@

/* Kernel text segment, and some constant data areas. */
#define TEXT_CONTENTS \
+ _text = .; \
__stext = . ; \
*(.text) \
SCHED_TEXT \
_