Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
objtool: Generalize elf_create_symbol()
In preparation for the objtool klp diff subcommand, broaden the
elf_create_symbol() interface to give callers more control and reduce
duplication of some subtle setup logic.
While at it, make elf_create_symbol() and elf_create_section_symbol()
global so sections can be created by the upcoming klp diff code.
Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
+69
-53
+59
-52
tools/objtool/elf.c
+59
-52
tools/objtool/elf.c
···
763
763
return 0;
764
764
}
765
765
766
-
static struct symbol *
767
-
__elf_create_symbol(struct elf *elf, struct symbol *sym)
766
+
static int elf_add_string(struct elf *elf, struct section *strtab, const char *str);
767
+
768
+
struct symbol *elf_create_symbol(struct elf *elf, const char *name,
769
+
struct section *sec, unsigned int bind,
770
+
unsigned int type, unsigned long offset,
771
+
size_t size)
768
772
{
769
773
struct section *symtab, *symtab_shndx;
770
774
Elf32_Word first_non_local, new_idx;
771
-
struct symbol *old;
775
+
struct symbol *old, *sym;
776
+
777
+
sym = calloc(1, sizeof(*sym));
778
+
if (!sym) {
779
+
ERROR_GLIBC("calloc");
780
+
return NULL;
781
+
}
782
+
783
+
sym->name = strdup(name);
784
+
if (!sym->name) {
785
+
ERROR_GLIBC("strdup");
786
+
return NULL;
787
+
}
788
+
789
+
if (type != STT_SECTION) {
790
+
sym->sym.st_name = elf_add_string(elf, NULL, sym->name);
791
+
if (sym->sym.st_name == -1)
792
+
return NULL;
793
+
}
794
+
795
+
if (sec) {
796
+
sym->sec = sec;
797
+
} else {
798
+
sym->sec = find_section_by_index(elf, 0);
799
+
if (!sym->sec) {
800
+
ERROR("no NULL section");
801
+
return NULL;
802
+
}
803
+
}
804
+
805
+
sym->sym.st_info = GELF_ST_INFO(bind, type);
806
+
sym->sym.st_value = offset;
807
+
sym->sym.st_size = size;
772
808
773
809
symtab = find_section_by_name(elf, ".symtab");
774
-
if (symtab) {
775
-
symtab_shndx = find_section_by_name(elf, ".symtab_shndx");
776
-
} else {
810
+
if (!symtab) {
777
811
ERROR("no .symtab");
778
812
return NULL;
779
813
}
780
814
815
+
symtab_shndx = find_section_by_name(elf, ".symtab_shndx");
816
+
781
817
new_idx = sec_num_entries(symtab);
782
818
783
-
if (GELF_ST_BIND(sym->sym.st_info) != STB_LOCAL)
819
+
if (bind != STB_LOCAL)
784
820
goto non_local;
785
821
786
822
/*
···
854
818
855
819
non_local:
856
820
sym->idx = new_idx;
857
-
if (elf_update_symbol(elf, symtab, symtab_shndx, sym)) {
858
-
ERROR("elf_update_symbol");
821
+
if (sym->idx && elf_update_symbol(elf, symtab, symtab_shndx, sym))
859
822
return NULL;
860
-
}
861
823
862
824
symtab->sh.sh_size += symtab->sh.sh_entsize;
863
825
mark_sec_changed(elf, symtab, true);
···
865
831
mark_sec_changed(elf, symtab_shndx, true);
866
832
}
867
833
834
+
elf_add_symbol(elf, sym);
835
+
868
836
return sym;
869
837
}
870
838
871
-
static struct symbol *
872
-
elf_create_section_symbol(struct elf *elf, struct section *sec)
839
+
struct symbol *elf_create_section_symbol(struct elf *elf, struct section *sec)
873
840
{
874
841
struct symbol *sym = calloc(1, sizeof(*sym));
875
842
876
-
if (!sym) {
877
-
ERROR_GLIBC("malloc");
843
+
sym = elf_create_symbol(elf, sec->name, sec, STB_LOCAL, STT_SECTION, 0, 0);
844
+
if (!sym)
878
845
return NULL;
879
-
}
880
846
881
-
sym->name = sec->name;
882
-
sym->sec = sec;
883
-
884
-
// st_name 0
885
-
sym->sym.st_info = GELF_ST_INFO(STB_LOCAL, STT_SECTION);
886
-
// st_other 0
887
-
// st_value 0
888
-
// st_size 0
889
-
890
-
sym = __elf_create_symbol(elf, sym);
891
-
if (sym)
892
-
elf_add_symbol(elf, sym);
847
+
sec->sym = sym;
893
848
894
849
return sym;
895
850
}
896
-
897
-
static int elf_add_string(struct elf *elf, struct section *strtab, const char *str);
898
851
899
852
struct symbol *
900
-
elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, long size)
853
+
elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, size_t size)
901
854
{
902
-
struct symbol *sym = calloc(1, sizeof(*sym));
903
855
size_t namelen = strlen(orig->name) + sizeof("__pfx_");
904
-
char *name = malloc(namelen);
905
-
906
-
if (!sym || !name) {
907
-
ERROR_GLIBC("malloc");
908
-
return NULL;
909
-
}
856
+
char name[SYM_NAME_LEN];
857
+
unsigned long offset;
910
858
911
859
snprintf(name, namelen, "__pfx_%s", orig->name);
912
860
913
-
sym->name = name;
914
-
sym->sec = orig->sec;
861
+
offset = orig->sym.st_value - size;
915
862
916
-
sym->sym.st_name = elf_add_string(elf, NULL, name);
917
-
sym->sym.st_info = orig->sym.st_info;
918
-
sym->sym.st_value = orig->sym.st_value - size;
919
-
sym->sym.st_size = size;
920
-
921
-
sym = __elf_create_symbol(elf, sym);
922
-
if (sym)
923
-
elf_add_symbol(elf, sym);
924
-
925
-
return sym;
863
+
return elf_create_symbol(elf, name, orig->sec,
864
+
GELF_ST_BIND(orig->sym.st_info),
865
+
GELF_ST_TYPE(orig->sym.st_info),
866
+
offset, size);
926
867
}
927
868
928
869
static struct reloc *elf_init_reloc(struct elf *elf, struct section *rsec,
···
943
934
unsigned long insn_off)
944
935
{
945
936
struct symbol *sym = insn_sec->sym;
946
-
int addend = insn_off;
937
+
s64 addend = insn_off;
947
938
948
939
if (!is_text_sec(insn_sec)) {
949
940
ERROR("bad call to %s() for data symbol %s", __func__, sym->name);
···
960
951
sym = elf_create_section_symbol(elf, insn_sec);
961
952
if (!sym)
962
953
return NULL;
963
-
964
-
insn_sec->sym = sym;
965
954
}
966
955
967
956
return elf_init_reloc(elf, sec->rsec, reloc_idx, offset, sym, addend,
+10
-1
tools/objtool/include/objtool/elf.h
+10
-1
tools/objtool/include/objtool/elf.h
···
15
15
#include <linux/jhash.h>
16
16
#include <arch/elf.h>
17
17
18
+
#define SYM_NAME_LEN 512
19
+
18
20
#ifdef LIBELF_USE_DEPRECATED
19
21
# define elf_getshdrnum elf_getshnum
20
22
# define elf_getshdrstrndx elf_getshstrndx
···
122
120
size_t entsize, unsigned int nr,
123
121
unsigned int reloc_nr);
124
122
125
-
struct symbol *elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, long size);
123
+
struct symbol *elf_create_symbol(struct elf *elf, const char *name,
124
+
struct section *sec, unsigned int bind,
125
+
unsigned int type, unsigned long offset,
126
+
size_t size);
127
+
struct symbol *elf_create_section_symbol(struct elf *elf, struct section *sec);
128
+
struct symbol *elf_create_prefix_symbol(struct elf *elf, struct symbol *orig,
129
+
size_t size);
130
+
126
131
127
132
struct reloc *elf_init_reloc_text_sym(struct elf *elf, struct section *sec,
128
133
unsigned long offset,