编译linux内核生成的system.map文件详解

system.map内容格式为：线性地址 类型 符号

具体内容如下：

00100000 A phys_startup_32

c0100000 T startup_32

c0100000 A _text 注:表示内核代码第一个字节的地址

c01000c6 t checkCPUtype

c0100147 t is486

c010014e t is386

c0100199 t L6

c010019b t check_x87

c01001c2 t setup_idt

c01001df t rp_sidt

c01001ec t ignore_int

c0100220 t rest_init

c0100220 T stext

c0100220 T _stext

c0100252 t do_pre_smp_initcalls

c0100257 t run_init_process

c0100283 t init

c01003a8 t try_name

c0100529 T name_to_dev_t

c0100790 t calibrate_delay_direct

...

c02f95d7 T register_kretprobe

c02f96cd T unregister_kretprobe

c02f9760 t .text.lock.kprobes

c02f97b0 T __kprobes_text_end

c02f9abe t iret_exc

c02fa1af A _etext 注:内核代码结束的位置，之后为内核初始化的数据

c02fa1b0 A __start___ex_table

c02facc0 A __stop___ex_table

c02fb000 r __func__.12

c02fb000 A __start_rodata

c02fb00c r __func__.13

c02fb020 r __func__.2

c02fb02c r __func__.3

c02fb040 R linux_banner

c02fb0bb r __func__.0

c02fb0c7 r __func__.1

c02fb0e0 r __func__.0

c02fb0ec r __func__.1

c02fb100 r border

c02fb160 r cplens

...

c03e1b08 D ip_statistics

c03e1b10 D tcp_statistics

c03e1b18 D udp_statistics

c03e1b20 D icmp_statistics

c03e1b28 D net_statistics

c03e1b30 d fn_hash_kmem

c03e1b34 d fn_alias_kmem

c03e1b38 d xfrm_dst_cache

c03e1b3c d secpath_cachep

c03e1b40 A _edata 注:内核初始化数据结束，之后为未初始化数据

c03e2000 D init_thread_union

c03e4000 A __init_begin

c03e4000 t no_halt

c03e4000 T _sinittext

c03e400d t mca_pentium

c03e401d t no_387

c03e4033 t check_fpu

...

c043a058 b pfkey_table

c043a05c b pfkey_table_lock

c043a05c b pfkey_table_users

c043a060 b pfkey_socks_nr

c043a064 b acqseq.4

c043a068 b acqseq_lock.5

c043a068 A __bss_stop

c043a068 A _end 注:内核未初始化数据结束

c043b000 A pg0

ffffe400 A __kernel_vsyscall

ffffe410 A SYSENTER_RETURN

ffffe420 A __kernel_sigreturn

ffffe440 A __kernel_rt_sigreturn

符号类型.

小写字母表示局部; 大写字母表示全局(外部).

A

The symbol's value is absolute, and will not be changed by further linking.

B

The symbol is in the uninitialized data section (known as BSS).

C

The symbol is common. Common symbols are uninitialized data. When
linking, multiple common symbols may appear with the same name. If the
symbol is defined anywhere, the common symbols are treated as undefined
references. For more details on common symbols, see the discussion of
-warn-common in Linker options.

D

The symbol is in the initialized data section.

G

The symbol is in an initialized data section for small objects. Some
object file formats permit more efficient access to small data objects,
such as a global int variable as opposed to a large global array.

I

The symbol is an indirect reference to another symbol. This is a GNU
extension to the a.out object file format which is rarely used.

N

The symbol is a debugging symbol.

R

The symbol is in a read only data section.

S

The symbol is in an uninitialized data section for small objects.

T

The symbol is in the text (code) section.

U

The symbol is undefined.

V

The symbol is a weak object. When a weak defined symbol is linked with
a normal defined symbol, the normal defined symbol is used with no
error. When a weak undefined symbol is linked and the symbol is not
defined, the value of the weak symbol becomes zero with no error.

W

The symbol is a weak symbol that has not been specifically tagged as a
weak object symbol. When a weak defined symbol is linked with a normal
defined symbol, the normal defined symbol is used with no error. When a
weak undefined symbol is linked and the symbol is not defined, the
value of the weak symbol becomes zero with no error.

-

The symbol is a stabs symbol in an a.out object file. In this case, the
next values printed are the stabs other field, the stabs desc field,
and the stab type. Stabs symbols are used to hold debugging
information. For more information, see Stabs.

?

The symbol type is unknown, or object file format specific.