ARM10C : 108 주차
일시 : 2015.07.04 (108 주차 스터디 진행)
모임명 : NAVER개발자커뮤니티지원_10차ARM-C
장소 : 토즈 타워점
장소지원 : NAVER 개발자 커뮤니티 지원 프로그램
참여인원 : 3명
108 주차 진도
- parse_args() 복습
- console_init()->con_init()
- console_init()->s3c24xx_serial_console_init()
__setup("console=", console_setup)을 복습
// static_command_line: "console=ttySAC2,115200 init=/linuxrc"
parse_args("Booting kernel", static_command_line, __start___param,
__stop___param - __start___param,
-1, -1, &unknown_bootoption);
/* Args looks like "foo=bar,bar2 baz=fuz wiz". */
// ARM10C 20131019
// parse_args("early options", cmdline, NULL, 0, 0, 0, do_early_param);
// ARM10C 20150627
// "Booting kernel", "console=ttySAC2,115200 init=/linuxrc",
// __start___param, 120, -1, -1, &unknown_bootoption
int parse_args(const char *doing,
char *args,
const struct kernel_param *params,
unsigned num,
s16 min_level,
s16 max_level,
int (*unknown)(char *param, char *val, const char *doing))
{
char *param, *val;
/* Chew leading spaces */
// string의 앞 공백 제거
// args: "console=ttySAC2,115200 init=/linuxrc"
// args: "console=ttySAC2,115200 init=/linuxrc"
args = skip_spaces(args);
// args: "console=ttySAC2,115200 init=/linuxrc"
// args: "console=ttySAC2,115200 init=/linuxrc"
// ARM10C 20150627
// "Booting kernel", "console=ttySAC2,115200 init=/linuxrc",
// __start___param, 120, -1, -1, &unknown_bootoption
int parse_args(const char *doing,
char *args,
const struct kernel_param *params,
unsigned num,
s16 min_level,
s16 max_level,
int (*unknown)(char *param, char *val, const char *doing))
{
...
// args: "console=ttySAC2,115200 init=/linuxrc"
args = skip_spaces(args);
// args: "console=ttySAC2,115200 init=/linuxrc"
// dtb 에서 복사된 값
// "console=ttySAC2,115200 init=/linuxrc" 이 args 값임
// args: "console=ttySAC2,115200 init=/linuxrc"
if (*args)
// doing: "Booting kernel", args: "console=ttySAC2,115200 init=/linuxrc"
pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);
// "doing Booting kernel, parsing ARGS: 'console=ttySAC2,115200 init=/linuxrc'\n"
// args: "console=ttySAC2,115200 init=/linuxrc"
while (*args) {
int ret;
int irq_was_disabled;
// args: "console=ttySAC2,115200 init=/linuxrc"
// next_arg("console=ttySAC2,115200 init=/linuxrc", ¶m, &val): "init=/linuxrc"
args = next_arg(args, ¶m, &val);
// args: "init=/linuxrc", param: "console", val: "ttySAC2,115200"
- next_arg(args, ¶m, &val); 호출
// ARM10C 20150627
// args: "console=ttySAC2,115200 init=/linuxrc", ¶m, &val
static char *next_arg(char *args, char **param, char **val)
{
unsigned int i, equals = 0;
// equal: 0
// equal: 0
int in_quote = 0, quoted = 0;
// in_quote: 0, quoted: 0
// in_quote: 0, quoted: 0
char *next;
// *args: 'c'
// *args: 'c'
if (*args == '"') {
args++;
in_quote = 1;
quoted = 1;
}
// equals 값은 "=" string index 값
for (i = 0; args[i]; i++) {
// i: 0, args[0]: 'c', isspace('c'): 0, in_quote: 0
// i: 1, args[1]: 'o', isspace('o'): 0, in_quote: 0
// i: 2, args[2]: 'n', isspace('n'): 0, in_quote: 0
// i: 3, args[3]: 's', isspace('s'): 0, in_quote: 0
// i: 4, args[4]: 'o', isspace('o'): 0, in_quote: 0
// i: 5, args[5]: 'l', isspace('l'): 0, in_quote: 0
// i: 6, args[6]: 'e', isspace('e'): 0, in_quote: 0
// i: 7, args[7]: '=', isspace('='): 0, in_quote: 0
// ...
// i: 22, args[22]: ' ', isspace(' '): 1, in_quote: 0
if (isspace(args[i]) && !in_quote)
break;
// break 수행
// equals: 0
// equals: 0
// equals: 0
// equals: 0
// equals: 0
// equals: 0
// equals: 0
// equals: 0
// ...
// equals: 0
if (equals == 0) {
// i: 0, args[0]: 'c'
// i: 1, args[1]: 'o'
// i: 2, args[2]: 'n'
// i: 3, args[3]: 's'
// i: 4, args[4]: 'o'
// i: 5, args[5]: 'l'
// i: 6, args[6]: 'e'
// i: 7, args[7]: '='
// ...
// i: 21, args[21]: '0'
if (args[i] == '=')
// equals: 0, i: 7
equals = i;
// equals: 7
}
// i: 0, args[0]: 'c'
// i: 1, args[1]: 'o'
// i: 2, args[2]: 'n'
// i: 3, args[3]: 's'
// i: 4, args[4]: 'o'
// i: 5, args[5]: 'l'
// i: 6, args[6]: 'e'
// i: 7, args[7]: '='
// ...
// i: 21, args[21]: '0'
if (args[i] == '"')
in_quote = !in_quote;
// i: 7...22 까지 루프 수행
}
// *param: param, args: "console=ttySAC2,115200 init=/linuxrc"
*param = args;
// *param: param: "console=ttySAC2,115200 init=/linuxrc"
// equals: 7
if (!equals)
*val = NULL;
else {
// equals: 7, args[7]: '='
args[equals] = '\0';
// args[7]: '\0'
// *val: val, args: "console\0ttySAC2,115200 init=/linuxrc", equals: 7
*val = args + equals + 1;
// *val: val: "ttySAC2,115200 init=/linuxrc"
/* Don't include quotes in value. */
// **val: *val: 't'
if (**val == '"') {
(*val)++;
if (args[i-1] == '"')
args[i-1] = '\0';
}
// quoted: 0, i: 22, arg[21]: '0'
if (quoted && args[i-1] == '"')
args[i-1] = '\0';
}
// i: 22, arg[22]: ' '
if (args[i]) {
// i: 22, arg[22]: ' '
args[i] = '\0';
// arg[22]: '\0'
// args: "console\0ttySAC2,115200\0init=/linuxrc", i: 22
next = args + i + 1;
// next: "init=/linuxrc"
} else
next = args + i;
/* Chew up trailing spaces. */
// next: "init=/linuxrc"
return skip_spaces(next);
// return "init=/linuxrc"
}
// ARM10C 20150627
// "Booting kernel", "console=ttySAC2,115200 init=/linuxrc",
// __start___param, 120, -1, -1, &unknown_bootoption
int parse_args(const char *doing,
char *args,
const struct kernel_param *params,
unsigned num,
s16 min_level,
s16 max_level,
int (*unknown)(char *param, char *val, const char *doing))
{
...
// args: "console=ttySAC2,115200 init=/linuxrc"
while (*args) {
int ret;
int irq_was_disabled;
// args: "console=ttySAC2,115200 init=/linuxrc"
// next_arg("console=ttySAC2,115200 init=/linuxrc", ¶m, &val): "init=/linuxrc"
args = next_arg(args, ¶m, &val);
// args: "init=/linuxrc", param: "console", val: "ttySAC2,115200"
// irqs_disabled(): 1
irq_was_disabled = irqs_disabled();
// irq_was_disabled: 1
// param: "console", val: "ttySAC2,115200", doing: "Booting kernel",
// params: __start___param, num: 120, min_level, -1, max_level: -1, unknown: unknown_bootoption
// parse_one("console", "ttySAC2,115200", "Booting kernel", __start___param, 120, -1, -1, unknown_bootoption): 0
ret = parse_one(param, val, doing, params, num,
min_level, max_level, unknown);
// ret: 0
- ret = parse_one(param, val, doing, params, num, min_level, max_level, unknown);호출
// ARM10C 20150627
// param: "console", val: "ttySAC2,115200", doing: "Booting kernel",
// params: __start___param, num: 120, min_level, -1, max_level: -1, unknown: unknown_bootoption
static int parse_one(char *param,
char *val,
const char *doing,
const struct kernel_param *params,
unsigned num_params,
s16 min_level,
s16 max_level,
int (*handle_unknown)(char *param, char *val,
const char *doing))
{
unsigned int i;
int err;
/* Find parameter */
// num_params: 120
for (i = 0; i < num_params; i++) {
// i: 0, param: "console", params[0].name
if (parameq(param, params[i].name)) {
if (params[i].level < min_level
|| params[i].level > max_level)
return 0;
/* No one handled NULL, so do it here. */
if (!val &&
!(params[i].ops->flags & KERNEL_PARAM_FL_NOARG))
return -EINVAL;
pr_debug("handling %s with %p\n", param,
params[i].ops->set);
mutex_lock(¶m_lock);
err = params[i].ops->set(val, ¶ms[i]);
mutex_unlock(¶m_lock);
return err;
}
// i: 1...120 루프 수행
}
// 위 루프 수행 결과 param: "console"과 동일한 param이 없음
// handle_unknown: unknown_bootoption
if (handle_unknown) {
// doing: "Booting kernel", param: "console", val: "ttySAC2,115200"
pr_debug("doing %s: %s='%s'\n", doing, param, val);
// "doing Booting kernel: console=ttySAC2,115200\n"
// handle_unknown: unknown_bootoption
// param: "console", val: "ttySAC2,115200", doing: "Booting kernel"
// unknown_bootoption("console", "ttySAC2,115200", "Booting kernel"): 0
return handle_unknown(param, val, doing);
// return 0
- return handle_unknown(param, val, doing); 에서 unknown_bootoption() 호출
// ARM10C 20150627
// param: "console", val: "ttySAC2,115200", doing: "Booting kernel"
static int __init unknown_bootoption(char *param, char *val, const char *unused)
{
// param: "console", val: "ttySAC2,115200", unused: "Booting kernel"
repair_env_string(param, val, unused);
// repair_env_string에서 한일:
// param: "console=ttySAC2,115200"
/* Handle obsolete-style parameters */
// param: "console=ttySAC2,115200"
// obsolete_checksetup("console=ttySAC2,115200"): 1
if (obsolete_checksetup(param))
return 0;
// return 0
- obsolete_checksetup(param) 에서 호출
// ARM10C 20150627
// param: "console=ttySAC2,115200"
static int __init obsolete_checksetup(char *line)
{
const struct obs_kernel_param *p;
int had_early_param = 0;
// had_early_param: 0
p = __setup_start;
do {
// p->str: __setup_console_setup.str: "console=", strlen("console="): 8
int n = strlen(p->str);
// n: 8
// line: "console=ttySAC2,115200", p->str: __setup_console_setup.str: "console=", n: 8
// parameqn("console=ttySAC2,115200", "console=", 8): true
if (parameqn(line, p->str, n)) {
// p->early: __setup_console_setup.early: 0,
// p->setup_func: __setup_console_setup.setup_func: console_setup
// line: "console=ttySAC2,115200", n: 8
// console_setup("ttySAC2,115200"): 1
if (p->early) {
/* Already done in parse_early_param?
* (Needs exact match on param part).
* Keep iterating, as we can have early
* params and __setups of same names 8( */
if (line[n] == '\0' || line[n] == '=')
had_early_param = 1;
} else if (!p->setup_func) {
pr_warn("Parameter %s is obsolete, ignored\n",
p->str);
return 1;
} else if (p->setup_func(line + n))
return 1;
// return 1
// ARM10C 20150627
// "ttySAC2,115200"
static int __init console_setup(char *str)
{
// sizeof(console_cmdline[0].name): 8
char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */
char *s, *options, *brl_options = NULL;
// brl_options: NULL
int idx;
// &str: &"ttySAC2,115200", &brl_options: &NULL
// _braille_console_setup(&"ttySAC2,115200", &NULL): NULL
if (_braille_console_setup(&str, &brl_options))
return 1;
/*
* Decode str into name, index, options.
*/
// str[0]: 't'
if (str[0] >= '0' && str[0] <= '9') {
strcpy(buf, "ttyS");
strncpy(buf + 4, str, sizeof(buf) - 5);
} else {
// str: "ttySAC2,115200", sizeof(buf): 12
strncpy(buf, str, sizeof(buf) - 1);
// buf: "ttySAC2,115"
}
// sizeof(buf): 12
buf[sizeof(buf) - 1] = 0;
// buf: "ttySAC2,11"
// str: "ttySAC2,115200", strchr("ttySAC2,115200", ','): ",115200"
if ((options = strchr(str, ',')) != NULL)
// options: ",115200"
*(options++) = 0;
// options: "115200"
#ifdef __sparc__
if (!strcmp(str, "ttya"))
strcpy(buf, "ttyS0");
if (!strcmp(str, "ttyb"))
strcpy(buf, "ttyS1");
#endif
// buf: "ttySAC2,11"
for (s = buf; *s; s++)
// *s: 't'
// *s: 't'
// *s: 'y'
// *s: 'S'
// *s: 'A'
// *s: 'C'
// *s: '2'
if ((*s >= '0' && *s <= '9') || *s == ',')
break;
// break 수행
// s: "2,11", simple_strtoul("2,11", NULL, 10): 2
idx = simple_strtoul(s, NULL, 10);
// idx: 2
// *s: '2'
*s = 0;
// buf: "ttySAC"
// buf: "ttySAC", idx: 2, options: "115200", brl_options: NULL
__add_preferred_console(buf, idx, options, brl_options);
// __add_preferred_console에서 한일:
// selected_console: 0
// console_cmdline[0].name: "ttySAC"
// console_cmdline[0].options: "115200"
// console_cmdline[0].index: 2
console_set_on_cmdline = 1;
// console_set_on_cmdline: 1
return 1;
// return 1
}
__setup("console=", console_setup);
- console_setup에서 한일: // selected_console: 0 // console_cmdline[0].name: "ttySAC" // console_cmdline[0].options: "115200" // console_cmdline[0].index: 2 // console_set_on_cmdline: 1
// ARM10C 20150627
// param: "console=ttySAC2,115200"
static int __init obsolete_checksetup(char *line)
{
const struct obs_kernel_param *p;
int had_early_param = 0;
// had_early_param: 0
p = __setup_start;
do {
// p->str: __setup_console_setup.str: "console=", strlen("console="): 8
int n = strlen(p->str);
// n: 8
// line: "console=ttySAC2,115200", p->str: __setup_console_setup.str: "console=", n: 8
// parameqn("console=ttySAC2,115200", "console=", 8): true
if (parameqn(line, p->str, n)) {
// p->early: __setup_console_setup.early: 0,
// p->setup_func: __setup_console_setup.setup_func: console_setup
// line: "console=ttySAC2,115200", n: 8
// console_setup("ttySAC2,115200"): 1
if (p->early) {
/* Already done in parse_early_param?
* (Needs exact match on param part).
* Keep iterating, as we can have early
* params and __setups of same names 8( */
if (line[n] == '\0' || line[n] == '=')
had_early_param = 1;
} else if (!p->setup_func) {
pr_warn("Parameter %s is obsolete, ignored\n",
p->str);
return 1;
} else if (p->setup_func(line + n))
return 1;
// return 1
// console_setup에서 한일:
// selected_console: 0
// console_cmdline[0].name: "ttySAC"
// console_cmdline[0].options: "115200"
// console_cmdline[0].index: 2
// console_set_on_cmdline: 1
}
p++;
} while (p < __setup_end);
return had_early_param;
}
- obsolete_checksetup에서 한일: // selected_console: 0 // console_cmdline[0].name: "ttySAC" // console_cmdline[0].options: "115200" // console_cmdline[0].index: 2 // console_set_on_cmdline: 1
// ARM10C 20150627
// param: "console", val: "ttySAC2,115200", doing: "Booting kernel"
static int __init unknown_bootoption(char *param, char *val, const char *unused)
{
// param: "console", val: "ttySAC2,115200", unused: "Booting kernel"
repair_env_string(param, val, unused);
// repair_env_string에서 한일:
// param: "console=ttySAC2,115200"
/* Handle obsolete-style parameters */
// param: "console=ttySAC2,115200"
// obsolete_checksetup("console=ttySAC2,115200"): 1
if (obsolete_checksetup(param))
return 0;
// return 0
// obsolete_checksetup에서 한일:
// selected_console: 0
// console_cmdline[0].name: "ttySAC"
// console_cmdline[0].options: "115200"
// console_cmdline[0].index: 2
// console_set_on_cmdline: 1
/* Unused module parameter. */
if (strchr(param, '.') && (!val || strchr(param, '.') < val))
return 0;
if (panic_later)
return 0;
if (val) {
/* Environment option */
unsigned int i;
for (i = 0; envp_init[i]; i++) {
if (i == MAX_INIT_ENVS) {
panic_later = "Too many boot env vars at `%s'";
panic_param = param;
}
if (!strncmp(param, envp_init[i], val - param))
break;
}
envp_init[i] = param;
} else {
/* Command line option */
unsigned int i;
for (i = 0; argv_init[i]; i++) {
if (i == MAX_INIT_ARGS) {
panic_later = "Too many boot init vars at `%s'";
panic_param = param;
}
}
argv_init[i] = param;
}
return 0;
}
// ARM10C 20150627
// "Booting kernel", "console=ttySAC2,115200 init=/linuxrc",
// __start___param, 120, -1, -1, &unknown_bootoption
int parse_args(const char *doing,
char *args,
const struct kernel_param *params,
unsigned num,
s16 min_level,
s16 max_level,
int (*unknown)(char *param, char *val, const char *doing))
{
char *param, *val;
/* Chew leading spaces */
// string의 앞 공백 제거
// args: "console=ttySAC2,115200 init=/linuxrc"
args = skip_spaces(args);
// args: "console=ttySAC2,115200 init=/linuxrc"
// dtb 에서 복사된 값
// "console=ttySAC2,115200 init=/linuxrc" 이 args 값임
// args: "console=ttySAC2,115200 init=/linuxrc"
if (*args)
// doing: "Booting kernel", args: "console=ttySAC2,115200 init=/linuxrc"
pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);
// "doing Booting kernel, parsing ARGS: 'console=ttySAC2,115200 init=/linuxrc'\n"
// args: "console=ttySAC2,115200 init=/linuxrc"
while (*args) {
int ret;
int irq_was_disabled;
// args: "console=ttySAC2,115200 init=/linuxrc"
// next_arg("console=ttySAC2,115200 init=/linuxrc", ¶m, &val): "init=/linuxrc"
args = next_arg(args, ¶m, &val);
// args: "init=/linuxrc", param: "console", val: "ttySAC2,115200"
// irqs_disabled(): 1
irq_was_disabled = irqs_disabled();
// irq_was_disabled: 1
// param: "console", val: "ttySAC2,115200", doing: "Booting kernel",
// params: __start___param, num: 120, min_level, -1, max_level: -1, unknown: unknown_bootoption
// parse_one("console", "ttySAC2,115200", "Booting kernel", __start___param, 120, -1, -1, unknown_bootoption): 0
ret = parse_one(param, val, doing, params, num,
min_level, max_level, unknown);
// ret: 0
// irq 값이 바뀌었는지 확인
// irq_was_disabled: 1, irqs_disabled(): 1
if (irq_was_disabled && !irqs_disabled())
pr_warn("%s: option '%s' enabled irq's!\n",
doing, param);
// ret: 0
switch (ret) {
case -ENOENT:
pr_err("%s: Unknown parameter `%s'\n", doing, param);
return ret;
case -ENOSPC:
pr_err("%s: `%s' too large for parameter `%s'\n",
doing, val ?: "", param);
return ret;
case 0:
break;
// break 수행
default:
pr_err("%s: `%s' invalid for parameter `%s'\n",
doing, val ?: "", param);
return ret;
}
}
/* All parsed OK. */
return 0;
// return 0
}
- 여기서 __setup()에서 foo(), bar() 함수를 동적할당해서 사용하는 것을 분석했다.
- 다시 돌아가서 parse_args()에서는
- DTB에서 넘어온 bootargs를 파싱하여 param, val을 뽑아내고 그에 대응되는
- kernel_param 구조체에 값을 등록함.
main.c::main.c()
asmlinkage void __init start_kernel(void)
{
...
// irqs_disabled(): 1
WARN(!irqs_disabled(), "Interrupts were enabled early\n");
// early_boot_irqs_disabled: true
early_boot_irqs_disabled = false;
// early_boot_irqs_disabled: false
local_irq_enable();
// IRQ를 enable 함
kmem_cache_init_late(); // null function
/*
* HACK ALERT! This is early. We're enabling the console before
* we've done PCI setups etc, and console_init() must be aware of
* this. But we do want output early, in case something goes wrong.
*/
console_init();
- call: start_kernel()->console_init()
tty_io.c::console_init()
- called: start_kernel()->console_init()
// ARM10C 20150627
void __init console_init(void)
{
initcall_t *call;
/* Setup the default TTY line discipline. */
tty_ldisc_begin();
// tty_ldisc_begin에서 한일:
// tty_ldiscs[0]: &tty_ldisc_N_TTY
// (&tty_ldisc_N_TTY)->num: 0
// (&tty_ldisc_N_TTY)->refcount: 0
/*
* set up the console device so that later boot sequences can
* inform about problems etc..
*/
call = __con_initcall_start;
// call: &__con_initcall_start
// call: &__con_initcall_start
while (call < __con_initcall_end) {
// call:__initcall_s3c24xx_serial_console_init:
// s3c24xx_serial_console_init
(*call)();
call++;
}
- call: start_kernel()->console_init()->s3c24xx_serial_console_init()
samsung.c::s3c24xx_serial_console_init()
- called: start_kernel()->console_init()->s3c24xx_serial_console_init()
// ARM10C 20150627
static struct console s3c24xx_serial_console;
// ARM10C 20150627
static int __init s3c24xx_serial_console_init(void)
{
register_console(&s3c24xx_serial_console);
return 0;
}
console_initcall(s3c24xx_serial_console_init);
// ARM10C 20150627
static struct console s3c24xx_serial_console = {
.name = S3C24XX_SERIAL_NAME,
.device = uart_console_device,
// CON_PRINTBUFFER: 1
.flags = CON_PRINTBUFFER,
.index = -1,
.write = s3c24xx_serial_console_write,
.setup = s3c24xx_serial_console_setup,
.data = &s3c24xx_uart_drv,
};
#endif /* CONFIG_SERIAL_SAMSUNG_CONSOLE */
- call: start_kernel()->console_init()->s3c24xx_serial_console_init()
- register_console(&s3c24xx_serial_console);
printk.c::register_console()
- called: start_kernel()->console_init()->s3c24xx_serial_console_init()
- register_console(&s3c24xx_serial_console);
// ARM10C 20150627
// &s3c24xx_serial_console
void register_console(struct console *newcon)
{
int i;
unsigned long flags;
struct console *bcon = NULL;
// bcon: NULL
struct console_cmdline *c;
// console_drivers: NULL
if (console_drivers)
for_each_console(bcon)
if (WARN(bcon == newcon,
"console '%s%d' already registered\n",
bcon->name, bcon->index))
return;
/*
* before we register a new CON_BOOT console, make sure we don't
* already have a valid console
*/
// console_drivers: NULL, newcon->flags: (&s3c24xx_serial_console)->flags: 1, CON_BOOT: 8
if (console_drivers && newcon->flags & CON_BOOT) {
/* find the last or real console */
for_each_console(bcon) {
if (!(bcon->flags & CON_BOOT)) {
pr_info("Too late to register bootconsole %s%d\n",
newcon->name, newcon->index);
return;
}
}
}
// console_drivers: NULL
if (console_drivers && console_drivers->flags & CON_BOOT)
bcon = console_drivers;
// preferred_console: -1, bcon: NULL, console_drivers: NULL
if (preferred_console < 0 || bcon || !console_drivers)
// selected_console: 0
preferred_console = selected_console;
// preferred_console: 0
// newcon->early_setup: (&s3c24xx_serial_console)->early_setup: NULL
if (newcon->early_setup)
newcon->early_setup();
/*
* See if we want to use this console driver. If we
* didn't select a console we take the first one
* that registers here.
*/
// preferred_console: 0
if (preferred_console < 0) {
if (newcon->index < 0)
newcon->index = 0;
if (newcon->setup == NULL ||
newcon->setup(newcon, NULL) == 0) {
newcon->flags |= CON_ENABLED;
if (newcon->device) {
newcon->flags |= CON_CONSDEV;
preferred_console = 0;
}
}
}
// MAX_CMDLINECONSOLES: 8, c->name[0]: console_cmdline[0].name[0]: 't'
for (i = 0, c = console_cmdline;
i < MAX_CMDLINECONSOLES && c->name[0];
i++, c++) {
// console_cmdline[0].name: 'ttySAC",
// newcon->name (&s3c24xx_serial_console).name: 'ttySAC'
// strcmp(c->name, newcon->name): 0
if (strcmp(c->name, newcon->name) != 0)
continue;
if (newcon->index >= 0 &&
newcon->index != c->index)
continue;
if (newcon->index < 0)
newcon->index = c->index;
if (_braille_register_console(newcon, c))
return;
if (newcon->setup &&
newcon->setup(newcon, console_cmdline[i].options) != 0)
break;
newcon->flags |= CON_ENABLED;
newcon->index = c->index;
if (i == selected_console) {
newcon->flags |= CON_CONSDEV;
preferred_console = selected_console;
}
break;
}
// newcon->flags: (&s3c24xx_serial_console)->flags: 1, CON_ENABLED: 4
if (!(newcon->flags & CON_ENABLED))
return;
// return 수행
- called: start_kernel()->console_init()->s3c24xx_serial_console_init()
- register_console(&s3c24xx_serial_console);
- s3c24xx_serial_console_setup()
samsung.c::s3c24xx_serial_console_setup()
// ARM10C 20150627
// newcon: &s3c24xx_serial_console, NULL
static int __init
s3c24xx_serial_console_setup(struct console *co, char *options)
{
struct uart_port *port;
int baud = 9600;
// baud: 9600
int bits = 8;
// bits: 8
int parity = 'n';
// parity: 'n'
int flow = 'n';
// flow: 'n'
// co: &s3c24xx_serial_console, co->index: (&s3c24xx_serial_console)->index: 0,
// options: NULL
dbg("s3c24xx_serial_console_setup: co=%p (%d), %s\n",
co, co->index, options); // null function
/* is this a valid port */
// co->index: (&s3c24xx_serial_console)->index: 0, CONFIG_SERIAL_SAMSUNG_UARTS: 4
if (co->index == -1 || co->index >= CONFIG_SERIAL_SAMSUNG_UARTS)
co->index = 0;
// co->index: (&s3c24xx_serial_console)->index: 0
port = &s3c24xx_serial_ports[co->index].port;
// port: &s3c24xx_serial_ports[0].port
/* is the port configured? */
// port->mapbase: (&s3c24xx_serial_ports[0].port)->mapbase: NULL
if (port->mapbase == 0x0)
// ENODEV: 19
return -ENODEV;
// return -19
- return: start_kernel()->console_init()->s3c24xx_serial_console_init()
- register_console(&s3c24xx_serial_console);
- s3c24xx_serial_console_setup(): -19
printk.c::register_console()
- return: start_kernel()->console_init()->s3c24xx_serial_console_init()
- register_console(&s3c24xx_serial_console);
- s3c24xx_serial_console_setup(): -19
// ARM10C 20150627
// &s3c24xx_serial_console
void register_console(struct console *newcon)
{
...
// preferred_console: 0
if (preferred_console < 0) {
if (newcon->index < 0)
newcon->index = 0;
if (newcon->setup == NULL ||
newcon->setup(newcon, NULL) == 0) {
newcon->flags |= CON_ENABLED;
if (newcon->device) {
newcon->flags |= CON_CONSDEV;
preferred_console = 0;
}
}
}
/*
* See if this console matches one we selected on
* the command line.
*/
// MAX_CMDLINECONSOLES: 8, c->name[0]: console_cmdline[0].name[0]: NULL
for (i = 0, c = console_cmdline;
i < MAX_CMDLINECONSOLES && c->name[0];
i++, c++) {
if (strcmp(c->name, newcon->name) != 0)
continue;
if (newcon->index >= 0 &&
newcon->index != c->index)
continue;
if (newcon->index < 0)
newcon->index = c->index;
if (_braille_register_console(newcon, c))
return;
if (newcon->setup &&
newcon->setup(newcon, console_cmdline[i].options) != 0)
// s3c24xx_serial_console_setup()
- call: start_kernel()->console_init()->s3c24xx_serial_console_init()
- register_console(&s3c24xx_serial_console);
- s3c24xx_serial_console_setup()
samsung.c::s3c24xx_serial_console_setup()
- called: start_kernel()->console_init()->s3c24xx_serial_console_init()
- register_console(&s3c24xx_serial_console);
- s3c24xx_serial_console_setup()
// ARM10C 20150627
// newcon: &s3c24xx_serial_console, NULL
static int __init
s3c24xx_serial_console_setup(struct console *co, char *options)
{
struct uart_port *port;
int baud = 9600;
// baud: 9600
int bits = 8;
// bits: 8
int parity = 'n';
// parity: 'n'
int flow = 'n';
// flow: 'n'
// co: &s3c24xx_serial_console, co->index: (&s3c24xx_serial_console)->index: 0,
// options: NULL
dbg("s3c24xx_serial_console_setup: co=%p (%d), %s\n",
co, co->index, options); // null function
/* is this a valid port */
// co->index: (&s3c24xx_serial_console)->index: 0, CONFIG_SERIAL_SAMSUNG_UARTS: 4
if (co->index == -1 || co->index >= CONFIG_SERIAL_SAMSUNG_UARTS)
co->index = 0;
// co->index: (&s3c24xx_serial_console)->index: 0
port = &s3c24xx_serial_ports[co->index].port;
// port: &s3c24xx_serial_ports[0].port
/* is the port configured? */
// port->mapbase: (&s3c24xx_serial_ports[0].port)->mapbase: NULL
if (port->mapbase == 0x0)
// ENODEV: 19
return -ENODEV;
// return -19
- called: start_kernel()->console_init()->s3c24xx_serial_console_init()
- register_console(&s3c24xx_serial_console);
- s3c24xx_serial_console_setup()
- return -19
printk.c::register_console()
- return: start_kernel()->console_init()->s3c24xx_serial_console_init()
- register_console(&s3c24xx_serial_console);
- s3c24xx_serial_console_setup()
- return -19
// ARM10C 20150627
// &s3c24xx_serial_console
void register_console(struct console *newcon)
{
...
// MAX_CMDLINECONSOLES: 8, c->name[0]: console_cmdline[0].name[0]: NULL
for (i = 0, c = console_cmdline;
i < MAX_CMDLINECONSOLES && c->name[0];
i++, c++) {
if (strcmp(c->name, newcon->name) != 0)
continue;
if (newcon->index >= 0 &&
newcon->index != c->index)
continue;
if (newcon->index < 0)
newcon->index = c->index;
if (_braille_register_console(newcon, c))
return;
if (newcon->setup &&
newcon->setup(newcon, console_cmdline[i].options) != 0)
// s3c24xx_serial_console_setup(): -19
break;
- 여기서 -19리턴값이면 이상하다. 그래서 다시 살펴 보니.
- console_init()에서 __con_initcall_con_init 이 먼저 호출되어야만 했다.
- 따라서 다시 con_init()을 분석한다.
tty_io.c::console_init()
- called: start_kernel()->console_init()
// ARM10C 20150627
void __init console_init(void)
{
initcall_t *call;
/* Setup the default TTY line discipline. */
tty_ldisc_begin();
// tty_ldisc_begin에서 한일:
// tty_ldiscs[0]: &tty_ldisc_N_TTY
// (&tty_ldisc_N_TTY)->num: 0
// (&tty_ldisc_N_TTY)->refcount: 0
/*
* set up the console device so that later boot sequences can
* inform about problems etc..
*/
call = __con_initcall_start;
// call: &__con_initcall_start
// call: &__con_initcall_start
while (call < __con_initcall_end) {
// call: con_init()
(*call)();
call++;
}
}
- con_init()을 분석하자.
- call: start_kernel()->console_init()->con_init()
- while (call < __con_initcall_end) {
- call: con_init()
vt.c::con_init()
- called: start_kernel()->console_init()->con_init()
static int __init con_init(void)
{
const char *display_desc = NULL;
struct vc_data *vc;
unsigned int currcons = 0, i;
console_lock();
- call: start_kernel()->console_init()->con_init()
- call: con_init()
- console_lock()
printk.c::console_lock()
- called: start_kernel()->console_init()->con_init()
- call: con_init()
- console_lock()
void console_lock(void)
{
might_sleep();
down(&console_sem);
if (console_suspended)
return;
console_locked = 1;
console_may_schedule = 1;
mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_);
}
EXPORT_SYMBOL(console_lock);
- call: start_kernel()->console_init()->con_init()
- call: con_init()
- console_lock()
printk.c::down()
#define DEFINE_SEMAPHORE(name) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1)
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.lock = __RAW_SPIN_LOCK_UNLOCKED((name).lock), \
.count = n, \
.wait_list = LIST_HEAD_INIT((name).wait_list), \
}
#define __RAW_SPIN_LOCK_UNLOCKED(lockname) \
(raw_spinlock_t) __RAW_SPIN_LOCK_INITIALIZER(lockname)
// ARM10C 20150411
// __RAW_SPIN_LOCK_INITIALIZER(clockevents_lock):
// {
// .raw_lock = { { 0 } },
// .magic = 0xdead4ead,
// .owner_cpu = -1,
// .owner = 0xffffffff,
// }
//
// #define __RAW_SPIN_LOCK_UNLOCKED(clockevents_lock):
// (raw_spinlock_t)
// {
// .raw_lock = { { 0 } },
// .magic = 0xdead4ead,
// .owner_cpu = -1,
// .owner = 0xffffffff,
// }
void down(struct semaphore *sem)
{
unsigned long flags;
raw_spin_lock_irqsave(&sem->lock, flags);
// (&console_sem)->count: 1
if (likely(sem->count > 0))
// (&console_sem)->count: 1
sem->count--;
// (&console_sem)->count: 0
else
__down(sem);
raw_spin_unlock_irqrestore(&sem->lock, flags);
}
EXPORT_SYMBOL(down);
printk.c::console_lock()
- return: start_kernel()->console_init()->con_init()
- call: con_init()
- console_lock()
void console_lock(void)
{
might_sleep();
down(&console_sem);
if (console_suspended)
return;
console_locked = 1;
console_may_schedule = 1;
mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_);
}
EXPORT_SYMBOL(console_lock);
- call: start_kernel()->console_init()->con_init()
- call: con_init()
- console_lock()
- mutex_acquire(&console_lock_dep_map, 0, 0, RET_IP);
lockdep.h::mutex_acquire()
- called: start_kernel()->console_init()->con_init()
- call: con_init()
- console_lock()
- mutex_acquire(&console_lock_dep_map, 0, 0, RET_IP);
#define mutex_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
- return: start_kernel()->console_init()->con_init()
- call: con_init()
- console_lock()
- mutex_acquire(&console_lock_dep_map, 0, 0, RET_IP);
vt.c::con_init()
- return: start_kernel()->console_init()->con_init()
- call: con_init()
- console_lock()
- down(&console_sem);
- mutex_acquire(&console_lock_dep_map, 0, 0, RET_IP);
- 리턴하여 진행.
static int __init con_init(void)
{
const char *display_desc = NULL;
struct vc_data *vc;
unsigned int currcons = 0, i;
console_lock();
// conswitchp:: &dummy_con
if (conswitchp)
// (&dummy_con)->con_startup()
display_desc = conswitchp->con_startup();
- (&dummy_con)->con_startup()을 찾아보면.
- 여기서 dummycon_startup함수가 있다.
// ARM10C 20140215
// DUMMY: 0
const struct consw dummy_con = {
.owner = THIS_MODULE,
.con_startup = dummycon_startup,
.con_init = dummycon_init,
.con_deinit = DUMMY,
.con_clear = DUMMY,
.con_putc = DUMMY,
.con_putcs = DUMMY,
.con_cursor = DUMMY,
.con_scroll = DUMMY,
.con_bmove = DUMMY,
.con_switch = DUMMY,
.con_blank = DUMMY,
.con_font_set = DUMMY,
.con_font_get = DUMMY,
.con_font_default = DUMMY,
.con_font_copy = DUMMY,
.con_set_palette = DUMMY,
.con_scrolldelta = DUMMY,
};
- (&dummy_con)->con_startup()을 찾아보면.
- 여기서 dummycon_startup함수를 보면
static const char *dummycon_startup(void)
{
return "dummy device";
}
- dummycon_startup: "dummy device" 가 리턴된다.
vt.c::con_init()
static int __init con_init(void)
{
...
if (conswitchp)
display_desc = conswitchp->con_startup();
if (!display_desc) {
fg_console = 0;
console_unlock();
return 0;
}
// MAX_NR_CON_DRIVER: 16
for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
struct con_driver *con_driver = ®istered_con_driver[i];
// con_driver: ®istered_con_driver[0]
// con_driver->con: ®istered_con_driver[0]->con: NULL
if (con_driver->con == NULL) {
con_driver->con = conswitchp;
// con_driver->con: ®istered_con_driver[0]->con: :dummy device"
con_driver->desc = display_desc;
// con_driver->desc: ®istered_con_driver[0]->desc: &"dummy device"
con_driver->flag = CON_DRIVER_FLAG_INIT;
// con_driver->flag: ®istered_con_driver[0]->flag: CON_DRIVER_FLAG_INIT: 2
con_driver->first = 0;
// con_driver->first: ®istered_con_driver[0]->first: 0
con_driver->last = MAX_NR_CONSOLES - 1;
// con_driver->last: ®istered_con_driver[0]->last: -1
break;
}
}
// MAX_NR_CON_DRIVER: 63
for (i = 0; i < MAX_NR_CONSOLES; i++)
con_driver_map[i] = conswitchp;
// con_driver_map[0...63]: &dummy_con 을 loop 실행
// blankinterval: 600
if (blankinterval) {
blank_state = blank_normal_wait;
// blank_state: blank_normal_wait: 1
// console_timer:
mod_timer(&console_timer, jiffies + (blankinterval * HZ));
}
timer.c::mod_timer()
#define DEFINE_TIMER(_name, _function, _expires, _data) \
struct timer_list _name = \
TIMER_INITIALIZER(_function, _expires, _data)
#define TIMER_INITIALIZER(_function, _expires, _data) \
__TIMER_INITIALIZER((_function), (_expires), (_data), 0)
- __TIMER_INITIALIZER 을 알아보면.
#define __TIMER_INITIALIZER(_function, _expires, _data, _flags) { \
.entry = { .prev = TIMER_ENTRY_STATIC }, \
.function = (_function), \
.expires = (_expires), \
.data = (_data), \
.base = (void *)((unsigned long)&boot_tvec_bases + (_flags)), \
.slack = -1, \
__TIMER_LOCKDEP_MAP_INITIALIZER( \
__FILE__ ":" __stringify(__LINE__)) \
}
#define TIMER_ENTRY_STATIC ((void *) 0x74737461)
- __TIMER_LOCKDEP_MAP_INITIALIZER 는
#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn) \
.lockdep_map = STATIC_LOCKDEP_MAP_INIT(_kn, &_kn),
struct timer_list {
/*
* All fields that change during normal runtime grouped to the
* same cacheline
*/
struct list_head entry;
unsigned long expires;
struct tvec_base *base;
void (*function)(unsigned long);
unsigned long data;
int slack;
#ifdef CONFIG_TIMER_STATS // CONFIG_TIMER_STATS=n
int start_pid;
void *start_site;
char start_comm[16];
#endif
#ifdef CONFIG_LOCKDEP
struct lockdep_map lockdep_map;
#endif
};
int mod_timer(struct timer_list *timer, unsigned long expires)
{
expires = apply_slack(timer, expires);
/*
* This is a common optimization triggered by the
* networking code - if the timer is re-modified
* to be the same thing then just return:
*/
if (timer_pending(timer) && timer->expires == expires)
return 1;
return __mod_timer(timer, expires, false, TIMER_NOT_PINNED);
}
EXPORT_SYMBOL(mod_timer);
log
9b98f31..91641d4 master -> origin/master
Updating 9b98f31..91641d4
Fast-forward
arch/arm/kernel/vmlinux.lds.S | 1 +
drivers/tty/serial/samsung.c | 20 ++++++----
drivers/tty/tty_io.c | 3 +-
drivers/tty/vt/vt.c | 79 ++++++++++++++++++++++++++++++++++++++++
drivers/video/console/dummycon.c | 3 ++
include/asm-generic/param.h | 1 +
include/linux/console.h | 1 +
include/linux/console_struct.h | 1 +
include/linux/kernel.h | 1 +
include/linux/list.h | 1 +
include/linux/lockdep.h | 6 +++
include/linux/poison.h | 2 +
include/linux/semaphore.h | 52 ++++++++++++++++++++++++++
include/linux/spinlock.h | 2 +
include/linux/spinlock_types.h | 10 +++++
include/linux/timer.h | 63 ++++++++++++++++++++++++++++++--
include/uapi/linux/vt.h | 2 +
init/main.c | 3 ++
kernel/locking/semaphore.c | 15 ++++++++
kernel/printk/braille.h | 2 +
kernel/printk/printk.c | 67 +++++++++++++++++++++++++++-------
kernel/timer.c | 8 ++++
22 files changed, 318 insertions(+), 25 deletions(-)
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