diff options
| -rw-r--r-- | kernel/debug/debug_core.c | 34 | ||||
| -rw-r--r-- | kernel/debug/debug_core.h | 3 | ||||
| -rw-r--r-- | kernel/debug/kdb/kdb_bt.c | 116 | ||||
| -rw-r--r-- | kernel/debug/kdb/kdb_io.c | 231 | ||||
| -rw-r--r-- | kernel/debug/kdb/kdb_private.h | 1 |
5 files changed, 208 insertions, 177 deletions
diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index f76d6f77dd5e..2b7c9b67931d 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -441,6 +441,37 @@ setundefined: return 0; } +#ifdef CONFIG_KGDB_KDB +void kdb_dump_stack_on_cpu(int cpu) +{ + if (cpu == raw_smp_processor_id() || !IS_ENABLED(CONFIG_SMP)) { + dump_stack(); + return; + } + + if (!(kgdb_info[cpu].exception_state & DCPU_IS_SLAVE)) { + kdb_printf("ERROR: Task on cpu %d didn't stop in the debugger\n", + cpu); + return; + } + + /* + * In general, architectures don't support dumping the stack of a + * "running" process that's not the current one. From the point of + * view of the Linux, kernel processes that are looping in the kgdb + * slave loop are still "running". There's also no API (that actually + * works across all architectures) that can do a stack crawl based + * on registers passed as a parameter. + * + * Solve this conundrum by asking slave CPUs to do the backtrace + * themselves. + */ + kgdb_info[cpu].exception_state |= DCPU_WANT_BT; + while (kgdb_info[cpu].exception_state & DCPU_WANT_BT) + cpu_relax(); +} +#endif + /* * Return true if there is a valid kgdb I/O module. Also if no * debugger is attached a message can be printed to the console about @@ -580,6 +611,9 @@ cpu_loop: atomic_xchg(&kgdb_active, cpu); break; } + } else if (kgdb_info[cpu].exception_state & DCPU_WANT_BT) { + dump_stack(); + kgdb_info[cpu].exception_state &= ~DCPU_WANT_BT; } else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) { if (!raw_spin_is_locked(&dbg_slave_lock)) goto return_normal; diff --git a/kernel/debug/debug_core.h b/kernel/debug/debug_core.h index b4a7c326d546..cd22b5f68831 100644 --- a/kernel/debug/debug_core.h +++ b/kernel/debug/debug_core.h @@ -33,7 +33,7 @@ struct kgdb_state { #define DCPU_WANT_MASTER 0x1 /* Waiting to become a master kgdb cpu */ #define DCPU_NEXT_MASTER 0x2 /* Transition from one master cpu to another */ #define DCPU_IS_SLAVE 0x4 /* Slave cpu enter exception */ -#define DCPU_SSTEP 0x8 /* CPU is single stepping */ +#define DCPU_WANT_BT 0x8 /* Slave cpu should backtrace then clear flag */ struct debuggerinfo_struct { void *debuggerinfo; @@ -76,6 +76,7 @@ extern int kdb_stub(struct kgdb_state *ks); extern int kdb_parse(const char *cmdstr); extern int kdb_common_init_state(struct kgdb_state *ks); extern int kdb_common_deinit_state(void); +extern void kdb_dump_stack_on_cpu(int cpu); #else /* ! CONFIG_KGDB_KDB */ static inline int kdb_stub(struct kgdb_state *ks) { diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c index 7e2379aa0a1e..4af48ac53625 100644 --- a/kernel/debug/kdb/kdb_bt.c +++ b/kernel/debug/kdb/kdb_bt.c @@ -22,20 +22,15 @@ static void kdb_show_stack(struct task_struct *p, void *addr) { int old_lvl = console_loglevel; + console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH; kdb_trap_printk++; - kdb_set_current_task(p); - if (addr) { - show_stack((struct task_struct *)p, addr); - } else if (kdb_current_regs) { -#ifdef CONFIG_X86 - show_stack(p, &kdb_current_regs->sp); -#else - show_stack(p, NULL); -#endif - } else { - show_stack(p, NULL); - } + + if (!addr && kdb_task_has_cpu(p)) + kdb_dump_stack_on_cpu(kdb_process_cpu(p)); + else + show_stack(p, addr); + console_loglevel = old_lvl; kdb_trap_printk--; } @@ -78,12 +73,12 @@ static void kdb_show_stack(struct task_struct *p, void *addr) */ static int -kdb_bt1(struct task_struct *p, unsigned long mask, - int argcount, int btaprompt) +kdb_bt1(struct task_struct *p, unsigned long mask, bool btaprompt) { - char buffer[2]; - if (kdb_getarea(buffer[0], (unsigned long)p) || - kdb_getarea(buffer[0], (unsigned long)(p+1)-1)) + char ch; + + if (kdb_getarea(ch, (unsigned long)p) || + kdb_getarea(ch, (unsigned long)(p+1)-1)) return KDB_BADADDR; if (!kdb_task_state(p, mask)) return 0; @@ -91,22 +86,47 @@ kdb_bt1(struct task_struct *p, unsigned long mask, kdb_ps1(p); kdb_show_stack(p, NULL); if (btaprompt) { - kdb_getstr(buffer, sizeof(buffer), - "Enter <q> to end, <cr> to continue:"); - if (buffer[0] == 'q') { - kdb_printf("\n"); + kdb_printf("Enter <q> to end, <cr> or <space> to continue:"); + do { + ch = kdb_getchar(); + } while (!strchr("\r\n q", ch)); + kdb_printf("\n"); + + /* reset the pager */ + kdb_nextline = 1; + + if (ch == 'q') return 1; - } } touch_nmi_watchdog(); return 0; } +static void +kdb_bt_cpu(unsigned long cpu) +{ + struct task_struct *kdb_tsk; + + if (cpu >= num_possible_cpus() || !cpu_online(cpu)) { + kdb_printf("WARNING: no process for cpu %ld\n", cpu); + return; + } + + /* If a CPU failed to round up we could be here */ + kdb_tsk = KDB_TSK(cpu); + if (!kdb_tsk) { + kdb_printf("WARNING: no task for cpu %ld\n", cpu); + return; + } + + kdb_set_current_task(kdb_tsk); + kdb_bt1(kdb_tsk, ~0UL, false); +} + int kdb_bt(int argc, const char **argv) { int diag; - int argcount = 5; int btaprompt = 1; int nextarg; unsigned long addr; @@ -125,7 +145,7 @@ kdb_bt(int argc, const char **argv) /* Run the active tasks first */ for_each_online_cpu(cpu) { p = kdb_curr_task(cpu); - if (kdb_bt1(p, mask, argcount, btaprompt)) + if (kdb_bt1(p, mask, btaprompt)) return 0; } /* Now the inactive tasks */ @@ -134,7 +154,7 @@ kdb_bt(int argc, const char **argv) return 0; if (task_curr(p)) continue; - if (kdb_bt1(p, mask, argcount, btaprompt)) + if (kdb_bt1(p, mask, btaprompt)) return 0; } kdb_while_each_thread(g, p); } else if (strcmp(argv[0], "btp") == 0) { @@ -148,7 +168,7 @@ kdb_bt(int argc, const char **argv) p = find_task_by_pid_ns(pid, &init_pid_ns); if (p) { kdb_set_current_task(p); - return kdb_bt1(p, ~0UL, argcount, 0); + return kdb_bt1(p, ~0UL, false); } kdb_printf("No process with pid == %ld found\n", pid); return 0; @@ -159,11 +179,10 @@ kdb_bt(int argc, const char **argv) if (diag) return diag; kdb_set_current_task((struct task_struct *)addr); - return kdb_bt1((struct task_struct *)addr, ~0UL, argcount, 0); + return kdb_bt1((struct task_struct *)addr, ~0UL, false); } else if (strcmp(argv[0], "btc") == 0) { unsigned long cpu = ~0; struct task_struct *save_current_task = kdb_current_task; - char buf[80]; if (argc > 1) return KDB_ARGCOUNT; if (argc == 1) { @@ -171,35 +190,22 @@ kdb_bt(int argc, const char **argv) if (diag) return diag; } - /* Recursive use of kdb_parse, do not use argv after - * this point */ - argv = NULL; if (cpu != ~0) { - if (cpu >= num_possible_cpus() || !cpu_online(cpu)) { - kdb_printf("no process for cpu %ld\n", cpu); - return 0; - } - sprintf(buf, "btt 0x%px\n", KDB_TSK(cpu)); - kdb_parse(buf); - return 0; - } - kdb_printf("btc: cpu status: "); - kdb_parse("cpu\n"); - for_each_online_cpu(cpu) { - void *kdb_tsk = KDB_TSK(cpu); - - /* If a CPU failed to round up we could be here */ - if (!kdb_tsk) { - kdb_printf("WARNING: no task for cpu %ld\n", - cpu); - continue; + kdb_bt_cpu(cpu); + } else { + /* + * Recursive use of kdb_parse, do not use argv after + * this point. + */ + argv = NULL; + kdb_printf("btc: cpu status: "); + kdb_parse("cpu\n"); + for_each_online_cpu(cpu) { + kdb_bt_cpu(cpu); + touch_nmi_watchdog(); } - - sprintf(buf, "btt 0x%px\n", kdb_tsk); - kdb_parse(buf); - touch_nmi_watchdog(); + kdb_set_current_task(save_current_task); } - kdb_set_current_task(save_current_task); return 0; } else { if (argc) { @@ -211,7 +217,7 @@ kdb_bt(int argc, const char **argv) kdb_show_stack(kdb_current_task, (void *)addr); return 0; } else { - return kdb_bt1(kdb_current_task, ~0UL, argcount, 0); + return kdb_bt1(kdb_current_task, ~0UL, false); } } diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c index 3a5184eb6977..8bcdded5d61f 100644 --- a/kernel/debug/kdb/kdb_io.c +++ b/kernel/debug/kdb/kdb_io.c @@ -49,14 +49,88 @@ static int kgdb_transition_check(char *buffer) return 0; } -static int kdb_read_get_key(char *buffer, size_t bufsize) +/** + * kdb_handle_escape() - validity check on an accumulated escape sequence. + * @buf: Accumulated escape characters to be examined. Note that buf + * is not a string, it is an array of characters and need not be + * nil terminated. + * @sz: Number of accumulated escape characters. + * + * Return: -1 if the escape sequence is unwanted, 0 if it is incomplete, + * otherwise it returns a mapped key value to pass to the upper layers. + */ +static int kdb_handle_escape(char *buf, size_t sz) +{ + char *lastkey = buf + sz - 1; + + switch (sz) { + case 1: + if (*lastkey == '\e') + return 0; + break; + + case 2: /* \e<something> */ + if (*lastkey == '[') + return 0; + break; + + case 3: + switch (*lastkey) { + case 'A': /* \e[A, up arrow */ + return 16; + case 'B': /* \e[B, down arrow */ + return 14; + case 'C': /* \e[C, right arrow */ + return 6; + case 'D': /* \e[D, left arrow */ + return 2; + case '1': /* \e[<1,3,4>], may be home, del, end */ + case '3': + case '4': + return 0; + } + break; + + case 4: + if (*lastkey == '~') { + switch (buf[2]) { + case '1': /* \e[1~, home */ + return 1; + case '3': /* \e[3~, del */ + return 4; + case '4': /* \e[4~, end */ + return 5; + } + } + break; + } + + return -1; +} + +/** + * kdb_getchar() - Read a single character from a kdb console (or consoles). + * + * Other than polling the various consoles that are currently enabled, + * most of the work done in this function is dealing with escape sequences. + * + * An escape key could be the start of a vt100 control sequence such as \e[D + * (left arrow) or it could be a character in its own right. The standard + * method for detecting the difference is to wait for 2 seconds to see if there + * are any other characters. kdb is complicated by the lack of a timer service + * (interrupts are off), by multiple input sources. Escape sequence processing + * has to be done as states in the polling loop. + * + * Return: The key pressed or a control code derived from an escape sequence. + */ +char kdb_getchar(void) { #define ESCAPE_UDELAY 1000 #define ESCAPE_DELAY (2*1000000/ESCAPE_UDELAY) /* 2 seconds worth of udelays */ - char escape_data[5]; /* longest vt100 escape sequence is 4 bytes */ - char *ped = escape_data; + char buf[4]; /* longest vt100 escape sequence is 4 bytes */ + char *pbuf = buf; int escape_delay = 0; - get_char_func *f, *f_escape = NULL; + get_char_func *f, *f_prev = NULL; int key; for (f = &kdb_poll_funcs[0]; ; ++f) { @@ -65,109 +139,37 @@ static int kdb_read_get_key(char *buffer, size_t bufsize) touch_nmi_watchdog(); f = &kdb_poll_funcs[0]; } - if (escape_delay == 2) { - *ped = '\0'; - ped = escape_data; - --escape_delay; - } - if (escape_delay == 1) { - key = *ped++; - if (!*ped) - --escape_delay; - break; - } + key = (*f)(); if (key == -1) { if (escape_delay) { udelay(ESCAPE_UDELAY); - --escape_delay; + if (--escape_delay == 0) + return '\e'; } continue; } - if (bufsize <= 2) { - if (key == '\r') - key = '\n'; - *buffer++ = key; - *buffer = '\0'; - return -1; - } - if (escape_delay == 0 && key == '\e') { + + /* + * When the first character is received (or we get a change + * input source) we set ourselves up to handle an escape + * sequences (just in case). + */ + if (f_prev != f) { + f_prev = f; + pbuf = buf; escape_delay = ESCAPE_DELAY; - ped = escape_data; - f_escape = f; - } - if (escape_delay) { - *ped++ = key; - if (f_escape != f) { - escape_delay = 2; - continue; - } - if (ped - escape_data == 1) { - /* \e */ - continue; - } else if (ped - escape_data == 2) { - /* \e<something> */ - if (key != '[') - escape_delay = 2; - continue; - } else if (ped - escape_data == 3) { - /* \e[<something> */ - int mapkey = 0; - switch (key) { - case 'A': /* \e[A, up arrow */ - mapkey = 16; - break; - case 'B': /* \e[B, down arrow */ - mapkey = 14; - break; - case 'C': /* \e[C, right arrow */ - mapkey = 6; - break; - case 'D': /* \e[D, left arrow */ - mapkey = 2; - break; - case '1': /* dropthrough */ - case '3': /* dropthrough */ - /* \e[<1,3,4>], may be home, del, end */ - case '4': - mapkey = -1; - break; - } - if (mapkey != -1) { - if (mapkey > 0) { - escape_data[0] = mapkey; - escape_data[1] = '\0'; - } - escape_delay = 2; - } - continue; - } else if (ped - escape_data == 4) { - /* \e[<1,3,4><something> */ - int mapkey = 0; - if (key == '~') { - switch (escape_data[2]) { - case '1': /* \e[1~, home */ - mapkey = 1; - break; - case '3': /* \e[3~, del */ - mapkey = 4; - break; - case '4': /* \e[4~, end */ - mapkey = 5; - break; - } - } - if (mapkey > 0) { - escape_data[0] = mapkey; - escape_data[1] = '\0'; - } - escape_delay = 2; - continue; - } } - break; /* A key to process */ + + *pbuf++ = key; + key = kdb_handle_escape(buf, pbuf - buf); + if (key < 0) /* no escape sequence; return best character */ + return buf[pbuf - buf == 2 ? 1 : 0]; + if (key > 0) + return key; } - return key; + + unreachable(); } /* @@ -188,17 +190,7 @@ static int kdb_read_get_key(char *buffer, size_t bufsize) * function. It is not reentrant - it relies on the fact * that while kdb is running on only one "master debug" cpu. * Remarks: - * - * The buffer size must be >= 2. A buffer size of 2 means that the caller only - * wants a single key. - * - * An escape key could be the start of a vt100 control sequence such as \e[D - * (left arrow) or it could be a character in its own right. The standard - * method for detecting the difference is to wait for 2 seconds to see if there - * are any other characters. kdb is complicated by the lack of a timer service - * (interrupts are off), by multiple input sources and by the need to sometimes - * return after just one key. Escape sequence processing has to be done as - * states in the polling loop. + * The buffer size must be >= 2. */ static char *kdb_read(char *buffer, size_t bufsize) @@ -233,9 +225,7 @@ static char *kdb_read(char *buffer, size_t bufsize) *cp = '\0'; kdb_printf("%s", buffer); poll_again: - key = kdb_read_get_key(buffer, bufsize); - if (key == -1) - return buffer; + key = kdb_getchar(); if (key != 9) tab = 0; switch (key) { @@ -746,7 +736,7 @@ kdb_printit: /* check for having reached the LINES number of printed lines */ if (kdb_nextline >= linecount) { - char buf1[16] = ""; + char ch; /* Watch out for recursion here. Any routine that calls * kdb_printf will come back through here. And kdb_read @@ -781,39 +771,38 @@ kdb_printit: if (logging) printk("%s", moreprompt); - kdb_read(buf1, 2); /* '2' indicates to return - * immediately after getting one key. */ + ch = kdb_getchar(); kdb_nextline = 1; /* Really set output line 1 */ /* empty and reset the buffer: */ kdb_buffer[0] = '\0'; next_avail = kdb_buffer; size_avail = sizeof(kdb_buffer); - if ((buf1[0] == 'q') || (buf1[0] == 'Q')) { + if ((ch == 'q') || (ch == 'Q')) { /* user hit q or Q */ KDB_FLAG_SET(CMD_INTERRUPT); /* command interrupted */ KDB_STATE_CLEAR(PAGER); /* end of command output; back to normal mode */ kdb_grepping_flag = 0; kdb_printf("\n"); - } else if (buf1[0] == ' ') { + } else if (ch == ' ') { kdb_printf("\r"); suspend_grep = 1; /* for this recursion */ - } else if (buf1[0] == '\n') { + } else if (ch == '\n' || ch == '\r') { kdb_nextline = linecount - 1; kdb_printf("\r"); suspend_grep = 1; /* for this recursion */ - } else if (buf1[0] == '/' && !kdb_grepping_flag) { + } else if (ch == '/' && !kdb_grepping_flag) { kdb_printf("\r"); kdb_getstr(kdb_grep_string, KDB_GREP_STRLEN, kdbgetenv("SEARCHPROMPT") ?: "search> "); *strchrnul(kdb_grep_string, '\n') = '\0'; kdb_grepping_flag += KDB_GREPPING_FLAG_SEARCH; suspend_grep = 1; /* for this recursion */ - } else if (buf1[0] && buf1[0] != '\n') { - /* user hit something other than enter */ + } else if (ch) { + /* user hit something unexpected */ suspend_grep = 1; /* for this recursion */ - if (buf1[0] != '/') + if (ch != '/') kdb_printf( "\nOnly 'q', 'Q' or '/' are processed at " "more prompt, input ignored\n"); diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h index 2118d8258b7c..55d052061ef9 100644 --- a/kernel/debug/kdb/kdb_private.h +++ b/kernel/debug/kdb/kdb_private.h @@ -210,6 +210,7 @@ extern void kdb_ps1(const struct task_struct *p); extern void kdb_print_nameval(const char *name, unsigned long val); extern void kdb_send_sig(struct task_struct *p, int sig); extern void kdb_meminfo_proc_show(void); +extern char kdb_getchar(void); extern char *kdb_getstr(char *, size_t, const char *); extern void kdb_gdb_state_pass(char *buf); |