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Diffstat (limited to 'kernel/debug/kdb/kdb_io.c')
-rw-r--r--kernel/debug/kdb/kdb_io.c218
1 files changed, 127 insertions, 91 deletions
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 683a799618ad..6a77f1c779c4 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -9,7 +9,6 @@
* Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved.
*/
-#include <linux/module.h>
#include <linux/types.h>
#include <linux/ctype.h>
#include <linux/kernel.h>
@@ -132,6 +131,7 @@ char kdb_getchar(void)
int escape_delay = 0;
get_char_func *f, *f_prev = NULL;
int key;
+ static bool last_char_was_cr;
for (f = &kdb_poll_funcs[0]; ; ++f) {
if (*f == NULL) {
@@ -151,6 +151,18 @@ char kdb_getchar(void)
}
/*
+ * The caller expects that newlines are either CR or LF. However
+ * some terminals send _both_ CR and LF. Avoid having to handle
+ * this in the caller by stripping the LF if we saw a CR right
+ * before.
+ */
+ if (last_char_was_cr && key == '\n') {
+ last_char_was_cr = false;
+ continue;
+ }
+ last_char_was_cr = (key == '\r');
+
+ /*
* 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).
@@ -172,6 +184,33 @@ char kdb_getchar(void)
unreachable();
}
+/**
+ * kdb_position_cursor() - Place cursor in the correct horizontal position
+ * @prompt: Nil-terminated string containing the prompt string
+ * @buffer: Nil-terminated string containing the entire command line
+ * @cp: Cursor position, pointer the character in buffer where the cursor
+ * should be positioned.
+ *
+ * The cursor is positioned by sending a carriage-return and then printing
+ * the content of the line until we reach the correct cursor position.
+ *
+ * There is some additional fine detail here.
+ *
+ * Firstly, even though kdb_printf() will correctly format zero-width fields
+ * we want the second call to kdb_printf() to be conditional. That keeps things
+ * a little cleaner when LOGGING=1.
+ *
+ * Secondly, we can't combine everything into one call to kdb_printf() since
+ * that renders into a fixed length buffer and the combined print could result
+ * in unwanted truncation.
+ */
+static void kdb_position_cursor(char *prompt, char *buffer, char *cp)
+{
+ kdb_printf("\r%s", prompt);
+ if (cp > buffer)
+ kdb_printf("%.*s", (int)(cp - buffer), buffer);
+}
+
/*
* kdb_read
*
@@ -208,8 +247,7 @@ static char *kdb_read(char *buffer, size_t bufsize)
int count;
int i;
int diag, dtab_count;
- int key, buf_size, ret;
-
+ int key, ret;
diag = kdbgetintenv("DTABCOUNT", &dtab_count);
if (diag)
@@ -231,21 +269,15 @@ poll_again:
switch (key) {
case 8: /* backspace */
if (cp > buffer) {
- if (cp < lastchar) {
- memcpy(tmpbuffer, cp, lastchar - cp);
- memcpy(cp-1, tmpbuffer, lastchar - cp);
- }
- *(--lastchar) = '\0';
- --cp;
- kdb_printf("\b%s \r", cp);
- tmp = *cp;
- *cp = '\0';
- kdb_printf(kdb_prompt_str);
- kdb_printf("%s", buffer);
- *cp = tmp;
+ memmove(cp-1, cp, lastchar - cp + 1);
+ lastchar--;
+ cp--;
+ kdb_printf("\b%s ", cp);
+ kdb_position_cursor(kdb_prompt_str, buffer, cp);
}
break;
- case 13: /* enter */
+ case 10: /* linefeed */
+ case 13: /* carriage return */
*lastchar++ = '\n';
*lastchar++ = '\0';
if (!KDB_STATE(KGDB_TRANS)) {
@@ -256,22 +288,16 @@ poll_again:
return buffer;
case 4: /* Del */
if (cp < lastchar) {
- memcpy(tmpbuffer, cp+1, lastchar - cp - 1);
- memcpy(cp, tmpbuffer, lastchar - cp - 1);
- *(--lastchar) = '\0';
- kdb_printf("%s \r", cp);
- tmp = *cp;
- *cp = '\0';
- kdb_printf(kdb_prompt_str);
- kdb_printf("%s", buffer);
- *cp = tmp;
+ memmove(cp, cp+1, lastchar - cp);
+ lastchar--;
+ kdb_printf("%s ", cp);
+ kdb_position_cursor(kdb_prompt_str, buffer, cp);
}
break;
case 1: /* Home */
if (cp > buffer) {
- kdb_printf("\r");
- kdb_printf(kdb_prompt_str);
cp = buffer;
+ kdb_position_cursor(kdb_prompt_str, buffer, cp);
}
break;
case 5: /* End */
@@ -287,11 +313,10 @@ poll_again:
}
break;
case 14: /* Down */
- memset(tmpbuffer, ' ',
- strlen(kdb_prompt_str) + (lastchar-buffer));
- *(tmpbuffer+strlen(kdb_prompt_str) +
- (lastchar-buffer)) = '\0';
- kdb_printf("\r%s\r", tmpbuffer);
+ case 16: /* Up */
+ kdb_printf("\r%*c\r",
+ (int)(strlen(kdb_prompt_str) + (lastchar - buffer)),
+ ' ');
*lastchar = (char)key;
*(lastchar+1) = '\0';
return lastchar;
@@ -301,33 +326,19 @@ poll_again:
++cp;
}
break;
- case 16: /* Up */
- memset(tmpbuffer, ' ',
- strlen(kdb_prompt_str) + (lastchar-buffer));
- *(tmpbuffer+strlen(kdb_prompt_str) +
- (lastchar-buffer)) = '\0';
- kdb_printf("\r%s\r", tmpbuffer);
- *lastchar = (char)key;
- *(lastchar+1) = '\0';
- return lastchar;
case 9: /* Tab */
if (tab < 2)
++tab;
- p_tmp = buffer;
- while (*p_tmp == ' ')
- p_tmp++;
- if (p_tmp > cp)
- break;
- memcpy(tmpbuffer, p_tmp, cp-p_tmp);
- *(tmpbuffer + (cp-p_tmp)) = '\0';
- p_tmp = strrchr(tmpbuffer, ' ');
- if (p_tmp)
- ++p_tmp;
- else
- p_tmp = tmpbuffer;
- len = strlen(p_tmp);
- buf_size = sizeof(tmpbuffer) - (p_tmp - tmpbuffer);
- count = kallsyms_symbol_complete(p_tmp, buf_size);
+
+ tmp = *cp;
+ *cp = '\0';
+ p_tmp = strrchr(buffer, ' ');
+ p_tmp = (p_tmp ? p_tmp + 1 : buffer);
+ strscpy(tmpbuffer, p_tmp, sizeof(tmpbuffer));
+ *cp = tmp;
+
+ len = strlen(tmpbuffer);
+ count = kallsyms_symbol_complete(tmpbuffer, sizeof(tmpbuffer));
if (tab == 2 && count > 0) {
kdb_printf("\n%d symbols are found.", count);
if (count > dtab_count) {
@@ -339,46 +350,51 @@ poll_again:
}
kdb_printf("\n");
for (i = 0; i < count; i++) {
- ret = kallsyms_symbol_next(p_tmp, i, buf_size);
+ ret = kallsyms_symbol_next(tmpbuffer, i, sizeof(tmpbuffer));
if (WARN_ON(!ret))
break;
if (ret != -E2BIG)
- kdb_printf("%s ", p_tmp);
+ kdb_printf("%s ", tmpbuffer);
else
- kdb_printf("%s... ", p_tmp);
- *(p_tmp + len) = '\0';
+ kdb_printf("%s... ", tmpbuffer);
+ tmpbuffer[len] = '\0';
}
if (i >= dtab_count)
kdb_printf("...");
kdb_printf("\n");
- kdb_printf(kdb_prompt_str);
+ kdb_printf("%s", kdb_prompt_str);
kdb_printf("%s", buffer);
+ if (cp != lastchar)
+ kdb_position_cursor(kdb_prompt_str, buffer, cp);
} else if (tab != 2 && count > 0) {
- len_tmp = strlen(p_tmp);
- strncpy(p_tmp+len_tmp, cp, lastchar-cp+1);
- len_tmp = strlen(p_tmp);
- strncpy(cp, p_tmp+len, len_tmp-len + 1);
- len = len_tmp - len;
- kdb_printf("%s", cp);
- cp += len;
- lastchar += len;
+ /* How many new characters do we want from tmpbuffer? */
+ len_tmp = strlen(tmpbuffer) - len;
+ if (lastchar + len_tmp >= bufend)
+ len_tmp = bufend - lastchar;
+
+ if (len_tmp) {
+ /* + 1 ensures the '\0' is memmove'd */
+ memmove(cp+len_tmp, cp, (lastchar-cp) + 1);
+ memcpy(cp, tmpbuffer+len, len_tmp);
+ kdb_printf("%s", cp);
+ cp += len_tmp;
+ lastchar += len_tmp;
+ if (cp != lastchar)
+ kdb_position_cursor(kdb_prompt_str,
+ buffer, cp);
+ }
}
kdb_nextline = 1; /* reset output line number */
break;
default:
if (key >= 32 && lastchar < bufend) {
if (cp < lastchar) {
- memcpy(tmpbuffer, cp, lastchar - cp);
- memcpy(cp+1, tmpbuffer, lastchar - cp);
- *++lastchar = '\0';
+ memmove(cp+1, cp, lastchar - cp + 1);
+ lastchar++;
*cp = key;
- kdb_printf("%s\r", cp);
+ kdb_printf("%s", cp);
++cp;
- tmp = *cp;
- *cp = '\0';
- kdb_printf(kdb_prompt_str);
- kdb_printf("%s", buffer);
- *cp = tmp;
+ kdb_position_cursor(kdb_prompt_str, buffer, cp);
} else {
*++lastchar = '\0';
*cp++ = key;
@@ -437,7 +453,7 @@ char *kdb_getstr(char *buffer, size_t bufsize, const char *prompt)
{
if (prompt && kdb_prompt_str != prompt)
strscpy(kdb_prompt_str, prompt, CMD_BUFLEN);
- kdb_printf(kdb_prompt_str);
+ kdb_printf("%s", kdb_prompt_str);
kdb_nextline = 1; /* Prompt and input resets line number */
return kdb_read(buffer, bufsize);
}
@@ -545,25 +561,40 @@ static int kdb_search_string(char *searched, char *searchfor)
static void kdb_msg_write(const char *msg, int msg_len)
{
struct console *c;
+ const char *cp;
+ int cookie;
+ int len;
if (msg_len == 0)
return;
- if (dbg_io_ops) {
- const char *cp = msg;
- int len = msg_len;
+ cp = msg;
+ len = msg_len;
- while (len--) {
- dbg_io_ops->write_char(*cp);
- cp++;
- }
+ while (len--) {
+ dbg_io_ops->write_char(*cp);
+ cp++;
}
- for_each_console(c) {
- if (!(c->flags & CON_ENABLED))
+ /*
+ * The console_srcu_read_lock() only provides safe console list
+ * traversal. The use of the ->write() callback relies on all other
+ * CPUs being stopped at the moment and console drivers being able to
+ * handle reentrance when @oops_in_progress is set.
+ *
+ * There is no guarantee that every console driver can handle
+ * reentrance in this way; the developer deploying the debugger
+ * is responsible for ensuring that the console drivers they
+ * have selected handle reentrance appropriately.
+ */
+ cookie = console_srcu_read_lock();
+ for_each_console_srcu(c) {
+ if (!(console_srcu_read_flags(c) & CON_ENABLED))
continue;
if (c == dbg_io_ops->cons)
continue;
+ if (!c->write)
+ continue;
/*
* Set oops_in_progress to encourage the console drivers to
* disregard their internal spin locks: in the current calling
@@ -578,6 +609,7 @@ static void kdb_msg_write(const char *msg, int msg_len)
--oops_in_progress;
touch_nmi_watchdog();
}
+ console_srcu_read_unlock(cookie);
}
int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
@@ -591,7 +623,7 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
int this_cpu, old_cpu;
char *cp, *cp2, *cphold = NULL, replaced_byte = ' ';
char *moreprompt = "more> ";
- unsigned long uninitialized_var(flags);
+ unsigned long flags;
/* Serialize kdb_printf if multiple cpus try to write at once.
* But if any cpu goes recursive in kdb, just print the output,
@@ -706,12 +738,16 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
size_avail = sizeof(kdb_buffer) - len;
goto kdb_print_out;
}
- if (kdb_grepping_flag >= KDB_GREPPING_FLAG_SEARCH)
+ if (kdb_grepping_flag >= KDB_GREPPING_FLAG_SEARCH) {
/*
* This was a interactive search (using '/' at more
- * prompt) and it has completed. Clear the flag.
+ * prompt) and it has completed. Replace the \0 with
+ * its original value to ensure multi-line strings
+ * are handled properly, and return to normal mode.
*/
+ *cphold = replaced_byte;
kdb_grepping_flag = 0;
+ }
/*
* at this point the string is a full line and
* should be printed, up to the null.
generated by cgit (git 2.34.1) at 2025-07-24 07:13:20 +0000