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Merge tag 'printk-for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

Browse Source 
Pull printk updates from Petr Mladek:

 - Benjamin Herrenschmidt solved a problem with non-matched console
   aliases by first checking consoles defined on the command line. It is
   a more conservative approach than the previous attempts.

 - Benjamin also made sure that the console accessible via /dev/console
   always has CON_CONSDEV flag.

 - Andy Shevchenko added the %ptT modifier for printing struct time64_t.
   It extends the existing %ptR handling for struct rtc_time.

 - Bruno Meneguele fixed /dev/kmsg error value returned by unsupported
   SEEK_CUR.

 - Tetsuo Handa removed unused pr_cont_once().

... and a few small fixes.

* tag 'printk-for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
  printk: Remove pr_cont_once()
  printk: handle blank console arguments passed in.
  kernel/printk: add kmsg SEEK_CUR handling
  printk: Fix a typo in comment "interator"->"iterator"
  usb: pulse8-cec: Switch to use %ptT
  ARM: bcm2835: Switch to use %ptT
  lib/vsprintf: Print time64_t in human readable format
  lib/vsprintf: update comment about simple_strto<foo>() functions
  printk: Correctly set CON_CONSDEV even when preferred console was not registered
  printk: Fix preferred console selection with multiple matches
  printk: Move console matching logic into a separate function
  printk: Convert a use of sprintf to snprintf in console_unlock
This commit is contained in:
Linus Torvalds
2020-06-01 12:13:30 -07:00
parent 4d67829e11 8b390ab725
commit ca1f5df23f
10 changed files with 163 additions and 85 deletions
Download Patch File Download Diff File Expand all files Collapse all files

145
kernel/printk/printk.c
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@@ -280,6 +280,7 @@ static struct console *exclusive_console;
static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES];
static int preferred_console = -1;
static bool has_preferred_console;
int console_set_on_cmdline;
EXPORT_SYMBOL(console_set_on_cmdline);
@@ -974,6 +975,16 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
user->idx = log_next_idx;
user->seq = log_next_seq;
break;
case SEEK_CUR:
/*
* It isn't supported due to the record nature of this
* interface: _SET _DATA and _END point to very specific
* record positions, while _CUR would be more useful in case
* of a byte-based log. Because of that, return the default
* errno value for invalid seek operation.
*/
ret = -ESPIPE;
break;
default:
ret = -EINVAL;
}
@@ -2140,7 +2151,7 @@ asmlinkage __visible void early_printk(const char *fmt, ...)
#endif
static int __add_preferred_console(char *name, int idx, char *options,
char *brl_options)
char *brl_options, bool user_specified)
{
struct console_cmdline *c;
int i;
@@ -2155,6 +2166,8 @@ static int __add_preferred_console(char *name, int idx, char *options,
if (strcmp(c->name, name) == 0 && c->index == idx) {
if (!brl_options)
preferred_console = i;
if (user_specified)
c->user_specified = true;
return 0;
}
}
@@ -2164,6 +2177,7 @@ static int __add_preferred_console(char *name, int idx, char *options,
preferred_console = i;
strlcpy(c->name, name, sizeof(c->name));
c->options = options;
c->user_specified = user_specified;
braille_set_options(c, brl_options);
c->index = idx;
@@ -2190,6 +2204,9 @@ static int __init console_setup(char *str)
char *s, *options, *brl_options = NULL;
int idx;
if (str[0] == 0)
return 1;
if (_braille_console_setup(&str, &brl_options))
return 1;
@@ -2218,7 +2235,7 @@ static int __init console_setup(char *str)
idx = simple_strtoul(s, NULL, 10);
*s = 0;
__add_preferred_console(buf, idx, options, brl_options);
__add_preferred_console(buf, idx, options, brl_options, true);
console_set_on_cmdline = 1;
return 1;
}
@@ -2239,7 +2256,7 @@ __setup("console=", console_setup);
*/
int add_preferred_console(char *name, int idx, char *options)
{
return __add_preferred_console(name, idx, options, NULL);
return __add_preferred_console(name, idx, options, NULL, false);
}
bool console_suspend_enabled = true;
@@ -2438,9 +2455,9 @@ again:
printk_safe_enter_irqsave(flags);
raw_spin_lock(&logbuf_lock);
if (console_seq < log_first_seq) {
len = sprintf(text,
"** %llu printk messages dropped **\n",
log_first_seq - console_seq);
len = snprintf(text, sizeof(text),
"** %llu printk messages dropped **\n",
log_first_seq - console_seq);
/* messages are gone, move to first one */
console_seq = log_first_seq;
@@ -2651,6 +2668,63 @@ static int __init keep_bootcon_setup(char *str)
early_param("keep_bootcon", keep_bootcon_setup);
/*
* This is called by register_console() to try to match
* the newly registered console with any of the ones selected
* by either the command line or add_preferred_console() and
* setup/enable it.
*
* Care need to be taken with consoles that are statically
* enabled such as netconsole
*/
static int try_enable_new_console(struct console *newcon, bool user_specified)
{
struct console_cmdline *c;
int i;
for (i = 0, c = console_cmdline;
i < MAX_CMDLINECONSOLES && c->name[0];
i++, c++) {
if (c->user_specified != user_specified)
continue;
if (!newcon->match ||
newcon->match(newcon, c->name, c->index, c->options) != 0) {
/* default matching */
BUILD_BUG_ON(sizeof(c->name) != sizeof(newcon->name));
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 0;
if (newcon->setup &&
newcon->setup(newcon, c->options) != 0)
return -EIO;
}
newcon->flags |= CON_ENABLED;
if (i == preferred_console) {
newcon->flags |= CON_CONSDEV;
has_preferred_console = true;
}
return 0;
}
/*
* Some consoles, such as pstore and netconsole, can be enabled even
* without matching. Accept the pre-enabled consoles only when match()
* and setup() had a change to be called.
*/
if (newcon->flags & CON_ENABLED && c->user_specified == user_specified)
return 0;
return -ENOENT;
}
/*
* The console driver calls this routine during kernel initialization
* to register the console printing procedure with printk() and to
@@ -2672,11 +2746,9 @@ early_param("keep_bootcon", keep_bootcon_setup);
*/
void register_console(struct console *newcon)
{
int i;
unsigned long flags;
struct console *bcon = NULL;
struct console_cmdline *c;
static bool has_preferred;
int err;
for_each_console(bcon) {
if (WARN(bcon == newcon, "console '%s%d' already registered\n",
@@ -2701,15 +2773,15 @@ void register_console(struct console *newcon)
if (console_drivers && console_drivers->flags & CON_BOOT)
bcon = console_drivers;
if (!has_preferred || bcon || !console_drivers)
has_preferred = preferred_console >= 0;
if (!has_preferred_console || bcon || !console_drivers)
has_preferred_console = preferred_console >= 0;
/*
* See if we want to use this console driver. If we
* didn't select a console we take the first one
* that registers here.
*/
if (!has_preferred) {
if (!has_preferred_console) {
if (newcon->index < 0)
newcon->index = 0;
if (newcon->setup == NULL ||
@@ -2717,47 +2789,20 @@ void register_console(struct console *newcon)
newcon->flags |= CON_ENABLED;
if (newcon->device) {
newcon->flags |= CON_CONSDEV;
has_preferred = true;
has_preferred_console = true;
}
}
}
/*
* See if this console matches one we selected on
* the command line.
*/
for (i = 0, c = console_cmdline;
i < MAX_CMDLINECONSOLES && c->name[0];
i++, c++) {
if (!newcon->match ||
newcon->match(newcon, c->name, c->index, c->options) != 0) {
/* default matching */
BUILD_BUG_ON(sizeof(c->name) != sizeof(newcon->name));
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;
/* See if this console matches one we selected on the command line */
err = try_enable_new_console(newcon, true);
if (_braille_register_console(newcon, c))
return;
/* If not, try to match against the platform default(s) */
if (err == -ENOENT)
err = try_enable_new_console(newcon, false);
if (newcon->setup &&
newcon->setup(newcon, c->options) != 0)
break;
}
newcon->flags |= CON_ENABLED;
if (i == preferred_console) {
newcon->flags |= CON_CONSDEV;
has_preferred = true;
}
break;
}
if (!(newcon->flags & CON_ENABLED))
/* printk() messages are not printed to the Braille console. */
if (err || newcon->flags & CON_BRL)
return;
/*
@@ -2779,6 +2824,8 @@ void register_console(struct console *newcon)
console_drivers = newcon;
if (newcon->next)
newcon->next->flags &= ~CON_CONSDEV;
/* Ensure this flag is always set for the head of the list */
newcon->flags |= CON_CONSDEV;
} else {
newcon->next = console_drivers->next;
console_drivers->next = newcon;
@@ -3384,7 +3431,7 @@ out:
EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
/**
* kmsg_dump_rewind_nolock - reset the interator (unlocked version)
* kmsg_dump_rewind_nolock - reset the iterator (unlocked version)
* @dumper: registered kmsg dumper
*
* Reset the dumper's iterator so that kmsg_dump_get_line() and
@@ -3402,7 +3449,7 @@ void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
}
/**
* kmsg_dump_rewind - reset the interator
* kmsg_dump_rewind - reset the iterator
* @dumper: registered kmsg dumper
*
* Reset the dumper's iterator so that kmsg_dump_get_line() and