diff options
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 9 | ||||
| -rw-r--r-- | kernel/printk/printk.c | 30 | ||||
| -rw-r--r-- | lib/vsprintf.c | 36 |
3 files changed, 50 insertions, 25 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 49f495c9a7f8..86e2b586c171 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -724,6 +724,12 @@ hvc<n> Use the hypervisor console device <n>. This is for both Xen and PowerPC hypervisors. + { null | "" } + Use to disable console output, i.e., to have kernel + console messages discarded. + This must be the only console= parameter used on the + kernel command line. + If the device connected to the port is not a TTY but a braille device, prepend "brl," before the device type, for instance console=brl,ttyS0 @@ -3485,8 +3491,7 @@ difficult since unequal pointers can no longer be compared. However, if this command-line option is specified, then all normal pointers will have their true - value printed. Pointers printed via %pK may still be - hashed. This option should only be specified when + value printed. This option should only be specified when debugging the kernel. Please do not use on production kernels. diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 155229f0cf0f..21fb4e1cd7db 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -146,8 +146,10 @@ static int __control_devkmsg(char *str) static int __init control_devkmsg(char *str) { - if (__control_devkmsg(str) < 0) + if (__control_devkmsg(str) < 0) { + pr_warn("printk.devkmsg: bad option string '%s'\n", str); return 1; + } /* * Set sysctl string accordingly: @@ -166,7 +168,7 @@ static int __init control_devkmsg(char *str) */ devkmsg_log |= DEVKMSG_LOG_MASK_LOCK; - return 0; + return 1; } __setup("printk.devkmsg=", control_devkmsg); @@ -2323,6 +2325,20 @@ asmlinkage __visible void early_printk(const char *fmt, ...) } #endif +static void set_user_specified(struct console_cmdline *c, bool user_specified) +{ + if (!user_specified) + return; + + /* + * @c console was defined by the user on the command line. + * Do not clear when added twice also by SPCR or the device tree. + */ + c->user_specified = true; + /* At least one console defined by the user on the command line. */ + console_set_on_cmdline = 1; +} + static int __add_preferred_console(char *name, int idx, char *options, char *brl_options, bool user_specified) { @@ -2339,8 +2355,7 @@ 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; + set_user_specified(c, user_specified); return 0; } } @@ -2350,7 +2365,7 @@ 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; + set_user_specified(c, user_specified); braille_set_options(c, brl_options); c->index = idx; @@ -2416,7 +2431,6 @@ static int __init console_setup(char *str) *s = 0; __add_preferred_console(buf, idx, options, brl_options, true); - console_set_on_cmdline = 1; return 1; } __setup("console=", console_setup); @@ -3226,7 +3240,7 @@ static DEFINE_PER_CPU(int, printk_pending); static void wake_up_klogd_work_func(struct irq_work *irq_work) { - int pending = __this_cpu_xchg(printk_pending, 0); + int pending = this_cpu_xchg(printk_pending, 0); if (pending & PRINTK_PENDING_OUTPUT) { /* If trylock fails, someone else is doing the printing */ @@ -3260,7 +3274,7 @@ void defer_console_output(void) return; preempt_disable(); - __this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT); + this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT); irq_work_queue(this_cpu_ptr(&wake_up_klogd_work)); preempt_enable(); } diff --git a/lib/vsprintf.c b/lib/vsprintf.c index f96c66899df6..51495c1aceb8 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -54,6 +54,10 @@ #include <linux/string_helpers.h> #include "kstrtox.h" +/* Disable pointer hashing if requested */ +bool no_hash_pointers __ro_after_init; +EXPORT_SYMBOL_GPL(no_hash_pointers); + static noinline unsigned long long simple_strntoull(const char *startp, size_t max_chars, char **endp, unsigned int base) { const char *cp; @@ -849,6 +853,19 @@ static char *ptr_to_id(char *buf, char *end, const void *ptr, return pointer_string(buf, end, (const void *)hashval, spec); } +static char *default_pointer(char *buf, char *end, const void *ptr, + struct printf_spec spec) +{ + /* + * default is to _not_ leak addresses, so hash before printing, + * unless no_hash_pointers is specified on the command line. + */ + if (unlikely(no_hash_pointers)) + return pointer_string(buf, end, ptr, spec); + + return ptr_to_id(buf, end, ptr, spec); +} + int kptr_restrict __read_mostly; static noinline_for_stack @@ -858,7 +875,7 @@ char *restricted_pointer(char *buf, char *end, const void *ptr, switch (kptr_restrict) { case 0: /* Handle as %p, hash and do _not_ leak addresses. */ - return ptr_to_id(buf, end, ptr, spec); + return default_pointer(buf, end, ptr, spec); case 1: { const struct cred *cred; @@ -2236,10 +2253,6 @@ char *fwnode_string(char *buf, char *end, struct fwnode_handle *fwnode, return widen_string(buf, buf - buf_start, end, spec); } -/* Disable pointer hashing if requested */ -bool no_hash_pointers __ro_after_init; -EXPORT_SYMBOL_GPL(no_hash_pointers); - int __init no_hash_pointers_enable(char *str) { if (no_hash_pointers) @@ -2468,7 +2481,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, case 'e': /* %pe with a non-ERR_PTR gets treated as plain %p */ if (!IS_ERR(ptr)) - break; + return default_pointer(buf, end, ptr, spec); return err_ptr(buf, end, ptr, spec); case 'u': case 'k': @@ -2478,16 +2491,9 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, default: return error_string(buf, end, "(einval)", spec); } + default: + return default_pointer(buf, end, ptr, spec); } - - /* - * default is to _not_ leak addresses, so hash before printing, - * unless no_hash_pointers is specified on the command line. - */ - if (unlikely(no_hash_pointers)) - return pointer_string(buf, end, ptr, spec); - else - return ptr_to_id(buf, end, ptr, spec); } /* |