user/sven/linux.git/include/linux/printk.h, branch v4.0

hexdump: make it return number of bytes placed in buffer

2015-02-13T02:54:15Z

This patch makes hexdump return the number of bytes placed in the buffer excluding trailing NUL. In the case of overflow it returns the desired amount of bytes to produce the entire dump. Thus, it mimics snprintf(). This will be useful for users that would like to repeat with a bigger buffer. [akpm@linux-foundation.org: fix printk warning] Signed-off-by: Andy Shevchenko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

printk: add dummy routine for when CONFIG_PRINTK=n

2015-01-26T21:37:18Z

There are missing dummy routines for log_buf_addr_get() and log_buf_len_get() for when CONFIG_PRINTK is not set causing build failures. This patch adds these dummy routines at the appropriate location. Signed-off-by: Pranith Kumar Cc: Michael Ellerman Reviewed-by: Petr Mladek Acked-by: Steven Rostedt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge tag 'trace-seq-buf-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2014-12-11T04:35:41Z

Pull nmi-safe seq_buf printk update from Steven Rostedt: "This code is a fork from the trace-3.19 pull as it needed the trace_seq clean ups from that branch. This code solves the issue of performing stack dumps from NMI context. The issue is that printk() is not safe from NMI context as if the NMI were to trigger when a printk() was being performed, the NMI could deadlock from the printk() internal locks. This has been seen in practice. With lots of review from Petr Mladek, this code went through several iterations, and we feel that it is now at a point of quality to be accepted into mainline. Here's what is contained in this patch set: - Creates a "seq_buf" generic buffer utility that allows a descriptor to be passed around where functions can write their own "printk()" formatted strings into it. The generic version was pulled out of the trace_seq() code that was made specifically for tracing. - The seq_buf code was change to model the seq_file code. I have a patch (not included for 3.19) that converts the seq_file.c code over to use seq_buf.c like the trace_seq.c code does. This was done to make sure that seq_buf.c is compatible with seq_file.c. I may try to get that patch in for 3.20. - The seq_buf.c file was moved to lib/ to remove it from being dependent on CONFIG_TRACING. - The printk() was updated to allow for a per_cpu "override" of the internal calls. That is, instead of writing to the console, a call to printk() may do something else. This made it easier to allow the NMI to change what printk() does in order to call dump_stack() without needing to update that code as well. - Finally, the dump_stack from all CPUs via NMI code was converted to use the seq_buf code. The caller to trigger the NMI code would wait till all the NMIs finished, and then it would print the seq_buf data to the console safely from a non NMI context One added bonus is that this code also makes the NMI dump stack work on PREEMPT_RT kernels. As printk() includes sleeping locks on PREEMPT_RT, printk() only writes to console if the console does not use any rt_mutex converted spin locks. Which a lot do" * tag 'trace-seq-buf-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: x86/nmi: Fix use of unallocated cpumask_var_t printk/percpu: Define printk_func when printk is not defined x86/nmi: Perform a safe NMI stack trace on all CPUs printk: Add per_cpu printk func to allow printk to be diverted seq_buf: Move the seq_buf code to lib/ seq-buf: Make seq_buf_bprintf() conditional on CONFIG_BINARY_PRINTF tracing: Add seq_buf_get_buf() and seq_buf_commit() helper functions tracing: Have seq_buf use full buffer seq_buf: Add seq_buf_can_fit() helper function tracing: Add paranoid size check in trace_printk_seq() tracing: Use trace_seq_used() and seq_buf_used() instead of len tracing: Clean up tracing_fill_pipe_page() seq_buf: Create seq_buf_used() to find out how much was written tracing: Add a seq_buf_clear() helper and clear len and readpos in init tracing: Convert seq_buf fields to be like seq_file fields tracing: Convert seq_buf_path() to be like seq_path() tracing: Create seq_buf layer in trace_seq

printk: remove used-once early_vprintk

2014-12-11T01:41:10Z

Eliminate the unlikely possibility of message interleaving for early_printk/early_vprintk use. early_vprintk can be done via the %pV extension so remove this unnecessary function and change early_printk to have the equivalent vprintk code. All uses of early_printk already end with a newline so also remove the unnecessary newline from the early_printk function. Signed-off-by: Joe Perches Acked-by: Chris Metcalf Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

printk/percpu: Define printk_func when printk is not defined

2014-11-21T16:19:15Z

To avoid include hell, the per_cpu variable printk_func was declared in percpu.h. But it is only defined if printk is defined. As users of printk may also use the printk_func variable, it needs to be defined even if CONFIG_PRINTK is not. Also add a printk.h include in percpu.h just to be safe. Link: http://lkml.kernel.org/r/20141121183215.01ba539c@canb.auug.org.au Reported-by: Stephen Rothwell Signed-off-by: Steven Rostedt

printk: Add per_cpu printk func to allow printk to be diverted

2014-11-20T03:01:21Z

Being able to divert printk to call another function besides the normal logging is useful for such things like NMI handling. If some functions are to be called from NMI that does printk() it is possible to lock up the box if the nmi handler triggers when another printk is happening. One example of this use is to perform a stack trace on all CPUs via NMI. But if the NMI is to do the printk() it can cause the system to lock up. By allowing the printk to be diverted to another function that can safely record the printk output and then print it when it in a safe context then NMIs will be safe to call these functions like show_regs(). Link: http://lkml.kernel.org/p/20140619213952.209176403@goodmis.org Tested-by: Jiri Kosina Acked-by: Jiri Kosina Acked-by: Paul E. McKenney Reviewed-by: Petr Mladek Signed-off-by: Steven Rostedt

printk: Add function to return log buffer address and size

2014-08-13T05:13:44Z

Platforms like IBM Power Systems supports service processor assisted dump. It provides interface to add memory region to be captured when system is crashed. During initialization/running we can add kernel memory region to be collected. Presently we don't have a way to get the log buffer base address and size. This patch adds support to return log buffer address and size. Signed-off-by: Vasant Hegde Signed-off-by: Benjamin Herrenschmidt Acked-by: Andrew Morton

printk: rename DEFAULT_MESSAGE_LOGLEVEL

2014-08-07T01:01:24Z

Commit a8fe19ebfbfd ("kernel/printk: use symbolic defines for console loglevels") makes consistent use of symbolic values for printk() log levels. The naming scheme used is different from the one used for DEFAULT_MESSAGE_LOGLEVEL though. Change that symbol name to be MESSAGE_LOGLEVEL_DEFAULT for consistency. And because the value of that symbol comes from a similarly-named config option, rename CONFIG_DEFAULT_MESSAGE_LOGLEVEL as well. Signed-off-by: Alex Elder Cc: Andi Kleen Cc: Borislav Petkov Cc: Jan Kara Cc: John Stultz Cc: Petr Mladek Cc: Steven Rostedt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/printk: use symbolic defines for console loglevels

2014-06-04T23:54:17Z

... instead of naked numbers. Stuff in sysrq.c used to set it to 8 which is supposed to mean above default level so set it to DEBUG instead as we're terminating/killing all tasks and we want to be verbose there. Also, correct the check in x86_64_start_kernel which should be >= as we're clearly issuing the string there for all debug levels, not only the magical 10. Signed-off-by: Borislav Petkov Acked-by: Kees Cook Acked-by: Randy Dunlap Cc: Joe Perches Cc: Valdis Kletnieks Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Documentation: expand/clarify debug documentation

2014-06-04T23:54:17Z

The pr_debug() and related debug print macros all differ from the normal pr_XXX() macros, in that the normal ones print unconditionally, while the debug macros are compiled out unless DEBUG is defined or CONFIG_DYNAMIC_DEBUG is set. This isn't obvious, and the only way to find this out is either to review the actual printk.h code or to read CodingStyle, and the message there doesn't highlight the fact. Change Documentation/CodingStyle to clearly indicate that pr_debug() and related debug printing macros behave differently than all other pr_XXX() macros, and attempt to clarify when and where the different debug printing methods might be used. Add short comment to printk.h above the pr_XXX() macros indicating that while these macros print unconditionally, pr_debug() does not. Signed-off-by: Dan Streetman Cc: Joe Perches Cc: Fabian Frederick Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds