These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / Documentation / printk-formats.txt

diff --git a/kernel/Documentation/printk-formats.txt b/kernel/Documentation/printk-formats.txt
index 2216eb1..b784c27 100644 (file)
--- a/kernel/Documentation/printk-formats.txt
+++ b/kernel/Documentation/printk-formats.txt
@@ -23,6 +23,10 @@ Example:
 
 Reminder: sizeof() result is of type size_t.
 
+The kernel's printf does not support %n. For obvious reasons, floating
+point formats (%e, %f, %g, %a) are also not recognized. Use of any
+unsupported specifier or length qualifier results in a WARN and early
+return from vsnprintf.
 
 Raw pointer value SHOULD be printed with %p. The kernel supports
 the following extended format specifiers for pointer types:
@@ -119,6 +123,7 @@ Raw buffer as an escaped string:
        If field width is omitted the 1 byte only will be escaped.
 
 Raw buffer as a hex string:
+
        %*ph    00 01 02  ...  3f
        %*phC   00:01:02: ... :3f
        %*phD   00-01-02- ... -3f
@@ -234,6 +239,7 @@ UUID/GUID addresses:
        Passed by reference.
 
 dentry names:
+
        %pd{,2,3,4}
        %pD{,2,3,4}
 
@@ -256,6 +262,8 @@ struct va_format:
                va_list *va;
        };
 
+       Implements a "recursive vsnprintf".
+
        Do not use this feature without some mechanism to verify the
        correctness of the format string and va_list arguments.
 
@@ -284,6 +292,27 @@ bitmap and its derivatives such as cpumask and nodemask:
 
        Passed by reference.
 
+Network device features:
+
+       %pNF    0x000000000000c000
+
+       For printing netdev_features_t.
+
+       Passed by reference.
+
+Command from struct task_struct
+
+       %pT     ls
+
+       For printing executable name excluding path from struct
+       task_struct.
+
+       Passed by reference.
+
+If you add other %p extensions, please extend lib/test_printf.c with
+one or more test cases, if at all feasible.
+
+
 Thank you for your cooperation and attention.