X-Git-Url: https://git.kernelconcepts.de/?a=blobdiff_plain;f=Documentation%2Fprintk-formats.txt;h=b784c270105f40e8320cd388cb9a8ef1e2d463f4;hb=refs%2Fheads%2Fkaro-tx6-stable;hp=2216eb187c213b4c0c5140a760f9df3098150e41;hpb=4a10a91756ef381bced7b88cfb9232f660b92d93;p=karo-tx-linux.git

diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt
index 2216eb187c21..b784c270105f 100644
--- a/Documentation/printk-formats.txt
+++ b/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.