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Merge tag 'trace-v4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

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Pull tracing fixes from Steven Rostedt:
 "There was some breakage with the changes for jump labels in the 4.11
  merge window:

   - powerpc broke as jump labels uses the two LSB bits as flags in
     initialization.

     A check was added to make sure that all jump label entries were 4
     bytes aligned, but powerpc didn't work that way for modules. Adding
     an alignment in the module linker script appeared to be the best
     solution.

   - Jump labels also added an anonymous union to access those LSB bits
     as a normal long. But because this structure had static
     initialization, it broke older compilers that could not statically
     initialize anonymous unions without brackets.

   - The command line parameter for setting function graph filter broke
     the "EMPTY_HASH" descriptor by modifying it instead of creating a
     new hash to hold the entries.

   - The command line parameter ftrace_graph_max_depth was added to
     allow its setting at boot time. It uses existing code and only the
     command line hook was added.

     This is not really a fix, but as it uses existing code without
     affecting anything else, I added it to this release. It was ready
     before the merge window closed, but I wanted to let it sit in
     linux-next for a couple of days first"

* tag 'trace-v4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace/graph: Add ftrace_graph_max_depth kernel parameter
  tracing: Add #undef to fix compile error
  jump_label: Add comment about initialization order for anonymous unions
  jump_label: Fix anonymous union initialization
  module: set __jump_table alignment to 8
  ftrace/graph: Do not modify the EMPTY_HASH for the function_graph filter
  tracing: Fix code comment for ftrace_ops_get_func()
This commit is contained in:
Linus Torvalds
2017-03-07 09:37:28 -08:00
parent c1ae3cfa0e 65a50c6562
commit f26db9649a
5 changed files with 36 additions and 7 deletions
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11
include/linux/jump_label.h
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@@ -90,6 +90,13 @@ extern bool static_key_initialized;
struct static_key {
atomic_t enabled;
/*
* Note:
* To make anonymous unions work with old compilers, the static
* initialization of them requires brackets. This creates a dependency
* on the order of the struct with the initializers. If any fields
* are added, STATIC_KEY_INIT_TRUE and STATIC_KEY_INIT_FALSE may need
* to be modified.
*
* bit 0 => 1 if key is initially true
* 0 if initially false
* bit 1 => 1 if points to struct static_key_mod
@@ -166,10 +173,10 @@ extern void static_key_disable(struct static_key *key);
*/
#define STATIC_KEY_INIT_TRUE \
{ .enabled = { 1 }, \
.entries = (void *)JUMP_TYPE_TRUE }
{ .entries = (void *)JUMP_TYPE_TRUE } }
#define STATIC_KEY_INIT_FALSE \
{ .enabled = { 0 }, \
.entries = (void *)JUMP_TYPE_FALSE }
{ .entries = (void *)JUMP_TYPE_FALSE } }
#else /* !HAVE_JUMP_LABEL */