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authorAndy Lutomirski <luto@kernel.org>2016-09-13 14:29:24 -0700
committerIngo Molnar <mingo@kernel.org>2016-09-15 08:25:13 +0200
commitc65eacbe290b8141554c71b2c94489e73ade8c8d (patch)
tree001c2aa33a3dded758550c659ced4b70e341e03e /init
parentd896fa20a70c9e596438728561e058a74ed3196b (diff)
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sched/core: Allow putting thread_info into task_struct
If an arch opts in by setting CONFIG_THREAD_INFO_IN_TASK_STRUCT, then thread_info is defined as a single 'u32 flags' and is the first entry of task_struct. thread_info::task is removed (it serves no purpose if thread_info is embedded in task_struct), and thread_info::cpu gets its own slot in task_struct. This is heavily based on a patch written by Linus. Originally-from: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jann Horn <jann@thejh.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/a0898196f0476195ca02713691a5037a14f2aac5.1473801993.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'init')
-rw-r--r--init/Kconfig7
-rw-r--r--init/init_task.c7
2 files changed, 12 insertions, 2 deletions
diff --git a/init/Kconfig b/init/Kconfig
index cac3f096050d..ec8d43894b02 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -26,6 +26,13 @@ config IRQ_WORK
config BUILDTIME_EXTABLE_SORT
bool
+config THREAD_INFO_IN_TASK
+ bool
+ help
+ Select this to move thread_info off the stack into task_struct. To
+ make this work, an arch will need to remove all thread_info fields
+ except flags and fix any runtime bugs.
+
menu "General setup"
config BROKEN
diff --git a/init/init_task.c b/init/init_task.c
index ba0a7f362d9e..11f83be1fa79 100644
--- a/init/init_task.c
+++ b/init/init_task.c
@@ -22,5 +22,8 @@ EXPORT_SYMBOL(init_task);
* Initial thread structure. Alignment of this is handled by a special
* linker map entry.
*/
-union thread_union init_thread_union __init_task_data =
- { INIT_THREAD_INFO(init_task) };
+union thread_union init_thread_union __init_task_data = {
+#ifndef CONFIG_THREAD_INFO_IN_TASK
+ INIT_THREAD_INFO(init_task)
+#endif
+};