[tip: x86/merge] x86/fpu: Introduce the x86_task_fpu() helper method

[tip-bot2 for Ingo Molnar]

The following commit has been merged into the x86/merge branch of tip:

Commit-ID:     77fbccede633a5565cae084348b5459f6849086d
Gitweb:        https://git.kernel.org/tip/77fbccede633a5565cae084348b5459f6849086d
Author:        Ingo Molnar <mingo@xxxxxxxxxx>
AuthorDate:    Wed, 09 Apr 2025 23:11:20 +02:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Mon, 14 Apr 2025 08:18:29 +02:00

x86/fpu: Introduce the x86_task_fpu() helper method

The per-task FPU context/save area is allocated right
next to task_struct, currently in a variable-size
array via task_struct::thread.fpu[], but we plan to
fully hide it from the C type scope.

Introduce the x86_task_fpu() accessor that gets to the
FPU context pointer explicitly from the task pointer.

Right now this is a simple (task)->thread.fpu wrapper.

Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Chang S. Bae <chang.seok.bae@xxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20250409211127.3544993-2-mingo@xxxxxxxxxx
---
 arch/x86/include/asm/processor.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 5d2f7e5..2f631e0 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -523,6 +523,8 @@ struct thread_struct {
 	 */
 };
 
+#define x86_task_fpu(task) (&(task)->thread.fpu)
+
 extern void fpu_thread_struct_whitelist(unsigned long *offset, unsigned long *size);
 
 static inline void arch_thread_struct_whitelist(unsigned long *offset,