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

Commit-ID:     ec2227e03a46a162f2721917262adc553b212e2d
Gitweb:        https://git.kernel.org/tip/ec2227e03a46a162f2721917262adc553b212e2d
Author:        Ingo Molnar <mingo@kernel.org>
AuthorDate:    Wed, 09 Apr 2025 23:11:24 +02:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Mon, 14 Apr 2025 08:18:29 +02:00

x86/fpu: Push 'fpu' pointer calculation into the fpu__drop() call

This encapsulates the fpu__drop() functionality better, and it
will also enable other changes that want to check a task for
PF_KTHREAD before calling x86_task_fpu().

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chang S. Bae <chang.seok.bae@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250409211127.3544993-6-mingo@kernel.org
---
 arch/x86/include/asm/fpu/sched.h | 2 +-
 arch/x86/kernel/fpu/core.c       | 4 +++-
 arch/x86/kernel/process.c        | 3 +--
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/fpu/sched.h b/arch/x86/include/asm/fpu/sched.h
index 1feaa68..5fd1263 100644
--- a/arch/x86/include/asm/fpu/sched.h
+++ b/arch/x86/include/asm/fpu/sched.h
@@ -10,7 +10,7 @@
 #include <asm/trace/fpu.h>
 
 extern void save_fpregs_to_fpstate(struct fpu *fpu);
-extern void fpu__drop(struct fpu *fpu);
+extern void fpu__drop(struct task_struct *tsk);
 extern int  fpu_clone(struct task_struct *dst, unsigned long clone_flags, bool minimal,
 		      unsigned long shstk_addr);
 extern void fpu_flush_thread(void);
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 974b276..e4c2090 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -681,8 +681,10 @@ int fpu_clone(struct task_struct *dst, unsigned long clone_flags, bool minimal,
  * a state-restore is coming: either an explicit one,
  * or a reschedule.
  */
-void fpu__drop(struct fpu *fpu)
+void fpu__drop(struct task_struct *tsk)
 {
+	struct fpu *fpu = x86_task_fpu(tsk);
+
 	preempt_disable();
 
 	if (fpu == x86_task_fpu(current)) {
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 88868a9..5fb502c 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -120,7 +120,6 @@ void arch_release_task_struct(struct task_struct *tsk)
 void exit_thread(struct task_struct *tsk)
 {
 	struct thread_struct *t = &tsk->thread;
-	struct fpu *fpu = x86_task_fpu(tsk);
 
 	if (test_thread_flag(TIF_IO_BITMAP))
 		io_bitmap_exit(tsk);
@@ -128,7 +127,7 @@ void exit_thread(struct task_struct *tsk)
 	free_vm86(t);
 
 	shstk_free(tsk);
-	fpu__drop(fpu);
+	fpu__drop(tsk);
 }
 
 static int set_new_tls(struct task_struct *p, unsigned long tls)