linux-kernel - [PATCH 5/9] x86/fpu: Push 'fpu' pointer calculation into the fpu_

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Date: Sat,  8 Jun 2024 09:31:30 +0200
From: Ingo Molnar <mingo@...nel.org>
To: linux-kernel@...r.kernel.org
Cc: Andy Lutomirski <luto@...capital.net>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Dave Hansen <dave@...1.net>,
	Peter Zijlstra <peterz@...radead.org>,
	Borislav Petkov <bp@...en8.de>,
	Brian Gerst <brgerst@...il.com>,
	"H . Peter Anvin" <hpa@...or.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Oleg Nesterov <oleg@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Uros Bizjak <ubizjak@...il.com>
Subject: [PATCH 5/9] 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@...nel.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 1feaa68b7567..5fd12634bcc4 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 167a9c7ed6d3..c85667c0695d 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -672,8 +672,10 @@ 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 4184c085627e..0a24997c8cc6 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -114,7 +114,6 @@ 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);
@@ -122,7 +121,7 @@ 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)
-- 
2.43.0