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Sender: Ingo Molnar <mingo.kernel.org@gmail.com>
Date: Thu, 6 Jun 2024 11:06:08 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Brian Gerst <brgerst@gmail.com>
Cc: linux-kernel@vger.kernel.org, Andy Lutomirski <luto@amacapital.net>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dave Hansen <dave@sr71.net>, Peter Zijlstra <peterz@infradead.org>,
	Borislav Petkov <bp@alien8.de>, "H . Peter Anvin" <hpa@zytor.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Uros Bizjak <ubizjak@gmail.com>
Subject: [PATCH] x86/fpu: Introduce the x86_task_fpu() helper method
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 <CAMzpN2hms-cpsaief4j_1LhXXznreE+it8nnsH2-8yoQ2Bn0Rw@mail.gmail.com>
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* Brian Gerst <brgerst@gmail.com> wrote:

> >  17 files changed, 104 insertions(+), 107 deletions(-)
> 
> This series would be better if you added the x86_task_fpu() helper in
> an initial patch without any other changes.  That would make the
> actual changes more visible with less code churn.

Makes sense - I've split out the patch below and adjusted the rest of the 
series. Is this what you had in mind?

Note that I also robustified the macro a bit:

 -# define x86_task_fpu(task) ((struct fpu *)((void *)task + sizeof(*task)))
 +# define x86_task_fpu(task) ((struct fpu *)((void *)(task) + sizeof(*(task))))

Thanks,

	Ingo

========================>
From: Ingo Molnar <mingo@kernel.org>
Date: Thu, 6 Jun 2024 11:01:14 +0200
Subject: [PATCH] x86/fpu: Introduce the x86_task_fpu() helper method

The per-task FPU context/save area is allocated right
next to task_struct() - introduce the x86_task_fpu()
helper that calculates this explicitly from the
task pointer.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 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 920b0beebd11..fb6f030f0692 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -507,6 +507,8 @@ struct thread_struct {
 	struct fpu		*fpu;
 };
 
+#define x86_task_fpu(task) ((struct fpu *)((void *)(task) + sizeof(*(task))))
+
 /*
  * X86 doesn't need any embedded-FPU-struct quirks:
  */