linux-kernel - [patch 11/21] x86/fpu: Remove fpu::state

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Message-ID: <20211013145322.765063318@linutronix.de>
Date:   Wed, 13 Oct 2021 16:55:42 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, "Chang S. Bae" <chang.seok.bae@...el.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Arjan van de Ven <arjan@...ux.intel.com>,
        kvm@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>
Subject: [patch 11/21] x86/fpu: Remove fpu::state

All users converted. Remove it along with the sanity checks.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 arch/x86/include/asm/fpu/types.h |   18 +++++++-----------
 arch/x86/kernel/fpu/init.c       |    4 ----
 2 files changed, 7 insertions(+), 15 deletions(-)

--- a/arch/x86/include/asm/fpu/types.h
+++ b/arch/x86/include/asm/fpu/types.h
@@ -352,20 +352,16 @@ struct fpu {
 	struct fpstate			*fpstate;
 
 	/*
-	 * @state:
+	 * @__fpstate:
 	 *
-	 * In-memory copy of all FPU registers that we save/restore
-	 * over context switches. If the task is using the FPU then
-	 * the registers in the FPU are more recent than this state
-	 * copy. If the task context-switches away then they get
-	 * saved here and represent the FPU state.
+	 * Initial in-memory storage for FPU registers which are saved in
+	 * context switch and when the kernel uses the FPU. The registers
+	 * are restored from this storage on return to user space if they
+	 * are not longer containing the tasks FPU register state.
 	 */
-	union {
-		struct fpstate			__fpstate;
-		union fpregs_state		state;
-	};
+	struct fpstate			__fpstate;
 	/*
-	 * WARNING: 'state' is dynamically-sized.  Do not put
+	 * WARNING: '__fpstate' is dynamically-sized.  Do not put
 	 * anything after it here.
 	 */
 };
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -184,10 +184,6 @@ static void __init fpu__init_task_struct
 	CHECK_MEMBER_AT_END_OF(struct thread_struct, fpu);
 	CHECK_MEMBER_AT_END_OF(struct task_struct, thread);
 
-	BUILD_BUG_ON(sizeof(struct fpstate) != sizeof(union fpregs_state));
-	BUILD_BUG_ON(offsetof(struct thread_struct, fpu.state) !=
-		     offsetof(struct thread_struct, fpu.__fpstate));
-
 	arch_task_struct_size = task_size;
 }