linux-kernel - [patch V2 05/30] x86/fpu: Cleanup the on_boot

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Date:   Fri, 15 Oct 2021 03:16:01 +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>,
        "Liu, Jing2" <jing2.liu@...el.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Xiaoyao Li <xiaoyao.li@...el.com>
Subject: [patch V2 05/30] x86/fpu: Cleanup the on_boot_cpu clutter

Defensive programming is useful, but this on_boot_cpu debug is really
silly.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>

---
 arch/x86/kernel/fpu/init.c   | 16 ----------------
 arch/x86/kernel/fpu/xstate.c |  9 ---------
 2 files changed, 25 deletions(-)
---
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index 64e29927cc32..86bc9759fc8b 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -192,11 +192,6 @@ static void __init fpu__init_task_struct_size(void)
  */
 static void __init fpu__init_system_xstate_size_legacy(void)
 {
-	static int on_boot_cpu __initdata = 1;
-
-	WARN_ON_FPU(!on_boot_cpu);
-	on_boot_cpu = 0;
-
 	/*
 	 * Note that xstate sizes might be overwritten later during
 	 * fpu__init_system_xstate().
@@ -216,15 +211,6 @@ static void __init fpu__init_system_xstate_size_legacy(void)
 	fpu_user_xstate_size = fpu_kernel_xstate_size;
 }
 
-/* Legacy code to initialize eager fpu mode. */
-static void __init fpu__init_system_ctx_switch(void)
-{
-	static bool on_boot_cpu __initdata = 1;
-
-	WARN_ON_FPU(!on_boot_cpu);
-	on_boot_cpu = 0;
-}
-
 /*
  * Called on the boot CPU once per system bootup, to set up the initial
  * FPU state that is later cloned into all processes:
@@ -243,6 +229,4 @@ void __init fpu__init_system(struct cpuinfo_x86 *c)
 	fpu__init_system_xstate_size_legacy();
 	fpu__init_system_xstate();
 	fpu__init_task_struct_size();
-
-	fpu__init_system_ctx_switch();
 }
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 5a76df965337..d6b5f2266143 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -379,15 +379,10 @@ static void __init print_xstate_offset_size(void)
  */
 static void __init setup_init_fpu_buf(void)
 {
-	static int on_boot_cpu __initdata = 1;
-
 	BUILD_BUG_ON((XFEATURE_MASK_USER_SUPPORTED |
 		      XFEATURE_MASK_SUPERVISOR_SUPPORTED) !=
 		     XFEATURES_INIT_FPSTATE_HANDLED);
 
-	WARN_ON_FPU(!on_boot_cpu);
-	on_boot_cpu = 0;
-
 	if (!boot_cpu_has(X86_FEATURE_XSAVE))
 		return;
 
@@ -721,14 +716,10 @@ static void fpu__init_disable_system_xstate(void)
 void __init fpu__init_system_xstate(void)
 {
 	unsigned int eax, ebx, ecx, edx;
-	static int on_boot_cpu __initdata = 1;
 	u64 xfeatures;
 	int err;
 	int i;
 
-	WARN_ON_FPU(!on_boot_cpu);
-	on_boot_cpu = 0;
-
 	if (!boot_cpu_has(X86_FEATURE_FPU)) {
 		pr_info("x86/fpu: No FPU detected\n");
 		return;