[V2,17/30] x86/fpu: Move context switch and exit to user inlines into sched.h

Message ID	20211015011539.349132461@linutronix.de (mailing list archive)
State	New, archived
Headers	show Return-Path: <kvm-owner@kernel.org> Message-ID: <20211015011539.349132461@linutronix.de> From: Thomas Gleixner <tglx@linutronix.de> To: LKML <linux-kernel@vger.kernel.org> Cc: x86@kernel.org, "Chang S. Bae" <chang.seok.bae@intel.com>, Dave Hansen <dave.hansen@linux.intel.com>, Arjan van de Ven <arjan@linux.intel.com>, kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>, "Liu, Jing2" <jing2.liu@intel.com>, Sean Christopherson <seanjc@google.com>, Xiaoyao Li <xiaoyao.li@intel.com> Subject: [patch V2 17/30] x86/fpu: Move context switch and exit to user inlines into sched.h References: <20211015011411.304289784@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Date: Fri, 15 Oct 2021 03:16:20 +0200 (CEST) Precedence: bulk
Series	x86/fpu: Preparatory cleanups for AMX support (part 1) \| expand [V2,00/30] x86/fpu: Preparatory cleanups for AMX support (part 1) [V2,01/30] x86/fpu: Remove pointless argument from switch_fpu_finish() [V2,02/30] x86/fpu: Update stale comments [V2,03/30] x86/pkru: Remove useless include [V2,04/30] x86/fpu: Restrict xsaves()/xrstors() to independent states [V2,05/30] x86/fpu: Cleanup the on_boot_cpu clutter [V2,06/30] x86/fpu: Remove pointless memset in fpu_clone() [V2,07/30] x86/process: Clone FPU in copy_thread() [V2,08/30] x86/fpu: Do not inherit FPU context for kernel and IO worker threads [V2,09/30] x86/fpu: Cleanup xstate xcomp_bv initialization [V2,10/30] x86/fpu/xstate: Provide and use for_each_xfeature() [V2,11/30] x86/fpu/xstate: Mark all init only functions __init [V2,12/30] x86/fpu: Move KVMs FPU swapping to FPU core [V2,13/30] x86/fpu: Replace KVMs home brewed FPU copy from user [V2,14/30] x86/fpu: Rework copy_xstate_to_uabi_buf() [V2,15/30] x86/fpu: Replace KVMs home brewed FPU copy to user [V2,16/30] x86/fpu: Mark fpu__init_prepare_fx_sw_frame() as __init [V2,17/30] x86/fpu: Move context switch and exit to user inlines into sched.h [V2,18/30] x86/fpu: Clean up cpu feature tests [V2,19/30] x86/fpu: Make os_xrstor_booting() private [V2,20/30] x86/fpu: Move os_xsave() and os_xrstor() to core [V2,21/30] x86/fpu: Move legacy ASM wrappers to core [V2,22/30] x86/fpu: Make WARN_ON_FPU() private [V2,23/30] x86/fpu: Move fpregs_restore_userregs() to core [V2,24/30] x86/fpu: Move mxcsr related code to core [V2,25/30] x86/fpu: Move fpstate functions to api.h [V2,26/30] x86/fpu: Remove internal.h dependency from fpu/signal.h [V2,27/30] x86/sev: Include fpu/xcr.h [V2,28/30] x86/fpu: Mop up the internal.h leftovers [V2,29/30] x86/fpu: Replace the includes of fpu/internal.h [V2,30/30] x86/fpu: Provide a proper function for ex_handler_fprestore()

diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 3ac55ba55782..398c87c8e199 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -27,16 +27,11 @@ * High level FPU state handling functions: */ extern bool fpu__restore_sig(void __user *buf, int ia32_frame); -extern void fpu__drop(struct fpu *fpu); extern void fpu__clear_user_states(struct fpu *fpu); extern int fpu__exception_code(struct fpu *fpu, int trap_nr); extern void fpu_sync_fpstate(struct fpu *fpu); -/* Clone and exit operations */ -extern int fpu_clone(struct task_struct *dst); -extern void fpu_flush_thread(void); - /* * Boot time FPU initialization functions: */ @@ -82,7 +77,6 @@ extern void fpstate_init_soft(struct swregs_state *soft); #else static inline void fpstate_init_soft(struct swregs_state *soft) {} #endif -extern void save_fpregs_to_fpstate(struct fpu *fpu); /* * Returns 0 on success or the trap number when the operation raises an @@ -464,58 +458,4 @@ static inline void fpregs_restore_userregs(void) clear_thread_flag(TIF_NEED_FPU_LOAD); } -/* - * FPU state switching for scheduling. - * - * This is a two-stage process: - * - * - switch_fpu_prepare() saves the old state. - * This is done within the context of the old process. - * - * - switch_fpu_finish() sets TIF_NEED_FPU_LOAD; the floating point state - * will get loaded on return to userspace, or when the kernel needs it. - * - * If TIF_NEED_FPU_LOAD is cleared then the CPU's FPU registers - * are saved in the current thread's FPU register state. - * - * If TIF_NEED_FPU_LOAD is set then CPU's FPU registers may not - * hold current()'s FPU registers. It is required to load the - * registers before returning to userland or using the content - * otherwise. - * - * The FPU context is only stored/restored for a user task and - * PF_KTHREAD is used to distinguish between kernel and user threads. - */ -static inline void switch_fpu_prepare(struct fpu *old_fpu, int cpu) -{ - if (static_cpu_has(X86_FEATURE_FPU) && !(current->flags & PF_KTHREAD)) { - save_fpregs_to_fpstate(old_fpu); - /* - * The save operation preserved register state, so the - * fpu_fpregs_owner_ctx is still @old_fpu. Store the - * current CPU number in @old_fpu, so the next return - * to user space can avoid the FPU register restore - * when is returns on the same CPU and still owns the - * context. - */ - old_fpu->last_cpu = cpu; - - trace_x86_fpu_regs_deactivated(old_fpu); - } -} - -/* - * Misc helper functions: - */ - -/* - * Delay loading of the complete FPU state until the return to userland. - * PKRU is handled separately. - */ -static inline void switch_fpu_finish(void) -{ - if (cpu_feature_enabled(X86_FEATURE_FPU)) - set_thread_flag(TIF_NEED_FPU_LOAD); -} - #endif /* _ASM_X86_FPU_INTERNAL_H */ diff --git a/arch/x86/include/asm/fpu/sched.h b/arch/x86/include/asm/fpu/sched.h new file mode 100644 index 000000000000..cdb78d590c86 --- /dev/null +++ b/arch/x86/include/asm/fpu/sched.h @@ -0,0 +1,68 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_FPU_SCHED_H +#define _ASM_X86_FPU_SCHED_H + +#include <linux/sched.h> + +#include <asm/cpufeature.h> +#include <asm/fpu/types.h> + +#include <asm/trace/fpu.h> + +extern void save_fpregs_to_fpstate(struct fpu *fpu); +extern void fpu__drop(struct fpu *fpu); +extern int fpu_clone(struct task_struct *dst); +extern void fpu_flush_thread(void); + +/* + * FPU state switching for scheduling. + * + * This is a two-stage process: + * + * - switch_fpu_prepare() saves the old state. + * This is done within the context of the old process. + * + * - switch_fpu_finish() sets TIF_NEED_FPU_LOAD; the floating point state + * will get loaded on return to userspace, or when the kernel needs it. + * + * If TIF_NEED_FPU_LOAD is cleared then the CPU's FPU registers + * are saved in the current thread's FPU register state. + * + * If TIF_NEED_FPU_LOAD is set then CPU's FPU registers may not + * hold current()'s FPU registers. It is required to load the + * registers before returning to userland or using the content + * otherwise. + * + * The FPU context is only stored/restored for a user task and + * PF_KTHREAD is used to distinguish between kernel and user threads. + */ +static inline void switch_fpu_prepare(struct fpu *old_fpu, int cpu) +{ + if (cpu_feature_enabled(X86_FEATURE_FPU) && + !(current->flags & PF_KTHREAD)) { + save_fpregs_to_fpstate(old_fpu); + /* + * The save operation preserved register state, so the + * fpu_fpregs_owner_ctx is still @old_fpu. Store the + * current CPU number in @old_fpu, so the next return + * to user space can avoid the FPU register restore + * when is returns on the same CPU and still owns the + * context. + */ + old_fpu->last_cpu = cpu; + + trace_x86_fpu_regs_deactivated(old_fpu); + } +} + +/* + * Delay loading of the complete FPU state until the return to userland. + * PKRU is handled separately. + */ +static inline void switch_fpu_finish(void) +{ + if (cpu_feature_enabled(X86_FEATURE_FPU)) + set_thread_flag(TIF_NEED_FPU_LOAD); +} + +#endif /* _ASM_X86_FPU_SCHED_H */ diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 5ed58b22a75b..4fb63a0cb4ef 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -8,6 +8,7 @@ */ #include <asm/fpu/internal.h> #include <asm/fpu/regset.h> +#include <asm/fpu/sched.h> #include <asm/fpu/signal.h> #include <asm/fpu/types.h> #include <asm/traps.h> diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index d2227c55e683..5cd82082353e 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -30,7 +30,7 @@ #include <asm/apic.h> #include <linux/uaccess.h> #include <asm/mwait.h> -#include <asm/fpu/internal.h> +#include <asm/fpu/sched.h> #include <asm/debugreg.h> #include <asm/nmi.h> #include <asm/tlbflush.h> diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index d008e222a302..26edb1cd07a4 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -41,7 +41,7 @@ #include <asm/ldt.h> #include <asm/processor.h> -#include <asm/fpu/internal.h> +#include <asm/fpu/sched.h> #include <asm/desc.h> #include <linux/err.h> diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 39f12ef1c85c..3402edec236c 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -42,7 +42,7 @@ #include <asm/processor.h> #include <asm/pkru.h> -#include <asm/fpu/internal.h> +#include <asm/fpu/sched.h> #include <asm/mmu_context.h> #include <asm/prctl.h> #include <asm/desc.h>

[V2,17/30] x86/fpu: Move context switch and exit to user inlines into sched.h

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