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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /arch/x86/kernel/fpu/context.h | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/kernel/fpu/context.h')
-rw-r--r-- | arch/x86/kernel/fpu/context.h | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/arch/x86/kernel/fpu/context.h b/arch/x86/kernel/fpu/context.h new file mode 100644 index 0000000000..f6d856bd50 --- /dev/null +++ b/arch/x86/kernel/fpu/context.h @@ -0,0 +1,82 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __X86_KERNEL_FPU_CONTEXT_H +#define __X86_KERNEL_FPU_CONTEXT_H + +#include <asm/fpu/xstate.h> +#include <asm/trace/fpu.h> + +/* Functions related to FPU context tracking */ + +/* + * The in-register FPU state for an FPU context on a CPU is assumed to be + * valid if the fpu->last_cpu matches the CPU, and the fpu_fpregs_owner_ctx + * matches the FPU. + * + * If the FPU register state is valid, the kernel can skip restoring the + * FPU state from memory. + * + * Any code that clobbers the FPU registers or updates the in-memory + * FPU state for a task MUST let the rest of the kernel know that the + * FPU registers are no longer valid for this task. + * + * Invalidate a resource you control: CPU if using the CPU for something else + * (with preemption disabled), FPU for the current task, or a task that + * is prevented from running by the current task. + */ +static inline void __cpu_invalidate_fpregs_state(void) +{ + __this_cpu_write(fpu_fpregs_owner_ctx, NULL); +} + +static inline void __fpu_invalidate_fpregs_state(struct fpu *fpu) +{ + fpu->last_cpu = -1; +} + +static inline int fpregs_state_valid(struct fpu *fpu, unsigned int cpu) +{ + return fpu == this_cpu_read(fpu_fpregs_owner_ctx) && cpu == fpu->last_cpu; +} + +static inline void fpregs_deactivate(struct fpu *fpu) +{ + __this_cpu_write(fpu_fpregs_owner_ctx, NULL); + trace_x86_fpu_regs_deactivated(fpu); +} + +static inline void fpregs_activate(struct fpu *fpu) +{ + __this_cpu_write(fpu_fpregs_owner_ctx, fpu); + trace_x86_fpu_regs_activated(fpu); +} + +/* Internal helper for switch_fpu_return() and signal frame setup */ +static inline void fpregs_restore_userregs(void) +{ + struct fpu *fpu = ¤t->thread.fpu; + int cpu = smp_processor_id(); + + if (WARN_ON_ONCE(current->flags & (PF_KTHREAD | PF_USER_WORKER))) + return; + + if (!fpregs_state_valid(fpu, cpu)) { + /* + * This restores _all_ xstate which has not been + * established yet. + * + * If PKRU is enabled, then the PKRU value is already + * correct because it was either set in switch_to() or in + * flush_thread(). So it is excluded because it might be + * not up to date in current->thread.fpu.xsave state. + * + * XFD state is handled in restore_fpregs_from_fpstate(). + */ + restore_fpregs_from_fpstate(fpu->fpstate, XFEATURE_MASK_FPSTATE); + + fpregs_activate(fpu); + fpu->last_cpu = cpu; + } + clear_thread_flag(TIF_NEED_FPU_LOAD); +} + +#endif |