arch/sh/include/asm/fpu.h

File Facts

System

Linux kernel

Corpus path

arch/sh/include/asm/fpu.h

Extension

.h

Size

1707 bytes

Lines

73

Domain

Architecture Layer

Bucket

arch/sh

Inferred role

Architecture Layer: implementation source

Status

source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

• CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• asm/ptrace.h

Detected Declarations

• struct task_struct
• struct user_regset
• function release_fpu
• function grab_fpu
• function __unlazy_fpu
• function unlazy_fpu
• function clear_fpu

Annotated Snippet

#ifndef __ASM_SH_FPU_H
#define __ASM_SH_FPU_H

#ifndef __ASSEMBLER__

#include <asm/ptrace.h>

struct task_struct;

#ifdef CONFIG_SH_FPU
static inline void release_fpu(struct pt_regs *regs)
{
	regs->sr |= SR_FD;
}

static inline void grab_fpu(struct pt_regs *regs)
{
	regs->sr &= ~SR_FD;
}

extern void save_fpu(struct task_struct *__tsk);
extern void restore_fpu(struct task_struct *__tsk);
extern void fpu_state_restore(struct pt_regs *regs);
extern void __fpu_state_restore(void);
#else
#define save_fpu(tsk)			do { } while (0)
#define restore_fpu(tsk)		do { } while (0)
#define release_fpu(regs)		do { } while (0)
#define grab_fpu(regs)			do { } while (0)
#define fpu_state_restore(regs)		do { } while (0)
#define __fpu_state_restore(regs)	do { } while (0)
#endif

struct user_regset;

extern int do_fpu_inst(unsigned short, struct pt_regs *);
extern int init_fpu(struct task_struct *);

static inline void __unlazy_fpu(struct task_struct *tsk, struct pt_regs *regs)
{
	if (task_thread_info(tsk)->status & TS_USEDFPU) {
		task_thread_info(tsk)->status &= ~TS_USEDFPU;
		save_fpu(tsk);
		release_fpu(regs);
	} else
		tsk->thread.fpu_counter = 0;
}

static inline void unlazy_fpu(struct task_struct *tsk, struct pt_regs *regs)
{
	preempt_disable();
	__unlazy_fpu(tsk, regs);
	preempt_enable();
}

static inline void clear_fpu(struct task_struct *tsk, struct pt_regs *regs)
{
	preempt_disable();
	if (task_thread_info(tsk)->status & TS_USEDFPU) {
		task_thread_info(tsk)->status &= ~TS_USEDFPU;
		release_fpu(regs);
	}
	preempt_enable();
}

void float_raise(unsigned int flags);
int float_rounding_mode(void);

#endif /* __ASSEMBLER__ */

#endif /* __ASM_SH_FPU_H */

Annotation

• Immediate include surface: `asm/ptrace.h`.
• Detected declarations: `struct task_struct`, `struct user_regset`, `function release_fpu`, `function grab_fpu`, `function __unlazy_fpu`, `function unlazy_fpu`, `function clear_fpu`.
• Atlas domain: Architecture Layer / arch/sh.
• Implementation status: source implementation candidate.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.