arch/loongarch/kernel/fpu.S

Source file repositories/reference/linux-study-clean/arch/loongarch/kernel/fpu.S

File Facts

System: Linux kernel
Corpus path: arch/loongarch/kernel/fpu.S
Extension: .S
Size: 17853 bytes
Lines: 657
Domain: Architecture Layer
Bucket: arch/loongarch
Inferred role: Architecture Layer: exported/initcall integration point
Status: integration 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.
Exports symbols or registers init work; inspect boot/module ordering and who consumes the exported contract.

Dependency Surface

linux/export.h
asm/asm.h
asm/asmmacro.h
asm/asm-extable.h
asm/asm-offsets.h
asm/errno.h
asm/fpregdef.h
asm/loongarch.h
asm/regdef.h
asm/unwind_hints.h

Detected Declarations

export _save_fp
export _save_lsx
export _restore_lsx_upper
export _save_lasx
export _restore_lasx_upper
export _save_fp_context
export _restore_fp_context
export _save_lsx_context
export _restore_lsx_context
export _save_lasx_context
export _restore_lasx_context

Annotated Snippet

#include <linux/export.h>
#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/asm-extable.h>
#include <asm/asm-offsets.h>
#include <asm/errno.h>
#include <asm/fpregdef.h>
#include <asm/loongarch.h>
#include <asm/regdef.h>
#include <asm/unwind_hints.h>

#define FPU_REG_WIDTH		8
#define LSX_REG_WIDTH		16
#define LASX_REG_WIDTH		32

	.macro	EX insn, reg, src, offs
.ex\@:	\insn	\reg, \src, \offs
	_asm_extable .ex\@, .L_fpu_fault
	.endm

	.macro sc_save_fp base
	EX	fst.d	$f0,  \base, (0 * FPU_REG_WIDTH)
	EX	fst.d	$f1,  \base, (1 * FPU_REG_WIDTH)
	EX	fst.d	$f2,  \base, (2 * FPU_REG_WIDTH)
	EX	fst.d	$f3,  \base, (3 * FPU_REG_WIDTH)
	EX	fst.d	$f4,  \base, (4 * FPU_REG_WIDTH)
	EX	fst.d	$f5,  \base, (5 * FPU_REG_WIDTH)
	EX	fst.d	$f6,  \base, (6 * FPU_REG_WIDTH)
	EX	fst.d	$f7,  \base, (7 * FPU_REG_WIDTH)
	EX	fst.d	$f8,  \base, (8 * FPU_REG_WIDTH)
	EX	fst.d	$f9,  \base, (9 * FPU_REG_WIDTH)
	EX	fst.d	$f10, \base, (10 * FPU_REG_WIDTH)
	EX	fst.d	$f11, \base, (11 * FPU_REG_WIDTH)
	EX	fst.d	$f12, \base, (12 * FPU_REG_WIDTH)
	EX	fst.d	$f13, \base, (13 * FPU_REG_WIDTH)
	EX	fst.d	$f14, \base, (14 * FPU_REG_WIDTH)
	EX	fst.d	$f15, \base, (15 * FPU_REG_WIDTH)
	EX	fst.d	$f16, \base, (16 * FPU_REG_WIDTH)
	EX	fst.d	$f17, \base, (17 * FPU_REG_WIDTH)
	EX	fst.d	$f18, \base, (18 * FPU_REG_WIDTH)
	EX	fst.d	$f19, \base, (19 * FPU_REG_WIDTH)
	EX	fst.d	$f20, \base, (20 * FPU_REG_WIDTH)
	EX	fst.d	$f21, \base, (21 * FPU_REG_WIDTH)
	EX	fst.d	$f22, \base, (22 * FPU_REG_WIDTH)
	EX	fst.d	$f23, \base, (23 * FPU_REG_WIDTH)
	EX	fst.d	$f24, \base, (24 * FPU_REG_WIDTH)
	EX	fst.d	$f25, \base, (25 * FPU_REG_WIDTH)
	EX	fst.d	$f26, \base, (26 * FPU_REG_WIDTH)
	EX	fst.d	$f27, \base, (27 * FPU_REG_WIDTH)
	EX	fst.d	$f28, \base, (28 * FPU_REG_WIDTH)
	EX	fst.d	$f29, \base, (29 * FPU_REG_WIDTH)
	EX	fst.d	$f30, \base, (30 * FPU_REG_WIDTH)
	EX	fst.d	$f31, \base, (31 * FPU_REG_WIDTH)
	.endm

	.macro sc_restore_fp base
	EX	fld.d	$f0,  \base, (0 * FPU_REG_WIDTH)
	EX	fld.d	$f1,  \base, (1 * FPU_REG_WIDTH)
	EX	fld.d	$f2,  \base, (2 * FPU_REG_WIDTH)
	EX	fld.d	$f3,  \base, (3 * FPU_REG_WIDTH)
	EX	fld.d	$f4,  \base, (4 * FPU_REG_WIDTH)
	EX	fld.d	$f5,  \base, (5 * FPU_REG_WIDTH)
	EX	fld.d	$f6,  \base, (6 * FPU_REG_WIDTH)
	EX	fld.d	$f7,  \base, (7 * FPU_REG_WIDTH)
	EX	fld.d	$f8,  \base, (8 * FPU_REG_WIDTH)
	EX	fld.d	$f9,  \base, (9 * FPU_REG_WIDTH)
	EX	fld.d	$f10, \base, (10 * FPU_REG_WIDTH)
	EX	fld.d	$f11, \base, (11 * FPU_REG_WIDTH)
	EX	fld.d	$f12, \base, (12 * FPU_REG_WIDTH)
	EX	fld.d	$f13, \base, (13 * FPU_REG_WIDTH)

Annotation

Immediate include surface: `linux/export.h`, `asm/asm.h`, `asm/asmmacro.h`, `asm/asm-extable.h`, `asm/asm-offsets.h`, `asm/errno.h`, `asm/fpregdef.h`, `asm/loongarch.h`.
Detected declarations: `export _save_fp`, `export _save_lsx`, `export _restore_lsx_upper`, `export _save_lasx`, `export _restore_lasx_upper`, `export _save_fp_context`, `export _restore_fp_context`, `export _save_lsx_context`, `export _restore_lsx_context`, `export _save_lasx_context`.
Atlas domain: Architecture Layer / arch/loongarch.
Implementation status: integration 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.