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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/loongarch/kernel/lbt.S
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/* SPDX-License-Identifier: GPL-2.0 */

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/*

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 * Author: Qi Hu <[email protected]>

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 *         Huacai Chen <[email protected]>

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 *

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 * Copyright (C) 2020-2023 Loongson Technology Corporation Limited

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 */

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#include <asm/asm.h>

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#include <asm/asmmacro.h>

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#include <asm/asm-extable.h>

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#include <asm/asm-offsets.h>

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#include <asm/errno.h>

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#include <asm/regdef.h>

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#include <asm/unwind_hints.h>

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#define SCR_REG_WIDTH 8

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	.macro	EX insn, reg, src, offs

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.ex\@:	\insn	\reg, \src, \offs

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	_asm_extable .ex\@, .L_lbt_fault

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	.endm

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/*

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 * Save a thread's lbt context.

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 */

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SYM_FUNC_START(_save_lbt)

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	movscr2gr	t1, $scr0		# save scr

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	stptr.d		t1, a0, THREAD_SCR0

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	movscr2gr	t1, $scr1

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	stptr.d		t1, a0, THREAD_SCR1

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	movscr2gr	t1, $scr2

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	stptr.d		t1, a0, THREAD_SCR2

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	movscr2gr	t1, $scr3

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	stptr.d		t1, a0, THREAD_SCR3

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	x86mfflag	t1, 0x3f		# save eflags

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	stptr.d		t1, a0, THREAD_EFLAGS

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	jr		ra

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SYM_FUNC_END(_save_lbt)

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EXPORT_SYMBOL(_save_lbt)

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/*

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 * Restore a thread's lbt context.

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 */

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SYM_FUNC_START(_restore_lbt)

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	ldptr.d		t1, a0, THREAD_SCR0	# restore scr

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	movgr2scr	$scr0, t1

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	ldptr.d		t1, a0, THREAD_SCR1

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	movgr2scr	$scr1, t1

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	ldptr.d		t1, a0, THREAD_SCR2

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	movgr2scr	$scr2, t1

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	ldptr.d		t1, a0, THREAD_SCR3

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	movgr2scr	$scr3, t1

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	ldptr.d		t1, a0, THREAD_EFLAGS	# restore eflags

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	x86mtflag	t1, 0x3f

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	jr		ra

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SYM_FUNC_END(_restore_lbt)

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EXPORT_SYMBOL(_restore_lbt)

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/*

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 * Load scr/eflag with zero.

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 */

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SYM_FUNC_START(_init_lbt)

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	movgr2scr	$scr0, zero

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	movgr2scr	$scr1, zero

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	movgr2scr	$scr2, zero

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	movgr2scr	$scr3, zero

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	x86mtflag	zero, 0x3f

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	jr		ra

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SYM_FUNC_END(_init_lbt)

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/*

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 * a0: scr

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 * a1: eflag

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 */

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SYM_FUNC_START(_save_lbt_context)

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	movscr2gr	t1, $scr0		# save scr

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	EX	st.d	t1, a0, (0 * SCR_REG_WIDTH)

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	movscr2gr	t1, $scr1

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	EX	st.d	t1, a0, (1 * SCR_REG_WIDTH)

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	movscr2gr	t1, $scr2

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	EX	st.d	t1, a0, (2 * SCR_REG_WIDTH)

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	movscr2gr	t1, $scr3

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	EX	st.d	t1, a0, (3 * SCR_REG_WIDTH)

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	x86mfflag	t1, 0x3f		# save eflags

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	EX 	st.w	t1, a1, 0

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	li.w		a0, 0			# success

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	jr		ra

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SYM_FUNC_END(_save_lbt_context)

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EXPORT_SYMBOL_GPL(_save_lbt_context)

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/*

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 * a0: scr

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 * a1: eflag

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 */

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SYM_FUNC_START(_restore_lbt_context)

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	EX	ld.d	t1, a0, (0 * SCR_REG_WIDTH)	# restore scr

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	movgr2scr	$scr0, t1

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	EX	ld.d	t1, a0, (1 * SCR_REG_WIDTH)

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	movgr2scr	$scr1, t1

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	EX	ld.d	t1, a0, (2 * SCR_REG_WIDTH)

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	movgr2scr	$scr2, t1

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	EX	ld.d	t1, a0, (3 * SCR_REG_WIDTH)

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	movgr2scr	$scr3, t1

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	EX 	ld.w	t1, a1, 0			# restore eflags

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	x86mtflag	t1, 0x3f

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	li.w		a0, 0			# success

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	jr		ra

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SYM_FUNC_END(_restore_lbt_context)

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EXPORT_SYMBOL_GPL(_restore_lbt_context)

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/*

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 * a0: ftop

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 */

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SYM_FUNC_START(_save_ftop_context)

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	x86mftop	t1

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	st.w		t1, a0, 0

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	li.w		a0, 0			# success

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	jr		ra

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SYM_FUNC_END(_save_ftop_context)

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EXPORT_SYMBOL_GPL(_save_ftop_context)

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/*

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 * a0: ftop

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 */

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SYM_FUNC_START(_restore_ftop_context)

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	ld.w		t1, a0, 0

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	andi		t1, t1, 0x7

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	la.pcrel	a0, 1f

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	alsl.d		a0, t1, a0, 3

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	jr		a0

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1:

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	x86mttop	0

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	b	2f

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	x86mttop	1

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	b	2f

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	x86mttop	2

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	b	2f

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	x86mttop	3

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	b	2f

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	x86mttop	4

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	b	2f

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	x86mttop	5

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	b	2f

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	x86mttop	6

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	b	2f

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	x86mttop	7

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2:

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	li.w		a0, 0			# success

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	jr		ra

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SYM_FUNC_END(_restore_ftop_context)

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EXPORT_SYMBOL_GPL(_restore_ftop_context)

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.L_lbt_fault:

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	li.w		a0, -EFAULT		# failure

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	jr		ra

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STACK_FRAME_NON_STANDARD _restore_ftop_context

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