1/*-
2 * Copyright (c) 2014 Andrew Turner
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD$
27 */
28
29#ifndef _MACHINE_ASM_H_
30#define	_MACHINE_ASM_H_
31
32#undef __FBSDID
33#if !defined(lint) && !defined(STRIP_FBSDID)
34#define	__FBSDID(s)     .ident s
35#else
36#define	__FBSDID(s)     /* nothing */
37#endif
38
39#define	_C_LABEL(x)	x
40
41#define	ENTRY(sym)						\
42	.text; .globl sym; .align 2; .type sym,#function; sym:
43#define	EENTRY(sym)						\
44	.globl	sym; sym:
45#define	END(sym) .size sym, . - sym
46#define	EEND(sym)
47
48#define	WEAK_REFERENCE(sym, alias)				\
49	.weak alias;						\
50	.set alias,sym
51
52#define	UINT64_C(x)	(x)
53
54#if defined(PIC)
55#define	PIC_SYM(x,y)	x ## @ ## y
56#else
57#define	PIC_SYM(x,y)	x
58#endif
59
60/* Alias for link register x30 */
61#define	lr		x30
62
63/*
64 * Sets the trap fault handler. The exception handler will return to the
65 * address in the handler register on a data abort or the xzr register to
66 * clear the handler. The tmp parameter should be a register able to hold
67 * the temporary data.
68 */
69#define	SET_FAULT_HANDLER(handler, tmp)					\
70	ldr	tmp, [x18, #PC_CURTHREAD];	/* Load curthread */	\
71	ldr	tmp, [tmp, #TD_PCB];		/* Load the pcb */	\
72	str	handler, [tmp, #PCB_ONFAULT]	/* Set the handler */
73
74#define	ENTER_USER_ACCESS(reg, tmp)					\
75	ldr	tmp, =has_pan;			/* Get the addr of has_pan */ \
76	ldr	reg, [tmp];			/* Read it */		\
77	cbz	reg, 997f;			/* If no PAN skip */	\
78	.inst	0xd500409f | (0 << 8);		/* Clear PAN */		\
79	997:
80
81#define	EXIT_USER_ACCESS(reg)						\
82	cbz	reg, 998f;			/* If no PAN skip */	\
83	.inst	0xd500409f | (1 << 8);		/* Set PAN */		\
84	998:
85
86#define	EXIT_USER_ACCESS_CHECK(reg, tmp)				\
87	ldr	tmp, =has_pan;			/* Get the addr of has_pan */ \
88	ldr	reg, [tmp];			/* Read it */		\
89	cbz	reg, 999f;			/* If no PAN skip */	\
90	.inst	0xd500409f | (1 << 8);		/* Set PAN */		\
91	999:
92
93/*
94 * Some AArch64 CPUs speculate past an eret instruction. As the user may
95 * control the registers at this point add a speculation barrier usable on
96 * all AArch64 CPUs after the eret instruction.
97 * TODO: ARMv8.5 adds a specific instruction for this, we could use that
98 * if we know we are running on something that supports it.
99 */
100#define	ERET								\
101	eret;								\
102	dsb	sy;							\
103	isb
104
105#endif /* _MACHINE_ASM_H_ */
106