1/*
2 * Copyright 2020, Data61, CSIRO (ABN 41 687 119 230)
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 */
6
7#pragma once
8
9#include <autoconf.h>
10#include <sel4/types.h>
11
12#ifdef CONFIG_KERNEL_MCS
13#define MCS_PARAM_DECL(r)    register seL4_Word reply_reg asm(r) = reply
14#define MCS_PARAM    , "r"(reply_reg)
15#else
16#define MCS_PARAM_DECL(r)
17#define MCS_PARAM
18#endif
19
20/*
21 * To simplify the definition of the various seL4 syscalls/syscall-wrappers we define
22 * some helper assembly functions. These functions are designed to cover the different
23 * cases of sending/receiving data in registers to/from the kernel. The most 'complex'
24 * version is arm_sys_send_recv, and all other functions are limited versions that allow
25 * for registers to not be unnecessarily clobbered
26 *
27 * arm_sys_send: Fills all registers into the kernel, expects nothing to be sent back
28 *      by the kernel. Used for direction one way sends that contain data (e.g. seL4_Send,
29 *      seL4_NBSend)
30 *
31 * arm_sys_send_null: Only fills metadata registers into the kernel (skips message
32 *      registers). Expects nothing to be sent back by the kernel. Used by directional
33 *      one way sends that do not contain data (e.g. seL4_Notify)
34 *
35 * arm_sys_reply: Similar to arm_sys_send except it does not take a word for the
36 *      destination register. Used for undirected one way sends that contain data
37 *      (e.g. seL4_Reply)
38 *
39 * arm_sys_recv: Sends one register (destination) to the kernel and expects all
40 *      registers to be returned by the kernel. Used for directed receives that return
41 *      data (e.g. seL4_Recv)
42 *
43 * arm_sys_send_recv: Fills all registers into the kernel and expects all of them
44 *      to be filled on return by the kernel. Used for directed send+receives
45 *      where data flows both directions (e.g. seL4_Call, seL4_ReplyWait)
46 *
47 * arm_sys_send_recv: Fills all registers into the kernel and expects all of them
48 *      to be filled on return by the kernel. Used for directed send+receives
49 *      where data flows both directions on separate caps (e.g. seL4_NBSendRecv)
50  *
51 * arm_sys_null: Does not send any registers to the kernel or expect anything to
52 *      be returned from the kernel. Used to trigger implicit kernel actions without
53 *      any data (e.g. seL4_Yield)
54 */
55
56static inline void arm_sys_send(seL4_Word sys, seL4_Word dest, seL4_Word info_arg, seL4_Word mr0, seL4_Word mr1,
57                                seL4_Word mr2, seL4_Word mr3)
58{
59    register seL4_Word destptr asm("r0") = dest;
60    register seL4_Word info asm("r1") = info_arg;
61
62    /* Load beginning of the message into registers. */
63    register seL4_Word msg0 asm("r2") = mr0;
64    register seL4_Word msg1 asm("r3") = mr1;
65    register seL4_Word msg2 asm("r4") = mr2;
66    register seL4_Word msg3 asm("r5") = mr3;
67
68    /* Perform the system call. */
69    register seL4_Word scno asm("r7") = sys;
70    asm volatile(
71        "swi $0"
72        : "+r"(destptr), "+r"(msg0), "+r"(msg1), "+r"(msg2),
73        "+r"(msg3), "+r"(info)
74        : "r"(scno)
75    );
76}
77
78#ifndef CONFIG_KERNEL_MCS
79static inline void arm_sys_reply(seL4_Word sys, seL4_Word info_arg, seL4_Word mr0, seL4_Word mr1, seL4_Word mr2,
80                                 seL4_Word mr3)
81{
82    register seL4_Word info asm("r1") = info_arg;
83
84    /* Load beginning of the message into registers. */
85    register seL4_Word msg0 asm("r2") = mr0;
86    register seL4_Word msg1 asm("r3") = mr1;
87    register seL4_Word msg2 asm("r4") = mr2;
88    register seL4_Word msg3 asm("r5") = mr3;
89
90    /* Perform the system call. */
91    register seL4_Word scno asm("r7") = sys;
92    asm volatile(
93        "swi $0"
94        : "+r"(msg0), "+r"(msg1), "+r"(msg2), "+r"(msg3),
95        "+r"(info)
96        : "r"(scno)
97    );
98}
99#endif
100
101static inline void arm_sys_send_null(seL4_Word sys, seL4_Word src, seL4_Word info_arg)
102{
103    register seL4_Word destptr asm("r0") = src;
104    register seL4_Word info asm("r1") = info_arg;
105
106    /* Perform the system call. */
107    register seL4_Word scno asm("r7") = sys;
108    asm volatile(
109        "swi $0"
110        : "+r"(destptr), "+r"(info)
111        : "r"(scno)
112    );
113}
114
115static inline void arm_sys_recv(seL4_Word sys, seL4_Word src, seL4_Word *out_badge, seL4_Word *out_info,
116                                seL4_Word *out_mr0, seL4_Word *out_mr1, seL4_Word *out_mr2, seL4_Word *out_mr3, LIBSEL4_UNUSED seL4_Word reply)
117{
118    register seL4_Word src_and_badge asm("r0") = src;
119    register seL4_Word info asm("r1");
120
121    /* Incoming message registers. */
122    register seL4_Word msg0 asm("r2");
123    register seL4_Word msg1 asm("r3");
124    register seL4_Word msg2 asm("r4");
125    register seL4_Word msg3 asm("r5");
126
127    MCS_PARAM_DECL("r6");
128
129    /* Perform the system call. */
130    register seL4_Word scno asm("r7") = sys;
131    asm volatile(
132        "swi $0"
133        : "=r"(msg0), "=r"(msg1), "=r"(msg2), "=r"(msg3),
134        "=r"(info), "+r"(src_and_badge)
135        : "r"(scno) MCS_PARAM
136        : "memory"
137    );
138    *out_badge = src_and_badge;
139    *out_info = info;
140    *out_mr0 = msg0;
141    *out_mr1 = msg1;
142    *out_mr2 = msg2;
143    *out_mr3 = msg3;
144}
145
146static inline void arm_sys_send_recv(seL4_Word sys, seL4_Word dest, seL4_Word *out_badge, seL4_Word info_arg,
147                                     seL4_Word *out_info, seL4_Word *in_out_mr0, seL4_Word *in_out_mr1, seL4_Word *in_out_mr2, seL4_Word *in_out_mr3,
148                                     LIBSEL4_UNUSED seL4_Word reply)
149{
150    register seL4_Word destptr asm("r0") = dest;
151    register seL4_Word info asm("r1") = info_arg;
152
153    /* Load beginning of the message into registers. */
154    register seL4_Word msg0 asm("r2") = *in_out_mr0;
155    register seL4_Word msg1 asm("r3") = *in_out_mr1;
156    register seL4_Word msg2 asm("r4") = *in_out_mr2;
157    register seL4_Word msg3 asm("r5") = *in_out_mr3;
158
159    /* Perform the system call. */
160    MCS_PARAM_DECL("r6");
161    register seL4_Word scno asm("r7") = sys;
162    asm volatile(
163        "swi $0"
164        : "+r"(msg0), "+r"(msg1), "+r"(msg2), "+r"(msg3),
165        "+r"(info), "+r"(destptr)
166        : "r"(scno) MCS_PARAM
167        : "memory"
168    );
169    *out_info = info;
170    *out_badge = destptr;
171    *in_out_mr0 = msg0;
172    *in_out_mr1 = msg1;
173    *in_out_mr2 = msg2;
174    *in_out_mr3 = msg3;
175}
176
177#ifdef CONFIG_KERNEL_MCS
178static inline void arm_sys_nbsend_recv(seL4_Word sys, seL4_Word dest, seL4_Word src, seL4_Word *out_badge,
179                                       seL4_Word info_arg,
180                                       seL4_Word *out_info, seL4_Word *in_out_mr0, seL4_Word *in_out_mr1, seL4_Word *in_out_mr2,
181                                       seL4_Word *in_out_mr3, seL4_Word reply)
182{
183    register seL4_Word src_and_badge asm("r0") = src;
184    register seL4_Word info asm("r1") = info_arg;
185
186    /* Load the beginning of the message info registers */
187    register seL4_Word msg0 asm("r2") = *in_out_mr0;
188    register seL4_Word msg1 asm("r3") = *in_out_mr1;
189    register seL4_Word msg2 asm("r4") = *in_out_mr2;
190    register seL4_Word msg3 asm("r5") = *in_out_mr3;
191
192    register seL4_Word reply_reg asm("r6") = reply;
193    register seL4_Word dest_reg asm("r8") = dest;
194
195    /* Perform the system call. */
196    register seL4_Word scno asm("r7") = sys;
197    asm volatile(
198        "swi $0"
199        : "+r"(msg0), "+r"(msg1), "+r"(msg2), "+r"(msg3),
200        "+r"(src_and_badge), "+r"(info)
201        : "r"(scno), "r"(reply_reg), "r"(dest_reg)
202        : "memory"
203    );
204
205    *out_badge = src_and_badge;
206    *out_info = info;
207    *in_out_mr0 = msg0;
208    *in_out_mr1 = msg1;
209    *in_out_mr2 = msg2;
210    *in_out_mr3 = msg3;
211}
212#endif
213
214static inline void arm_sys_null(seL4_Word sys)
215{
216    register seL4_Word scno asm("r7") = sys;
217    asm volatile(
218        "swi $0"
219        : /* no outputs */
220        : "r"(scno)
221    );
222}
223