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 */
27
28 #include "opt_platform.h"
29
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/limits.h>
33 #include <sys/proc.h>
34 #include <sys/sf_buf.h>
35 #include <sys/signal.h>
36 #include <sys/sysent.h>
37 #include <sys/unistd.h>
38
39 #include <vm/vm.h>
40 #include <vm/vm_page.h>
41 #include <vm/vm_map.h>
42 #include <vm/uma.h>
43 #include <vm/uma_int.h>
44
45 #include <machine/armreg.h>
46 #include <machine/cpu.h>
47 #include <machine/md_var.h>
48 #include <machine/pcb.h>
49 #include <machine/frame.h>
50
51 #ifdef VFP
52 #include <machine/vfp.h>
53 #endif
54
55 #include <dev/psci/psci.h>
56
57 /*
58 * psci.c is "default" in ARM64 kernel config files
59 * psci_reset will do nothing until/unless the psci device probes/attaches.
60 * Therefore, it is safe to default the cpu_reset_hook to psci_reset.
61 */
62 cpu_reset_hook_t cpu_reset_hook = psci_reset;
63
64 /*
65 * Finish a fork operation, with process p2 nearly set up.
66 * Copy and update the pcb, set up the stack so that the child
67 * ready to run and return to user mode.
68 */
69 void
cpu_fork(struct thread * td1,struct proc * p2,struct thread * td2,int flags)70 cpu_fork(struct thread *td1, struct proc *p2, struct thread *td2, int flags)
71 {
72 struct pcb *pcb2;
73 struct trapframe *tf;
74
75 if ((flags & RFPROC) == 0)
76 return;
77
78 if (td1 == curthread) {
79 /*
80 * Save the tpidr_el0 and the vfp state, these normally happen
81 * in cpu_switch, but if userland changes these then forks
82 * this may not have happened.
83 */
84 td1->td_pcb->pcb_tpidr_el0 = READ_SPECIALREG(tpidr_el0);
85 td1->td_pcb->pcb_tpidrro_el0 = READ_SPECIALREG(tpidrro_el0);
86 #ifdef VFP
87 if ((td1->td_pcb->pcb_fpflags & PCB_FP_STARTED) != 0)
88 vfp_save_state(td1, td1->td_pcb);
89 #endif
90 }
91
92 pcb2 = (struct pcb *)(td2->td_kstack +
93 td2->td_kstack_pages * PAGE_SIZE) - 1;
94
95 td2->td_pcb = pcb2;
96 bcopy(td1->td_pcb, pcb2, sizeof(*pcb2));
97
98 /* Clear the debug register state. */
99 bzero(&pcb2->pcb_dbg_regs, sizeof(pcb2->pcb_dbg_regs));
100
101 ptrauth_fork(td2, td1);
102
103 tf = (struct trapframe *)STACKALIGN((struct trapframe *)pcb2 - 1);
104 bcopy(td1->td_frame, tf, sizeof(*tf));
105 tf->tf_x[0] = 0;
106 tf->tf_x[1] = 0;
107 tf->tf_spsr = td1->td_frame->tf_spsr & (PSR_M_32 | PSR_DAIF);
108
109 td2->td_frame = tf;
110
111 /* Set the return value registers for fork() */
112 td2->td_pcb->pcb_x[PCB_X19] = (uintptr_t)fork_return;
113 td2->td_pcb->pcb_x[PCB_X20] = (uintptr_t)td2;
114 td2->td_pcb->pcb_x[PCB_LR] = (uintptr_t)fork_trampoline;
115 td2->td_pcb->pcb_sp = (uintptr_t)td2->td_frame;
116
117 vfp_new_thread(td2, td1, true);
118
119 /* Setup to release spin count in fork_exit(). */
120 td2->td_md.md_spinlock_count = 1;
121 td2->td_md.md_saved_daif = PSR_DAIF_DEFAULT;
122
123 #if defined(PERTHREAD_SSP)
124 /* Set the new canary */
125 arc4random_buf(&td2->td_md.md_canary, sizeof(td2->td_md.md_canary));
126 #endif
127 }
128
129 void
cpu_reset(void)130 cpu_reset(void)
131 {
132
133 cpu_reset_hook();
134
135 printf("cpu_reset failed");
136 while(1)
137 __asm volatile("wfi" ::: "memory");
138 }
139
140 void
cpu_set_syscall_retval(struct thread * td,int error)141 cpu_set_syscall_retval(struct thread *td, int error)
142 {
143 struct trapframe *frame;
144
145 frame = td->td_frame;
146
147 if (__predict_true(error == 0)) {
148 frame->tf_x[0] = td->td_retval[0];
149 frame->tf_x[1] = td->td_retval[1];
150 frame->tf_spsr &= ~PSR_C; /* carry bit */
151 return;
152 }
153
154 switch (error) {
155 case ERESTART:
156 frame->tf_elr -= 4;
157 break;
158 case EJUSTRETURN:
159 break;
160 default:
161 frame->tf_spsr |= PSR_C; /* carry bit */
162 frame->tf_x[0] = error;
163 break;
164 }
165 }
166
167 /*
168 * Initialize machine state, mostly pcb and trap frame for a new
169 * thread, about to return to userspace. Put enough state in the new
170 * thread's PCB to get it to go back to the fork_return(), which
171 * finalizes the thread state and handles peculiarities of the first
172 * return to userspace for the new thread.
173 */
174 void
cpu_copy_thread(struct thread * td,struct thread * td0)175 cpu_copy_thread(struct thread *td, struct thread *td0)
176 {
177 bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe));
178 bcopy(td0->td_pcb, td->td_pcb, sizeof(struct pcb));
179
180 td->td_pcb->pcb_x[PCB_X19] = (uintptr_t)fork_return;
181 td->td_pcb->pcb_x[PCB_X20] = (uintptr_t)td;
182 td->td_pcb->pcb_x[PCB_LR] = (uintptr_t)fork_trampoline;
183 td->td_pcb->pcb_sp = (uintptr_t)td->td_frame;
184
185 /* Update VFP state for the new thread */
186 vfp_new_thread(td, td0, false);
187
188 /* Setup to release spin count in fork_exit(). */
189 td->td_md.md_spinlock_count = 1;
190 td->td_md.md_saved_daif = PSR_DAIF_DEFAULT;
191
192 #if defined(PERTHREAD_SSP)
193 /* Set the new canary */
194 arc4random_buf(&td->td_md.md_canary, sizeof(td->td_md.md_canary));
195 #endif
196
197 /* Generate new pointer authentication keys. */
198 ptrauth_copy_thread(td, td0);
199 }
200
201 /*
202 * Set that machine state for performing an upcall that starts
203 * the entry function with the given argument.
204 */
205 int
cpu_set_upcall(struct thread * td,void (* entry)(void *),void * arg,stack_t * stack)206 cpu_set_upcall(struct thread *td, void (*entry)(void *), void *arg,
207 stack_t *stack)
208 {
209 struct trapframe *tf = td->td_frame;
210
211 /* 32bits processes use r13 for sp */
212 if (td->td_frame->tf_spsr & PSR_M_32) {
213 tf->tf_x[13] = STACKALIGN((uintptr_t)stack->ss_sp +
214 stack->ss_size);
215 if ((register_t)entry & 1)
216 tf->tf_spsr |= PSR_T;
217 } else
218 tf->tf_sp = STACKALIGN((uintptr_t)stack->ss_sp +
219 stack->ss_size);
220 tf->tf_elr = (register_t)entry;
221 tf->tf_x[0] = (register_t)arg;
222 tf->tf_x[29] = 0;
223 tf->tf_lr = 0;
224 return (0);
225 }
226
227 int
cpu_set_user_tls(struct thread * td,void * tls_base)228 cpu_set_user_tls(struct thread *td, void *tls_base)
229 {
230 struct pcb *pcb;
231
232 if ((uintptr_t)tls_base >= VM_MAXUSER_ADDRESS)
233 return (EINVAL);
234
235 pcb = td->td_pcb;
236 if (td->td_frame->tf_spsr & PSR_M_32) {
237 /* 32bits arm stores the user TLS into tpidrro */
238 pcb->pcb_tpidrro_el0 = (register_t)tls_base;
239 pcb->pcb_tpidr_el0 = (register_t)tls_base;
240 if (td == curthread) {
241 WRITE_SPECIALREG(tpidrro_el0, tls_base);
242 WRITE_SPECIALREG(tpidr_el0, tls_base);
243 }
244 } else {
245 pcb->pcb_tpidr_el0 = (register_t)tls_base;
246 if (td == curthread)
247 WRITE_SPECIALREG(tpidr_el0, tls_base);
248 }
249
250 return (0);
251 }
252
253 void
cpu_thread_exit(struct thread * td)254 cpu_thread_exit(struct thread *td)
255 {
256 }
257
258 void
cpu_thread_alloc(struct thread * td)259 cpu_thread_alloc(struct thread *td)
260 {
261
262 td->td_pcb = (struct pcb *)(td->td_kstack +
263 td->td_kstack_pages * PAGE_SIZE) - 1;
264 td->td_frame = (struct trapframe *)STACKALIGN(
265 (struct trapframe *)td->td_pcb - 1);
266 ptrauth_thread_alloc(td);
267 }
268
269 void
cpu_thread_free(struct thread * td)270 cpu_thread_free(struct thread *td)
271 {
272 }
273
274 void
cpu_thread_clean(struct thread * td)275 cpu_thread_clean(struct thread *td)
276 {
277 }
278
279 /*
280 * Intercept the return address from a freshly forked process that has NOT
281 * been scheduled yet.
282 *
283 * This is needed to make kernel threads stay in kernel mode.
284 */
285 void
cpu_fork_kthread_handler(struct thread * td,void (* func)(void *),void * arg)286 cpu_fork_kthread_handler(struct thread *td, void (*func)(void *), void *arg)
287 {
288
289 td->td_pcb->pcb_x[PCB_X19] = (uintptr_t)func;
290 td->td_pcb->pcb_x[PCB_X20] = (uintptr_t)arg;
291 }
292
293 void
cpu_update_pcb(struct thread * td)294 cpu_update_pcb(struct thread *td)
295 {
296 MPASS(td == curthread);
297 td->td_pcb->pcb_tpidr_el0 = READ_SPECIALREG(tpidr_el0);
298 td->td_pcb->pcb_tpidrro_el0 = READ_SPECIALREG(tpidrro_el0);
299 }
300
301 void
cpu_exit(struct thread * td)302 cpu_exit(struct thread *td)
303 {
304 }
305
306 bool
cpu_exec_vmspace_reuse(struct proc * p __unused,vm_map_t map __unused)307 cpu_exec_vmspace_reuse(struct proc *p __unused, vm_map_t map __unused)
308 {
309
310 return (true);
311 }
312
313 int
cpu_procctl(struct thread * td __unused,int idtype __unused,id_t id __unused,int com __unused,void * data __unused)314 cpu_procctl(struct thread *td __unused, int idtype __unused, id_t id __unused,
315 int com __unused, void *data __unused)
316 {
317
318 return (EINVAL);
319 }
320
321 void
cpu_sync_core(void)322 cpu_sync_core(void)
323 {
324 /*
325 * Do nothing. According to ARM ARMv8 D1.11 Exception return
326 * If FEAT_ExS is not implemented, or if FEAT_ExS is
327 * implemented and the SCTLR_ELx.EOS field is set, exception
328 * return from ELx is a context synchronization event.
329 */
330 }
331