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