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 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 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 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 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 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 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 254 cpu_thread_exit(struct thread *td) 255 { 256 } 257 258 void 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 270 cpu_thread_free(struct thread *td) 271 { 272 } 273 274 void 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 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 294 cpu_exit(struct thread *td) 295 { 296 } 297 298 bool 299 cpu_exec_vmspace_reuse(struct proc *p __unused, vm_map_t map __unused) 300 { 301 302 return (true); 303 } 304 305 int 306 cpu_procctl(struct thread *td __unused, int idtype __unused, id_t id __unused, 307 int com __unused, void *data __unused) 308 { 309 310 return (EINVAL); 311 } 312 313 void 314 cpu_sync_core(void) 315 { 316 /* 317 * Do nothing. According to ARM ARMv8 D1.11 Exception return 318 * If FEAT_ExS is not implemented, or if FEAT_ExS is 319 * implemented and the SCTLR_ELx.EOS field is set, exception 320 * return from ELx is a context synchronization event. 321 */ 322 } 323