/* $OpenBSD: fault.c,v 1.48 2024/04/29 12:33:17 jsg Exp $ */ /* $NetBSD: fault.c,v 1.46 2004/01/21 15:39:21 skrll Exp $ */ /* * Copyright 2003 Wasabi Systems, Inc. * All rights reserved. * * Written by Steve C. Woodford for Wasabi Systems, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed for the NetBSD Project by * Wasabi Systems, Inc. * 4. The name of Wasabi Systems, Inc. may not be used to endorse * or promote products derived from this software without specific prior * written permission. * * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ /* * Copyright (c) 1994-1997 Mark Brinicombe. * Copyright (c) 1994 Brini. * All rights reserved. * * This code is derived from software written for Brini by Mark Brinicombe * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by Brini. * 4. The name of the company nor the name of the author may be used to * endorse or promote products derived from this software without specific * prior written permission. * * THIS SOFTWARE IS PROVIDED BY BRINI ``AS IS'' AND ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL BRINI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * RiscBSD kernel project * * fault.c * * Fault handlers * * Created : 28/11/94 */ #include #include #include #include #include #include #include #include #ifdef DDB #include #endif #include #include #include struct sigdata { int signo; int code; vaddr_t addr; int trap; }; struct data_abort { int (*func)(trapframe_t *, u_int, u_int, struct proc *, struct sigdata *); const char *desc; }; static int dab_fatal(trapframe_t *, u_int, u_int, struct proc *, struct sigdata *sd); static int dab_align(trapframe_t *, u_int, u_int, struct proc *, struct sigdata *sd); static int dab_buserr(trapframe_t *, u_int, u_int, struct proc *, struct sigdata *sd); extern int dab_access(trapframe_t *, u_int, u_int, struct proc *, struct sigdata *sd); static const struct data_abort data_aborts[] = { {dab_fatal, "V7 fault 00000"}, {dab_align, "Alignment fault"}, {dab_fatal, "Debug event"}, {dab_fatal, "Access flag fault (L1)"}, {dab_buserr, "Fault on instruction cache maintenance"}, {NULL, "Translation fault (L1)"}, {dab_access, "Access flag fault (L2)"}, {NULL, "Translation fault (L2)"}, {dab_buserr, "Synchronous external abort"}, {NULL, "Domain fault (L1)"}, {dab_fatal, "V7 fault 01010"}, {NULL, "Domain fault (L2)"}, {dab_buserr, "Synchronous external abort on translation table walk (L1)"}, {NULL, "Permission fault (L1)"}, {dab_buserr, "Synchronous external abort on translation table walk (L2)"}, {NULL, "Permission fault (L2)"}, {dab_fatal, "TLB conflict abort"}, {dab_fatal, "V7 fault 10001"}, {dab_fatal, "V7 fault 10010"}, {dab_fatal, "V7 fault 10011"}, {dab_fatal, "Lockdown"}, {dab_fatal, "V7 fault 10101"}, {dab_fatal, "Asynchronous external abort"}, {dab_fatal, "V7 fault 10111"}, {dab_fatal, "Asynchronous parity error on memory access"}, {dab_fatal, "Synchronous parity error on memory access"}, {dab_fatal, "Coprocessor Abort"}, {dab_fatal, "V7 fault 11011"}, {dab_buserr, "Synchronous parity error on translation table walk (L1)"}, {dab_fatal, "V7 fault 11101"}, {dab_buserr, "Synchronous parity error on translation table walk (L2)"}, {NULL, "V7 fault 11111"}, }; /* Determine if 'ftyp' is a permission fault */ #define IS_PERMISSION_FAULT(ftyp) \ (((1 << (ftyp)) & \ ((1 << FAULT_PERM_P) | (1 << FAULT_PERM_S))) != 0) void data_abort_handler(trapframe_t *tf) { struct vm_map *map; struct pcb *pcb; struct proc *p; u_int user, far, fsr, ftyp; vm_prot_t ftype; void *onfault; vaddr_t va; int error; union sigval sv; struct sigdata sd; /* Grab FAR/FSR before enabling interrupts */ far = cpu_dfar(); fsr = cpu_dfsr(); ftyp = FAULT_TYPE_V7(fsr); /* Update vmmeter statistics */ uvmexp.traps++; /* Before enabling interrupts, save FPU state */ vfp_save(); /* Re-enable interrupts if they were enabled previously */ if (__predict_true((tf->tf_spsr & PSR_I) == 0)) enable_interrupts(PSR_I); /* Get the current proc structure or proc0 if there is none */ p = (curproc != NULL) ? curproc : &proc0; /* Data abort came from user mode? */ user = TRAP_USERMODE(tf); /* Grab the current pcb */ pcb = &p->p_addr->u_pcb; if (user) { pcb->pcb_tf = tf; refreshcreds(p); } /* Invoke the appropriate handler, if necessary */ if (__predict_false(data_aborts[ftyp].func != NULL)) { if ((data_aborts[ftyp].func)(tf, fsr, far, p, &sd)) { goto do_trapsignal; } goto out; } va = trunc_page((vaddr_t)far); /* * Flush BP cache on processors that are vulnerable to branch * target injection attacks if access is outside user space. */ if (va < VM_MIN_ADDRESS || va >= VM_MAX_ADDRESS) curcpu()->ci_flush_bp(); if (user) { if (!uvm_map_inentry(p, &p->p_spinentry, PROC_STACK(p), "[%s]%d/%d sp=%lx inside %lx-%lx: not MAP_STACK\n", uvm_map_inentry_sp, p->p_vmspace->vm_map.sserial)) goto out; } /* * At this point, we're dealing with one of the following data aborts: * * FAULT_TRANS_S - Translation -- Section * FAULT_TRANS_P - Translation -- Page * FAULT_DOMAIN_S - Domain -- Section * FAULT_DOMAIN_P - Domain -- Page * FAULT_PERM_S - Permission -- Section * FAULT_PERM_P - Permission -- Page * * These are the main virtual memory-related faults signalled by * the MMU. */ /* * Make sure the Program Counter is sane. We could fall foul of * someone executing Thumb code, in which case the PC might not * be word-aligned. This would cause a kernel alignment fault * further down if we have to decode the current instruction. * XXX: It would be nice to be able to support Thumb at some point. */ if (__predict_false((tf->tf_pc & 3) != 0)) { if (user) { /* * Give the user an illegal instruction signal. */ /* Deliver a SIGILL to the process */ sd.signo = SIGILL; sd.code = ILL_ILLOPC; sd.addr = far; sd.trap = fsr; goto do_trapsignal; } /* * The kernel never executes Thumb code. */ printf("\ndata_abort_fault: Misaligned Kernel-mode " "Program Counter\n"); dab_fatal(tf, fsr, far, p, NULL); } /* * It is only a kernel address space fault iff: * 1. user == 0 and * 2. pcb_onfault not set or * 3. pcb_onfault set and not LDRT/LDRBT/STRT/STRBT instruction. */ if (user == 0 && (va >= VM_MIN_KERNEL_ADDRESS || (va < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW)) && __predict_true((pcb->pcb_onfault == NULL || ((*(u_int *)tf->tf_pc) & 0x05200000) != 0x04200000))) { map = kernel_map; /* Was the fault due to the FPE/IPKDB ? */ if (__predict_false((tf->tf_spsr & PSR_MODE)==PSR_UND32_MODE)) { sd.signo = SIGSEGV; sd.code = SEGV_ACCERR; sd.addr = far; sd.trap = fsr; /* * Force exit via userret() * This is necessary as the FPE is an extension to * userland that actually runs in a privileged mode * but uses USR mode permissions for its accesses. */ user = 1; goto do_trapsignal; } } else { map = &p->p_vmspace->vm_map; #if 0 if (l->l_flag & L_SA) { KDASSERT(l->l_proc->p_sa != NULL); l->l_proc->p_sa->sa_vp_faultaddr = (vaddr_t)far; l->l_flag |= L_SA_PAGEFAULT; } #endif } ftype = fsr & FAULT_WNR ? PROT_WRITE : PROT_READ; if (__predict_false(curcpu()->ci_idepth > 0)) { if (pcb->pcb_onfault) { tf->tf_r0 = EINVAL; tf->tf_pc = (register_t) pcb->pcb_onfault; return; } printf("\nNon-emulated page fault with intr_depth > 0\n"); dab_fatal(tf, fsr, far, p, NULL); } onfault = pcb->pcb_onfault; pcb->pcb_onfault = NULL; KERNEL_LOCK(); error = uvm_fault(map, va, 0, ftype); KERNEL_UNLOCK(); pcb->pcb_onfault = onfault; #if 0 if (map != kernel_map) p->p_flag &= ~L_SA_PAGEFAULT; #endif if (error == 0) { if (map != kernel_map) uvm_grow(p, va); goto out; } if (user == 0) { if (pcb->pcb_onfault) { tf->tf_r0 = EFAULT; tf->tf_pc = (register_t) pcb->pcb_onfault; return; } printf("\nuvm_fault(%p, %lx, %x, 0) -> %x\n", map, va, ftype, error); dab_fatal(tf, fsr, far, p, NULL); } sd.signo = SIGSEGV; sd.code = SEGV_MAPERR; if (error == ENOMEM) { printf("UVM: pid %d (%s), uid %d killed: " "out of swap\n", p->p_p->ps_pid, p->p_p->ps_comm, p->p_ucred ? (int)p->p_ucred->cr_uid : -1); sd.signo = SIGKILL; sd.code = 0; } else if (error == EACCES) sd.code = SEGV_ACCERR; else if (error == EIO) { sd.signo = SIGBUS; sd.code = BUS_OBJERR; } sd.addr = far; sd.trap = fsr; do_trapsignal: sv.sival_int = sd.addr; trapsignal(p, sd.signo, sd.trap, sd.code, sv); out: /* If returning to user mode, make sure to invoke userret() */ if (user) userret(p); } /* * dab_fatal() handles the following data aborts: * * FAULT_WRTBUF_0 - Vector Exception * FAULT_WRTBUF_1 - Terminal Exception * * We should never see these on a properly functioning system. * * This function is also called by the other handlers if they * detect a fatal problem. * * Note: If 'p' is NULL, we assume we're dealing with a prefetch abort. */ static int dab_fatal(trapframe_t *tf, u_int fsr, u_int far, struct proc *p, struct sigdata *sd) { const char *mode; uint ftyp; mode = TRAP_USERMODE(tf) ? "user" : "kernel"; if (p != NULL) { ftyp = FAULT_TYPE_V7(fsr); printf("Fatal %s mode data abort: '%s'\n", mode, data_aborts[ftyp].desc); printf("trapframe: %p\nDFSR=%08x, DFAR=%08x", tf, fsr, far); printf(", spsr=%08lx\n", tf->tf_spsr); } else { printf("Fatal %s mode prefetch abort at 0x%08lx\n", mode, tf->tf_pc); printf("trapframe: %p\nIFSR=%08x, IFAR=%08x, spsr=%08lx\n", tf, fsr, far, tf->tf_spsr); } printf("r0 =%08lx, r1 =%08lx, r2 =%08lx, r3 =%08lx\n", tf->tf_r0, tf->tf_r1, tf->tf_r2, tf->tf_r3); printf("r4 =%08lx, r5 =%08lx, r6 =%08lx, r7 =%08lx\n", tf->tf_r4, tf->tf_r5, tf->tf_r6, tf->tf_r7); printf("r8 =%08lx, r9 =%08lx, r10=%08lx, r11=%08lx\n", tf->tf_r8, tf->tf_r9, tf->tf_r10, tf->tf_r11); printf("r12=%08lx, ", tf->tf_r12); if (TRAP_USERMODE(tf)) printf("usp=%08lx, ulr=%08lx", tf->tf_usr_sp, tf->tf_usr_lr); else printf("ssp=%08lx, slr=%08lx", tf->tf_svc_sp, tf->tf_svc_lr); printf(", pc =%08lx\n\n", tf->tf_pc); #ifdef DDB db_ktrap(T_FAULT, tf); #endif panic("Fatal abort"); /*NOTREACHED*/ } /* * dab_align() handles the following data aborts: * * FAULT_ALIGN_0 - Alignment fault * FAULT_ALIGN_0 - Alignment fault * * These faults are fatal if they happen in kernel mode. Otherwise, we * deliver a bus error to the process. */ static int dab_align(trapframe_t *tf, u_int fsr, u_int far, struct proc *p, struct sigdata *sd) { /* Alignment faults are always fatal if they occur in kernel mode */ if (!TRAP_USERMODE(tf)) dab_fatal(tf, fsr, far, p, NULL); /* pcb_onfault *must* be NULL at this point */ KDASSERT(p->p_addr->u_pcb.pcb_onfault == NULL); /* Deliver a bus error signal to the process */ sd->signo = SIGBUS; sd->code = BUS_ADRALN; sd->addr = far; sd->trap = fsr; return (1); } /* * dab_buserr() handles the following data aborts: * * FAULT_BUSERR_0 - External Abort on Linefetch -- Section * FAULT_BUSERR_1 - External Abort on Linefetch -- Page * FAULT_BUSERR_2 - External Abort on Non-linefetch -- Section * FAULT_BUSERR_3 - External Abort on Non-linefetch -- Page * FAULT_BUSTRNL1 - External abort on Translation -- Level 1 * FAULT_BUSTRNL2 - External abort on Translation -- Level 2 * * If pcb_onfault is set, flag the fault and return to the handler. * If the fault occurred in user mode, give the process a SIGBUS. * * Note: On XScale, FAULT_BUSERR_0, FAULT_BUSERR_1, and FAULT_BUSERR_2 * can be flagged as imprecise in the FSR. This causes a real headache * since some of the machine state is lost. In this case, tf->tf_pc * may not actually point to the offending instruction. In fact, if * we've taken a double abort fault, it generally points somewhere near * the top of "data_abort_entry" in exception.S. * * In all other cases, these data aborts are considered fatal. */ static int dab_buserr(trapframe_t *tf, u_int fsr, u_int far, struct proc *p, struct sigdata *sd) { struct pcb *pcb = &p->p_addr->u_pcb; if (pcb->pcb_onfault) { KDASSERT(TRAP_USERMODE(tf) == 0); tf->tf_r0 = EFAULT; tf->tf_pc = (register_t) pcb->pcb_onfault; return (0); } /* * At this point, if the fault happened in kernel mode or user mode, * we're toast */ dab_fatal(tf, fsr, far, p, NULL); return (1); } /* * void prefetch_abort_handler(trapframe_t *tf) * * Abort handler called when instruction execution occurs at * a non existent or restricted (access permissions) memory page. * If the address is invalid and we were in SVC mode then panic as * the kernel should never prefetch abort. * If the address is invalid and the page is mapped then the user process * does no have read or execute permission so send it a signal. * Otherwise fault the page in and try again. */ void prefetch_abort_handler(trapframe_t *tf) { struct proc *p = curproc; struct vm_map *map; vaddr_t va; int error; union sigval sv; uint fsr, far; /* Update vmmeter statistics */ uvmexp.traps++; /* Grab FAR/FSR before enabling interrupts */ far = cpu_ifar(); fsr = cpu_ifsr(); /* Prefetch aborts cannot happen in kernel mode */ if (__predict_false(!TRAP_USERMODE(tf))) dab_fatal(tf, fsr, far, NULL, NULL); /* Before enabling interrupts, save FPU state */ vfp_save(); /* * Enable IRQ's (disabled by the abort) This always comes * from user mode so we know interrupts were not disabled. * But we check anyway. */ if (__predict_true((tf->tf_spsr & PSR_I) == 0)) enable_interrupts(PSR_I); p->p_addr->u_pcb.pcb_tf = tf; /* Invoke access fault handler if appropriate */ if (FAULT_TYPE_V7(fsr) == FAULT_ACCESS_2) { dab_access(tf, fsr, far, p, NULL); goto out; } /* Ok validate the address, can only execute in USER space */ if (__predict_false(far >= VM_MAXUSER_ADDRESS || (far < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW))) { sv.sival_ptr = (u_int32_t *)far; trapsignal(p, SIGSEGV, 0, SEGV_ACCERR, sv); goto out; } map = &p->p_vmspace->vm_map; va = trunc_page(far); #ifdef DIAGNOSTIC if (__predict_false(curcpu()->ci_idepth > 0)) { printf("\nNon-emulated prefetch abort with intr_depth > 0\n"); dab_fatal(tf, fsr, far, NULL, NULL); } #endif KERNEL_LOCK(); error = uvm_fault(map, va, 0, PROT_EXEC); KERNEL_UNLOCK(); if (error == 0) { uvm_grow(p, va); goto out; } sv.sival_ptr = (u_int32_t *)far; if (error == ENOMEM) { printf("UVM: pid %d (%s), uid %d killed: " "out of swap\n", p->p_p->ps_pid, p->p_p->ps_comm, p->p_ucred ? (int)p->p_ucred->cr_uid : -1); trapsignal(p, SIGKILL, 0, SEGV_MAPERR, sv); } else { trapsignal(p, SIGSEGV, 0, SEGV_MAPERR, sv); } out: userret(p); } /* * Tentatively read an 8, 16, or 32-bit value from 'addr'. * If the read succeeds, the value is written to 'rptr' and zero is returned. * Else, return EFAULT. */ int badaddr_read(void *addr, size_t size, void *rptr) { extern int badaddr_read_1(const uint8_t *, uint8_t *); extern int badaddr_read_2(const uint16_t *, uint16_t *); extern int badaddr_read_4(const uint32_t *, uint32_t *); union { uint8_t v1; uint16_t v2; uint32_t v4; } u; int rv; cpu_drain_writebuf(); /* Read from the test address. */ switch (size) { case sizeof(uint8_t): rv = badaddr_read_1(addr, &u.v1); if (rv == 0 && rptr) *(uint8_t *) rptr = u.v1; break; case sizeof(uint16_t): rv = badaddr_read_2(addr, &u.v2); if (rv == 0 && rptr) *(uint16_t *) rptr = u.v2; break; case sizeof(uint32_t): rv = badaddr_read_4(addr, &u.v4); if (rv == 0 && rptr) *(uint32_t *) rptr = u.v4; break; default: panic("badaddr: invalid size (%lu)", (u_long) size); } /* Return EFAULT if the address was invalid, else zero */ return (rv); }