/* $NetBSD: fault.c,v 1.45 2003/11/20 14:44:36 scw Exp $ */ /*- * Copyright 2004 Olivier Houchard * 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 __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef KDB #include #endif extern char fusubailout[]; #ifdef DEBUG int last_fault_code; /* For the benefit of pmap_fault_fixup() */ #endif struct ksig { int signb; u_long code; }; struct data_abort { int (*func)(struct trapframe *, u_int, u_int, struct thread *, struct ksig *); const char *desc; }; static int dab_fatal(struct trapframe *, u_int, u_int, struct thread *, struct ksig *); static int dab_align(struct trapframe *, u_int, u_int, struct thread *, struct ksig *); static int dab_buserr(struct trapframe *, u_int, u_int, struct thread *, struct ksig *); static void prefetch_abort_handler(struct trapframe *); static const struct data_abort data_aborts[] = { {dab_fatal, "Vector Exception"}, {dab_align, "Alignment Fault 1"}, {dab_fatal, "Terminal Exception"}, {dab_align, "Alignment Fault 3"}, {dab_buserr, "External Linefetch Abort (S)"}, {NULL, "Translation Fault (S)"}, #if (ARM_MMU_V6 + ARM_MMU_V7) != 0 {NULL, "Translation Flag Fault"}, #else {dab_buserr, "External Linefetch Abort (P)"}, #endif {NULL, "Translation Fault (P)"}, {dab_buserr, "External Non-Linefetch Abort (S)"}, {NULL, "Domain Fault (S)"}, {dab_buserr, "External Non-Linefetch Abort (P)"}, {NULL, "Domain Fault (P)"}, {dab_buserr, "External Translation Abort (L1)"}, {NULL, "Permission Fault (S)"}, {dab_buserr, "External Translation Abort (L2)"}, {NULL, "Permission Fault (P)"} }; /* Determine if a fault came from user mode */ #define TRAP_USERMODE(tf) ((tf->tf_spsr & PSR_MODE) == PSR_USR32_MODE) /* Determine if 'x' is a permission fault */ #define IS_PERMISSION_FAULT(x) \ (((1 << ((x) & FAULT_TYPE_MASK)) & \ ((1 << FAULT_PERM_P) | (1 << FAULT_PERM_S))) != 0) static __inline void call_trapsignal(struct thread *td, int sig, u_long code) { ksiginfo_t ksi; ksiginfo_init_trap(&ksi); ksi.ksi_signo = sig; ksi.ksi_code = (int)code; trapsignal(td, &ksi); } void abort_handler(struct trapframe *tf, int type) { struct vm_map *map; struct pcb *pcb; struct thread *td; u_int user, far, fsr; vm_prot_t ftype; void *onfault; vm_offset_t va; int error = 0; struct ksig ksig; struct proc *p; if (type == 1) return (prefetch_abort_handler(tf)); /* Grab FAR/FSR before enabling interrupts */ far = cpu_faultaddress(); fsr = cpu_faultstatus(); #if 0 printf("data abort: fault address=%p (from pc=%p lr=%p)\n", (void*)far, (void*)tf->tf_pc, (void*)tf->tf_svc_lr); #endif /* Update vmmeter statistics */ #if 0 vmexp.traps++; #endif td = curthread; p = td->td_proc; PCPU_INC(cnt.v_trap); /* Data abort came from user mode? */ user = TRAP_USERMODE(tf); if (user) { td->td_pticks = 0; td->td_frame = tf; if (td->td_ucred != td->td_proc->p_ucred) cred_update_thread(td); } /* Grab the current pcb */ pcb = td->td_pcb; /* Re-enable interrupts if they were enabled previously */ if (td->td_md.md_spinlock_count == 0) { if (__predict_true(tf->tf_spsr & PSR_I) == 0) enable_interrupts(PSR_I); if (__predict_true(tf->tf_spsr & PSR_F) == 0) enable_interrupts(PSR_F); } /* Invoke the appropriate handler, if necessary */ if (__predict_false(data_aborts[fsr & FAULT_TYPE_MASK].func != NULL)) { if ((data_aborts[fsr & FAULT_TYPE_MASK].func)(tf, fsr, far, td, &ksig)) { goto do_trapsignal; } 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. */ /* fusubailout is used by [fs]uswintr to avoid page faulting */ if (__predict_false(pcb->pcb_onfault == fusubailout)) { tf->tf_r0 = EFAULT; tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; return; } /* * 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 */ ksig.signb = SIGILL; ksig.code = 0; goto do_trapsignal; } /* * The kernel never executes Thumb code. */ printf("\ndata_abort_fault: Misaligned Kernel-mode " "Program Counter\n"); dab_fatal(tf, fsr, far, td, &ksig); } va = trunc_page((vm_offset_t)far); /* * 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 || (ReadWord(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)) { /* * Force exit via userret() * This is necessary as the FPE is an extension to * userland that actually runs in a priveledged mode * but uses USR mode permissions for its accesses. */ user = 1; ksig.signb = SIGSEGV; ksig.code = 0; goto do_trapsignal; } } else { map = &td->td_proc->p_vmspace->vm_map; } /* * We need to know whether the page should be mapped as R or R/W. On * armv6 and later the fault status register indicates whether the * access was a read or write. Prior to armv6, we know that a * permission fault can only be the result of a write to a read-only * location, so we can deal with those quickly. Otherwise we need to * disassemble the faulting instruction to determine if it was a write. */ #if __ARM_ARCH >= 6 ftype = (fsr & FAULT_WNR) ? VM_PROT_READ | VM_PROT_WRITE : VM_PROT_READ; #else if (IS_PERMISSION_FAULT(fsr)) ftype = VM_PROT_WRITE; else { u_int insn = ReadWord(tf->tf_pc); if (((insn & 0x0c100000) == 0x04000000) || /* STR/STRB */ ((insn & 0x0e1000b0) == 0x000000b0) || /* STRH/STRD */ ((insn & 0x0a100000) == 0x08000000)) { /* STM/CDT */ ftype = VM_PROT_WRITE; } else { if ((insn & 0x0fb00ff0) == 0x01000090) /* SWP */ ftype = VM_PROT_READ | VM_PROT_WRITE; else ftype = VM_PROT_READ; } } #endif /* * See if the fault is as a result of ref/mod emulation, * or domain mismatch. */ #ifdef DEBUG last_fault_code = fsr; #endif if (pmap_fault_fixup(vmspace_pmap(td->td_proc->p_vmspace), va, ftype, user)) { goto out; } onfault = pcb->pcb_onfault; pcb->pcb_onfault = NULL; if (map != kernel_map) { PROC_LOCK(p); p->p_lock++; PROC_UNLOCK(p); } error = vm_fault(map, va, ftype, VM_FAULT_NORMAL); pcb->pcb_onfault = onfault; if (map != kernel_map) { PROC_LOCK(p); p->p_lock--; PROC_UNLOCK(p); } if (__predict_true(error == 0)) goto out; if (user == 0) { if (pcb->pcb_onfault) { tf->tf_r0 = error; tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; return; } printf("\nvm_fault(%p, %x, %x, 0) -> %x\n", map, va, ftype, error); dab_fatal(tf, fsr, far, td, &ksig); } if (error == ENOMEM) { printf("VM: pid %d (%s), uid %d killed: " "out of swap\n", td->td_proc->p_pid, td->td_name, (td->td_proc->p_ucred) ? td->td_proc->p_ucred->cr_uid : -1); ksig.signb = SIGKILL; } else { ksig.signb = SIGSEGV; } ksig.code = 0; do_trapsignal: call_trapsignal(td, ksig.signb, ksig.code); out: /* If returning to user mode, make sure to invoke userret() */ if (user) userret(td, tf); } /* * 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 'l' is NULL, we assume we're dealing with a prefetch abort. */ static int dab_fatal(struct trapframe *tf, u_int fsr, u_int far, struct thread *td, struct ksig *ksig) { const char *mode; mode = TRAP_USERMODE(tf) ? "user" : "kernel"; disable_interrupts(PSR_I|PSR_F); if (td != NULL) { printf("Fatal %s mode data abort: '%s'\n", mode, data_aborts[fsr & FAULT_TYPE_MASK].desc); printf("trapframe: %p\nFSR=%08x, FAR=", tf, fsr); if ((fsr & FAULT_IMPRECISE) == 0) printf("%08x, ", far); else printf("Invalid, "); printf("spsr=%08x\n", tf->tf_spsr); } else { printf("Fatal %s mode prefetch abort at 0x%08x\n", mode, tf->tf_pc); printf("trapframe: %p, spsr=%08x\n", tf, tf->tf_spsr); } printf("r0 =%08x, r1 =%08x, r2 =%08x, r3 =%08x\n", tf->tf_r0, tf->tf_r1, tf->tf_r2, tf->tf_r3); printf("r4 =%08x, r5 =%08x, r6 =%08x, r7 =%08x\n", tf->tf_r4, tf->tf_r5, tf->tf_r6, tf->tf_r7); printf("r8 =%08x, r9 =%08x, r10=%08x, r11=%08x\n", tf->tf_r8, tf->tf_r9, tf->tf_r10, tf->tf_r11); printf("r12=%08x, ", tf->tf_r12); if (TRAP_USERMODE(tf)) printf("usp=%08x, ulr=%08x", tf->tf_usr_sp, tf->tf_usr_lr); else printf("ssp=%08x, slr=%08x", tf->tf_svc_sp, tf->tf_svc_lr); printf(", pc =%08x\n\n", tf->tf_pc); #ifdef KDB if (debugger_on_panic || kdb_active) if (kdb_trap(fsr, 0, tf)) return (0); #endif panic("Fatal abort"); /*NOTREACHED*/ } /* * dab_align() handles the following data aborts: * * FAULT_ALIGN_0 - Alignment fault * FAULT_ALIGN_1 - 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(struct trapframe *tf, u_int fsr, u_int far, struct thread *td, struct ksig *ksig) { /* Alignment faults are always fatal if they occur in kernel mode */ if (!TRAP_USERMODE(tf)) { if (!td || !td->td_pcb->pcb_onfault) dab_fatal(tf, fsr, far, td, ksig); tf->tf_r0 = EFAULT; tf->tf_pc = (int)td->td_pcb->pcb_onfault; return (0); } /* pcb_onfault *must* be NULL at this point */ /* Deliver a bus error signal to the process */ ksig->code = 0; ksig->signb = SIGBUS; td->td_frame = tf; 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(struct trapframe *tf, u_int fsr, u_int far, struct thread *td, struct ksig *ksig) { struct pcb *pcb = td->td_pcb; #ifdef __XSCALE__ if ((fsr & FAULT_IMPRECISE) != 0 && (tf->tf_spsr & PSR_MODE) == PSR_ABT32_MODE) { /* * Oops, an imprecise, double abort fault. We've lost the * r14_abt/spsr_abt values corresponding to the original * abort, and the spsr saved in the trapframe indicates * ABT mode. */ tf->tf_spsr &= ~PSR_MODE; /* * We use a simple heuristic to determine if the double abort * happened as a result of a kernel or user mode access. * If the current trapframe is at the top of the kernel stack, * the fault _must_ have come from user mode. */ if (tf != ((struct trapframe *)pcb->pcb_regs.sf_sp) - 1) { /* * Kernel mode. We're either about to die a * spectacular death, or pcb_onfault will come * to our rescue. Either way, the current value * of tf->tf_pc is irrelevant. */ tf->tf_spsr |= PSR_SVC32_MODE; if (pcb->pcb_onfault == NULL) printf("\nKernel mode double abort!\n"); } else { /* * User mode. We've lost the program counter at the * time of the fault (not that it was accurate anyway; * it's not called an imprecise fault for nothing). * About all we can do is copy r14_usr to tf_pc and * hope for the best. The process is about to get a * SIGBUS, so it's probably history anyway. */ tf->tf_spsr |= PSR_USR32_MODE; tf->tf_pc = tf->tf_usr_lr; } } /* FAR is invalid for imprecise exceptions */ if ((fsr & FAULT_IMPRECISE) != 0) far = 0; #endif /* __XSCALE__ */ if (pcb->pcb_onfault) { tf->tf_r0 = EFAULT; tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; return (0); } /* * At this point, if the fault happened in kernel mode, we're toast */ if (!TRAP_USERMODE(tf)) dab_fatal(tf, fsr, far, td, ksig); /* Deliver a bus error signal to the process */ ksig->signb = SIGBUS; ksig->code = 0; td->td_frame = tf; return (1); } /* * void prefetch_abort_handler(struct trapframe *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 permission so send it a signal. * Otherwise fault the page in and try again. */ static void prefetch_abort_handler(struct trapframe *tf) { struct thread *td; struct proc * p; struct vm_map *map; vm_offset_t fault_pc, va; int error = 0; struct ksig ksig; #if 0 /* Update vmmeter statistics */ uvmexp.traps++; #endif #if 0 printf("prefetch abort handler: %p %p\n", (void*)tf->tf_pc, (void*)tf->tf_usr_lr); #endif td = curthread; p = td->td_proc; PCPU_INC(cnt.v_trap); if (TRAP_USERMODE(tf)) { td->td_frame = tf; if (td->td_ucred != td->td_proc->p_ucred) cred_update_thread(td); } fault_pc = tf->tf_pc; if (td->td_md.md_spinlock_count == 0) { if (__predict_true(tf->tf_spsr & PSR_I) == 0) enable_interrupts(PSR_I); if (__predict_true(tf->tf_spsr & PSR_F) == 0) enable_interrupts(PSR_F); } /* Prefetch aborts cannot happen in kernel mode */ if (__predict_false(!TRAP_USERMODE(tf))) dab_fatal(tf, 0, tf->tf_pc, NULL, &ksig); td->td_pticks = 0; /* Ok validate the address, can only execute in USER space */ if (__predict_false(fault_pc >= VM_MAXUSER_ADDRESS || (fault_pc < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW))) { ksig.signb = SIGSEGV; ksig.code = 0; goto do_trapsignal; } map = &td->td_proc->p_vmspace->vm_map; va = trunc_page(fault_pc); /* * See if the pmap can handle this fault on its own... */ #ifdef DEBUG last_fault_code = -1; #endif if (pmap_fault_fixup(map->pmap, va, VM_PROT_READ, 1)) goto out; if (map != kernel_map) { PROC_LOCK(p); p->p_lock++; PROC_UNLOCK(p); } error = vm_fault(map, va, VM_PROT_READ | VM_PROT_EXECUTE, VM_FAULT_NORMAL); if (map != kernel_map) { PROC_LOCK(p); p->p_lock--; PROC_UNLOCK(p); } if (__predict_true(error == 0)) goto out; if (error == ENOMEM) { printf("VM: pid %d (%s), uid %d killed: " "out of swap\n", td->td_proc->p_pid, td->td_name, (td->td_proc->p_ucred) ? td->td_proc->p_ucred->cr_uid : -1); ksig.signb = SIGKILL; } else { ksig.signb = SIGSEGV; } ksig.code = 0; do_trapsignal: call_trapsignal(td, ksig.signb, ksig.code); out: userret(td, tf); } 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 *); /* * 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) { 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); }