/* $NetBSD: trap.c,v 1.74 1995/03/22 23:25:13 mycroft Exp $ */ #undef DEBUG #define DEBUG /*- * Copyright (c) 1995 Charles Hannum. * Copyright (c) 1990 The Regents of the University of California. * All rights reserved. * * This code is derived from software contributed to Berkeley by * the University of Utah, and William Jolitz. * * 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 the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 THE REGENTS 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. * * @(#)trap.c 7.4 (Berkeley) 5/13/91 */ /* * 386 Trap and System call handling */ #include #include #include #include #include #include #include #ifdef KTRACE #include #endif #include #include #include #include #include #include #include #include #include #ifdef COMPAT_IBCS2 #include #include #endif #ifdef COMPAT_LINUX #include #include #endif #include "npx.h" /* * Define the code needed before returning to user mode, for * trap and syscall. */ static inline void userret(p, pc, oticks) register struct proc *p; int pc; u_quad_t oticks; { int sig, s; /* take pending signals */ while ((sig = CURSIG(p)) != 0) postsig(sig); p->p_priority = p->p_usrpri; if (want_resched) { /* * Since we are curproc, a clock interrupt could * change our priority without changing run queues * (the running process is not kept on a run queue). * If this happened after we setrunqueue ourselves but * before we switch()'ed, we might not be on the queue * indicated by our priority. */ s = splstatclock(); setrunqueue(p); p->p_stats->p_ru.ru_nivcsw++; mi_switch(); splx(s); while ((sig = CURSIG(p)) != 0) postsig(sig); } /* * If profiling, charge recent system time to the trapped pc. */ if (p->p_flag & P_PROFIL) { extern int psratio; addupc_task(p, pc, (int)(p->p_sticks - oticks) * psratio); } curpriority = p->p_priority; } char *trap_type[] = { "privileged instruction fault", /* 0 T_PRIVINFLT */ "breakpoint trap", /* 1 T_BPTFLT */ "arithmetic trap", /* 2 T_ARITHTRAP */ "asynchronous system trap", /* 3 T_ASTFLT */ "protection fault", /* 4 T_PROTFLT */ "trace trap", /* 5 T_TRCTRAP */ "page fault", /* 6 T_PAGEFLT */ "alignment fault", /* 7 T_ALIGNFLT */ "integer divide fault", /* 8 T_DIVIDE */ "non-maskable interrupt", /* 9 T_NMI */ "overflow trap", /* 10 T_OFLOW */ "bounds check fault", /* 11 T_BOUND */ "FPU not available fault", /* 12 T_DNA */ "double fault", /* 13 T_DOUBLEFLT */ "FPU operand fetch fault", /* 14 T_FPOPFLT */ "invalid TSS fault", /* 15 T_TSSFLT */ "segment not present fault", /* 16 T_SEGNPFLT */ "stack fault", /* 17 T_STKFLT */ "reserved trap", /* 18 T_RESERVED */ }; int trap_types = sizeof trap_type / sizeof trap_type[0]; #ifdef DEBUG int trapdebug = 0; #endif /* * trap(frame): * Exception, fault, and trap interface to BSD kernel. This * common code is called from assembly language IDT gate entry * routines that prepare a suitable stack frame, and restore this * frame after the exception has been processed. Note that the * effect is as if the arguments were passed call by reference. */ /*ARGSUSED*/ void trap(frame) struct trapframe frame; { register struct proc *p = curproc; int type = frame.tf_trapno; u_quad_t sticks; struct pcb *pcb; extern char fusubail[], resume_iret[], resume_pop_ds[], resume_pop_es[]; struct trapframe *vframe; int resume; cnt.v_trap++; #ifdef DEBUG if (trapdebug) { printf("trap %d code %x eip %x cs %x eflags %x cr2 %x cpl %x\n", frame.tf_trapno, frame.tf_err, frame.tf_eip, frame.tf_cs, frame.tf_eflags, rcr2(), cpl); printf("curproc %x\n", curproc); } #endif if (ISPL(frame.tf_cs) != SEL_KPL) { type |= T_USER; sticks = p->p_sticks; p->p_md.md_regs = (int *)&frame; } switch (type) { default: we_re_toast: #ifdef DDB if (kdb_trap(type, 0, &frame)) return; #endif if (frame.tf_trapno < trap_types) printf("fatal %s", trap_type[frame.tf_trapno]); else printf("unknown trap %d", frame.tf_trapno); printf(" in %s mode\n", (type & T_USER) ? "user" : "supervisor"); printf("trap type %d code %x eip %x cs %x eflags %x cr2 %x cpl %x\n", type, frame.tf_err, frame.tf_eip, frame.tf_cs, frame.tf_eflags, rcr2(), cpl); panic("trap"); /*NOTREACHED*/ case T_PROTFLT: case T_SEGNPFLT: case T_ALIGNFLT: /* Check for copyin/copyout fault. */ pcb = &p->p_addr->u_pcb; if (pcb->pcb_onfault != 0) { copyfault: frame.tf_eip = (int)pcb->pcb_onfault; return; } /* * Check for failure during return to user mode. * * We do this by looking at the instruction we faulted on. The * specific instructions we recognize only happen when * returning from a trap, syscall, or interrupt. * * XXX * The heuristic used here will currently fail for the case of * one of the 2 pop instructions faulting when returning from a * a fast interrupt. This should not be possible. It can be * fixed by rearranging the trap frame so that the stack format * at this point is the same as on exit from a `slow' * interrupt. */ switch (*(u_char *)frame.tf_eip) { case 0xcf: /* iret */ vframe = (void *)((int)&frame.tf_esp - 44); resume = (int)resume_iret; break; case 0x1f: /* popl %ds */ vframe = (void *)((int)&frame.tf_esp - 4); resume = (int)resume_pop_ds; break; case 0x07: /* popl %es */ vframe = (void *)((int)&frame.tf_esp - 0); resume = (int)resume_pop_es; break; default: goto we_re_toast; } if (ISPL(vframe->tf_cs) == SEL_KPL) goto we_re_toast; frame.tf_eip = resume; return; case T_SEGNPFLT|T_USER: case T_STKFLT|T_USER: case T_PROTFLT|T_USER: /* protection fault */ case T_ALIGNFLT|T_USER: trapsignal(p, SIGBUS, type &~ T_USER); goto out; case T_PRIVINFLT|T_USER: /* privileged instruction fault */ case T_FPOPFLT|T_USER: /* coprocessor operand fault */ trapsignal(p, SIGILL, type &~ T_USER); goto out; case T_ASTFLT|T_USER: /* Allow process switch */ cnt.v_soft++; if (p->p_flag & P_OWEUPC) { p->p_flag &= ~P_OWEUPC; ADDUPROF(p); } goto out; case T_DNA|T_USER: { #ifdef MATH_EMULATE int rv; if ((rv = math_emulate(&frame)) == 0) { if (frame.tf_eflags & PSL_T) goto trace; return; } trapsignal(p, rv, type &~ T_USER); goto out; #else printf("pid %d killed due to lack of floating point\n", p->p_pid); trapsignal(p, SIGKILL, type &~ T_USER); goto out; #endif } case T_BOUND|T_USER: case T_OFLOW|T_USER: case T_DIVIDE|T_USER: trapsignal(p, SIGFPE, type &~ T_USER); goto out; case T_ARITHTRAP|T_USER: trapsignal(p, SIGFPE, frame.tf_err); goto out; case T_PAGEFLT: /* allow page faults in kernel mode */ if (p == 0) goto we_re_toast; pcb = &p->p_addr->u_pcb; /* * fusubail is used by [fs]uswintr() to prevent page faulting * from inside the profiling interrupt. */ if (pcb->pcb_onfault == fusubail) goto copyfault; #if 0 /* XXX - check only applies to 386's and 486's with WP off */ if (frame.tf_err & PGEX_P) goto we_re_toast; #endif /* FALLTHROUGH */ case T_PAGEFLT|T_USER: { /* page fault */ register vm_offset_t va; register struct vmspace *vm = p->p_vmspace; register vm_map_t map; int rv; vm_prot_t ftype; extern vm_map_t kernel_map; unsigned nss, v; va = trunc_page((vm_offset_t)rcr2()); /* * It is only a kernel address space fault iff: * 1. (type & T_USER) == 0 and * 2. pcb_onfault not set or * 3. pcb_onfault set but supervisor space fault * The last can occur during an exec() copyin where the * argument space is lazy-allocated. */ if (type == T_PAGEFLT && va >= KERNBASE) map = kernel_map; else map = &vm->vm_map; if (frame.tf_err & PGEX_W) ftype = VM_PROT_READ | VM_PROT_WRITE; else ftype = VM_PROT_READ; #ifdef DIAGNOSTIC if (map == kernel_map && va == 0) { printf("trap: bad kernel access at %x\n", va); goto we_re_toast; } #endif nss = 0; if ((caddr_t)va >= vm->vm_maxsaddr && (caddr_t)va < (caddr_t)VM_MAXUSER_ADDRESS && map != kernel_map) { nss = clrnd(btoc(USRSTACK-(unsigned)va)); if (nss > btoc(p->p_rlimit[RLIMIT_STACK].rlim_cur)) { rv = KERN_FAILURE; goto nogo; } } /* check if page table is mapped, if not, fault it first */ if ((PTD[pdei(va)] & PG_V) == 0) { v = trunc_page(vtopte(va)); rv = vm_fault(map, v, ftype, FALSE); if (rv != KERN_SUCCESS) goto nogo; /* check if page table fault, increment wiring */ vm_map_pageable(map, v, round_page(v+1), FALSE); } else v = 0; rv = vm_fault(map, va, ftype, FALSE); if (rv == KERN_SUCCESS) { if (nss > vm->vm_ssize) vm->vm_ssize = nss; va = trunc_page(vtopte(va)); /* for page table, increment wiring as long as not a page table fault as well */ if (!v && map != kernel_map) vm_map_pageable(map, va, round_page(va+1), FALSE); if (type == T_PAGEFLT) return; goto out; } nogo: if (type == T_PAGEFLT) { if (pcb->pcb_onfault != 0) goto copyfault; printf("vm_fault(%x, %x, %x, 0) -> %x\n", map, va, ftype, rv); goto we_re_toast; } trapsignal(p, (rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV, T_PAGEFLT); break; } #ifndef DDB /* XXX need to deal with this when DDB is present, too */ case T_TRCTRAP: /* kernel trace trap; someone single stepping lcall's */ /* syscall has to turn off the trace bit itself */ return; #endif case T_BPTFLT|T_USER: /* bpt instruction fault */ case T_TRCTRAP|T_USER: /* trace trap */ trace: frame.tf_eflags &= ~PSL_T; trapsignal(p, SIGTRAP, type &~ T_USER); break; #include "isa.h" #if NISA > 0 case T_NMI: case T_NMI|T_USER: #ifdef DDB /* NMI can be hooked up to a pushbutton for debugging */ printf ("NMI ... going to debugger\n"); if (kdb_trap (type, 0, &frame)) return; #endif /* machine/parity/power fail/"kitchen sink" faults */ if (isa_nmi() == 0) return; else goto we_re_toast; #endif } if ((type & T_USER) == 0) return; out: userret(p, frame.tf_eip, sticks); } /* * Compensate for 386 brain damage (missing URKR) */ int trapwrite(addr) unsigned addr; { vm_offset_t va; unsigned nss; struct proc *p; struct vmspace *vm; va = trunc_page((vm_offset_t)addr); if (va >= VM_MAXUSER_ADDRESS) return 1; nss = 0; p = curproc; vm = p->p_vmspace; if ((caddr_t)va >= vm->vm_maxsaddr) { nss = clrnd(btoc(USRSTACK-(unsigned)va)); if (nss > btoc(p->p_rlimit[RLIMIT_STACK].rlim_cur)) return 1; } if (vm_fault(&vm->vm_map, va, VM_PROT_READ | VM_PROT_WRITE, FALSE) != KERN_SUCCESS) return 1; if (nss > vm->vm_ssize) vm->vm_ssize = nss; return 0; } /* * syscall(frame): * System call request from POSIX system call gate interface to kernel. * Like trap(), argument is call by reference. */ /*ARGSUSED*/ void syscall(frame) volatile struct trapframe frame; { register caddr_t params; register struct sysent *callp; register struct proc *p; int error, opc, nsys; size_t argsize; register_t code, args[8], rval[2]; u_quad_t sticks; #ifdef COMPAT_SVR4 extern int nsvr4_sysent; extern struct sysent svr4_sysent[]; extern int svr4_error[]; #endif #ifdef COMPAT_IBCS2 extern int nibcs2_sysent; extern struct sysent ibcs2_sysent[]; #endif #ifdef COMPAT_LINUX extern int nlinux_sysent; extern struct sysent linux_sysent[]; extern int linux_error[]; extern char sigcode[], esigcode[]; int fromtramp; #endif cnt.v_syscall++; if (ISPL(frame.tf_cs) != SEL_UPL) panic("syscall"); p = curproc; sticks = p->p_sticks; p->p_md.md_regs = (int *)&frame; opc = frame.tf_eip; code = frame.tf_eax; switch (p->p_emul) { case EMUL_NETBSD: nsys = nsysent; callp = sysent; break; #ifdef COMPAT_SVR4 case EMUL_IBCS2_ELF: nsys = nsvr4_sysent; callp = svr4_sysent; break; #endif #ifdef COMPAT_IBCS2 case EMUL_IBCS2_COFF: case EMUL_IBCS2_XOUT: nsys = nibcs2_sysent; callp = ibcs2_sysent; if (IBCS2_HIGH_SYSCALL(code)) code = IBCS2_CVT_HIGH_SYSCALL(code); break; #endif #ifdef COMPAT_LINUX case EMUL_LINUX: /* * XXXX * This is a kluge until Linux sendsig() and sigreturn() are * emulated correctly, and a Linux-compatible signal trampoline * is written. * Note that `opc' is the value of eip when the call gate is * entered, which is the address right *after* the instruction. */ if ((caddr_t)opc > (caddr_t)PS_STRINGS - (esigcode - sigcode) && (caddr_t)opc <= (caddr_t)PS_STRINGS) { nsys = nsysent; callp = sysent; fromtramp = 1; } else { nsys = nlinux_sysent; callp = linux_sysent; fromtramp = 0; } break; #endif #ifdef DIAGNOSTIC default: panic("invalid p_emul %d", p->p_emul); #endif } params = (caddr_t)frame.tf_esp + sizeof(int); switch (code) { case SYS_syscall: #ifdef COMPAT_LINUX /* Linux has a special system setup call as number 0 */ if (p->p_emul == EMUL_LINUX && !fromtramp) break; #endif /* * Code is first argument, followed by actual args. */ code = fuword(params); params += sizeof(int); break; case SYS___syscall: /* * Like syscall, but code is a quad, so as to maintain * quad alignment for the rest of the arguments. */ if (callp != sysent) break; code = fuword(params + _QUAD_LOWWORD * sizeof(int)); params += sizeof(quad_t); break; default: break; } if (code < 0 || code >= nsys) callp = &callp[0]; /* illegal */ else callp = &callp[code]; argsize = callp->sy_argsize; #ifdef COMPAT_LINUX /* XXX extra if() for every emul type.. */ if (p->p_emul == EMUL_LINUX && !fromtramp) { /* * Linux passes the args in ebx, ecx, edx, esi, edi, in * increasing order. */ switch (argsize) { case 20: args[4] = frame.tf_edi; case 16: args[3] = frame.tf_esi; case 12: args[2] = frame.tf_edx; case 8: args[1] = frame.tf_ecx; case 4: args[0] = frame.tf_ebx; case 0: break; default: panic("linux syscall with weird argument size %d", argsize); break; } error = 0; } else #endif if (argsize) error = copyin(params, (caddr_t)args, argsize); else error = 0; #ifdef SYSCALL_DEBUG scdebug_call(p, code, args); #endif #ifdef KTRACE if (KTRPOINT(p, KTR_SYSCALL)) ktrsyscall(p->p_tracep, code, callp->sy_narg, argsize, args); #endif if (error) goto bad; rval[0] = 0; rval[1] = frame.tf_edx; error = (*callp->sy_call)(p, args, rval); switch (error) { case 0: /* * Reinitialize proc pointer `p' as it may be different * if this is a child returning from fork syscall. */ p = curproc; frame.tf_eax = rval[0]; frame.tf_edx = rval[1]; frame.tf_eflags &= ~PSL_C; /* carry bit */ break; case ERESTART: /* * The offset to adjust the PC by depends on whether we entered * the kernel through the trap or call gate. We pushed the * size of the instruction into tf_err on entry. */ frame.tf_eip = opc - frame.tf_err; break; case EJUSTRETURN: /* nothing to do */ break; default: bad: #ifdef COMPAT_SVR4 if (p->p_emul == EMUL_IBCS2_ELF) error = svr4_error[error]; #endif #ifdef COMPAT_LINUX if (p->p_emul == EMUL_LINUX && !fromtramp) error = -linux_error[error]; #endif #ifdef COMPAT_IBCS2 if (p->p_emul == EMUL_IBCS2_COFF || p->p_emul == EMUL_IBCS2_XOUT) error = bsd2ibcs_errno[error]; #endif frame.tf_eax = error; frame.tf_eflags |= PSL_C; /* carry bit */ break; } #ifdef SYSCALL_DEBUG scdebug_ret(p, code, error, rval); #endif userret(p, frame.tf_eip, sticks); #ifdef KTRACE if (KTRPOINT(p, KTR_SYSRET)) ktrsysret(p->p_tracep, code, error, rval[0]); #endif }