/*- * Copyright (C) 1994, David Greenman * Copyright (c) 1990, 1993 * 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. * * from: @(#)trap.c 7.4 (Berkeley) 5/13/91 * $Id: trap.c,v 1.19 1997/05/05 13:12:52 kato Exp $ */ /* * 386 Trap and System call handling */ #include "opt_ktrace.h" #include "opt_ddb.h" #include "opt_smp.h" #include #include #include #include #include #include #include #include #include #ifdef KTRACE #include #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef POWERFAIL_NMI #include #include #endif #include "isa.h" #include "npx.h" #ifdef SMP extern struct i386tss *SMPcommon_tss_ptr[NCPU]; #else extern struct i386tss common_tss; #endif int (*pmath_emulate) __P((struct trapframe *)); extern void trap __P((struct trapframe frame)); extern int trapwrite __P((unsigned addr)); extern void syscall __P((struct trapframe frame)); #ifdef CPU_BUGGY_CYRIX static int trap_pfault __P((struct trapframe *, int, vm_offset_t)); #else static int trap_pfault __P((struct trapframe *, int)); #endif static void trap_fatal __P((struct trapframe *)); void dblfault_handler __P((void)); extern inthand_t IDTVEC(syscall); #define MAX_TRAP_MSG 28 static char *trap_msg[] = { "", /* 0 unused */ "privileged instruction fault", /* 1 T_PRIVINFLT */ "", /* 2 unused */ "breakpoint instruction fault", /* 3 T_BPTFLT */ "", /* 4 unused */ "", /* 5 unused */ "arithmetic trap", /* 6 T_ARITHTRAP */ "system forced exception", /* 7 T_ASTFLT */ "", /* 8 unused */ "general protection fault", /* 9 T_PROTFLT */ "trace trap", /* 10 T_TRCTRAP */ "", /* 11 unused */ "page fault", /* 12 T_PAGEFLT */ "", /* 13 unused */ "alignment fault", /* 14 T_ALIGNFLT */ "", /* 15 unused */ "", /* 16 unused */ "", /* 17 unused */ "integer divide fault", /* 18 T_DIVIDE */ "non-maskable interrupt trap", /* 19 T_NMI */ "overflow trap", /* 20 T_OFLOW */ "FPU bounds check fault", /* 21 T_BOUND */ "FPU device not available", /* 22 T_DNA */ "double fault", /* 23 T_DOUBLEFLT */ "FPU operand fetch fault", /* 24 T_FPOPFLT */ "invalid TSS fault", /* 25 T_TSSFLT */ "segment not present fault", /* 26 T_SEGNPFLT */ "stack fault", /* 27 T_STKFLT */ "machine check trap", /* 28 T_MCHK */ }; static void userret __P((struct proc *p, struct trapframe *frame, u_quad_t oticks)); static inline void userret(p, frame, oticks) struct proc *p; struct trapframe *frame; u_quad_t oticks; { int sig, s; while ((sig = CURSIG(p)) != 0) postsig(sig); p->p_priority = p->p_usrpri; if (want_resched) { /* * Since we are curproc, clock will normally just change * our priority without moving us from one queue to another * (since the running process is not on a queue.) * If that happened after we setrunqueue ourselves but before we * mi_switch()'ed, we might not be on the queue indicated by * our priority. */ s = splhigh(); setrunqueue(p); p->p_stats->p_ru.ru_nivcsw++; mi_switch(); splx(s); while ((sig = CURSIG(p)) != 0) postsig(sig); } /* * Charge system time if profiling. */ if (p->p_flag & P_PROFIL) addupc_task(p, frame->tf_eip, (u_int)(p->p_sticks - oticks) * psratio); curpriority = p->p_priority; } /* * Exception, fault, and trap interface to the FreeBSD 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. */ void trap(frame) struct trapframe frame; { struct proc *p = curproc; u_quad_t sticks = 0; int i = 0, ucode = 0, type, code; #ifdef DEBUG u_long eva; #endif #ifdef CPU_BUGGY_CYRIX vm_offset_t va; #endif type = frame.tf_trapno; code = frame.tf_err; #ifdef CPU_BUGGY_CYRIX /* XXX: * CYRIX 486 CPU FIX. * If you use cyrix cpu, you often encouter strange signal 11's? * I think this is due to cyrix cpu bugs. * In any way, the following trick is effective for the problem. * As soon as possible, we must get the fault page address. */ va = (vm_offset_t)(rcr2()); if( type == T_PAGEFLT && ( frame.tf_eflags & PSL_I ) ) asm("sti"); #endif /* CPU_BUGGY_CYRIX */ if (ISPL(frame.tf_cs) == SEL_UPL) { /* user trap */ sticks = p->p_sticks; p->p_md.md_regs = &frame; switch (type) { case T_PRIVINFLT: /* privileged instruction fault */ ucode = type; i = SIGILL; break; case T_BPTFLT: /* bpt instruction fault */ case T_TRCTRAP: /* trace trap */ frame.tf_eflags &= ~PSL_T; i = SIGTRAP; break; case T_ARITHTRAP: /* arithmetic trap */ ucode = code; i = SIGFPE; break; case T_ASTFLT: /* Allow process switch */ astoff(); cnt.v_soft++; if (p->p_flag & P_OWEUPC) { p->p_flag &= ~P_OWEUPC; addupc_task(p, p->p_stats->p_prof.pr_addr, p->p_stats->p_prof.pr_ticks); } goto out; case T_PROTFLT: /* general protection fault */ case T_SEGNPFLT: /* segment not present fault */ case T_STKFLT: /* stack fault */ case T_TSSFLT: /* invalid TSS fault */ case T_DOUBLEFLT: /* double fault */ default: ucode = code + BUS_SEGM_FAULT ; i = SIGBUS; break; case T_PAGEFLT: /* page fault */ #ifdef CPU_BUGGY_CYRIX i = trap_pfault(&frame, TRUE, va); #else i = trap_pfault(&frame, TRUE); #endif if (i == -1) return; if (i == 0) goto out; ucode = T_PAGEFLT; break; case T_DIVIDE: /* integer divide fault */ ucode = FPE_INTDIV_TRAP; i = SIGFPE; break; #if NISA > 0 case T_NMI: #ifdef POWERFAIL_NMI goto handle_powerfail; #else /* !POWERFAIL_NMI */ #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 /* DDB */ /* machine/parity/power fail/"kitchen sink" faults */ if (isa_nmi(code) == 0) return; panic("NMI indicates hardware failure"); #endif /* POWERFAIL_NMI */ #endif /* NISA > 0 */ case T_OFLOW: /* integer overflow fault */ ucode = FPE_INTOVF_TRAP; i = SIGFPE; break; case T_BOUND: /* bounds check fault */ ucode = FPE_SUBRNG_TRAP; i = SIGFPE; break; case T_DNA: #if NNPX > 0 /* if a transparent fault (due to context switch "late") */ if (npxdna()) return; #endif if (!pmath_emulate) { i = SIGFPE; ucode = FPE_FPU_NP_TRAP; break; } i = (*pmath_emulate)(&frame); if (i == 0) { if (!(frame.tf_eflags & PSL_T)) return; frame.tf_eflags &= ~PSL_T; i = SIGTRAP; } /* else ucode = emulator_only_knows() XXX */ break; case T_FPOPFLT: /* FPU operand fetch fault */ ucode = T_FPOPFLT; i = SIGILL; break; } } else { /* kernel trap */ switch (type) { case T_PAGEFLT: /* page fault */ #ifdef CPU_BUGGY_CYRIX (void) trap_pfault(&frame, FALSE, va); #else (void) trap_pfault(&frame, FALSE); #endif return; case T_DNA: #if NNPX > 0 /* * The kernel is apparently using npx for copying. * XXX this should be fatal unless the kernel has * registered such use. */ if (npxdna()) return; #endif break; case T_PROTFLT: /* general protection fault */ case T_SEGNPFLT: /* segment not present fault */ /* * Invalid segment selectors and out of bounds * %eip's and %esp's can be set up in user mode. * This causes a fault in kernel mode when the * kernel tries to return to user mode. We want * to get this fault so that we can fix the * problem here and not have to check all the * selectors and pointers when the user changes * them. */ #define MAYBE_DORETI_FAULT(where, whereto) \ do { \ if (frame.tf_eip == (int)where) { \ frame.tf_eip = (int)whereto; \ return; \ } \ } while (0) if (intr_nesting_level == 0) { MAYBE_DORETI_FAULT(doreti_iret, doreti_iret_fault); MAYBE_DORETI_FAULT(doreti_popl_ds, doreti_popl_ds_fault); MAYBE_DORETI_FAULT(doreti_popl_es, doreti_popl_es_fault); if (curpcb && curpcb->pcb_onfault) { frame.tf_eip = (int)curpcb->pcb_onfault; return; } } break; case T_TSSFLT: /* * PSL_NT can be set in user mode and isn't cleared * automatically when the kernel is entered. This * causes a TSS fault when the kernel attempts to * `iret' because the TSS link is uninitialized. We * want to get this fault so that we can fix the * problem here and not every time the kernel is * entered. */ if (frame.tf_eflags & PSL_NT) { frame.tf_eflags &= ~PSL_NT; return; } break; case T_TRCTRAP: /* trace trap */ if (frame.tf_eip == (int)IDTVEC(syscall)) { /* * We've just entered system mode via the * syscall lcall. Continue single stepping * silently until the syscall handler has * saved the flags. */ return; } if (frame.tf_eip == (int)IDTVEC(syscall) + 1) { /* * The syscall handler has now saved the * flags. Stop single stepping it. */ frame.tf_eflags &= ~PSL_T; return; } /* * Fall through. */ case T_BPTFLT: /* * If DDB is enabled, let it handle the debugger trap. * Otherwise, debugger traps "can't happen". */ #ifdef DDB if (kdb_trap (type, 0, &frame)) return; #endif break; #if NISA > 0 case T_NMI: #ifdef POWERFAIL_NMI #ifndef TIMER_FREQ # define TIMER_FREQ 1193182 #endif handle_powerfail: { static unsigned lastalert = 0; if(time.tv_sec - lastalert > 10) { log(LOG_WARNING, "NMI: power fail\n"); sysbeep(TIMER_FREQ/880, hz); lastalert = time.tv_sec; } return; } #else /* !POWERFAIL_NMI */ #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 /* DDB */ /* machine/parity/power fail/"kitchen sink" faults */ if (isa_nmi(code) == 0) return; /* FALL THROUGH */ #endif /* POWERFAIL_NMI */ #endif /* NISA > 0 */ } trap_fatal(&frame); return; } trapsignal(p, i, ucode); #ifdef DEBUG eva = rcr2(); if (type <= MAX_TRAP_MSG) { uprintf("fatal process exception: %s", trap_msg[type]); if ((type == T_PAGEFLT) || (type == T_PROTFLT)) uprintf(", fault VA = 0x%x", eva); uprintf("\n"); } #endif out: userret(p, &frame, sticks); } #ifdef notyet /* * This version doesn't allow a page fault to user space while * in the kernel. The rest of the kernel needs to be made "safe" * before this can be used. I think the only things remaining * to be made safe are the iBCS2 code and the process tracing/ * debugging code. */ static int #ifdef CPU_BUGGY_CYRIX trap_pfault(frame, usermode,faultva) struct trapframe *frame; int usermode; vm_offset_t faultva; #else trap_pfault(frame, usermode) struct trapframe *frame; int usermode; #endif { vm_offset_t va; struct vmspace *vm = NULL; vm_map_t map = 0; int rv = 0; vm_prot_t ftype; int eva; struct proc *p = curproc; if (frame->tf_err & PGEX_W) ftype = VM_PROT_READ | VM_PROT_WRITE; else ftype = VM_PROT_READ; #ifdef CPU_BUGGY_CYRIX eva = faultva; #else eva = rcr2(); #endif va = trunc_page((vm_offset_t)eva); if (va < VM_MIN_KERNEL_ADDRESS) { vm_offset_t v; vm_page_t mpte; if (p == NULL || (!usermode && va < VM_MAXUSER_ADDRESS && (intr_nesting_level != 0 || curpcb == NULL || curpcb->pcb_onfault == NULL))) { trap_fatal(frame); return (-1); } /* * This is a fault on non-kernel virtual memory. * vm is initialized above to NULL. If curproc is NULL * or curproc->p_vmspace is NULL the fault is fatal. */ vm = p->p_vmspace; if (vm == NULL) goto nogo; map = &vm->vm_map; /* * Keep swapout from messing with us during this * critical time. */ ++p->p_lock; /* * Grow the stack if necessary */ if ((caddr_t)va > vm->vm_maxsaddr && (caddr_t)va < (caddr_t)USRSTACK) { if (!grow(p, va)) { rv = KERN_FAILURE; --p->p_lock; goto nogo; } } /* Fault in the user page: */ rv = vm_fault(map, va, ftype, (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY : 0); --p->p_lock; } else { /* * Don't allow user-mode faults in kernel address space. */ if (usermode) goto nogo; /* * Since we know that kernel virtual address addresses * always have pte pages mapped, we just have to fault * the page. */ rv = vm_fault(kernel_map, va, ftype, FALSE); } if (rv == KERN_SUCCESS) return (0); nogo: if (!usermode) { if (intr_nesting_level == 0 && curpcb && curpcb->pcb_onfault) { frame->tf_eip = (int)curpcb->pcb_onfault; return (0); } trap_fatal(frame); return (-1); } /* kludge to pass faulting virtual address to sendsig */ frame->tf_err = eva; return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); } #endif int #ifdef CPU_BUGGY_CYRIX trap_pfault(frame, usermode,faultva) struct trapframe *frame; int usermode; vm_offset_t faultva; #else trap_pfault(frame, usermode) struct trapframe *frame; int usermode; #endif { vm_offset_t va; struct vmspace *vm = NULL; vm_map_t map = 0; int rv = 0; vm_prot_t ftype; int eva; struct proc *p = curproc; #ifdef CPU_BUGGY_CYRIX eva = faultva; #else eva = rcr2(); #endif va = trunc_page((vm_offset_t)eva); if (va >= KERNBASE) { /* * Don't allow user-mode faults in kernel address space. */ if (usermode) goto nogo; map = kernel_map; } else { /* * This is a fault on non-kernel virtual memory. * vm is initialized above to NULL. If curproc is NULL * or curproc->p_vmspace is NULL the fault is fatal. */ if (p != NULL) vm = p->p_vmspace; if (vm == NULL) goto nogo; map = &vm->vm_map; } if (frame->tf_err & PGEX_W) ftype = VM_PROT_READ | VM_PROT_WRITE; else ftype = VM_PROT_READ; if (map != kernel_map) { /* * Keep swapout from messing with us during this * critical time. */ ++p->p_lock; /* * Grow the stack if necessary */ if ((caddr_t)va > vm->vm_maxsaddr && (caddr_t)va < (caddr_t)USRSTACK) { if (!grow(p, va)) { rv = KERN_FAILURE; --p->p_lock; goto nogo; } } /* Fault in the user page: */ rv = vm_fault(map, va, ftype, (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY : 0); --p->p_lock; } else { /* * Don't have to worry about process locking or stacks in the kernel. */ rv = vm_fault(map, va, ftype, FALSE); } if (rv == KERN_SUCCESS) return (0); nogo: if (!usermode) { if (intr_nesting_level == 0 && curpcb && curpcb->pcb_onfault) { frame->tf_eip = (int)curpcb->pcb_onfault; return (0); } trap_fatal(frame); return (-1); } /* kludge to pass faulting virtual address to sendsig */ frame->tf_err = eva; return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); } static void trap_fatal(frame) struct trapframe *frame; { int code, type, eva, ss, esp; struct soft_segment_descriptor softseg; code = frame->tf_err; type = frame->tf_trapno; eva = rcr2(); sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg); if (type <= MAX_TRAP_MSG) printf("\n\nFatal trap %d: %s while in %s mode\n", type, trap_msg[type], ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); #ifdef SMP printf("cpunumber = %d\n", cpunumber()); #endif if (type == T_PAGEFLT) { printf("fault virtual address = 0x%x\n", eva); printf("fault code = %s %s, %s\n", code & PGEX_U ? "user" : "supervisor", code & PGEX_W ? "write" : "read", code & PGEX_P ? "protection violation" : "page not present"); } printf("instruction pointer = 0x%x:0x%x\n", frame->tf_cs & 0xffff, frame->tf_eip); if (ISPL(frame->tf_cs) == SEL_UPL) { ss = frame->tf_ss & 0xffff; esp = frame->tf_esp; } else { ss = GSEL(GDATA_SEL, SEL_KPL); esp = (int)&frame->tf_esp; } printf("stack pointer = 0x%x:0x%x\n", ss, esp); printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp); printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n", softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); printf(" = DPL %d, pres %d, def32 %d, gran %d\n", softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32, softseg.ssd_gran); printf("processor eflags = "); if (frame->tf_eflags & PSL_T) printf("trace trap, "); if (frame->tf_eflags & PSL_I) printf("interrupt enabled, "); if (frame->tf_eflags & PSL_NT) printf("nested task, "); if (frame->tf_eflags & PSL_RF) printf("resume, "); if (frame->tf_eflags & PSL_VM) printf("vm86, "); printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12); printf("current process = "); if (curproc) { printf("%lu (%s)\n", (u_long)curproc->p_pid, curproc->p_comm ? curproc->p_comm : ""); } else { printf("Idle\n"); } printf("interrupt mask = "); if ((cpl & net_imask) == net_imask) printf("net "); if ((cpl & tty_imask) == tty_imask) printf("tty "); if ((cpl & bio_imask) == bio_imask) printf("bio "); if (cpl == 0) printf("none"); printf("\n"); #ifdef KDB if (kdb_trap(&psl)) return; #endif #ifdef DDB if (kdb_trap (type, 0, frame)) return; #endif printf("trap number = %d\n", type); if (type <= MAX_TRAP_MSG) panic(trap_msg[type]); else panic("unknown/reserved trap"); } /* * Double fault handler. Called when a fault occurs while writing * a frame for a trap/exception onto the stack. This usually occurs * when the stack overflows (such is the case with infinite recursion, * for example). * * XXX Note that the current PTD gets replaced by IdlePTD when the * task switch occurs. This means that the stack that was active at * the time of the double fault is not available at unless * the machine was idle when the double fault occurred. The downside * of this is that "trace " in ddb won't work. */ void dblfault_handler() { #ifdef SMP int x = cpunumber(); #endif printf("\nFatal double fault:\n"); #ifdef SMP printf("eip = 0x%x\n", SMPcommon_tss_ptr[x]->tss_eip); printf("esp = 0x%x\n", SMPcommon_tss_ptr[x]->tss_esp); printf("ebp = 0x%x\n", SMPcommon_tss_ptr[x]->tss_ebp); #else printf("eip = 0x%x\n", common_tss.tss_eip); printf("esp = 0x%x\n", common_tss.tss_esp); printf("ebp = 0x%x\n", common_tss.tss_ebp); #endif panic("double fault"); } /* * Compensate for 386 brain damage (missing URKR). * This is a little simpler than the pagefault handler in trap() because * it the page tables have already been faulted in and high addresses * are thrown out early for other reasons. */ int trapwrite(addr) unsigned addr; { struct proc *p; vm_offset_t va; struct vmspace *vm; int rv; va = trunc_page((vm_offset_t)addr); /* * XXX - MAX is END. Changed > to >= for temp. fix. */ if (va >= VM_MAXUSER_ADDRESS) return (1); p = curproc; vm = p->p_vmspace; ++p->p_lock; if ((caddr_t)va >= vm->vm_maxsaddr && (caddr_t)va < (caddr_t)USRSTACK) { if (!grow(p, va)) { --p->p_lock; return (1); } } /* * fault the data page */ rv = vm_fault(&vm->vm_map, va, VM_PROT_READ|VM_PROT_WRITE, VM_FAULT_DIRTY); --p->p_lock; if (rv != KERN_SUCCESS) return 1; return (0); } /* * System call request from POSIX system call gate interface to kernel. * Like trap(), argument is call by reference. */ void syscall(frame) struct trapframe frame; { caddr_t params; int i; struct sysent *callp; struct proc *p = curproc; u_quad_t sticks; int error; int args[8], rval[2]; u_int code; sticks = p->p_sticks; if (ISPL(frame.tf_cs) != SEL_UPL) panic("syscall"); p->p_md.md_regs = &frame; params = (caddr_t)frame.tf_esp + sizeof(int); code = frame.tf_eax; if (p->p_sysent->sv_prepsyscall) { (*p->p_sysent->sv_prepsyscall)(&frame, args, &code, ¶ms); } else { /* * Need to check if this is a 32 bit or 64 bit syscall. */ if (code == SYS_syscall) { /* * Code is first argument, followed by actual args. */ code = fuword(params); params += sizeof(int); } else if (code == SYS___syscall) { /* * Like syscall, but code is a quad, so as to maintain * quad alignment for the rest of the arguments. */ code = fuword(params); params += sizeof(quad_t); } } if (p->p_sysent->sv_mask) code &= p->p_sysent->sv_mask; if (code >= p->p_sysent->sv_size) callp = &p->p_sysent->sv_table[0]; else callp = &p->p_sysent->sv_table[code]; if (params && (i = callp->sy_narg * sizeof(int)) && (error = copyin(params, (caddr_t)args, (u_int)i))) { #ifdef KTRACE if (KTRPOINT(p, KTR_SYSCALL)) ktrsyscall(p->p_tracep, code, callp->sy_narg, args); #endif goto bad; } #ifdef KTRACE if (KTRPOINT(p, KTR_SYSCALL)) ktrsyscall(p->p_tracep, code, callp->sy_narg, args); #endif 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; break; case ERESTART: /* * Reconstruct pc, assuming lcall $X,y is 7 bytes, * int 0x80 is 2 bytes. We saved this in tf_err. */ frame.tf_eip -= frame.tf_err; break; case EJUSTRETURN: break; default: bad: if (p->p_sysent->sv_errsize) if (error >= p->p_sysent->sv_errsize) error = -1; /* XXX */ else error = p->p_sysent->sv_errtbl[error]; frame.tf_eax = error; frame.tf_eflags |= PSL_C; break; } if (frame.tf_eflags & PSL_T) { /* Traced syscall. */ frame.tf_eflags &= ~PSL_T; trapsignal(p, SIGTRAP, 0); } userret(p, &frame, sticks); #ifdef KTRACE if (KTRPOINT(p, KTR_SYSRET)) ktrsysret(p->p_tracep, code, error, rval[0]); #endif } /* * Simplified back end of syscall(), used when returning from fork() * directly into user mode. */ void fork_return(p, frame) struct proc *p; struct trapframe frame; { frame.tf_eax = 0; /* Child returns zero */ frame.tf_eflags &= ~PSL_C; /* success */ frame.tf_edx = 1; userret(p, &frame, 0); #ifdef KTRACE if (KTRPOINT(p, KTR_SYSRET)) ktrsysret(p->p_tracep, SYS_fork, 0, 0); #endif }