/*- * 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 * $FreeBSD: src/sys/i386/i386/trap.c,v 1.147.2.11 2003/02/27 19:09:59 luoqi Exp $ */ /* * x86_64 Trap and System call handling */ #include "use_isa.h" #include "opt_ddb.h" #include "opt_ktrace.h" #include #include #include #include #include #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 #include #include #include #include #include #include #include #ifdef SMP #define MAKEMPSAFE(have_mplock) \ if (have_mplock == 0) { \ get_mplock(); \ have_mplock = 1; \ } #else #define MAKEMPSAFE(have_mplock) #endif int (*pmath_emulate) (struct trapframe *); extern int trapwrite (unsigned addr); static int trap_pfault (struct trapframe *, int, vm_offset_t); static void trap_fatal (struct trapframe *, int, vm_offset_t); void dblfault_handler (void); #if 0 extern inthand_t IDTVEC(syscall); #endif #define MAX_TRAP_MSG 30 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 */ "SIMD floating-point exception", /* 29 T_XMMFLT */ "reserved (unknown) fault", /* 30 T_RESERVED */ }; #ifdef DDB static int ddb_on_nmi = 1; SYSCTL_INT(_machdep, OID_AUTO, ddb_on_nmi, CTLFLAG_RW, &ddb_on_nmi, 0, "Go to DDB on NMI"); #endif static int panic_on_nmi = 1; SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, &panic_on_nmi, 0, "Panic on NMI"); static int fast_release; SYSCTL_INT(_machdep, OID_AUTO, fast_release, CTLFLAG_RW, &fast_release, 0, "Passive Release was optimal"); static int slow_release; SYSCTL_INT(_machdep, OID_AUTO, slow_release, CTLFLAG_RW, &slow_release, 0, "Passive Release was nonoptimal"); MALLOC_DEFINE(M_SYSMSG, "sysmsg", "sysmsg structure"); extern int max_sysmsg; /* * Passively intercepts the thread switch function to increase the thread * priority from a user priority to a kernel priority, reducing * syscall and trap overhead for the case where no switch occurs. * * Synchronizes td_ucred with p_ucred. This is used by system calls, * signal handling, faults, AST traps, and anything else that enters the * kernel from userland and provides the kernel with a stable read-only * copy of the process ucred. */ static __inline void userenter(struct thread *curtd, struct proc *curp) { struct ucred *ocred; struct ucred *ncred; curtd->td_release = lwkt_passive_release; if (curtd->td_ucred != curp->p_ucred) { ncred = crhold(curp->p_ucred); ocred = curtd->td_ucred; curtd->td_ucred = ncred; if (ocred) crfree(ocred); } } /* * Handle signals, upcalls, profiling, and other AST's and/or tasks that * must be completed before we can return to or try to return to userland. * * Note that td_sticks is a 64 bit quantity, but there's no point doing 64 * arithmatic on the delta calculation so the absolute tick values are * truncated to an integer. */ static void userret(struct lwp *lp, struct trapframe *frame, int sticks) { struct proc *p = lp->lwp_proc; int sig; /* * Charge system time if profiling. Note: times are in microseconds. * This may do a copyout and block, so do it first even though it * means some system time will be charged as user time. */ if (p->p_flag & P_PROFIL) { addupc_task(p, frame->tf_rip, (u_int)((int)lp->lwp_thread->td_sticks - sticks)); } recheck: /* * If the jungle wants us dead, so be it. */ if (lp->lwp_flag & LWP_WEXIT) { lwkt_gettoken(&p->p_token); lwp_exit(0); lwkt_reltoken(&p->p_token); /* NOT REACHED */ } /* * Block here if we are in a stopped state. */ if (p->p_stat == SSTOP) { get_mplock(); tstop(); rel_mplock(); goto recheck; } /* * Post any pending upcalls */ if (p->p_flag & P_UPCALLPEND) { lwkt_gettoken(&p->p_token); p->p_flag &= ~P_UPCALLPEND; postupcall(lp); lwkt_reltoken(&p->p_token); goto recheck; } /* * Post any pending signals * * WARNING! postsig() can exit and not return. */ if ((sig = CURSIG_TRACE(lp)) != 0) { lwkt_gettoken(&p->p_token); postsig(sig); lwkt_reltoken(&p->p_token); goto recheck; } /* * block here if we are swapped out, but still process signals * (such as SIGKILL). proc0 (the swapin scheduler) is already * aware of our situation, we do not have to wake it up. */ if (p->p_flag & P_SWAPPEDOUT) { get_mplock(); p->p_flag |= P_SWAPWAIT; swapin_request(); if (p->p_flag & P_SWAPWAIT) tsleep(p, PCATCH, "SWOUT", 0); p->p_flag &= ~P_SWAPWAIT; rel_mplock(); goto recheck; } /* * Make sure postsig() handled request to restore old signal mask after * running signal handler. */ KKASSERT((lp->lwp_flag & LWP_OLDMASK) == 0); } /* * Cleanup from userenter and any passive release that might have occured. * We must reclaim the current-process designation before we can return * to usermode. We also handle both LWKT and USER reschedule requests. */ static __inline void userexit(struct lwp *lp) { struct thread *td = lp->lwp_thread; /* globaldata_t gd = td->td_gd; */ /* * Handle stop requests at kernel priority. Any requests queued * after this loop will generate another AST. */ while (lp->lwp_proc->p_stat == SSTOP) { get_mplock(); tstop(); rel_mplock(); } /* * Reduce our priority in preparation for a return to userland. If * our passive release function was still in place, our priority was * never raised and does not need to be reduced. */ lwkt_passive_recover(td); /* * Become the current user scheduled process if we aren't already, * and deal with reschedule requests and other factors. */ lp->lwp_proc->p_usched->acquire_curproc(lp); /* WARNING: we may have migrated cpu's */ /* gd = td->td_gd; */ } #if !defined(KTR_KERNENTRY) #define KTR_KERNENTRY KTR_ALL #endif KTR_INFO_MASTER(kernentry); KTR_INFO(KTR_KERNENTRY, kernentry, trap, 0, "pid=%d, tid=%d, trapno=%d, eva=%p", sizeof(int) + sizeof(int) + sizeof(int) + sizeof(vm_offset_t)); KTR_INFO(KTR_KERNENTRY, kernentry, trap_ret, 0, "pid=%d, tid=%d", sizeof(int) + sizeof(int)); KTR_INFO(KTR_KERNENTRY, kernentry, syscall, 0, "pid=%d, tid=%d, call=%d", sizeof(int) + sizeof(int) + sizeof(int)); KTR_INFO(KTR_KERNENTRY, kernentry, syscall_ret, 0, "pid=%d, tid=%d, err=%d", sizeof(int) + sizeof(int) + sizeof(int)); KTR_INFO(KTR_KERNENTRY, kernentry, fork_ret, 0, "pid=%d, tid=%d", sizeof(int) + sizeof(int)); /* * Exception, fault, and trap interface to the 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. * * This function is also called from doreti in an interlock to handle ASTs. * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap * * NOTE! We have to retrieve the fault address prior to obtaining the * MP lock because get_mplock() may switch out. YYY cr2 really ought * to be retrieved by the assembly code, not here. * * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing * if an attempt is made to switch from a fast interrupt or IPI. This is * necessary to properly take fatal kernel traps on SMP machines if * get_mplock() has to block. */ void user_trap(struct trapframe *frame) { struct globaldata *gd = mycpu; struct thread *td = gd->gd_curthread; struct lwp *lp = td->td_lwp; struct proc *p; int sticks = 0; int i = 0, ucode = 0, type, code; #ifdef SMP int have_mplock = 0; #endif #ifdef INVARIANTS int crit_count = td->td_critcount; lwkt_tokref_t curstop = td->td_toks_stop; #endif vm_offset_t eva; p = td->td_proc; if (frame->tf_trapno == T_PAGEFLT) eva = frame->tf_addr; else eva = 0; #if 0 kprintf("USER_TRAP AT %08lx xflags %ld trapno %ld eva %08lx\n", frame->tf_rip, frame->tf_xflags, frame->tf_trapno, eva); #endif /* * Everything coming from user mode runs through user_trap, * including system calls. */ if (frame->tf_trapno == T_FAST_SYSCALL) { syscall2(frame); return; } KTR_LOG(kernentry_trap, lp->lwp_proc->p_pid, lp->lwp_tid, frame->tf_trapno, eva); #ifdef DDB if (db_active) { eva = (frame->tf_trapno == T_PAGEFLT ? rcr2() : 0); ++gd->gd_trap_nesting_level; MAKEMPSAFE(have_mplock); trap_fatal(frame, TRUE, eva); --gd->gd_trap_nesting_level; goto out2; } #endif #if defined(I586_CPU) && !defined(NO_F00F_HACK) restart: #endif type = frame->tf_trapno; code = frame->tf_err; userenter(td, p); sticks = (int)td->td_sticks; lp->lwp_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_rflags &= ~PSL_T; i = SIGTRAP; break; case T_ARITHTRAP: /* arithmetic trap */ ucode = code; i = SIGFPE; break; case T_ASTFLT: /* Allow process switch */ mycpu->gd_cnt.v_soft++; if (mycpu->gd_reqflags & RQF_AST_OWEUPC) { atomic_clear_int(&mycpu->gd_reqflags, RQF_AST_OWEUPC); addupc_task(p, p->p_prof.pr_addr, p->p_prof.pr_ticks); } goto out; /* * The following two traps can happen in * vm86 mode, and, if so, we want to handle * them specially. */ case T_PROTFLT: /* general protection fault */ case T_STKFLT: /* stack fault */ #if 0 if (frame->tf_eflags & PSL_VM) { i = vm86_emulate((struct vm86frame *)frame); if (i == 0) goto out; break; } #endif /* FALL THROUGH */ case T_SEGNPFLT: /* segment not present 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 */ MAKEMPSAFE(have_mplock); i = trap_pfault(frame, TRUE, eva); if (i == -1) goto out; #if defined(I586_CPU) && !defined(NO_F00F_HACK) if (i == -2) goto restart; #endif if (i == 0) goto out; ucode = T_PAGEFLT; break; case T_DIVIDE: /* integer divide fault */ ucode = FPE_INTDIV; i = SIGFPE; break; #if NISA > 0 case T_NMI: MAKEMPSAFE(have_mplock); /* machine/parity/power fail/"kitchen sink" faults */ if (isa_nmi(code) == 0) { #ifdef DDB /* * NMI can be hooked up to a pushbutton * for debugging. */ if (ddb_on_nmi) { kprintf ("NMI ... going to debugger\n"); kdb_trap (type, 0, frame); } #endif /* DDB */ goto out2; } else if (panic_on_nmi) panic("NMI indicates hardware failure"); break; #endif /* NISA > 0 */ case T_OFLOW: /* integer overflow fault */ ucode = FPE_INTOVF; i = SIGFPE; break; case T_BOUND: /* bounds check fault */ ucode = FPE_FLTSUB; i = SIGFPE; break; case T_DNA: /* * Virtual kernel intercept - pass the DNA exception * to the (emulated) virtual kernel if it asked to handle * it. This occurs when the virtual kernel is holding * onto the FP context for a different emulated * process then the one currently running. * * We must still call npxdna() since we may have * saved FP state that the (emulated) virtual kernel * needs to hand over to a different emulated process. */ if (lp->lwp_vkernel && lp->lwp_vkernel->ve && (td->td_pcb->pcb_flags & FP_VIRTFP) ) { npxdna(frame); break; } /* * The kernel may have switched out the FP unit's * state, causing the user process to take a fault * when it tries to use the FP unit. Restore the * state here */ if (npxdna(frame)) goto out; if (!pmath_emulate) { i = SIGFPE; ucode = FPE_FPU_NP_TRAP; break; } i = (*pmath_emulate)(frame); if (i == 0) { if (!(frame->tf_rflags & PSL_T)) goto out2; frame->tf_rflags &= ~PSL_T; i = SIGTRAP; } /* else ucode = emulator_only_knows() XXX */ break; case T_FPOPFLT: /* FPU operand fetch fault */ ucode = T_FPOPFLT; i = SIGILL; break; case T_XMMFLT: /* SIMD floating-point exception */ ucode = 0; /* XXX */ i = SIGFPE; break; } /* * Virtual kernel intercept - if the fault is directly related to a * VM context managed by a virtual kernel then let the virtual kernel * handle it. */ if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { vkernel_trap(lp, frame); goto out; } /* * Translate fault for emulators (e.g. Linux) */ if (*p->p_sysent->sv_transtrap) i = (*p->p_sysent->sv_transtrap)(i, type); MAKEMPSAFE(have_mplock); trapsignal(lp, i, ucode); #ifdef DEBUG if (type <= MAX_TRAP_MSG) { uprintf("fatal process exception: %s", trap_msg[type]); if ((type == T_PAGEFLT) || (type == T_PROTFLT)) uprintf(", fault VA = 0x%lx", (u_long)eva); uprintf("\n"); } #endif out: userret(lp, frame, sticks); userexit(lp); out2: ; #ifdef SMP if (have_mplock) rel_mplock(); #endif KTR_LOG(kernentry_trap_ret, lp->lwp_proc->p_pid, lp->lwp_tid); #ifdef INVARIANTS KASSERT(crit_count == td->td_critcount, ("trap: critical section count mismatch! %d/%d", crit_count, td->td_pri)); KASSERT(curstop == td->td_toks_stop, ("trap: extra tokens held after trap! %ld/%ld", curstop - &td->td_toks_base, td->td_toks_stop - &td->td_toks_base)); #endif } void kern_trap(struct trapframe *frame) { struct globaldata *gd = mycpu; struct thread *td = gd->gd_curthread; struct lwp *lp; struct proc *p; int i = 0, ucode = 0, type, code; #ifdef SMP int have_mplock = 0; #endif #ifdef INVARIANTS int crit_count = td->td_critcount; lwkt_tokref_t curstop = td->td_toks_stop; #endif vm_offset_t eva; lp = td->td_lwp; p = td->td_proc; if (frame->tf_trapno == T_PAGEFLT) eva = frame->tf_addr; else eva = 0; #ifdef DDB if (db_active) { ++gd->gd_trap_nesting_level; MAKEMPSAFE(have_mplock); trap_fatal(frame, FALSE, eva); --gd->gd_trap_nesting_level; goto out2; } #endif type = frame->tf_trapno; code = frame->tf_err; #if 0 kernel_trap: #endif /* kernel trap */ switch (type) { case T_PAGEFLT: /* page fault */ MAKEMPSAFE(have_mplock); trap_pfault(frame, FALSE, eva); goto out2; case T_DNA: /* * The kernel may be using npx for copying or other * purposes. */ panic("kernel NPX should not happen"); if (npxdna(frame)) goto out2; 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. */ if (mycpu->gd_intr_nesting_level == 0) { if (td->td_pcb->pcb_onfault) { frame->tf_rip = (register_t)td->td_pcb->pcb_onfault; goto out2; } } 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_rflags & PSL_NT) { frame->tf_rflags &= ~PSL_NT; goto out2; } break; case T_TRCTRAP: /* trace trap */ #if 0 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. */ goto out2; } 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; goto out2; } #endif #if 0 /* * Ignore debug register trace traps due to * accesses in the user's address space, which * can happen under several conditions such as * if a user sets a watchpoint on a buffer and * then passes that buffer to a system call. * We still want to get TRCTRAPS for addresses * in kernel space because that is useful when * debugging the kernel. */ if (user_dbreg_trap()) { /* * Reset breakpoint bits because the * processor doesn't */ load_dr6(rdr6() & 0xfffffff0); goto out2; } #endif /* * Fall through (TRCTRAP kernel mode, kernel address) */ case T_BPTFLT: /* * If DDB is enabled, let it handle the debugger trap. * Otherwise, debugger traps "can't happen". */ #ifdef DDB MAKEMPSAFE(have_mplock); if (kdb_trap (type, 0, frame)) goto out2; #endif break; case T_DIVIDE: MAKEMPSAFE(have_mplock); trap_fatal(frame, FALSE, eva); goto out2; case T_NMI: MAKEMPSAFE(have_mplock); trap_fatal(frame, FALSE, eva); goto out2; case T_SYSCALL80: case T_FAST_SYSCALL: /* * Ignore this trap generated from a spurious SIGTRAP. * * single stepping in / syscalls leads to spurious / SIGTRAP * so ignore * * Haiku (c) 2007 Simon 'corecode' Schubert */ goto out2; } /* * Translate fault for emulators (e.g. Linux) */ if (*p->p_sysent->sv_transtrap) i = (*p->p_sysent->sv_transtrap)(i, type); MAKEMPSAFE(have_mplock); trapsignal(lp, i, ucode); #ifdef DEBUG if (type <= MAX_TRAP_MSG) { uprintf("fatal process exception: %s", trap_msg[type]); if ((type == T_PAGEFLT) || (type == T_PROTFLT)) uprintf(", fault VA = 0x%lx", (u_long)eva); uprintf("\n"); } #endif out2: ; #ifdef SMP if (have_mplock) rel_mplock(); #endif #ifdef INVARIANTS KASSERT(crit_count == td->td_critcount, ("trap: critical section count mismatch! %d/%d", crit_count, td->td_pri)); KASSERT(curstop == td->td_toks_stop, ("trap: extra tokens held after trap! %ld/%ld", curstop - &td->td_toks_base, td->td_toks_stop - &td->td_toks_base)); #endif } int trap_pfault(struct trapframe *frame, int usermode, vm_offset_t eva) { vm_offset_t va; struct vmspace *vm = NULL; vm_map_t map = 0; int rv = 0; vm_prot_t ftype; thread_t td = curthread; struct lwp *lp = td->td_lwp; va = trunc_page(eva); if (usermode == FALSE) { /* * This is a fault on kernel virtual memory. */ 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 (lp != NULL) vm = lp->lwp_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. */ PHOLD(lp->lwp_proc); /* * Grow the stack if necessary */ /* grow_stack returns false only if va falls into * a growable stack region and the stack growth * fails. It returns true if va was not within * a growable stack region, or if the stack * growth succeeded. */ if (!grow_stack (lp->lwp_proc, va)) { rv = KERN_FAILURE; PRELE(lp->lwp_proc); goto nogo; } /* Fault in the user page: */ rv = vm_fault(map, va, ftype, (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY : VM_FAULT_NORMAL); PRELE(lp->lwp_proc); } else { /* * Don't have to worry about process locking or stacks in the kernel. */ rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); } if (rv == KERN_SUCCESS) return (0); nogo: if (!usermode) { if (td->td_gd->gd_intr_nesting_level == 0 && td->td_pcb->pcb_onfault) { frame->tf_rip = (register_t)td->td_pcb->pcb_onfault; return (0); } trap_fatal(frame, usermode, eva); return (-1); } /* * NOTE: on x86_64 we have a tf_addr field in the trapframe, no * kludge is needed to pass the fault address to signal handlers. */ struct proc *p = td->td_proc; kprintf("seg-fault accessing address %p rip=%p pid=%d p_comm=%s\n", (void *)va, (void *)frame->tf_rip, p->p_pid, p->p_comm); /* Debugger("seg-fault"); */ return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); } static void trap_fatal(struct trapframe *frame, int usermode, vm_offset_t eva) { int code, type, ss; long rsp; code = frame->tf_xflags; type = frame->tf_trapno; if (type <= MAX_TRAP_MSG) { kprintf("\n\nFatal trap %d: %s while in %s mode\n", type, trap_msg[type], (usermode ? "user" : "kernel")); } #ifdef SMP /* two separate prints in case of a trap on an unmapped page */ kprintf("cpuid = %d\n", mycpu->gd_cpuid); #endif if (type == T_PAGEFLT) { kprintf("fault virtual address = %p\n", (void *)eva); kprintf("fault code = %s %s, %s\n", usermode ? "user" : "supervisor", code & PGEX_W ? "write" : "read", code & PGEX_P ? "protection violation" : "page not present"); } kprintf("instruction pointer = 0x%lx:0x%lx\n", frame->tf_cs & 0xffff, frame->tf_rip); if (usermode) { ss = frame->tf_ss & 0xffff; rsp = frame->tf_rsp; } else { ss = GSEL(GDATA_SEL, SEL_KPL); rsp = (long)&frame->tf_rsp; } kprintf("stack pointer = 0x%x:0x%lx\n", ss, rsp); kprintf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); kprintf("processor eflags = "); if (frame->tf_rflags & PSL_T) kprintf("trace trap, "); if (frame->tf_rflags & PSL_I) kprintf("interrupt enabled, "); if (frame->tf_rflags & PSL_NT) kprintf("nested task, "); if (frame->tf_rflags & PSL_RF) kprintf("resume, "); #if 0 if (frame->tf_eflags & PSL_VM) kprintf("vm86, "); #endif kprintf("IOPL = %jd\n", (intmax_t)((frame->tf_rflags & PSL_IOPL) >> 12)); kprintf("current process = "); if (curproc) { kprintf("%lu (%s)\n", (u_long)curproc->p_pid, curproc->p_comm ? curproc->p_comm : ""); } else { kprintf("Idle\n"); } kprintf("current thread = pri %d ", curthread->td_pri); if (curthread->td_critcount) kprintf("(CRIT)"); kprintf("\n"); #ifdef SMP /** * XXX FIXME: * we probably SHOULD have stopped the other CPUs before now! * another CPU COULD have been touching cpl at this moment... */ kprintf(" <- SMP: XXX"); #endif kprintf("\n"); #ifdef KDB if (kdb_trap(&psl)) return; #endif #ifdef DDB if ((debugger_on_panic || db_active) && kdb_trap(type, code, frame)) return; #endif kprintf("trap number = %d\n", type); if (type <= MAX_TRAP_MSG) panic("%s", 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(void) { #if JG struct mdglobaldata *gd = mdcpu; #endif kprintf("\nFatal double fault:\n"); #if JG kprintf("rip = 0x%lx\n", gd->gd_common_tss.tss_rip); kprintf("rsp = 0x%lx\n", gd->gd_common_tss.tss_rsp); kprintf("rbp = 0x%lx\n", gd->gd_common_tss.tss_rbp); #endif #ifdef SMP /* two separate prints in case of a trap on an unmapped page */ kprintf("cpuid = %d\n", mycpu->gd_cpuid); #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(unsigned addr) { struct lwp *lp; 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_MAX_USER_ADDRESS) return (1); lp = curthread->td_lwp; vm = lp->lwp_vmspace; PHOLD(lp->lwp_proc); if (!grow_stack (lp->lwp_proc, va)) { PRELE(lp->lwp_proc); return (1); } /* * fault the data page */ rv = vm_fault(&vm->vm_map, va, VM_PROT_WRITE, VM_FAULT_DIRTY); PRELE(lp->lwp_proc); if (rv != KERN_SUCCESS) return 1; return (0); } /* * syscall2 - MP aware system call request C handler * * A system call is essentially treated as a trap except that the * MP lock is not held on entry or return. We are responsible for * obtaining the MP lock if necessary and for handling ASTs * (e.g. a task switch) prior to return. * * In general, only simple access and manipulation of curproc and * the current stack is allowed without having to hold MP lock. * * MPSAFE - note that large sections of this routine are run without * the MP lock. */ void syscall2(struct trapframe *frame) { struct thread *td = curthread; struct proc *p = td->td_proc; struct lwp *lp = td->td_lwp; caddr_t params; struct sysent *callp; register_t orig_tf_rflags; int sticks; int error; int narg; #ifdef INVARIANTS int crit_count = td->td_critcount; lwkt_tokref_t curstop = td->td_toks_stop; #endif #ifdef SMP int have_mplock = 0; #endif register_t *argp; u_int code; int reg, regcnt; union sysunion args; register_t *argsdst; mycpu->gd_cnt.v_syscall++; KTR_LOG(kernentry_syscall, lp->lwp_proc->p_pid, lp->lwp_tid, frame->tf_eax); userenter(td, p); /* lazy raise our priority */ reg = 0; regcnt = 6; /* * Misc */ sticks = (int)td->td_sticks; orig_tf_rflags = frame->tf_rflags; /* * Virtual kernel intercept - if a VM context managed by a virtual * kernel issues a system call the virtual kernel handles it, not us. * Restore the virtual kernel context and return from its system * call. The current frame is copied out to the virtual kernel. */ if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { vkernel_trap(lp, frame); error = EJUSTRETURN; goto out; } /* * Get the system call parameters and account for time */ lp->lwp_md.md_regs = frame; params = (caddr_t)frame->tf_rsp + sizeof(register_t); code = frame->tf_rax; if (p->p_sysent->sv_prepsyscall) { (*p->p_sysent->sv_prepsyscall)( frame, (int *)(&args.nosys.sysmsg + 1), &code, ¶ms); } else { if (code == SYS_syscall || code == SYS___syscall) { code = frame->tf_rdi; reg++; regcnt--; } } 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]; narg = callp->sy_narg & SYF_ARGMASK; /* * On x86_64 we get up to six arguments in registers. The rest are * on the stack. The first six members of 'struct trapframe' happen * to be the registers used to pass arguments, in exactly the right * order. */ argp = &frame->tf_rdi; argp += reg; argsdst = (register_t *)(&args.nosys.sysmsg + 1); /* * JG can we overflow the space pointed to by 'argsdst' * either with 'bcopy' or with 'copyin'? */ bcopy(argp, argsdst, sizeof(register_t) * regcnt); /* * copyin is MP aware, but the tracing code is not */ if (narg > regcnt) { KASSERT(params != NULL, ("copyin args with no params!")); error = copyin(params, &argsdst[regcnt], (narg - regcnt) * sizeof(register_t)); if (error) { #ifdef KTRACE if (KTRPOINT(td, KTR_SYSCALL)) { MAKEMPSAFE(have_mplock); ktrsyscall(lp, code, narg, (void *)(&args.nosys.sysmsg + 1)); } #endif goto bad; } } #ifdef KTRACE if (KTRPOINT(td, KTR_SYSCALL)) { MAKEMPSAFE(have_mplock); ktrsyscall(lp, code, narg, (void *)(&args.nosys.sysmsg + 1)); } #endif /* * Default return value is 0 (will be copied to %rax). Double-value * returns use %rax and %rdx. %rdx is left unchanged for system * calls which return only one result. */ args.sysmsg_fds[0] = 0; args.sysmsg_fds[1] = frame->tf_rdx; /* * The syscall might manipulate the trap frame. If it does it * will probably return EJUSTRETURN. */ args.sysmsg_frame = frame; STOPEVENT(p, S_SCE, narg); /* MP aware */ /* * NOTE: All system calls run MPSAFE now. The system call itself * is responsible for getting the MP lock. */ error = (*callp->sy_call)(&args); #if 0 kprintf("system call %d returned %d\n", code, error); #endif out: /* * MP SAFE (we may or may not have the MP lock at this point) */ switch (error) { case 0: /* * Reinitialize proc pointer `p' as it may be different * if this is a child returning from fork syscall. */ p = curproc; lp = curthread->td_lwp; frame->tf_rax = args.sysmsg_fds[0]; frame->tf_rdx = args.sysmsg_fds[1]; frame->tf_rflags &= ~PSL_C; break; case ERESTART: /* * Reconstruct pc, we know that 'syscall' is 2 bytes. * We have to do a full context restore so that %r10 * (which was holding the value of %rcx) is restored for * the next iteration. */ frame->tf_rip -= frame->tf_err; frame->tf_r10 = frame->tf_rcx; break; case EJUSTRETURN: break; case EASYNC: panic("Unexpected EASYNC return value (for now)"); 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_rax = error; frame->tf_rflags |= PSL_C; break; } /* * Traced syscall. trapsignal() is not MP aware. */ if (orig_tf_rflags & PSL_T) { MAKEMPSAFE(have_mplock); frame->tf_rflags &= ~PSL_T; trapsignal(lp, SIGTRAP, 0); } /* * Handle reschedule and other end-of-syscall issues */ userret(lp, frame, sticks); #ifdef KTRACE if (KTRPOINT(td, KTR_SYSRET)) { MAKEMPSAFE(have_mplock); ktrsysret(lp, code, error, args.sysmsg_result); } #endif /* * This works because errno is findable through the * register set. If we ever support an emulation where this * is not the case, this code will need to be revisited. */ STOPEVENT(p, S_SCX, code); userexit(lp); #ifdef SMP /* * Release the MP lock if we had to get it */ if (have_mplock) rel_mplock(); #endif KTR_LOG(kernentry_syscall_ret, lp->lwp_proc->p_pid, lp->lwp_tid, error); #ifdef INVARIANTS KASSERT(&td->td_toks_base == td->td_toks_stop, ("syscall: critical section count mismatch! %d/%d", crit_count, td->td_pri)); KASSERT(curstop == td->td_toks_stop, ("syscall: extra tokens held after trap! %ld", td->td_toks_stop - &td->td_toks_base)); #endif } /* * NOTE: mplock not held at any point */ void fork_return(struct lwp *lp, struct trapframe *frame) { frame->tf_rax = 0; /* Child returns zero */ frame->tf_rflags &= ~PSL_C; /* success */ frame->tf_rdx = 1; generic_lwp_return(lp, frame); KTR_LOG(kernentry_fork_ret, lp->lwp_proc->p_pid, lp->lwp_tid); } /* * Simplified back end of syscall(), used when returning from fork() * directly into user mode. * * This code will return back into the fork trampoline code which then * runs doreti. * * NOTE: The mplock is not held at any point. */ void generic_lwp_return(struct lwp *lp, struct trapframe *frame) { struct proc *p = lp->lwp_proc; /* * Newly forked processes are given a kernel priority. We have to * adjust the priority to a normal user priority and fake entry * into the kernel (call userenter()) to install a passive release * function just in case userret() decides to stop the process. This * can occur when ^Z races a fork. If we do not install the passive * release function the current process designation will not be * released when the thread goes to sleep. */ lwkt_setpri_self(TDPRI_USER_NORM); userenter(lp->lwp_thread, p); userret(lp, frame, 0); #ifdef KTRACE if (KTRPOINT(lp->lwp_thread, KTR_SYSRET)) ktrsysret(lp, SYS_fork, 0, 0); #endif p->p_flag |= P_PASSIVE_ACQ; userexit(lp); p->p_flag &= ~P_PASSIVE_ACQ; } /* * doreti has turned into this. The frame is directly on the stack. We * pull everything else we need (fpu and tls context) from the current * thread. * * Note on fpu interactions: In a virtual kernel, the fpu context for * an emulated user mode process is not shared with the virtual kernel's * fpu context, so we only have to 'stack' fpu contexts within the virtual * kernel itself, and not even then since the signal() contexts that we care * about save and restore the FPU state (I think anyhow). * * vmspace_ctl() returns an error only if it had problems instaling the * context we supplied or problems copying data to/from our VM space. */ void go_user(struct intrframe *frame) { struct trapframe *tf = (void *)&frame->if_rdi; int r; /* * Interrupts may be disabled on entry, make sure all signals * can be received before beginning our loop. */ sigsetmask(0); /* * Switch to the current simulated user process, then call * user_trap() when we break out of it (usually due to a signal). */ for (;;) { /* * Tell the real kernel whether it is ok to use the FP * unit or not. */ if (mdcpu->gd_npxthread == curthread) { tf->tf_xflags &= ~PGEX_FPFAULT; } else { tf->tf_xflags |= PGEX_FPFAULT; } /* * Run emulated user process context. This call interlocks * with new mailbox signals. * * Set PGEX_U unconditionally, indicating a user frame (the * bit is normally set only by T_PAGEFLT). */ r = vmspace_ctl(&curproc->p_vmspace->vm_pmap, VMSPACE_CTL_RUN, tf, &curthread->td_savevext); frame->if_xflags |= PGEX_U; #if 0 kprintf("GO USER %d trap %ld EVA %08lx RIP %08lx RSP %08lx XFLAGS %02lx/%02lx\n", r, tf->tf_trapno, tf->tf_addr, tf->tf_rip, tf->tf_rsp, tf->tf_xflags, frame->if_xflags); #endif if (r < 0) { if (errno != EINTR) panic("vmspace_ctl failed error %d", errno); } else { if (tf->tf_trapno) { user_trap(tf); } } if (mycpu->gd_reqflags & RQF_AST_MASK) { tf->tf_trapno = T_ASTFLT; user_trap(tf); } tf->tf_trapno = 0; } } /* * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA * fault (which is then passed back to the virtual kernel) if an attempt is * made to use the FP unit. * * XXX this is a fairly big hack. */ void set_vkernel_fp(struct trapframe *frame) { struct thread *td = curthread; if (frame->tf_xflags & PGEX_FPFAULT) { td->td_pcb->pcb_flags |= FP_VIRTFP; if (mdcpu->gd_npxthread == td) npxexit(); } else { td->td_pcb->pcb_flags &= ~FP_VIRTFP; } } /* * Called from vkernel_trap() to fixup the vkernel's syscall * frame for vmspace_ctl() return. */ void cpu_vkernel_trap(struct trapframe *frame, int error) { frame->tf_rax = error; if (error) frame->tf_rflags |= PSL_C; else frame->tf_rflags &= ~PSL_C; }