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/*- * Copyright (c) 1989, 1990 William F. Jolitz. * Copyright (c) 1990 The Regents of the University of California. * Copyright (c) 2007 The FreeBSD Foundation * All rights reserved. * * Portions of this software were developed by A. Joseph Koshy under * sponsorship from the FreeBSD Foundation and Google, 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. * 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. * * $FreeBSD: release/9.1.0/sys/i386/i386/exception.s 234144 2012-04-11 20:04:31Z jhb $ */ #include "opt_apic.h" #include "opt_atpic.h" #include "opt_hwpmc_hooks.h" #include "opt_kdtrace.h" #include "opt_npx.h" #include <machine/asmacros.h> #include <machine/psl.h> #include <machine/trap.h> #include "assym.s" #define SEL_RPL_MASK 0x0003 #define GSEL_KPL 0x0020 /* GSEL(GCODE_SEL, SEL_KPL) */ #ifdef KDTRACE_HOOKS .bss .globl dtrace_invop_jump_addr .align 4 .type dtrace_invop_jump_addr, @object .size dtrace_invop_jump_addr, 4 dtrace_invop_jump_addr: .zero 4 .globl dtrace_invop_calltrap_addr .align 4 .type dtrace_invop_calltrap_addr, @object .size dtrace_invop_calltrap_addr, 4 dtrace_invop_calltrap_addr: .zero 8 #endif .text #ifdef HWPMC_HOOKS ENTRY(start_exceptions) #endif /*****************************************************************************/ /* Trap handling */ /*****************************************************************************/ /* * Trap and fault vector routines. * * Most traps are 'trap gates', SDT_SYS386TGT. A trap gate pushes state on * the stack that mostly looks like an interrupt, but does not disable * interrupts. A few of the traps we are use are interrupt gates, * SDT_SYS386IGT, which are nearly the same thing except interrupts are * disabled on entry. * * The cpu will push a certain amount of state onto the kernel stack for * the current process. The amount of state depends on the type of trap * and whether the trap crossed rings or not. See i386/include/frame.h. * At the very least the current EFLAGS (status register, which includes * the interrupt disable state prior to the trap), the code segment register, * and the return instruction pointer are pushed by the cpu. The cpu * will also push an 'error' code for certain traps. We push a dummy * error code for those traps where the cpu doesn't in order to maintain * a consistent frame. We also push a contrived 'trap number'. * * The cpu does not push the general registers, we must do that, and we * must restore them prior to calling 'iret'. The cpu adjusts the %cs and * %ss segment registers, but does not mess with %ds, %es, or %fs. Thus we * must load them with appropriate values for supervisor mode operation. */ MCOUNT_LABEL(user) MCOUNT_LABEL(btrap) #define TRAP(a) pushl $(a) ; jmp alltraps IDTVEC(div) pushl $0; TRAP(T_DIVIDE) IDTVEC(dbg) pushl $0; TRAP(T_TRCTRAP) IDTVEC(nmi) pushl $0; TRAP(T_NMI) IDTVEC(bpt) pushl $0; TRAP(T_BPTFLT) IDTVEC(dtrace_ret) pushl $0; TRAP(T_DTRACE_RET) IDTVEC(ofl) pushl $0; TRAP(T_OFLOW) IDTVEC(bnd) pushl $0; TRAP(T_BOUND) #ifndef KDTRACE_HOOKS IDTVEC(ill) pushl $0; TRAP(T_PRIVINFLT) #endif IDTVEC(dna) pushl $0; TRAP(T_DNA) IDTVEC(fpusegm) pushl $0; TRAP(T_FPOPFLT) IDTVEC(tss) TRAP(T_TSSFLT) IDTVEC(missing) TRAP(T_SEGNPFLT) IDTVEC(stk) TRAP(T_STKFLT) IDTVEC(prot) TRAP(T_PROTFLT) IDTVEC(page) TRAP(T_PAGEFLT) IDTVEC(mchk) pushl $0; TRAP(T_MCHK) IDTVEC(rsvd) pushl $0; TRAP(T_RESERVED) IDTVEC(fpu) pushl $0; TRAP(T_ARITHTRAP) IDTVEC(align) TRAP(T_ALIGNFLT) IDTVEC(xmm) pushl $0; TRAP(T_XMMFLT) /* * alltraps entry point. Interrupts are enabled if this was a trap * gate (TGT), else disabled if this was an interrupt gate (IGT). * Note that int0x80_syscall is a trap gate. Interrupt gates are * used by page faults, non-maskable interrupts, debug and breakpoint * exceptions. */ SUPERALIGN_TEXT .globl alltraps .type alltraps,@function alltraps: pushal pushl %ds pushl %es pushl %fs alltraps_with_regs_pushed: SET_KERNEL_SREGS cld FAKE_MCOUNT(TF_EIP(%esp)) calltrap: pushl %esp call trap add $4, %esp /* * Return via doreti to handle ASTs. */ MEXITCOUNT jmp doreti /* * Privileged instruction fault. */ #ifdef KDTRACE_HOOKS SUPERALIGN_TEXT IDTVEC(ill) /* Check if there is no DTrace hook registered. */ cmpl $0,dtrace_invop_jump_addr je norm_ill /* Check if this is a user fault. */ cmpl $GSEL_KPL, 4(%esp) /* Check the code segment. */ /* If so, just handle it as a normal trap. */ jne norm_ill /* * This is a kernel instruction fault that might have been caused * by a DTrace provider. */ pushal /* Push all registers onto the stack. */ /* * Set our jump address for the jump back in the event that * the exception wasn't caused by DTrace at all. */ movl $norm_ill, dtrace_invop_calltrap_addr /* Jump to the code hooked in by DTrace. */ jmpl *dtrace_invop_jump_addr /* * Process the instruction fault in the normal way. */ norm_ill: pushl $0 TRAP(T_PRIVINFLT) #endif /* * SYSCALL CALL GATE (old entry point for a.out binaries) * * The intersegment call has been set up to specify one dummy parameter. * * This leaves a place to put eflags so that the call frame can be * converted to a trap frame. Note that the eflags is (semi-)bogusly * pushed into (what will be) tf_err and then copied later into the * final spot. It has to be done this way because esp can't be just * temporarily altered for the pushfl - an interrupt might come in * and clobber the saved cs/eip. */ SUPERALIGN_TEXT IDTVEC(lcall_syscall) pushfl /* save eflags */ popl 8(%esp) /* shuffle into tf_eflags */ pushl $7 /* sizeof "lcall 7,0" */ subl $4,%esp /* skip over tf_trapno */ pushal pushl %ds pushl %es pushl %fs SET_KERNEL_SREGS cld FAKE_MCOUNT(TF_EIP(%esp)) pushl %esp call syscall add $4, %esp MEXITCOUNT jmp doreti /* * Call gate entry for FreeBSD ELF and Linux/NetBSD syscall (int 0x80) * * Even though the name says 'int0x80', this is actually a TGT (trap gate) * rather then an IGT (interrupt gate). Thus interrupts are enabled on * entry just as they are for a normal syscall. */ SUPERALIGN_TEXT IDTVEC(int0x80_syscall) pushl $2 /* sizeof "int 0x80" */ subl $4,%esp /* skip over tf_trapno */ pushal pushl %ds pushl %es pushl %fs SET_KERNEL_SREGS cld FAKE_MCOUNT(TF_EIP(%esp)) pushl %esp call syscall add $4, %esp MEXITCOUNT jmp doreti ENTRY(fork_trampoline) pushl %esp /* trapframe pointer */ pushl %ebx /* arg1 */ pushl %esi /* function */ call fork_exit addl $12,%esp /* cut from syscall */ /* * Return via doreti to handle ASTs. */ MEXITCOUNT jmp doreti /* * To efficiently implement classification of trap and interrupt handlers * for profiling, there must be only trap handlers between the labels btrap * and bintr, and only interrupt handlers between the labels bintr and * eintr. This is implemented (partly) by including files that contain * some of the handlers. Before including the files, set up a normal asm * environment so that the included files doen't need to know that they are * included. */ .data .p2align 4 .text SUPERALIGN_TEXT MCOUNT_LABEL(bintr) #ifdef DEV_ATPIC #include <i386/i386/atpic_vector.s> #endif #if defined(DEV_APIC) && defined(DEV_ATPIC) .data .p2align 4 .text SUPERALIGN_TEXT #endif #ifdef DEV_APIC #include <i386/i386/apic_vector.s> #endif .data .p2align 4 .text SUPERALIGN_TEXT #include <i386/i386/vm86bios.s> .text MCOUNT_LABEL(eintr) /* * void doreti(struct trapframe) * * Handle return from interrupts, traps and syscalls. */ .text SUPERALIGN_TEXT .type doreti,@function doreti: FAKE_MCOUNT($bintr) /* init "from" bintr -> doreti */ doreti_next: /* * Check if ASTs can be handled now. ASTs cannot be safely * processed when returning from an NMI. */ cmpb $T_NMI,TF_TRAPNO(%esp) #ifdef HWPMC_HOOKS je doreti_nmi #else je doreti_exit #endif /* * PSL_VM must be checked first since segment registers only * have an RPL in non-VM86 mode. */ testl $PSL_VM,TF_EFLAGS(%esp) /* are we in vm86 mode? */ jz doreti_notvm86 movl PCPU(CURPCB),%ecx testl $PCB_VM86CALL,PCB_FLAGS(%ecx) /* are we in a vm86 call? */ jz doreti_ast /* can handle ASTS now if not */ jmp doreti_exit doreti_notvm86: testb $SEL_RPL_MASK,TF_CS(%esp) /* are we returning to user mode? */ jz doreti_exit /* can't handle ASTs now if not */ doreti_ast: /* * Check for ASTs atomically with returning. Disabling CPU * interrupts provides sufficient locking even in the SMP case, * since we will be informed of any new ASTs by an IPI. */ cli movl PCPU(CURTHREAD),%eax testl $TDF_ASTPENDING | TDF_NEEDRESCHED,TD_FLAGS(%eax) je doreti_exit sti pushl %esp /* pass a pointer to the trapframe */ call ast add $4,%esp jmp doreti_ast /* * doreti_exit: pop registers, iret. * * The segment register pop is a special case, since it may * fault if (for example) a sigreturn specifies bad segment * registers. The fault is handled in trap.c. */ doreti_exit: MEXITCOUNT .globl doreti_popl_fs doreti_popl_fs: popl %fs .globl doreti_popl_es doreti_popl_es: popl %es .globl doreti_popl_ds doreti_popl_ds: popl %ds popal addl $8,%esp .globl doreti_iret doreti_iret: iret /* * doreti_iret_fault and friends. Alternative return code for * the case where we get a fault in the doreti_exit code * above. trap() (i386/i386/trap.c) catches this specific * case, sends the process a signal and continues in the * corresponding place in the code below. */ ALIGN_TEXT .globl doreti_iret_fault doreti_iret_fault: subl $8,%esp pushal pushl %ds .globl doreti_popl_ds_fault doreti_popl_ds_fault: pushl %es .globl doreti_popl_es_fault doreti_popl_es_fault: pushl %fs .globl doreti_popl_fs_fault doreti_popl_fs_fault: movl $0,TF_ERR(%esp) /* XXX should be the error code */ movl $T_PROTFLT,TF_TRAPNO(%esp) jmp alltraps_with_regs_pushed #ifdef HWPMC_HOOKS doreti_nmi: /* * Since we are returning from an NMI, check if the current trap * was from user mode and if so whether the current thread * needs a user call chain capture. */ testb $SEL_RPL_MASK,TF_CS(%esp) jz doreti_exit movl PCPU(CURTHREAD),%eax /* curthread present? */ orl %eax,%eax jz doreti_exit testl $TDP_CALLCHAIN,TD_PFLAGS(%eax) /* flagged for capture? */ jz doreti_exit /* * Take the processor out of NMI mode by executing a fake "iret". */ pushfl pushl %cs pushl $outofnmi iret outofnmi: /* * Call the callchain capture hook after turning interrupts back on. */ movl pmc_hook,%ecx orl %ecx,%ecx jz doreti_exit pushl %esp /* frame pointer */ pushl $PMC_FN_USER_CALLCHAIN /* command */ movl PCPU(CURTHREAD),%eax pushl %eax /* curthread */ sti call *%ecx addl $12,%esp jmp doreti_ast ENTRY(end_exceptions) #endif