Clean up userret/ast handling. Now called ONLY when its 100% clear that it is
returning to userland.
This commit is contained in:
reinoud
parent
1d7281ae96
commit
e6afed1597
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@ -1,4 +1,4 @@
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/* $NetBSD: trap.c,v 1.57 2012/01/14 21:45:28 reinoud Exp $ */
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/* $NetBSD: trap.c,v 1.58 2012/01/17 19:46:55 reinoud Exp $ */
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/*-
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* Copyright (c) 2011 Reinoud Zandijk <reinoud@netbsd.org>
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@ -27,7 +27,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.57 2012/01/14 21:45:28 reinoud Exp $");
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__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.58 2012/01/17 19:46:55 reinoud Exp $");
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#include <sys/types.h>
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#include <sys/param.h>
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@ -50,14 +50,13 @@ __KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.57 2012/01/14 21:45:28 reinoud Exp $");
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/* forwards and externals */
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void setup_signal_handlers(void);
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void stop_all_signal_handlers(void);
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void userret(struct lwp *l);
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static void mem_access_handler(int sig, siginfo_t *info, void *ctx);
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static void illegal_instruction_handler(int sig, siginfo_t *info, void *ctx);
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extern int errno;
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static void pagefault(vaddr_t pc, vaddr_t va);
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static void illegal_instruction(void);
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static void pagefault(vaddr_t from_userland, vaddr_t pc, vaddr_t va);
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static void illegal_instruction(vaddr_t from_userland);
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bool pmap_fault(pmap_t pmap, vaddr_t va, vm_prot_t *atype);
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@ -120,6 +119,33 @@ stop_all_signal_handlers(void)
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}
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/* ast and userret */
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void
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userret(struct lwp *l)
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{
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/* invoke MI userret code */
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mi_userret(l);
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while (astpending) {
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astpending = 0;
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curcpu()->ci_data.cpu_ntrap++;
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#if 0
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/* profiling */
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if (l->l_pflag & LP_OWEUPC) {
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l->l_pflag &= ~LP_OWEUPC;
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ADDUPROF(l);
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}
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#endif
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/* allow a forced task switch */
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if (l->l_cpu->ci_want_resched)
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preempt();
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mi_userret(l);
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}
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}
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/* signal handler switching to a pagefault context */
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static void
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mem_access_handler(int sig, siginfo_t *info, void *ctx)
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@ -128,6 +154,7 @@ mem_access_handler(int sig, siginfo_t *info, void *ctx)
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struct lwp *l;
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struct pcb *pcb;
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vaddr_t va, sp, pc, fp;
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int from_userland;
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assert((info->si_signo == SIGSEGV) || (info->si_signo == SIGBUS));
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@ -176,9 +203,12 @@ mem_access_handler(int sig, siginfo_t *info, void *ctx)
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#endif
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/* if we're running on a stack of our own, use the system stack */
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from_userland = 0;
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if ((sp < (vaddr_t) pcb->sys_stack) || (sp > (vaddr_t) pcb->sys_stack_top)) {
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sp = (vaddr_t) pcb->sys_stack_top - sizeof(register_t);
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fp = (vaddr_t) &pcb->pcb_userret_ucp;
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if (pc < kmem_user_end)
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from_userland = 1;
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} else {
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/* stack grows down */
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fp = sp - sizeof(ucontext_t) - sizeof(register_t); /* slack */
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@ -198,56 +228,13 @@ mem_access_handler(int sig, siginfo_t *info, void *ctx)
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pcb->pcb_ucp.uc_flags = _UC_STACK | _UC_CPU;
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thunk_makecontext(&pcb->pcb_ucp, (void (*)(void)) pagefault,
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2, (void *) pc, (void *) va, NULL);
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3, (void *) from_userland, (void *) pc, (void *) va);
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/* switch to the new pagefault entry on return from signal */
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memcpy(ctx, &pcb->pcb_ucp, sizeof(ucontext_t));
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}
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/* ast and userret */
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void
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userret(struct lwp *l)
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{
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struct pcb *pcb;
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ucontext_t ucp, *nucp;
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vaddr_t pc;
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KASSERT(l);
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/* are we going back to userland? */
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pcb = lwp_getpcb(l);
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KASSERT(pcb);
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/* where are we going back to ? */
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thunk_getcontext(&ucp);
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nucp = (ucontext_t *) ucp.uc_link;
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pc = md_get_pc(nucp);
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if (pc >= kmem_k_start)
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return;
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/* ok, going to userland, proceed! */
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if (astpending) {
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astpending = 0;
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curcpu()->ci_data.cpu_ntrap++;
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#if 0
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/* profiling */
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if (l->l_pflag & LP_OWEUPC) {
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l->l_pflag &= ~LP_OWEUPC;
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ADDUPROF(l);
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}
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#endif
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/* allow a forced task switch */
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if (l->l_cpu->ci_want_resched)
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preempt();
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}
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/* invoke MI userret code */
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mi_userret(l);
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}
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/* signal handler switching to a illegal instruction context */
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static void
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illegal_instruction_handler(int sig, siginfo_t *info, void *ctx)
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@ -255,7 +242,8 @@ illegal_instruction_handler(int sig, siginfo_t *info, void *ctx)
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ucontext_t *ucp = ctx;
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struct lwp *l;
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struct pcb *pcb;
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vaddr_t sp, fp;
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vaddr_t sp, pc, fp;
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int from_userland;
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assert(info->si_signo == SIGILL);
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#if 0
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@ -291,14 +279,21 @@ illegal_instruction_handler(int sig, siginfo_t *info, void *ctx)
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l = curlwp;
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pcb = lwp_getpcb(l);
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/* get PC address of faulted instruction */
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pc = md_get_pc(ctx);
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/* setup for illegal_instruction context */
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sp = md_get_sp(ctx);
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/* if we're running on a stack of our own, use the system stack */
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from_userland = 0;
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if ((sp < (vaddr_t) pcb->sys_stack) ||
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(sp > (vaddr_t) pcb->sys_stack_top)) {
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sp = (vaddr_t) pcb->sys_stack_top - sizeof(register_t);
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fp = (vaddr_t) &pcb->pcb_userret_ucp;
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KASSERT(pc < kmem_user_end);
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from_userland = 1;
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} else {
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panic("illegal instruction inside kernel?");
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#if 0
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@ -321,7 +316,7 @@ illegal_instruction_handler(int sig, siginfo_t *info, void *ctx)
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pcb->pcb_ucp.uc_flags = _UC_STACK | _UC_CPU;
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thunk_makecontext(&pcb->pcb_ucp, (void (*)(void)) illegal_instruction,
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0, NULL, NULL, NULL);
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1, (void *) from_userland, NULL, NULL);
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/* switch to the new illegal instruction entry on return from signal */
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memcpy(ctx, &pcb->pcb_ucp, sizeof(ucontext_t));
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@ -333,7 +328,7 @@ illegal_instruction_handler(int sig, siginfo_t *info, void *ctx)
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* pmap reference fault or let uvm handle it.
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*/
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static void
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pagefault(vaddr_t pc, vaddr_t va)
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pagefault(vaddr_t from_userland, vaddr_t pc, vaddr_t va)
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{
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struct proc *p;
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struct lwp *l;
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@ -435,6 +430,7 @@ pagefault(vaddr_t pc, vaddr_t va)
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// thunk_printf("pagefault leave\n");
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out:
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if (from_userland)
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userret(l);
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out_quick:
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thunk_seterrno(lwp_errno);
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@ -445,7 +441,7 @@ out_quick:
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* Context for handing illegal instruction from the sigill handler
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*/
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static void
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illegal_instruction(void)
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illegal_instruction(vaddr_t from_userland)
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{
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struct lwp *l = curlwp;
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struct pcb *pcb = lwp_getpcb(l);
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@ -457,6 +453,7 @@ illegal_instruction(void)
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if (md_syscall_check_opcode(ucp)) {
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syscall();
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// thunk_printf("illegal instruction leave\n");
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KASSERT(from_userland);
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userret(l);
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return;
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}
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@ -475,6 +472,7 @@ illegal_instruction(void)
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#else
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trapsignal(l, &ksi);
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#endif
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KASSERT(from_userland);
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userret(l);
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}
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