Module Name: src Committed By: reinoud Date: Tue Jan 17 19:46:55 UTC 2012
Modified Files: src/sys/arch/usermode/usermode: trap.c Log Message: Clean up userret/ast handling. Now called ONLY when its 100% clear that it is returning to userland. To generate a diff of this commit: cvs rdiff -u -r1.57 -r1.58 src/sys/arch/usermode/usermode/trap.c Please note that diffs are not public domain; they are subject to the copyright notices on the relevant files.
Modified files: Index: src/sys/arch/usermode/usermode/trap.c diff -u src/sys/arch/usermode/usermode/trap.c:1.57 src/sys/arch/usermode/usermode/trap.c:1.58 --- src/sys/arch/usermode/usermode/trap.c:1.57 Sat Jan 14 21:45:28 2012 +++ src/sys/arch/usermode/usermode/trap.c Tue Jan 17 19:46:55 2012 @@ -1,4 +1,4 @@ -/* $NetBSD: trap.c,v 1.57 2012/01/14 21:45:28 reinoud Exp $ */ +/* $NetBSD: trap.c,v 1.58 2012/01/17 19:46:55 reinoud Exp $ */ /*- * Copyright (c) 2011 Reinoud Zandijk <rein...@netbsd.org> @@ -27,7 +27,7 @@ */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.57 2012/01/14 21:45:28 reinoud Exp $"); +__KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.58 2012/01/17 19:46:55 reinoud Exp $"); #include <sys/types.h> #include <sys/param.h> @@ -50,14 +50,13 @@ __KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.5 /* forwards and externals */ void setup_signal_handlers(void); void stop_all_signal_handlers(void); -void userret(struct lwp *l); static void mem_access_handler(int sig, siginfo_t *info, void *ctx); static void illegal_instruction_handler(int sig, siginfo_t *info, void *ctx); extern int errno; -static void pagefault(vaddr_t pc, vaddr_t va); -static void illegal_instruction(void); +static void pagefault(vaddr_t from_userland, vaddr_t pc, vaddr_t va); +static void illegal_instruction(vaddr_t from_userland); bool pmap_fault(pmap_t pmap, vaddr_t va, vm_prot_t *atype); @@ -120,6 +119,33 @@ stop_all_signal_handlers(void) } +/* ast and userret */ +void +userret(struct lwp *l) +{ + /* invoke MI userret code */ + mi_userret(l); + + while (astpending) { + astpending = 0; + + curcpu()->ci_data.cpu_ntrap++; +#if 0 + /* profiling */ + if (l->l_pflag & LP_OWEUPC) { + l->l_pflag &= ~LP_OWEUPC; + ADDUPROF(l); + } +#endif + /* allow a forced task switch */ + if (l->l_cpu->ci_want_resched) + preempt(); + + mi_userret(l); + } +} + + /* signal handler switching to a pagefault context */ static void mem_access_handler(int sig, siginfo_t *info, void *ctx) @@ -128,6 +154,7 @@ mem_access_handler(int sig, siginfo_t *i struct lwp *l; struct pcb *pcb; vaddr_t va, sp, pc, fp; + int from_userland; assert((info->si_signo == SIGSEGV) || (info->si_signo == SIGBUS)); @@ -176,9 +203,12 @@ mem_access_handler(int sig, siginfo_t *i #endif /* if we're running on a stack of our own, use the system stack */ + from_userland = 0; if ((sp < (vaddr_t) pcb->sys_stack) || (sp > (vaddr_t) pcb->sys_stack_top)) { sp = (vaddr_t) pcb->sys_stack_top - sizeof(register_t); fp = (vaddr_t) &pcb->pcb_userret_ucp; + if (pc < kmem_user_end) + from_userland = 1; } else { /* stack grows down */ fp = sp - sizeof(ucontext_t) - sizeof(register_t); /* slack */ @@ -198,56 +228,13 @@ mem_access_handler(int sig, siginfo_t *i pcb->pcb_ucp.uc_flags = _UC_STACK | _UC_CPU; thunk_makecontext(&pcb->pcb_ucp, (void (*)(void)) pagefault, - 2, (void *) pc, (void *) va, NULL); + 3, (void *) from_userland, (void *) pc, (void *) va); /* switch to the new pagefault entry on return from signal */ memcpy(ctx, &pcb->pcb_ucp, sizeof(ucontext_t)); } -/* ast and userret */ -void -userret(struct lwp *l) -{ - struct pcb *pcb; - ucontext_t ucp, *nucp; - vaddr_t pc; - - KASSERT(l); - - /* are we going back to userland? */ - pcb = lwp_getpcb(l); - KASSERT(pcb); - - /* where are we going back to ? */ - thunk_getcontext(&ucp); - nucp = (ucontext_t *) ucp.uc_link; - pc = md_get_pc(nucp); - - if (pc >= kmem_k_start) - return; - - /* ok, going to userland, proceed! */ - if (astpending) { - astpending = 0; - - curcpu()->ci_data.cpu_ntrap++; -#if 0 - /* profiling */ - if (l->l_pflag & LP_OWEUPC) { - l->l_pflag &= ~LP_OWEUPC; - ADDUPROF(l); - } -#endif - /* allow a forced task switch */ - if (l->l_cpu->ci_want_resched) - preempt(); - } - - /* invoke MI userret code */ - mi_userret(l); -} - /* signal handler switching to a illegal instruction context */ static void illegal_instruction_handler(int sig, siginfo_t *info, void *ctx) @@ -255,7 +242,8 @@ illegal_instruction_handler(int sig, sig ucontext_t *ucp = ctx; struct lwp *l; struct pcb *pcb; - vaddr_t sp, fp; + vaddr_t sp, pc, fp; + int from_userland; assert(info->si_signo == SIGILL); #if 0 @@ -291,14 +279,21 @@ illegal_instruction_handler(int sig, sig l = curlwp; pcb = lwp_getpcb(l); + /* get PC address of faulted instruction */ + pc = md_get_pc(ctx); + /* setup for illegal_instruction context */ sp = md_get_sp(ctx); /* if we're running on a stack of our own, use the system stack */ + from_userland = 0; if ((sp < (vaddr_t) pcb->sys_stack) || (sp > (vaddr_t) pcb->sys_stack_top)) { sp = (vaddr_t) pcb->sys_stack_top - sizeof(register_t); fp = (vaddr_t) &pcb->pcb_userret_ucp; + + KASSERT(pc < kmem_user_end); + from_userland = 1; } else { panic("illegal instruction inside kernel?"); #if 0 @@ -321,7 +316,7 @@ illegal_instruction_handler(int sig, sig pcb->pcb_ucp.uc_flags = _UC_STACK | _UC_CPU; thunk_makecontext(&pcb->pcb_ucp, (void (*)(void)) illegal_instruction, - 0, NULL, NULL, NULL); + 1, (void *) from_userland, NULL, NULL); /* switch to the new illegal instruction entry on return from signal */ memcpy(ctx, &pcb->pcb_ucp, sizeof(ucontext_t)); @@ -333,7 +328,7 @@ illegal_instruction_handler(int sig, sig * pmap reference fault or let uvm handle it. */ static void -pagefault(vaddr_t pc, vaddr_t va) +pagefault(vaddr_t from_userland, vaddr_t pc, vaddr_t va) { struct proc *p; struct lwp *l; @@ -435,7 +430,8 @@ pagefault(vaddr_t pc, vaddr_t va) // thunk_printf("pagefault leave\n"); out: - userret(l); + if (from_userland) + userret(l); out_quick: thunk_seterrno(lwp_errno); pcb->pcb_errno = lwp_errno; @@ -445,7 +441,7 @@ out_quick: * Context for handing illegal instruction from the sigill handler */ static void -illegal_instruction(void) +illegal_instruction(vaddr_t from_userland) { struct lwp *l = curlwp; struct pcb *pcb = lwp_getpcb(l); @@ -457,6 +453,7 @@ illegal_instruction(void) if (md_syscall_check_opcode(ucp)) { syscall(); // thunk_printf("illegal instruction leave\n"); + KASSERT(from_userland); userret(l); return; } @@ -475,6 +472,7 @@ illegal_instruction(void) #else trapsignal(l, &ksi); #endif + KASSERT(from_userland); userret(l); }