/* * linux/arch/x86_64/kernel/signal.c * * Copyright (C) 1991, 1992 Linus Torvalds * Copyright (C) 2000, 2001 SuSE Labs * * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes * 2000-2001 x86-64 support by Andi Kleen * * $Id: signal.c,v 1.1.1.1 2008/10/15 03:26:21 james26_jang Exp $ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define DEBUG_SIG 0 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset); void ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set, struct pt_regs * regs); void ia32_setup_frame(int sig, struct k_sigaction *ka, sigset_t *set, struct pt_regs * regs); void signal_fault(struct pt_regs *regs, void *frame, char *where); extern int exception_trace; int copy_siginfo_to_user(siginfo_t *to, siginfo_t *from) { if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) return -EFAULT; if (from->si_code < 0) return __copy_to_user(to, from, sizeof(siginfo_t)); else { int err; /* If you change siginfo_t structure, please be sure this code is fixed accordingly. It should never copy any pad contained in the structure to avoid security leaks, but must copy the generic 3 ints plus the relevant union member. */ err = __put_user(from->si_signo, &to->si_signo); err |= __put_user(from->si_errno, &to->si_errno); err |= __put_user((short)from->si_code, &to->si_code); /* First 32bits of unions are always present. */ err |= __put_user(from->si_pid, &to->si_pid); switch (from->si_code >> 16) { case __SI_FAULT >> 16: break; case __SI_CHLD >> 16: err |= __put_user(from->si_utime, &to->si_utime); err |= __put_user(from->si_stime, &to->si_stime); err |= __put_user(from->si_status, &to->si_status); default: err |= __put_user(from->si_uid, &to->si_uid); break; /* case __SI_RT: This is not generated by the kernel as of now. */ } return err; } } asmlinkage long sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, struct pt_regs regs) { sigset_t saveset, newset; if (sigsetsize != sizeof(sigset_t)) return -EINVAL; if (copy_from_user(&newset, unewset, sizeof(newset))) return -EFAULT; sigdelsetmask(&newset, ~_BLOCKABLE); spin_lock_irq(¤t->sigmask_lock); saveset = current->blocked; current->blocked = newset; recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); #if DEBUG_SIG printk("rt_sigsuspend savset(%lx) newset(%lx) regs(%p) rip(%lx)\n", saveset, newset, ®s, regs.rip); #endif regs.rax = -EINTR; while (1) { current->state = TASK_INTERRUPTIBLE; schedule(); if (do_signal(®s, &saveset)) return -EINTR; } } asmlinkage long sys_sigaltstack(const stack_t *uss, stack_t *uoss, struct pt_regs regs) { return do_sigaltstack(uss, uoss, regs.rsp); } /* * Do a signal return; undo the signal stack. */ struct rt_sigframe { char *pretcode; struct ucontext uc; struct siginfo info; }; static int restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc, unsigned long *prax) { unsigned int err = 0; #define COPY(x) err |= __get_user(regs->x, &sc->x) #define COPY_CANON(x) \ COPY(x); \ if ((regs->x >> 48) != 0 && (regs->x >> 48) != 0xffff) \ regs->x = 0; { unsigned int seg; err |= __get_user(seg, &sc->gs); load_gs_index(seg); err |= __get_user(seg, &sc->fs); loadsegment(fs,seg); } COPY(rdi); COPY(rsi); COPY(rbp); COPY_CANON(rsp); COPY(rbx); COPY(rdx); COPY(rcx); COPY_CANON(rip); COPY(r8); COPY(r9); COPY(r10); COPY(r11); COPY(r12); COPY(r13); COPY(r14); COPY(r15); /* do not copy CS/SS because 64bit should not need it. also need IRET exception handling anyways. */ { unsigned int tmpflags; err |= __get_user(tmpflags, &sc->eflags); regs->eflags = (regs->eflags & ~0x40DD5) | (tmpflags & 0x40DD5); regs->orig_rax = -1; /* disable syscall checks */ } { struct _fpstate * buf; err |= __get_user(buf, &sc->fpstate); if (buf) { if (unlikely(verify_area(VERIFY_READ, buf, sizeof(*buf)))) return 1; err |= restore_i387(buf); } } err |= __get_user(*prax, &sc->rax); return err; } #undef COPY asmlinkage long sys_rt_sigreturn(struct pt_regs regs) { struct rt_sigframe *frame = (struct rt_sigframe *)(regs.rsp - 8); sigset_t set; stack_t st; long eax; if (verify_area(VERIFY_READ, frame, sizeof(*frame))) goto badframe; if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) goto badframe; sigdelsetmask(&set, ~_BLOCKABLE); spin_lock_irq(¤t->sigmask_lock); current->blocked = set; recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); if (restore_sigcontext(®s, &frame->uc.uc_mcontext, &eax)) goto badframe; #if DEBUG_SIG printk("%d sigreturn rip:%lx rsp:%lx frame:%p rax:%lx\n",current->pid,regs.rip,regs.rsp,frame,eax); #endif if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st))) goto badframe; /* It is more difficult to avoid calling this function than to call it and ignore errors. */ do_sigaltstack(&st, NULL, regs.rsp); return eax; badframe: signal_fault(®s, frame, "rt_sigreturn"); return 0; } /* * Set up a signal frame. */ static int setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs, unsigned long mask) { int tmp, err = 0; struct task_struct *me = current; tmp = 0; __asm__("movl %%gs,%0" : "=r"(tmp): "0"(tmp)); err |= __put_user(tmp, (unsigned int *)&sc->gs); __asm__("movl %%fs,%0" : "=r"(tmp): "0"(tmp)); err |= __put_user(tmp, (unsigned int *)&sc->fs); err |= __put_user(regs->rdi, &sc->rdi); err |= __put_user(regs->rsi, &sc->rsi); err |= __put_user(regs->rbp, &sc->rbp); err |= __put_user(regs->rsp, &sc->rsp); err |= __put_user(regs->rbx, &sc->rbx); err |= __put_user(regs->rdx, &sc->rdx); err |= __put_user(regs->rcx, &sc->rcx); err |= __put_user(regs->rax, &sc->rax); err |= __put_user(regs->r8, &sc->r8); err |= __put_user(regs->r9, &sc->r9); err |= __put_user(regs->r10, &sc->r10); err |= __put_user(regs->r11, &sc->r11); err |= __put_user(regs->r12, &sc->r12); err |= __put_user(regs->r13, &sc->r13); err |= __put_user(regs->r14, &sc->r14); err |= __put_user(regs->r15, &sc->r15); err |= __put_user(me->thread.trap_no, &sc->trapno); err |= __put_user(me->thread.error_code, &sc->err); err |= __put_user(regs->rip, &sc->rip); err |= __put_user(regs->cs, &sc->cs); err |= __put_user(regs->eflags, &sc->eflags); err |= __put_user(mask, &sc->oldmask); err |= __put_user(me->thread.cr2, &sc->cr2); return err; } /* * Determine which stack to use.. */ #define round_down(p, r) ((void *) ((unsigned long)((p) - (r) + 1) & ~((r)-1))) static void * get_stack(struct k_sigaction *ka, struct pt_regs *regs, unsigned long size) { unsigned long rsp; /* Default to using normal stack - redzone*/ rsp = regs->rsp - 128; /* This is the X/Open sanctioned signal stack switching. */ if (ka->sa.sa_flags & SA_ONSTACK) { if (! sas_ss_flags(rsp) == 0) rsp = current->sas_ss_sp + current->sas_ss_size; } return round_down(rsp - size, 16); } static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set, struct pt_regs * regs) { struct rt_sigframe *frame = NULL; struct _fpstate *fp = NULL; int err = 0; if (current->used_math) { fp = get_stack(ka, regs, sizeof(struct _fpstate)); frame = round_down((char *)fp - sizeof(struct rt_sigframe), 16) - 8; if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate))) { goto give_sigsegv; } if (save_i387(fp) < 0) err |= -1; } if (!frame) frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8; if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) { goto give_sigsegv; } if (ka->sa.sa_flags & SA_SIGINFO) { err |= copy_siginfo_to_user(&frame->info, info); if (err) goto give_sigsegv; } /* Create the ucontext. */ err |= __put_user(0, &frame->uc.uc_flags); err |= __put_user(0, &frame->uc.uc_link); err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp); err |= __put_user(sas_ss_flags(regs->rsp), &frame->uc.uc_stack.ss_flags); err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]); err |= __put_user(fp, &frame->uc.uc_mcontext.fpstate); err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); /* Set up to return from userspace. If provided, use a stub already in userspace. */ /* x86-64 should always use SA_RESTORER. */ if (ka->sa.sa_flags & SA_RESTORER) { err |= __put_user(ka->sa.sa_restorer, &frame->pretcode); } else { printk("%s forgot to set SA_RESTORER for signal %d.\n", current->comm, sig); goto give_sigsegv; } if (err) goto give_sigsegv; #if DEBUG_SIG printk("%d old rip %lx old rsp %lx old rax %lx\n", current->pid,regs->rip,regs->rsp,regs->rax); #endif /* Set up registers for signal handler */ { struct exec_domain *ed = current->exec_domain; if (unlikely(ed && ed->signal_invmap && sig < 32)) sig = ed->signal_invmap[sig]; } regs->rdi = sig; /* could reload DS/ES to __USER_DS here, but assume for now that 64bit does not care */ /* In case the signal handler was declared without prototypes */ regs->rax = 0; /* This also works for non SA_SIGINFO handlers because they expect the next argument after the signal number on the stack. */ regs->rsi = (unsigned long)&frame->info; regs->rdx = (unsigned long)&frame->uc; regs->rsp = (unsigned long) frame; regs->rip = (unsigned long) ka->sa.sa_handler; regs->cs = __USER_CS; regs->ss = __USER_DS; set_fs(USER_DS); regs->eflags &= ~TF_MASK; #if DEBUG_SIG printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n", current->comm, current->pid, frame, regs->rip, frame->pretcode); #endif return; give_sigsegv: if (sig == SIGSEGV) ka->sa.sa_handler = SIG_DFL; signal_fault(regs, frame, "signal deliver"); } /* * OK, we're invoking a handler */ static void handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *oldset, struct pt_regs * regs) { #if DEBUG_SIG printk("handle_signal pid:%d sig:%lu rip:%lx rsp:%lx regs=%p\n", current->pid, sig, regs->rip, regs->rsp, regs); #endif /* Are we from a system call? */ if (regs->orig_rax >= 0) { /* If so, check system call restarting.. */ switch (regs->rax) { case -ERESTARTNOHAND: regs->rax = -EINTR; break; case -ERESTARTSYS: if (!(ka->sa.sa_flags & SA_RESTART)) { regs->rax = -EINTR; break; } /* fallthrough */ case -ERESTARTNOINTR: regs->rax = regs->orig_rax; regs->rip -= 2; break; } } #ifdef CONFIG_IA32_EMULATION if (current->thread.flags & THREAD_IA32) { if (ka->sa.sa_flags & SA_SIGINFO) ia32_setup_rt_frame(sig, ka, info, oldset, regs); else ia32_setup_frame(sig, ka, oldset, regs); } else #endif setup_rt_frame(sig, ka, info, oldset, regs); if (ka->sa.sa_flags & SA_ONESHOT) ka->sa.sa_handler = SIG_DFL; if (!(ka->sa.sa_flags & SA_NODEFER)) { spin_lock_irq(¤t->sigmask_lock); sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask); sigaddset(¤t->blocked,sig); recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); } } /* * Note that 'init' is a special process: it doesn't get signals it doesn't * want to handle. Thus you cannot kill init even with a SIGKILL even by * mistake. */ int do_signal(struct pt_regs *regs, sigset_t *oldset) { siginfo_t info; struct k_sigaction *ka; /* * We want the common case to go fast, which * is why we may in certain cases get here from * kernel mode. Just return without doing anything * if so. */ if ((regs->cs & 3) != 3) { return 1; } if (!oldset) oldset = ¤t->blocked; for (;;) { unsigned long signr; spin_lock_irq(¤t->sigmask_lock); signr = dequeue_signal(¤t->blocked, &info); spin_unlock_irq(¤t->sigmask_lock); if (!signr) { break; } if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) { /* Let the debugger run. */ current->exit_code = signr; current->state = TASK_STOPPED; notify_parent(current, SIGCHLD); schedule(); /* We're back. Did the debugger cancel the sig? */ if (!(signr = current->exit_code)) continue; current->exit_code = 0; /* The debugger continued. Ignore SIGSTOP. */ if (signr == SIGSTOP) continue; /* Update the siginfo structure. Is this good? */ if (signr != info.si_signo) { info.si_signo = signr; info.si_errno = 0; info.si_code = SI_USER; info.si_pid = current->p_pptr->pid; info.si_uid = current->p_pptr->uid; } /* If the (new) signal is now blocked, requeue it. */ if (sigismember(¤t->blocked, signr)) { send_sig_info(signr, &info, current); continue; } } ka = ¤t->sig->action[signr-1]; if (ka->sa.sa_handler == SIG_IGN) { if (signr != SIGCHLD) continue; /* Check for SIGCHLD: it's special. */ while (sys_wait4(-1, NULL, WNOHANG, NULL) > 0) /* nothing */; continue; } if (ka->sa.sa_handler == SIG_DFL) { int exit_code = signr; /* Init gets no signals it doesn't want. */ if (current->pid == 1) continue; switch (signr) { case SIGCONT: case SIGCHLD: case SIGWINCH: case SIGURG: continue; case SIGTSTP: case SIGTTIN: case SIGTTOU: if (is_orphaned_pgrp(current->pgrp)) continue; /* FALLTHRU */ case SIGSTOP: { struct signal_struct *sig; current->state = TASK_STOPPED; current->exit_code = signr; sig = current->p_pptr->sig; if (sig && !(sig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) notify_parent(current, SIGCHLD); schedule(); continue; } case SIGQUIT: case SIGILL: case SIGTRAP: case SIGABRT: case SIGFPE: case SIGSEGV: case SIGBUS: case SIGSYS: case SIGXCPU: case SIGXFSZ: if (do_coredump(signr, regs)) exit_code |= 0x80; /* FALLTHRU */ default: sig_exit(signr, exit_code, &info); /* NOTREACHED */ } } /* Reenable any watchpoints before delivering the * signal to user space. The processor register will * have been cleared if the watchpoint triggered * inside the kernel. */ __asm__("movq %0,%%db7" : : "r" (current->thread.debugreg[7])); /* Whee! Actually deliver the signal. */ handle_signal(signr, ka, &info, oldset, regs); return 1; } /* Did we come from a system call? */ if (regs->orig_rax >= 0) { /* Restart the system call - no handlers present */ if (regs->rax == -ERESTARTNOHAND || regs->rax == -ERESTARTSYS || regs->rax == -ERESTARTNOINTR) { regs->rax = regs->orig_rax; regs->rip -= 2; } } return 0; } void signal_fault(struct pt_regs *regs, void *frame, char *where) { struct task_struct *me = current; if (exception_trace) printk("%s[%d] bad frame in %s frame:%p rip:%lx rsp:%lx orax:%lx\n", me->comm,me->pid,where,frame,regs->rip,regs->rsp,regs->orig_rax); force_sig(SIGSEGV, me); }