patch-2.4.20 linux-2.4.20/arch/x86_64/kernel/signal.c
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- Lines: 596
- Date:
Thu Nov 28 15:53:12 2002
- Orig file:
linux-2.4.19/arch/x86_64/kernel/signal.c
- Orig date:
Wed Dec 31 16:00:00 1969
diff -urN linux-2.4.19/arch/x86_64/kernel/signal.c linux-2.4.20/arch/x86_64/kernel/signal.c
@@ -0,0 +1,595 @@
+/*
+ * 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 1.35 2002/07/29 10:34:03 ak Exp $
+ */
+
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/errno.h>
+#include <linux/wait.h>
+#include <linux/ptrace.h>
+#include <linux/unistd.h>
+#include <linux/stddef.h>
+#include <linux/tty.h>
+#include <linux/personality.h>
+#include <linux/compiler.h>
+#include <linux/binfmts.h>
+#include <asm/ucontext.h>
+#include <asm/uaccess.h>
+#include <asm/i387.h>
+
+#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;
+
+ /* XXX: Don't preclude handling different sized sigset_t's. */
+ 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);
+}
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