+++ /dev/null
-/*
- * linux/arch/x86_64/kernel/signal.c
- *
- * Copyright (C) 1991, 1992 Linus Torvalds
- * Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
- *
- * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
- * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
- * 2000-2002 x86-64 support by Andi Kleen
- */
-
-#include <linux/sched.h>
-#include <linux/mm.h>
-#include <linux/smp.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/personality.h>
-#include <linux/compiler.h>
-#include <asm/ucontext.h>
-#include <asm/uaccess.h>
-#include <asm/i387.h>
-#include <asm/proto.h>
-#include <asm/ia32_unistd.h>
-#include <asm/mce.h>
-
-/* #define DEBUG_SIG 1 */
-
-#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
-
-int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
- sigset_t *set, struct pt_regs * regs);
-int ia32_setup_frame(int sig, struct k_sigaction *ka,
- sigset_t *set, struct pt_regs * regs);
-
-asmlinkage long
-sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
- struct pt_regs *regs)
-{
- return do_sigaltstack(uss, uoss, regs->rsp);
-}
-
-
-/*
- * Do a signal return; undo the signal stack.
- */
-
-struct rt_sigframe
-{
- char __user *pretcode;
- struct ucontext uc;
- struct siginfo info;
-};
-
-static int
-restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, unsigned long *prax)
-{
- unsigned int err = 0;
-
- /* Always make any pending restarted system calls return -EINTR */
- current_thread_info()->restart_block.fn = do_no_restart_syscall;
-
-#define COPY(x) err |= __get_user(regs->x, &sc->x)
-
- COPY(rdi); COPY(rsi); COPY(rbp); COPY(rsp); COPY(rbx);
- COPY(rdx); COPY(rcx); COPY(rip);
- COPY(r8);
- COPY(r9);
- COPY(r10);
- COPY(r11);
- COPY(r12);
- COPY(r13);
- COPY(r14);
- COPY(r15);
-
- /* Kernel saves and restores only the CS segment register on signals,
- * which is the bare minimum needed to allow mixed 32/64-bit code.
- * App's signal handler can save/restore other segments if needed. */
- {
- unsigned cs;
- err |= __get_user(cs, &sc->cs);
- regs->cs = cs | 3; /* Force into user mode */
- }
-
- {
- 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 __user * buf;
- err |= __get_user(buf, &sc->fpstate);
-
- if (buf) {
- if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
- goto badframe;
- err |= restore_i387(buf);
- } else {
- struct task_struct *me = current;
- if (used_math()) {
- clear_fpu(me);
- clear_used_math();
- }
- }
- }
-
- err |= __get_user(*prax, &sc->rax);
- return err;
-
-badframe:
- return 1;
-}
-
-asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
-{
- struct rt_sigframe __user *frame;
- sigset_t set;
- unsigned long eax;
-
- frame = (struct rt_sigframe __user *)(regs->rsp - 8);
- if (!access_ok(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->sighand->siglock);
- current->blocked = set;
- recalc_sigpending();
- spin_unlock_irq(¤t->sighand->siglock);
-
- if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &eax))
- goto badframe;
-
-#ifdef DEBUG_SIG
- printk("%d sigreturn rip:%lx rsp:%lx frame:%p rax:%lx\n",current->pid,regs->rip,regs->rsp,frame,eax);
-#endif
-
- if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->rsp) == -EFAULT)
- goto badframe;
-
- return eax;
-
-badframe:
- signal_fault(regs,frame,"sigreturn");
- return 0;
-}
-
-/*
- * Set up a signal frame.
- */
-
-static inline int
-setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned long mask, struct task_struct *me)
-{
- int err = 0;
-
- err |= __put_user(regs->cs, &sc->cs);
- err |= __put_user(0, &sc->gs);
- err |= __put_user(0, &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->eflags, &sc->eflags);
- err |= __put_user(mask, &sc->oldmask);
- err |= __put_user(me->thread.cr2, &sc->cr2);
-
- return err;
-}
-
-/*
- * Determine which stack to use..
- */
-
-static void __user *
-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 (void __user *)round_down(rsp - size, 16);
-}
-
-static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
- sigset_t *set, struct pt_regs * regs)
-{
- struct rt_sigframe __user *frame;
- struct _fpstate __user *fp = NULL;
- int err = 0;
- struct task_struct *me = current;
-
- if (used_math()) {
- fp = get_stack(ka, regs, sizeof(struct _fpstate));
- frame = (void __user *)round_down(
- (unsigned long)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;
- } else
- 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(me->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(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
- err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0], me);
- err |= __put_user(fp, &frame->uc.uc_mcontext.fpstate);
- if (sizeof(*set) == 16) {
- __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
- __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
- } else
- 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 {
- /* could use a vstub here */
- goto give_sigsegv;
- }
-
- if (err)
- goto give_sigsegv;
-
-#ifdef 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 */
- regs->rdi = sig;
- /* 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->rip = (unsigned long) ka->sa.sa_handler;
-
- regs->rsp = (unsigned long)frame;
-
- /* Set up the CS register to run signal handlers in 64-bit mode,
- even if the handler happens to be interrupting 32-bit code. */
- regs->cs = __USER_CS;
-
- /* This, by contrast, has nothing to do with segment registers -
- see include/asm-x86_64/uaccess.h for details. */
- set_fs(USER_DS);
-
- regs->eflags &= ~TF_MASK;
- if (test_thread_flag(TIF_SINGLESTEP))
- ptrace_notify(SIGTRAP);
-#ifdef DEBUG_SIG
- printk("SIG deliver (%s:%d): sp=%p pc=%lx ra=%p\n",
- current->comm, current->pid, frame, regs->rip, frame->pretcode);
-#endif
-
- return 0;
-
-give_sigsegv:
- force_sigsegv(sig, current);
- return -EFAULT;
-}
-
-/*
- * OK, we're invoking a handler
- */
-
-static int
-handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
- sigset_t *oldset, struct pt_regs *regs)
-{
- int ret;
-
-#ifdef 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 ((long)regs->orig_rax >= 0) {
- /* If so, check system call restarting.. */
- switch (regs->rax) {
- case -ERESTART_RESTARTBLOCK:
- 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;
- }
- }
-
- /*
- * If TF is set due to a debugger (PT_DTRACE), clear the TF
- * flag so that register information in the sigcontext is
- * correct.
- */
- if (unlikely(regs->eflags & TF_MASK)) {
- if (likely(current->ptrace & PT_DTRACE)) {
- current->ptrace &= ~PT_DTRACE;
- regs->eflags &= ~TF_MASK;
- }
- }
-
-#ifdef CONFIG_IA32_EMULATION
- if (test_thread_flag(TIF_IA32)) {
- if (ka->sa.sa_flags & SA_SIGINFO)
- ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs);
- else
- ret = ia32_setup_frame(sig, ka, oldset, regs);
- } else
-#endif
- ret = setup_rt_frame(sig, ka, info, oldset, regs);
-
- if (ret == 0) {
- spin_lock_irq(¤t->sighand->siglock);
- sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask);
- if (!(ka->sa.sa_flags & SA_NODEFER))
- sigaddset(¤t->blocked,sig);
- recalc_sigpending();
- spin_unlock_irq(¤t->sighand->siglock);
- }
-
- return ret;
-}
-
-/*
- * 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.
- */
-static void do_signal(struct pt_regs *regs)
-{
- struct k_sigaction ka;
- siginfo_t info;
- int signr;
- sigset_t *oldset;
-
- /*
- * 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 (!user_mode(regs))
- return;
-
- if (test_thread_flag(TIF_RESTORE_SIGMASK))
- oldset = ¤t->saved_sigmask;
- else
- oldset = ¤t->blocked;
-
- signr = get_signal_to_deliver(&info, &ka, regs, NULL);
- if (signr > 0) {
- /* Reenable any watchpoints before delivering the
- * signal to user space. The processor register will
- * have been cleared if the watchpoint triggered
- * inside the kernel.
- */
- if (current->thread.debugreg7)
- set_debugreg(current->thread.debugreg7, 7);
-
- /* Whee! Actually deliver the signal. */
- if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
- /* a signal was successfully delivered; the saved
- * sigmask will have been stored in the signal frame,
- * and will be restored by sigreturn, so we can simply
- * clear the TIF_RESTORE_SIGMASK flag */
- clear_thread_flag(TIF_RESTORE_SIGMASK);
- }
- return;
- }
-
- /* Did we come from a system call? */
- if ((long)regs->orig_rax >= 0) {
- /* Restart the system call - no handlers present */
- long res = regs->rax;
- switch (res) {
- case -ERESTARTNOHAND:
- case -ERESTARTSYS:
- case -ERESTARTNOINTR:
- regs->rax = regs->orig_rax;
- regs->rip -= 2;
- break;
- case -ERESTART_RESTARTBLOCK:
- regs->rax = test_thread_flag(TIF_IA32) ?
- __NR_ia32_restart_syscall :
- __NR_restart_syscall;
- regs->rip -= 2;
- break;
- }
- }
-
- /* if there's no signal to deliver, we just put the saved sigmask
- back. */
- if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
- clear_thread_flag(TIF_RESTORE_SIGMASK);
- sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
- }
-}
-
-void
-do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
-{
-#ifdef DEBUG_SIG
- printk("do_notify_resume flags:%x rip:%lx rsp:%lx caller:%p pending:%x\n",
- thread_info_flags, regs->rip, regs->rsp, __builtin_return_address(0),signal_pending(current));
-#endif
-
- /* Pending single-step? */
- if (thread_info_flags & _TIF_SINGLESTEP) {
- regs->eflags |= TF_MASK;
- clear_thread_flag(TIF_SINGLESTEP);
- }
-
-#ifdef CONFIG_X86_MCE
- /* notify userspace of pending MCEs */
- if (thread_info_flags & _TIF_MCE_NOTIFY)
- mce_notify_user();
-#endif /* CONFIG_X86_MCE */
-
- /* deal with pending signal delivery */
- if (thread_info_flags & (_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK))
- do_signal(regs);
-}
-
-void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
-{
- struct task_struct *me = current;
- if (show_unhandled_signals && printk_ratelimit())
- 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);
-}
git.samba.org / sfrench / cifs-2.6.git / blobdiff