742fa54a62
Switch struct sigcontext (defined in <asm/sigcontext*.h>) to using register names withut e- or r-prefixes for both 32- and 64-bit x86. This is intended as a preliminary step in unifying this code between architectures. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
492 lines
13 KiB
C
492 lines
13 KiB
C
/*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
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*
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* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
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* 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
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* 2000-2002 x86-64 support by Andi Kleen
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*/
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/kernel.h>
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#include <linux/signal.h>
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#include <linux/errno.h>
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#include <linux/wait.h>
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#include <linux/ptrace.h>
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#include <linux/unistd.h>
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#include <linux/stddef.h>
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#include <linux/personality.h>
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#include <linux/compiler.h>
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#include <asm/ucontext.h>
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#include <asm/uaccess.h>
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#include <asm/i387.h>
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#include <asm/proto.h>
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#include <asm/ia32_unistd.h>
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#include <asm/mce.h>
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/* #define DEBUG_SIG 1 */
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#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
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int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
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sigset_t *set, struct pt_regs * regs);
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int ia32_setup_frame(int sig, struct k_sigaction *ka,
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sigset_t *set, struct pt_regs * regs);
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asmlinkage long
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sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
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struct pt_regs *regs)
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{
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return do_sigaltstack(uss, uoss, regs->sp);
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}
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/*
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* Do a signal return; undo the signal stack.
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*/
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struct rt_sigframe
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{
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char __user *pretcode;
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struct ucontext uc;
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struct siginfo info;
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};
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static int
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restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, unsigned long *prax)
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{
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unsigned int err = 0;
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/* Always make any pending restarted system calls return -EINTR */
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current_thread_info()->restart_block.fn = do_no_restart_syscall;
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#define COPY(x) err |= __get_user(regs->x, &sc->x)
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COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
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COPY(dx); COPY(cx); COPY(ip);
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COPY(r8);
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COPY(r9);
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COPY(r10);
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COPY(r11);
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COPY(r12);
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COPY(r13);
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COPY(r14);
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COPY(r15);
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/* Kernel saves and restores only the CS segment register on signals,
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* which is the bare minimum needed to allow mixed 32/64-bit code.
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* App's signal handler can save/restore other segments if needed. */
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{
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unsigned cs;
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err |= __get_user(cs, &sc->cs);
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regs->cs = cs | 3; /* Force into user mode */
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}
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{
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unsigned int tmpflags;
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err |= __get_user(tmpflags, &sc->flags);
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regs->flags = (regs->flags & ~0x40DD5) | (tmpflags & 0x40DD5);
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regs->orig_ax = -1; /* disable syscall checks */
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}
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{
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struct _fpstate __user * buf;
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err |= __get_user(buf, &sc->fpstate);
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if (buf) {
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if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
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goto badframe;
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err |= restore_i387(buf);
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} else {
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struct task_struct *me = current;
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if (used_math()) {
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clear_fpu(me);
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clear_used_math();
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}
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}
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}
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err |= __get_user(*prax, &sc->ax);
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return err;
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badframe:
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return 1;
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}
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asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
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{
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struct rt_sigframe __user *frame;
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sigset_t set;
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unsigned long ax;
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frame = (struct rt_sigframe __user *)(regs->sp - 8);
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if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) {
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goto badframe;
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}
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if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) {
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goto badframe;
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}
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sigdelsetmask(&set, ~_BLOCKABLE);
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spin_lock_irq(¤t->sighand->siglock);
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current->blocked = set;
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recalc_sigpending();
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spin_unlock_irq(¤t->sighand->siglock);
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if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
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goto badframe;
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#ifdef DEBUG_SIG
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printk("%d sigreturn ip:%lx sp:%lx frame:%p ax:%lx\n",current->pid,regs->ip,regs->sp,frame,ax);
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#endif
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if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
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goto badframe;
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return ax;
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badframe:
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signal_fault(regs,frame,"sigreturn");
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return 0;
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}
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/*
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* Set up a signal frame.
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*/
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static inline int
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setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned long mask, struct task_struct *me)
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{
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int err = 0;
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err |= __put_user(regs->cs, &sc->cs);
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err |= __put_user(0, &sc->gs);
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err |= __put_user(0, &sc->fs);
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err |= __put_user(regs->di, &sc->di);
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err |= __put_user(regs->si, &sc->si);
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err |= __put_user(regs->bp, &sc->bp);
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err |= __put_user(regs->sp, &sc->sp);
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err |= __put_user(regs->bx, &sc->bx);
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err |= __put_user(regs->dx, &sc->dx);
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err |= __put_user(regs->cx, &sc->cx);
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err |= __put_user(regs->ax, &sc->ax);
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err |= __put_user(regs->r8, &sc->r8);
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err |= __put_user(regs->r9, &sc->r9);
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err |= __put_user(regs->r10, &sc->r10);
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err |= __put_user(regs->r11, &sc->r11);
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err |= __put_user(regs->r12, &sc->r12);
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err |= __put_user(regs->r13, &sc->r13);
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err |= __put_user(regs->r14, &sc->r14);
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err |= __put_user(regs->r15, &sc->r15);
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err |= __put_user(me->thread.trap_no, &sc->trapno);
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err |= __put_user(me->thread.error_code, &sc->err);
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err |= __put_user(regs->ip, &sc->ip);
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err |= __put_user(regs->flags, &sc->flags);
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err |= __put_user(mask, &sc->oldmask);
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err |= __put_user(me->thread.cr2, &sc->cr2);
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return err;
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}
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/*
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* Determine which stack to use..
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*/
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static void __user *
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get_stack(struct k_sigaction *ka, struct pt_regs *regs, unsigned long size)
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{
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unsigned long sp;
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/* Default to using normal stack - redzone*/
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sp = regs->sp - 128;
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/* This is the X/Open sanctioned signal stack switching. */
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if (ka->sa.sa_flags & SA_ONSTACK) {
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if (sas_ss_flags(sp) == 0)
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sp = current->sas_ss_sp + current->sas_ss_size;
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}
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return (void __user *)round_down(sp - size, 16);
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}
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static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
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sigset_t *set, struct pt_regs * regs)
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{
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struct rt_sigframe __user *frame;
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struct _fpstate __user *fp = NULL;
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int err = 0;
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struct task_struct *me = current;
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if (used_math()) {
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fp = get_stack(ka, regs, sizeof(struct _fpstate));
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frame = (void __user *)round_down(
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(unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8;
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if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate)))
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goto give_sigsegv;
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if (save_i387(fp) < 0)
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err |= -1;
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} else
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frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8;
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if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
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goto give_sigsegv;
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if (ka->sa.sa_flags & SA_SIGINFO) {
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err |= copy_siginfo_to_user(&frame->info, info);
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if (err)
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goto give_sigsegv;
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}
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/* Create the ucontext. */
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err |= __put_user(0, &frame->uc.uc_flags);
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err |= __put_user(0, &frame->uc.uc_link);
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err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
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err |= __put_user(sas_ss_flags(regs->sp),
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&frame->uc.uc_stack.ss_flags);
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err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
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err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0], me);
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err |= __put_user(fp, &frame->uc.uc_mcontext.fpstate);
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if (sizeof(*set) == 16) {
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__put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
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__put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
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} else
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err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
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/* Set up to return from userspace. If provided, use a stub
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already in userspace. */
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/* x86-64 should always use SA_RESTORER. */
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if (ka->sa.sa_flags & SA_RESTORER) {
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err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
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} else {
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/* could use a vstub here */
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goto give_sigsegv;
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}
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if (err)
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goto give_sigsegv;
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#ifdef DEBUG_SIG
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printk("%d old ip %lx old sp %lx old ax %lx\n", current->pid,regs->ip,regs->sp,regs->ax);
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#endif
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/* Set up registers for signal handler */
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regs->di = sig;
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/* In case the signal handler was declared without prototypes */
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regs->ax = 0;
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/* This also works for non SA_SIGINFO handlers because they expect the
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next argument after the signal number on the stack. */
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regs->si = (unsigned long)&frame->info;
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regs->dx = (unsigned long)&frame->uc;
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regs->ip = (unsigned long) ka->sa.sa_handler;
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regs->sp = (unsigned long)frame;
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/* Set up the CS register to run signal handlers in 64-bit mode,
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even if the handler happens to be interrupting 32-bit code. */
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regs->cs = __USER_CS;
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/* This, by contrast, has nothing to do with segment registers -
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see include/asm-x86_64/uaccess.h for details. */
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set_fs(USER_DS);
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regs->flags &= ~TF_MASK;
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if (test_thread_flag(TIF_SINGLESTEP))
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ptrace_notify(SIGTRAP);
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#ifdef DEBUG_SIG
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printk("SIG deliver (%s:%d): sp=%p pc=%lx ra=%p\n",
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current->comm, current->pid, frame, regs->ip, frame->pretcode);
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#endif
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return 0;
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give_sigsegv:
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force_sigsegv(sig, current);
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return -EFAULT;
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}
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/*
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* OK, we're invoking a handler
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*/
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static int
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handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
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sigset_t *oldset, struct pt_regs *regs)
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{
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int ret;
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#ifdef DEBUG_SIG
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printk("handle_signal pid:%d sig:%lu ip:%lx sp:%lx regs=%p\n",
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current->pid, sig,
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regs->ip, regs->sp, regs);
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#endif
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/* Are we from a system call? */
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if ((long)regs->orig_ax >= 0) {
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/* If so, check system call restarting.. */
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switch (regs->ax) {
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case -ERESTART_RESTARTBLOCK:
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case -ERESTARTNOHAND:
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regs->ax = -EINTR;
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break;
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case -ERESTARTSYS:
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if (!(ka->sa.sa_flags & SA_RESTART)) {
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regs->ax = -EINTR;
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break;
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}
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/* fallthrough */
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case -ERESTARTNOINTR:
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regs->ax = regs->orig_ax;
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regs->ip -= 2;
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break;
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}
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}
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/*
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* If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
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* flag so that register information in the sigcontext is correct.
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*/
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if (unlikely(regs->flags & X86_EFLAGS_TF) &&
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likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
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regs->flags &= ~X86_EFLAGS_TF;
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#ifdef CONFIG_IA32_EMULATION
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if (test_thread_flag(TIF_IA32)) {
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if (ka->sa.sa_flags & SA_SIGINFO)
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ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs);
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else
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ret = ia32_setup_frame(sig, ka, oldset, regs);
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} else
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#endif
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ret = setup_rt_frame(sig, ka, info, oldset, regs);
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if (ret == 0) {
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spin_lock_irq(¤t->sighand->siglock);
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sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask);
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if (!(ka->sa.sa_flags & SA_NODEFER))
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sigaddset(¤t->blocked,sig);
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recalc_sigpending();
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spin_unlock_irq(¤t->sighand->siglock);
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}
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return ret;
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}
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/*
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* Note that 'init' is a special process: it doesn't get signals it doesn't
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* want to handle. Thus you cannot kill init even with a SIGKILL even by
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* mistake.
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*/
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static void do_signal(struct pt_regs *regs)
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{
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struct k_sigaction ka;
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siginfo_t info;
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int signr;
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sigset_t *oldset;
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/*
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* We want the common case to go fast, which
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* is why we may in certain cases get here from
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* kernel mode. Just return without doing anything
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* if so.
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*/
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if (!user_mode(regs))
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return;
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if (test_thread_flag(TIF_RESTORE_SIGMASK))
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oldset = ¤t->saved_sigmask;
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else
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oldset = ¤t->blocked;
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signr = get_signal_to_deliver(&info, &ka, regs, NULL);
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if (signr > 0) {
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/* Re-enable any watchpoints before delivering the
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* signal to user space. The processor register will
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* have been cleared if the watchpoint triggered
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* inside the kernel.
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*/
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if (current->thread.debugreg7)
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set_debugreg(current->thread.debugreg7, 7);
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/* Whee! Actually deliver the signal. */
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if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
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/* a signal was successfully delivered; the saved
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* sigmask will have been stored in the signal frame,
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* and will be restored by sigreturn, so we can simply
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* clear the TIF_RESTORE_SIGMASK flag */
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clear_thread_flag(TIF_RESTORE_SIGMASK);
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}
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return;
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}
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/* Did we come from a system call? */
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if ((long)regs->orig_ax >= 0) {
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/* Restart the system call - no handlers present */
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long res = regs->ax;
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switch (res) {
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case -ERESTARTNOHAND:
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case -ERESTARTSYS:
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case -ERESTARTNOINTR:
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regs->ax = regs->orig_ax;
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regs->ip -= 2;
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break;
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case -ERESTART_RESTARTBLOCK:
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regs->ax = test_thread_flag(TIF_IA32) ?
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__NR_ia32_restart_syscall :
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__NR_restart_syscall;
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regs->ip -= 2;
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break;
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}
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}
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/* if there's no signal to deliver, we just put the saved sigmask
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back. */
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if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
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clear_thread_flag(TIF_RESTORE_SIGMASK);
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sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
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}
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}
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void
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do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
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{
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#ifdef DEBUG_SIG
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printk("do_notify_resume flags:%x ip:%lx sp:%lx caller:%p pending:%x\n",
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thread_info_flags, regs->ip, regs->sp, __builtin_return_address(0),signal_pending(current));
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#endif
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/* Pending single-step? */
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if (thread_info_flags & _TIF_SINGLESTEP) {
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regs->flags |= TF_MASK;
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clear_thread_flag(TIF_SINGLESTEP);
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}
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#ifdef CONFIG_X86_MCE
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/* notify userspace of pending MCEs */
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if (thread_info_flags & _TIF_MCE_NOTIFY)
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mce_notify_user();
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#endif /* CONFIG_X86_MCE */
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/* deal with pending signal delivery */
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if (thread_info_flags & (_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK))
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do_signal(regs);
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if (thread_info_flags & _TIF_HRTICK_RESCHED)
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hrtick_resched();
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}
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void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
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{
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struct task_struct *me = current;
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if (show_unhandled_signals && printk_ratelimit())
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printk("%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx\n",
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me->comm,me->pid,where,frame,regs->ip,regs->sp,regs->orig_ax);
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force_sig(SIGSEGV, me);
|
|
}
|