patch-2.4.20 linux-2.4.20/arch/x86_64/kernel/signal.c

• 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(&current->sigmask_lock);
+	saveset = current->blocked;
+	current->blocked = newset;
+	recalc_sigpending(current);
+	spin_unlock_irq(&current->sigmask_lock);
+#if DEBUG_SIG
+	printk("rt_sigsuspend savset(%lx) newset(%lx) regs(%p) rip(%lx)\n",
+		saveset, newset, &regs, regs.rip);
+#endif 
+	regs.rax = -EINTR;
+	while (1) {
+		current->state = TASK_INTERRUPTIBLE;
+		schedule();
+		if (do_signal(&regs, &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(&current->sigmask_lock);
+	current->blocked = set;
+	recalc_sigpending(current);
+	spin_unlock_irq(&current->sigmask_lock);
+	
+	if (restore_sigcontext(&regs, &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(&regs, 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(&current->sigmask_lock);
+		sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
+		sigaddset(&current->blocked,sig);
+		recalc_sigpending(current);
+		spin_unlock_irq(&current->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 = &current->blocked;
+
+	for (;;) {
+		unsigned long signr;
+
+		spin_lock_irq(&current->sigmask_lock);
+		signr = dequeue_signal(&current->blocked, &info);
+		spin_unlock_irq(&current->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(&current->blocked, signr)) {
+				send_sig_info(signr, &info, current);
+				continue;
+			}
+		}
+
+		ka = &current->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); 
+}