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-rw-r--r--arch/i386/kernel/signal.c665
1 files changed, 665 insertions, 0 deletions
diff --git a/arch/i386/kernel/signal.c b/arch/i386/kernel/signal.c
new file mode 100644
index 000000000000..ef3602e1c052
--- /dev/null
+++ b/arch/i386/kernel/signal.c
@@ -0,0 +1,665 @@
+/*
+ * linux/arch/i386/kernel/signal.c
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
+ * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
+ */
+
+#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/unistd.h>
+#include <linux/stddef.h>
+#include <linux/personality.h>
+#include <linux/suspend.h>
+#include <linux/ptrace.h>
+#include <linux/elf.h>
+#include <asm/processor.h>
+#include <asm/ucontext.h>
+#include <asm/uaccess.h>
+#include <asm/i387.h>
+#include "sigframe.h"
+
+#define DEBUG_SIG 0
+
+#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
+
+/*
+ * Atomically swap in the new signal mask, and wait for a signal.
+ */
+asmlinkage int
+sys_sigsuspend(int history0, int history1, old_sigset_t mask)
+{
+ struct pt_regs * regs = (struct pt_regs *) &history0;
+ sigset_t saveset;
+
+ mask &= _BLOCKABLE;
+ spin_lock_irq(&current->sighand->siglock);
+ saveset = current->blocked;
+ siginitset(&current->blocked, mask);
+ recalc_sigpending();
+ spin_unlock_irq(&current->sighand->siglock);
+
+ regs->eax = -EINTR;
+ while (1) {
+ current->state = TASK_INTERRUPTIBLE;
+ schedule();
+ if (do_signal(regs, &saveset))
+ return -EINTR;
+ }
+}
+
+asmlinkage int
+sys_rt_sigsuspend(struct pt_regs regs)
+{
+ sigset_t saveset, newset;
+
+ /* XXX: Don't preclude handling different sized sigset_t's. */
+ if (regs.ecx != sizeof(sigset_t))
+ return -EINVAL;
+
+ if (copy_from_user(&newset, (sigset_t __user *)regs.ebx, sizeof(newset)))
+ return -EFAULT;
+ sigdelsetmask(&newset, ~_BLOCKABLE);
+
+ spin_lock_irq(&current->sighand->siglock);
+ saveset = current->blocked;
+ current->blocked = newset;
+ recalc_sigpending();
+ spin_unlock_irq(&current->sighand->siglock);
+
+ regs.eax = -EINTR;
+ while (1) {
+ current->state = TASK_INTERRUPTIBLE;
+ schedule();
+ if (do_signal(&regs, &saveset))
+ return -EINTR;
+ }
+}
+
+asmlinkage int
+sys_sigaction(int sig, const struct old_sigaction __user *act,
+ struct old_sigaction __user *oact)
+{
+ struct k_sigaction new_ka, old_ka;
+ int ret;
+
+ if (act) {
+ old_sigset_t mask;
+ if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
+ __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
+ __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
+ return -EFAULT;
+ __get_user(new_ka.sa.sa_flags, &act->sa_flags);
+ __get_user(mask, &act->sa_mask);
+ siginitset(&new_ka.sa.sa_mask, mask);
+ }
+
+ ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
+
+ if (!ret && oact) {
+ if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
+ __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
+ __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
+ return -EFAULT;
+ __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
+ __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
+ }
+
+ return ret;
+}
+
+asmlinkage int
+sys_sigaltstack(unsigned long ebx)
+{
+ /* This is needed to make gcc realize it doesn't own the "struct pt_regs" */
+ struct pt_regs *regs = (struct pt_regs *)&ebx;
+ const stack_t __user *uss = (const stack_t __user *)ebx;
+ stack_t __user *uoss = (stack_t __user *)regs->ecx;
+
+ return do_sigaltstack(uss, uoss, regs->esp);
+}
+
+
+/*
+ * Do a signal return; undo the signal stack.
+ */
+
+static int
+restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *peax)
+{
+ 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)
+
+#define COPY_SEG(seg) \
+ { unsigned short tmp; \
+ err |= __get_user(tmp, &sc->seg); \
+ regs->x##seg = tmp; }
+
+#define COPY_SEG_STRICT(seg) \
+ { unsigned short tmp; \
+ err |= __get_user(tmp, &sc->seg); \
+ regs->x##seg = tmp|3; }
+
+#define GET_SEG(seg) \
+ { unsigned short tmp; \
+ err |= __get_user(tmp, &sc->seg); \
+ loadsegment(seg,tmp); }
+
+#define FIX_EFLAGS (X86_EFLAGS_AC | X86_EFLAGS_OF | X86_EFLAGS_DF | \
+ X86_EFLAGS_TF | X86_EFLAGS_SF | X86_EFLAGS_ZF | \
+ X86_EFLAGS_AF | X86_EFLAGS_PF | X86_EFLAGS_CF)
+
+ GET_SEG(gs);
+ GET_SEG(fs);
+ COPY_SEG(es);
+ COPY_SEG(ds);
+ COPY(edi);
+ COPY(esi);
+ COPY(ebp);
+ COPY(esp);
+ COPY(ebx);
+ COPY(edx);
+ COPY(ecx);
+ COPY(eip);
+ COPY_SEG_STRICT(cs);
+ COPY_SEG_STRICT(ss);
+
+ {
+ unsigned int tmpflags;
+ err |= __get_user(tmpflags, &sc->eflags);
+ regs->eflags = (regs->eflags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
+ regs->orig_eax = -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(*peax, &sc->eax);
+ return err;
+
+badframe:
+ return 1;
+}
+
+asmlinkage int sys_sigreturn(unsigned long __unused)
+{
+ struct pt_regs *regs = (struct pt_regs *) &__unused;
+ struct sigframe __user *frame = (struct sigframe __user *)(regs->esp - 8);
+ sigset_t set;
+ int eax;
+
+ if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
+ goto badframe;
+ if (__get_user(set.sig[0], &frame->sc.oldmask)
+ || (_NSIG_WORDS > 1
+ && __copy_from_user(&set.sig[1], &frame->extramask,
+ sizeof(frame->extramask))))
+ goto badframe;
+
+ sigdelsetmask(&set, ~_BLOCKABLE);
+ spin_lock_irq(&current->sighand->siglock);
+ current->blocked = set;
+ recalc_sigpending();
+ spin_unlock_irq(&current->sighand->siglock);
+
+ if (restore_sigcontext(regs, &frame->sc, &eax))
+ goto badframe;
+ return eax;
+
+badframe:
+ force_sig(SIGSEGV, current);
+ return 0;
+}
+
+asmlinkage int sys_rt_sigreturn(unsigned long __unused)
+{
+ struct pt_regs *regs = (struct pt_regs *) &__unused;
+ struct rt_sigframe __user *frame = (struct rt_sigframe __user *)(regs->esp - 4);
+ sigset_t set;
+ int eax;
+
+ 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(&current->sighand->siglock);
+ current->blocked = set;
+ recalc_sigpending();
+ spin_unlock_irq(&current->sighand->siglock);
+
+ if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &eax))
+ goto badframe;
+
+ if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->esp) == -EFAULT)
+ goto badframe;
+
+ return eax;
+
+badframe:
+ force_sig(SIGSEGV, current);
+ return 0;
+}
+
+/*
+ * Set up a signal frame.
+ */
+
+static int
+setup_sigcontext(struct sigcontext __user *sc, struct _fpstate __user *fpstate,
+ struct pt_regs *regs, unsigned long mask)
+{
+ int tmp, err = 0;
+
+ tmp = 0;
+ __asm__("movl %%gs,%0" : "=r"(tmp): "0"(tmp));
+ err |= __put_user(tmp, (unsigned int __user *)&sc->gs);
+ __asm__("movl %%fs,%0" : "=r"(tmp): "0"(tmp));
+ err |= __put_user(tmp, (unsigned int __user *)&sc->fs);
+
+ err |= __put_user(regs->xes, (unsigned int __user *)&sc->es);
+ err |= __put_user(regs->xds, (unsigned int __user *)&sc->ds);
+ err |= __put_user(regs->edi, &sc->edi);
+ err |= __put_user(regs->esi, &sc->esi);
+ err |= __put_user(regs->ebp, &sc->ebp);
+ err |= __put_user(regs->esp, &sc->esp);
+ err |= __put_user(regs->ebx, &sc->ebx);
+ err |= __put_user(regs->edx, &sc->edx);
+ err |= __put_user(regs->ecx, &sc->ecx);
+ err |= __put_user(regs->eax, &sc->eax);
+ err |= __put_user(current->thread.trap_no, &sc->trapno);
+ err |= __put_user(current->thread.error_code, &sc->err);
+ err |= __put_user(regs->eip, &sc->eip);
+ err |= __put_user(regs->xcs, (unsigned int __user *)&sc->cs);
+ err |= __put_user(regs->eflags, &sc->eflags);
+ err |= __put_user(regs->esp, &sc->esp_at_signal);
+ err |= __put_user(regs->xss, (unsigned int __user *)&sc->ss);
+
+ tmp = save_i387(fpstate);
+ if (tmp < 0)
+ err = 1;
+ else
+ err |= __put_user(tmp ? fpstate : NULL, &sc->fpstate);
+
+ /* non-iBCS2 extensions.. */
+ err |= __put_user(mask, &sc->oldmask);
+ err |= __put_user(current->thread.cr2, &sc->cr2);
+
+ return err;
+}
+
+/*
+ * Determine which stack to use..
+ */
+static inline void __user *
+get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
+{
+ unsigned long esp;
+
+ /* Default to using normal stack */
+ esp = regs->esp;
+
+ /* This is the X/Open sanctioned signal stack switching. */
+ if (ka->sa.sa_flags & SA_ONSTACK) {
+ if (sas_ss_flags(esp) == 0)
+ esp = current->sas_ss_sp + current->sas_ss_size;
+ }
+
+ /* This is the legacy signal stack switching. */
+ else if ((regs->xss & 0xffff) != __USER_DS &&
+ !(ka->sa.sa_flags & SA_RESTORER) &&
+ ka->sa.sa_restorer) {
+ esp = (unsigned long) ka->sa.sa_restorer;
+ }
+
+ return (void __user *)((esp - frame_size) & -8ul);
+}
+
+/* These symbols are defined with the addresses in the vsyscall page.
+ See vsyscall-sigreturn.S. */
+extern void __user __kernel_sigreturn;
+extern void __user __kernel_rt_sigreturn;
+
+static void setup_frame(int sig, struct k_sigaction *ka,
+ sigset_t *set, struct pt_regs * regs)
+{
+ void __user *restorer;
+ struct sigframe __user *frame;
+ int err = 0;
+ int usig;
+
+ frame = get_sigframe(ka, regs, sizeof(*frame));
+
+ if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+ goto give_sigsegv;
+
+ usig = current_thread_info()->exec_domain
+ && current_thread_info()->exec_domain->signal_invmap
+ && sig < 32
+ ? current_thread_info()->exec_domain->signal_invmap[sig]
+ : sig;
+
+ err = __put_user(usig, &frame->sig);
+ if (err)
+ goto give_sigsegv;
+
+ err = setup_sigcontext(&frame->sc, &frame->fpstate, regs, set->sig[0]);
+ if (err)
+ goto give_sigsegv;
+
+ if (_NSIG_WORDS > 1) {
+ err = __copy_to_user(&frame->extramask, &set->sig[1],
+ sizeof(frame->extramask));
+ if (err)
+ goto give_sigsegv;
+ }
+
+ restorer = &__kernel_sigreturn;
+ if (ka->sa.sa_flags & SA_RESTORER)
+ restorer = ka->sa.sa_restorer;
+
+ /* Set up to return from userspace. */
+ err |= __put_user(restorer, &frame->pretcode);
+
+ /*
+ * This is popl %eax ; movl $,%eax ; int $0x80
+ *
+ * WE DO NOT USE IT ANY MORE! It's only left here for historical
+ * reasons and because gdb uses it as a signature to notice
+ * signal handler stack frames.
+ */
+ err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
+ err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
+ err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
+
+ if (err)
+ goto give_sigsegv;
+
+ /* Set up registers for signal handler */
+ regs->esp = (unsigned long) frame;
+ regs->eip = (unsigned long) ka->sa.sa_handler;
+ regs->eax = (unsigned long) sig;
+ regs->edx = (unsigned long) 0;
+ regs->ecx = (unsigned long) 0;
+
+ set_fs(USER_DS);
+ regs->xds = __USER_DS;
+ regs->xes = __USER_DS;
+ regs->xss = __USER_DS;
+ regs->xcs = __USER_CS;
+
+ /*
+ * Clear TF when entering the signal handler, but
+ * notify any tracer that was single-stepping it.
+ * The tracer may want to single-step inside the
+ * handler too.
+ */
+ regs->eflags &= ~TF_MASK;
+ if (test_thread_flag(TIF_SINGLESTEP))
+ ptrace_notify(SIGTRAP);
+
+#if DEBUG_SIG
+ printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
+ current->comm, current->pid, frame, regs->eip, frame->pretcode);
+#endif
+
+ return;
+
+give_sigsegv:
+ force_sigsegv(sig, current);
+}
+
+static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
+ sigset_t *set, struct pt_regs * regs)
+{
+ void __user *restorer;
+ struct rt_sigframe __user *frame;
+ int err = 0;
+ int usig;
+
+ frame = get_sigframe(ka, regs, sizeof(*frame));
+
+ if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+ goto give_sigsegv;
+
+ usig = current_thread_info()->exec_domain
+ && current_thread_info()->exec_domain->signal_invmap
+ && sig < 32
+ ? current_thread_info()->exec_domain->signal_invmap[sig]
+ : sig;
+
+ err |= __put_user(usig, &frame->sig);
+ err |= __put_user(&frame->info, &frame->pinfo);
+ err |= __put_user(&frame->uc, &frame->puc);
+ 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->esp),
+ &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, &frame->fpstate,
+ regs, set->sig[0]);
+ err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+ if (err)
+ goto give_sigsegv;
+
+ /* Set up to return from userspace. */
+ restorer = &__kernel_rt_sigreturn;
+ if (ka->sa.sa_flags & SA_RESTORER)
+ restorer = ka->sa.sa_restorer;
+ err |= __put_user(restorer, &frame->pretcode);
+
+ /*
+ * This is movl $,%eax ; int $0x80
+ *
+ * WE DO NOT USE IT ANY MORE! It's only left here for historical
+ * reasons and because gdb uses it as a signature to notice
+ * signal handler stack frames.
+ */
+ err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
+ err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
+ err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
+
+ if (err)
+ goto give_sigsegv;
+
+ /* Set up registers for signal handler */
+ regs->esp = (unsigned long) frame;
+ regs->eip = (unsigned long) ka->sa.sa_handler;
+ regs->eax = (unsigned long) usig;
+ regs->edx = (unsigned long) &frame->info;
+ regs->ecx = (unsigned long) &frame->uc;
+
+ set_fs(USER_DS);
+ regs->xds = __USER_DS;
+ regs->xes = __USER_DS;
+ regs->xss = __USER_DS;
+ regs->xcs = __USER_CS;
+
+ /*
+ * Clear TF when entering the signal handler, but
+ * notify any tracer that was single-stepping it.
+ * The tracer may want to single-step inside the
+ * handler too.
+ */
+ regs->eflags &= ~TF_MASK;
+ if (test_thread_flag(TIF_SINGLESTEP))
+ ptrace_notify(SIGTRAP);
+
+#if DEBUG_SIG
+ printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
+ current->comm, current->pid, frame, regs->eip, frame->pretcode);
+#endif
+
+ return;
+
+give_sigsegv:
+ force_sigsegv(sig, current);
+}
+
+/*
+ * OK, we're invoking a handler
+ */
+
+static void
+handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
+ sigset_t *oldset, struct pt_regs * regs)
+{
+ /* Are we from a system call? */
+ if (regs->orig_eax >= 0) {
+ /* If so, check system call restarting.. */
+ switch (regs->eax) {
+ case -ERESTART_RESTARTBLOCK:
+ case -ERESTARTNOHAND:
+ regs->eax = -EINTR;
+ break;
+
+ case -ERESTARTSYS:
+ if (!(ka->sa.sa_flags & SA_RESTART)) {
+ regs->eax = -EINTR;
+ break;
+ }
+ /* fallthrough */
+ case -ERESTARTNOINTR:
+ regs->eax = regs->orig_eax;
+ regs->eip -= 2;
+ }
+ }
+
+ /*
+ * 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)
+ && likely(current->ptrace & PT_DTRACE)) {
+ current->ptrace &= ~PT_DTRACE;
+ regs->eflags &= ~TF_MASK;
+ }
+
+ /* Set up the stack frame */
+ if (ka->sa.sa_flags & SA_SIGINFO)
+ setup_rt_frame(sig, ka, info, oldset, regs);
+ else
+ setup_frame(sig, ka, oldset, regs);
+
+ if (!(ka->sa.sa_flags & SA_NODEFER)) {
+ spin_lock_irq(&current->sighand->siglock);
+ sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
+ sigaddset(&current->blocked,sig);
+ recalc_sigpending();
+ spin_unlock_irq(&current->sighand->siglock);
+ }
+}
+
+/*
+ * 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 fastcall do_signal(struct pt_regs *regs, sigset_t *oldset)
+{
+ siginfo_t info;
+ int signr;
+ 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->xcs & 3) != 3)
+ return 1;
+
+ if (current->flags & PF_FREEZE) {
+ refrigerator(0);
+ goto no_signal;
+ }
+
+ if (!oldset)
+ oldset = &current->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 (unlikely(current->thread.debugreg[7])) {
+ __asm__("movl %0,%%db7" : : "r" (current->thread.debugreg[7]));
+ }
+
+ /* Whee! Actually deliver the signal. */
+ handle_signal(signr, &info, &ka, oldset, regs);
+ return 1;
+ }
+
+ no_signal:
+ /* Did we come from a system call? */
+ if (regs->orig_eax >= 0) {
+ /* Restart the system call - no handlers present */
+ if (regs->eax == -ERESTARTNOHAND ||
+ regs->eax == -ERESTARTSYS ||
+ regs->eax == -ERESTARTNOINTR) {
+ regs->eax = regs->orig_eax;
+ regs->eip -= 2;
+ }
+ if (regs->eax == -ERESTART_RESTARTBLOCK){
+ regs->eax = __NR_restart_syscall;
+ regs->eip -= 2;
+ }
+ }
+ return 0;
+}
+
+/*
+ * notification of userspace execution resumption
+ * - triggered by current->work.notify_resume
+ */
+__attribute__((regparm(3)))
+void do_notify_resume(struct pt_regs *regs, sigset_t *oldset,
+ __u32 thread_info_flags)
+{
+ /* Pending single-step? */
+ if (thread_info_flags & _TIF_SINGLESTEP) {
+ regs->eflags |= TF_MASK;
+ clear_thread_flag(TIF_SINGLESTEP);
+ }
+ /* deal with pending signal delivery */
+ if (thread_info_flags & _TIF_SIGPENDING)
+ do_signal(regs,oldset);
+
+ clear_thread_flag(TIF_IRET);
+}