diff options
Diffstat (limited to 'arch/x86_64/kernel/signal.c')
| -rw-r--r-- | arch/x86_64/kernel/signal.c | 486 |
1 files changed, 486 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/signal.c b/arch/x86_64/kernel/signal.c new file mode 100644 index 00000000000..5ace32c6ac5 --- /dev/null +++ b/arch/x86_64/kernel/signal.c @@ -0,0 +1,486 @@ +/* + * 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 + * + * $Id: signal.c,v 1.18 2001/10/17 22:30:37 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/personality.h> +#include <linux/compiler.h> +#include <asm/ucontext.h> +#include <asm/uaccess.h> +#include <asm/i387.h> +#include <asm/proto.h> + +/* #define DEBUG_SIG 1 */ + +#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) + +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); + +asmlinkage long +sys_rt_sigsuspend(sigset_t __user *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->sighand->siglock); + saveset = current->blocked; + current->blocked = newset; + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); +#ifdef 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 __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 *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); + + { + 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; + unsigned long eflags; + + 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); + eflags = regs->eflags; + if (current->ptrace & PT_PTRACED) { + eflags &= ~TF_MASK; + } + err |= __put_user(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. */ + /* RED-PEN: redzone on that stack? */ + 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 void 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 */ + { + struct exec_domain *ed = current_thread_info()->exec_domain; + if (unlikely(ed && ed->signal_invmap && sig < 32)) + sig = ed->signal_invmap[sig]; + } + 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_fs(USER_DS); + if (regs->eflags & TF_MASK) { + if ((current->ptrace & (PT_PTRACED | PT_DTRACE)) == (PT_PTRACED | PT_DTRACE)) { + ptrace_notify(SIGTRAP); + } else { + regs->eflags &= ~TF_MASK; + } + } + +#ifdef 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: + 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) +{ +#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; + } + } + +#ifdef CONFIG_IA32_EMULATION + if (test_thread_flag(TIF_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_NODEFER)) { + spin_lock_irq(¤t->sighand->siglock); + sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask); + sigaddset(¤t->blocked,sig); + recalc_sigpending(); + spin_unlock_irq(¤t->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 do_signal(struct pt_regs *regs, sigset_t *oldset) +{ + struct k_sigaction ka; + siginfo_t info; + int signr; + + /* + * 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 (try_to_freeze(0)) + goto no_signal; + + if (!oldset) + 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) + asm volatile("movq %0,%%db7" : : "r" (current->thread.debugreg7)); + + /* Whee! Actually deliver the signal. */ + handle_signal(signr, &info, &ka, oldset, regs); + return 1; + } + + no_signal: + /* Did we come from a system call? */ + if ((long)regs->orig_rax >= 0) { + /* Restart the system call - no handlers present */ + long res = regs->rax; + if (res == -ERESTARTNOHAND || + res == -ERESTARTSYS || + res == -ERESTARTNOINTR) { + regs->rax = regs->orig_rax; + regs->rip -= 2; + } + if (regs->rax == (unsigned long)-ERESTART_RESTARTBLOCK) { + regs->rax = __NR_restart_syscall; + regs->rip -= 2; + } + } + return 0; +} + +void do_notify_resume(struct pt_regs *regs, sigset_t *oldset, __u32 thread_info_flags) +{ +#ifdef DEBUG_SIG + printk("do_notify_resume flags:%x rip:%lx rsp:%lx caller:%lx pending:%lx\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); + } + + /* deal with pending signal delivery */ + if (thread_info_flags & _TIF_SIGPENDING) + do_signal(regs,oldset); +} + +void signal_fault(struct pt_regs *regs, void __user *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); +} |