diff options
Diffstat (limited to 'arch/s390/kernel/signal.c')
| -rw-r--r-- | arch/s390/kernel/signal.c | 522 |
1 files changed, 522 insertions, 0 deletions
diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c new file mode 100644 index 00000000..f7582b27 --- /dev/null +++ b/arch/s390/kernel/signal.c @@ -0,0 +1,522 @@ +/* + * arch/s390/kernel/signal.c + * + * Copyright (C) IBM Corp. 1999,2006 + * Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com) + * + * Based on Intel version + * + * Copyright (C) 1991, 1992 Linus Torvalds + * + * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson + */ + +#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/tty.h> +#include <linux/personality.h> +#include <linux/binfmts.h> +#include <linux/tracehook.h> +#include <linux/syscalls.h> +#include <linux/compat.h> +#include <asm/ucontext.h> +#include <asm/uaccess.h> +#include <asm/lowcore.h> +#include <asm/switch_to.h> +#include "entry.h" + +#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) + + +typedef struct +{ + __u8 callee_used_stack[__SIGNAL_FRAMESIZE]; + struct sigcontext sc; + _sigregs sregs; + int signo; + __u8 retcode[S390_SYSCALL_SIZE]; +} sigframe; + +typedef struct +{ + __u8 callee_used_stack[__SIGNAL_FRAMESIZE]; + __u8 retcode[S390_SYSCALL_SIZE]; + struct siginfo info; + struct ucontext uc; +} rt_sigframe; + +/* + * Atomically swap in the new signal mask, and wait for a signal. + */ +SYSCALL_DEFINE3(sigsuspend, int, history0, int, history1, old_sigset_t, mask) +{ + sigset_t blocked; + + current->saved_sigmask = current->blocked; + mask &= _BLOCKABLE; + siginitset(&blocked, mask); + set_current_blocked(&blocked); + set_current_state(TASK_INTERRUPTIBLE); + schedule(); + set_restore_sigmask(); + return -ERESTARTNOHAND; +} + +SYSCALL_DEFINE3(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) || + __get_user(new_ka.sa.sa_flags, &act->sa_flags) || + __get_user(mask, &act->sa_mask)) + return -EFAULT; + 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) || + __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || + __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) + return -EFAULT; + } + + return ret; +} + +SYSCALL_DEFINE2(sigaltstack, const stack_t __user *, uss, + stack_t __user *, uoss) +{ + struct pt_regs *regs = task_pt_regs(current); + return do_sigaltstack(uss, uoss, regs->gprs[15]); +} + +/* Returns non-zero on fault. */ +static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs) +{ + _sigregs user_sregs; + + save_access_regs(current->thread.acrs); + + /* Copy a 'clean' PSW mask to the user to avoid leaking + information about whether PER is currently on. */ + user_sregs.regs.psw.mask = psw_user_bits | + (regs->psw.mask & PSW_MASK_USER); + user_sregs.regs.psw.addr = regs->psw.addr; + memcpy(&user_sregs.regs.gprs, ®s->gprs, sizeof(sregs->regs.gprs)); + memcpy(&user_sregs.regs.acrs, current->thread.acrs, + sizeof(sregs->regs.acrs)); + /* + * We have to store the fp registers to current->thread.fp_regs + * to merge them with the emulated registers. + */ + save_fp_regs(¤t->thread.fp_regs); + memcpy(&user_sregs.fpregs, ¤t->thread.fp_regs, + sizeof(s390_fp_regs)); + return __copy_to_user(sregs, &user_sregs, sizeof(_sigregs)); +} + +/* Returns positive number on error */ +static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs) +{ + int err; + _sigregs user_sregs; + + /* Alwys make any pending restarted system call return -EINTR */ + current_thread_info()->restart_block.fn = do_no_restart_syscall; + + err = __copy_from_user(&user_sregs, sregs, sizeof(_sigregs)); + if (err) + return err; + /* Use regs->psw.mask instead of psw_user_bits to preserve PER bit. */ + regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) | + (user_sregs.regs.psw.mask & PSW_MASK_USER); + /* Check for invalid amode */ + if (regs->psw.mask & PSW_MASK_EA) + regs->psw.mask |= PSW_MASK_BA; + regs->psw.addr = user_sregs.regs.psw.addr; + memcpy(®s->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs)); + memcpy(¤t->thread.acrs, &user_sregs.regs.acrs, + sizeof(sregs->regs.acrs)); + restore_access_regs(current->thread.acrs); + + memcpy(¤t->thread.fp_regs, &user_sregs.fpregs, + sizeof(s390_fp_regs)); + current->thread.fp_regs.fpc &= FPC_VALID_MASK; + + restore_fp_regs(¤t->thread.fp_regs); + clear_thread_flag(TIF_SYSCALL); /* No longer in a system call */ + return 0; +} + +SYSCALL_DEFINE0(sigreturn) +{ + struct pt_regs *regs = task_pt_regs(current); + sigframe __user *frame = (sigframe __user *)regs->gprs[15]; + sigset_t set; + + if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) + goto badframe; + if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE)) + goto badframe; + sigdelsetmask(&set, ~_BLOCKABLE); + set_current_blocked(&set); + if (restore_sigregs(regs, &frame->sregs)) + goto badframe; + return regs->gprs[2]; +badframe: + force_sig(SIGSEGV, current); + return 0; +} + +SYSCALL_DEFINE0(rt_sigreturn) +{ + struct pt_regs *regs = task_pt_regs(current); + rt_sigframe __user *frame = (rt_sigframe __user *)regs->gprs[15]; + sigset_t set; + + if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) + goto badframe; + if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set))) + goto badframe; + sigdelsetmask(&set, ~_BLOCKABLE); + set_current_blocked(&set); + if (restore_sigregs(regs, &frame->uc.uc_mcontext)) + goto badframe; + if (do_sigaltstack(&frame->uc.uc_stack, NULL, + regs->gprs[15]) == -EFAULT) + goto badframe; + return regs->gprs[2]; +badframe: + force_sig(SIGSEGV, current); + return 0; +} + +/* + * Set up a signal frame. + */ + + +/* + * 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 sp; + + /* Default to using normal stack */ + sp = regs->gprs[15]; + + /* Overflow on alternate signal stack gives SIGSEGV. */ + if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL)) + return (void __user *) -1UL; + + /* This is the X/Open sanctioned signal stack switching. */ + if (ka->sa.sa_flags & SA_ONSTACK) { + if (! sas_ss_flags(sp)) + sp = current->sas_ss_sp + current->sas_ss_size; + } + + /* This is the legacy signal stack switching. */ + else if (!user_mode(regs) && + !(ka->sa.sa_flags & SA_RESTORER) && + ka->sa.sa_restorer) { + sp = (unsigned long) ka->sa.sa_restorer; + } + + return (void __user *)((sp - frame_size) & -8ul); +} + +static inline int map_signal(int sig) +{ + if (current_thread_info()->exec_domain + && current_thread_info()->exec_domain->signal_invmap + && sig < 32) + return current_thread_info()->exec_domain->signal_invmap[sig]; + else + return sig; +} + +static int setup_frame(int sig, struct k_sigaction *ka, + sigset_t *set, struct pt_regs * regs) +{ + sigframe __user *frame; + + frame = get_sigframe(ka, regs, sizeof(sigframe)); + if (!access_ok(VERIFY_WRITE, frame, sizeof(sigframe))) + goto give_sigsegv; + + if (frame == (void __user *) -1UL) + goto give_sigsegv; + + if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE)) + goto give_sigsegv; + + if (save_sigregs(regs, &frame->sregs)) + goto give_sigsegv; + if (__put_user(&frame->sregs, &frame->sc.sregs)) + goto give_sigsegv; + + /* Set up to return from userspace. If provided, use a stub + already in userspace. */ + if (ka->sa.sa_flags & SA_RESTORER) { + regs->gprs[14] = (unsigned long) + ka->sa.sa_restorer | PSW_ADDR_AMODE; + } else { + regs->gprs[14] = (unsigned long) + frame->retcode | PSW_ADDR_AMODE; + if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn, + (u16 __user *)(frame->retcode))) + goto give_sigsegv; + } + + /* Set up backchain. */ + if (__put_user(regs->gprs[15], (addr_t __user *) frame)) + goto give_sigsegv; + + /* Set up registers for signal handler */ + regs->gprs[15] = (unsigned long) frame; + regs->psw.mask |= PSW_MASK_EA | PSW_MASK_BA; /* 64 bit amode */ + regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE; + + regs->gprs[2] = map_signal(sig); + regs->gprs[3] = (unsigned long) &frame->sc; + + /* We forgot to include these in the sigcontext. + To avoid breaking binary compatibility, they are passed as args. */ + if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL || + sig == SIGTRAP || sig == SIGFPE) { + /* set extra registers only for synchronous signals */ + regs->gprs[4] = regs->int_code & 127; + regs->gprs[5] = regs->int_parm_long; + regs->gprs[6] = task_thread_info(current)->last_break; + } + + /* Place signal number on stack to allow backtrace from handler. */ + if (__put_user(regs->gprs[2], (int __user *) &frame->signo)) + goto give_sigsegv; + return 0; + +give_sigsegv: + force_sigsegv(sig, current); + return -EFAULT; +} + +static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, + sigset_t *set, struct pt_regs * regs) +{ + int err = 0; + rt_sigframe __user *frame; + + frame = get_sigframe(ka, regs, sizeof(rt_sigframe)); + if (!access_ok(VERIFY_WRITE, frame, sizeof(rt_sigframe))) + goto give_sigsegv; + + if (frame == (void __user *) -1UL) + goto give_sigsegv; + + if (copy_siginfo_to_user(&frame->info, info)) + goto give_sigsegv; + + /* Create the ucontext. */ + err |= __put_user(0, &frame->uc.uc_flags); + err |= __put_user(NULL, &frame->uc.uc_link); + err |= __put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp); + err |= __put_user(sas_ss_flags(regs->gprs[15]), + &frame->uc.uc_stack.ss_flags); + err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); + err |= save_sigregs(regs, &frame->uc.uc_mcontext); + err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); + if (err) + goto give_sigsegv; + + /* Set up to return from userspace. If provided, use a stub + already in userspace. */ + if (ka->sa.sa_flags & SA_RESTORER) { + regs->gprs[14] = (unsigned long) + ka->sa.sa_restorer | PSW_ADDR_AMODE; + } else { + regs->gprs[14] = (unsigned long) + frame->retcode | PSW_ADDR_AMODE; + if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn, + (u16 __user *)(frame->retcode))) + goto give_sigsegv; + } + + /* Set up backchain. */ + if (__put_user(regs->gprs[15], (addr_t __user *) frame)) + goto give_sigsegv; + + /* Set up registers for signal handler */ + regs->gprs[15] = (unsigned long) frame; + regs->psw.mask |= PSW_MASK_EA | PSW_MASK_BA; /* 64 bit amode */ + regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE; + + regs->gprs[2] = map_signal(sig); + regs->gprs[3] = (unsigned long) &frame->info; + regs->gprs[4] = (unsigned long) &frame->uc; + regs->gprs[5] = task_thread_info(current)->last_break; + return 0; + +give_sigsegv: + force_sigsegv(sig, current); + return -EFAULT; +} + +static int handle_signal(unsigned long sig, struct k_sigaction *ka, + siginfo_t *info, sigset_t *oldset, + struct pt_regs *regs) +{ + int ret; + + /* Set up the stack frame */ + if (ka->sa.sa_flags & SA_SIGINFO) + ret = setup_rt_frame(sig, ka, info, oldset, regs); + else + ret = setup_frame(sig, ka, oldset, regs); + if (ret) + return ret; + block_sigmask(ka, sig); + return 0; +} + +/* + * 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. + * + * Note that we go through the signals twice: once to check the signals that + * the kernel can handle, and then we build all the user-level signal handling + * stack-frames in one go after that. + */ +void do_signal(struct pt_regs *regs) +{ + siginfo_t info; + int signr; + struct k_sigaction ka; + 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; + + /* + * Get signal to deliver. When running under ptrace, at this point + * the debugger may change all our registers, including the system + * call information. + */ + current_thread_info()->system_call = + test_thread_flag(TIF_SYSCALL) ? regs->int_code : 0; + signr = get_signal_to_deliver(&info, &ka, regs, NULL); + + if (signr > 0) { + /* Whee! Actually deliver the signal. */ + if (current_thread_info()->system_call) { + regs->int_code = current_thread_info()->system_call; + /* Check for system call restarting. */ + switch (regs->gprs[2]) { + case -ERESTART_RESTARTBLOCK: + case -ERESTARTNOHAND: + regs->gprs[2] = -EINTR; + break; + case -ERESTARTSYS: + if (!(ka.sa.sa_flags & SA_RESTART)) { + regs->gprs[2] = -EINTR; + break; + } + /* fallthrough */ + case -ERESTARTNOINTR: + regs->gprs[2] = regs->orig_gpr2; + regs->psw.addr = + __rewind_psw(regs->psw, + regs->int_code >> 16); + break; + } + } + /* No longer in a system call */ + clear_thread_flag(TIF_SYSCALL); + + if ((is_compat_task() ? + handle_signal32(signr, &ka, &info, oldset, regs) : + handle_signal(signr, &ka, &info, 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. + */ + if (test_thread_flag(TIF_RESTORE_SIGMASK)) + clear_thread_flag(TIF_RESTORE_SIGMASK); + + /* + * Let tracing know that we've done the handler setup. + */ + tracehook_signal_handler(signr, &info, &ka, regs, + test_thread_flag(TIF_SINGLE_STEP)); + } + return; + } + + /* No handlers present - check for system call restart */ + clear_thread_flag(TIF_SYSCALL); + if (current_thread_info()->system_call) { + regs->int_code = current_thread_info()->system_call; + switch (regs->gprs[2]) { + case -ERESTART_RESTARTBLOCK: + /* Restart with sys_restart_syscall */ + regs->int_code = __NR_restart_syscall; + /* fallthrough */ + case -ERESTARTNOHAND: + case -ERESTARTSYS: + case -ERESTARTNOINTR: + /* Restart system call with magic TIF bit. */ + regs->gprs[2] = regs->orig_gpr2; + set_thread_flag(TIF_SYSCALL); + 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) +{ + clear_thread_flag(TIF_NOTIFY_RESUME); + tracehook_notify_resume(regs); + if (current->replacement_session_keyring) + key_replace_session_keyring(); +} |