| /* |
| * Copyright 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" |
| |
| 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; |
| |
| /* 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 | PSW_MASK_RI)); |
| 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(user_sregs.regs.acrs)); |
| /* |
| * We have to store the fp registers to current->thread.fp_regs |
| * to merge them with the emulated registers. |
| */ |
| save_fp_ctl(¤t->thread.fp_regs.fpc); |
| save_fp_regs(current->thread.fp_regs.fprs); |
| memcpy(&user_sregs.fpregs, ¤t->thread.fp_regs, |
| sizeof(user_sregs.fpregs)); |
| if (__copy_to_user(sregs, &user_sregs, sizeof(_sigregs))) |
| return -EFAULT; |
| return 0; |
| } |
| |
| static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs) |
| { |
| _sigregs user_sregs; |
| |
| /* Alwys make any pending restarted system call return -EINTR */ |
| current_thread_info()->restart_block.fn = do_no_restart_syscall; |
| |
| if (__copy_from_user(&user_sregs, sregs, sizeof(user_sregs))) |
| return -EFAULT; |
| |
| if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW_MASK_RI)) |
| return -EINVAL; |
| |
| /* Loading the floating-point-control word can fail. Do that first. */ |
| if (restore_fp_ctl(&user_sregs.fpregs.fpc)) |
| return -EINVAL; |
| |
| /* 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 | PSW_MASK_RI)); |
| /* Check for invalid user address space control. */ |
| if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME) |
| regs->psw.mask = PSW_ASC_PRIMARY | |
| (regs->psw.mask & ~PSW_MASK_ASC); |
| /* 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(current->thread.acrs)); |
| restore_access_regs(current->thread.acrs); |
| |
| memcpy(¤t->thread.fp_regs, &user_sregs.fpregs, |
| sizeof(current->thread.fp_regs)); |
| |
| restore_fp_regs(current->thread.fp_regs.fprs); |
| 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 (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE)) |
| goto badframe; |
| 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 (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set))) |
| goto badframe; |
| set_current_blocked(&set); |
| if (restore_sigregs(regs, &frame->uc.uc_mcontext)) |
| goto badframe; |
| if (restore_altstack(&frame->uc.uc_stack)) |
| 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; |
| } |
| |
| 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 (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; |
| /* Force default amode and default user address space control. */ |
| regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA | |
| (PSW_USER_BITS & PSW_MASK_ASC) | |
| (regs->psw.mask & ~PSW_MASK_ASC); |
| 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 (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 |= __save_altstack(&frame->uc.uc_stack, regs->gprs[15]); |
| 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; |
| /* Force default amode and default user address space control. */ |
| regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA | |
| (PSW_USER_BITS & PSW_MASK_ASC) | |
| (regs->psw.mask & ~PSW_MASK_ASC); |
| 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 void 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; |
| signal_delivered(sig, info, ka, regs, |
| test_thread_flag(TIF_SINGLE_STEP)); |
| } |
| |
| /* |
| * 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 = sigmask_to_save(); |
| |
| /* |
| * 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); |
| else |
| handle_signal(signr, &ka, &info, oldset, regs); |
| 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); |
| if (test_thread_flag(TIF_SINGLE_STEP)) |
| set_thread_flag(TIF_PER_TRAP); |
| break; |
| } |
| } |
| |
| /* |
| * If there's no signal to deliver, we just put the saved sigmask back. |
| */ |
| restore_saved_sigmask(); |
| } |
| |
| void do_notify_resume(struct pt_regs *regs) |
| { |
| clear_thread_flag(TIF_NOTIFY_RESUME); |
| tracehook_notify_resume(regs); |
| } |