| /* |
| * 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" |
| |
| /* |
| * Layout of an old-style signal-frame: |
| * ----------------------------------------- |
| * | save area (_SIGNAL_FRAMESIZE) | |
| * ----------------------------------------- |
| * | struct sigcontext | |
| * | oldmask | |
| * | _sigregs * | |
| * ----------------------------------------- |
| * | _sigregs with | |
| * | _s390_regs_common | |
| * | _s390_fp_regs | |
| * ----------------------------------------- |
| * | int signo | |
| * ----------------------------------------- |
| * | _sigregs_ext with | |
| * | gprs_high 64 byte (opt) | |
| * | vxrs_low 128 byte (opt) | |
| * | vxrs_high 256 byte (opt) | |
| * | reserved 128 byte (opt) | |
| * ----------------------------------------- |
| * | __u16 svc_insn | |
| * ----------------------------------------- |
| * The svc_insn entry with the sigreturn system call opcode does not |
| * have a fixed position and moves if gprs_high or vxrs exist. |
| * Future extensions will be added to _sigregs_ext. |
| */ |
| struct sigframe |
| { |
| __u8 callee_used_stack[__SIGNAL_FRAMESIZE]; |
| struct sigcontext sc; |
| _sigregs sregs; |
| int signo; |
| _sigregs_ext sregs_ext; |
| __u16 svc_insn; /* Offset of svc_insn is NOT fixed! */ |
| }; |
| |
| /* |
| * Layout of an rt signal-frame: |
| * ----------------------------------------- |
| * | save area (_SIGNAL_FRAMESIZE) | |
| * ----------------------------------------- |
| * | svc __NR_rt_sigreturn 2 byte | |
| * ----------------------------------------- |
| * | struct siginfo | |
| * ----------------------------------------- |
| * | struct ucontext_extended with | |
| * | unsigned long uc_flags | |
| * | struct ucontext *uc_link | |
| * | stack_t uc_stack | |
| * | _sigregs uc_mcontext with | |
| * | _s390_regs_common | |
| * | _s390_fp_regs | |
| * | sigset_t uc_sigmask | |
| * | _sigregs_ext uc_mcontext_ext | |
| * | gprs_high 64 byte (opt) | |
| * | vxrs_low 128 byte (opt) | |
| * | vxrs_high 256 byte (opt)| |
| * | reserved 128 byte (opt) | |
| * ----------------------------------------- |
| * Future extensions will be added to _sigregs_ext. |
| */ |
| struct rt_sigframe |
| { |
| __u8 callee_used_stack[__SIGNAL_FRAMESIZE]; |
| __u16 svc_insn; |
| struct siginfo info; |
| struct ucontext_extended uc; |
| }; |
| |
| /* Store registers needed to create the signal frame */ |
| static void store_sigregs(void) |
| { |
| save_access_regs(current->thread.acrs); |
| save_fpu_regs(); |
| } |
| |
| /* Load registers after signal return */ |
| static void load_sigregs(void) |
| { |
| restore_access_regs(current->thread.acrs); |
| } |
| |
| /* Returns non-zero on fault. */ |
| static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs) |
| { |
| _sigregs user_sregs; |
| |
| /* 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)); |
| fpregs_store(&user_sregs.fpregs, ¤t->thread.fpu); |
| 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->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; |
| |
| /* Test the floating-point-control word. */ |
| if (test_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 | PSW_MASK_RI)) | |
| (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)); |
| |
| fpregs_load(&user_sregs.fpregs, ¤t->thread.fpu); |
| |
| clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */ |
| return 0; |
| } |
| |
| /* Returns non-zero on fault. */ |
| static int save_sigregs_ext(struct pt_regs *regs, |
| _sigregs_ext __user *sregs_ext) |
| { |
| __u64 vxrs[__NUM_VXRS_LOW]; |
| int i; |
| |
| /* Save vector registers to signal stack */ |
| if (MACHINE_HAS_VX) { |
| for (i = 0; i < __NUM_VXRS_LOW; i++) |
| vxrs[i] = *((__u64 *)(current->thread.fpu.vxrs + i) + 1); |
| if (__copy_to_user(&sregs_ext->vxrs_low, vxrs, |
| sizeof(sregs_ext->vxrs_low)) || |
| __copy_to_user(&sregs_ext->vxrs_high, |
| current->thread.fpu.vxrs + __NUM_VXRS_LOW, |
| sizeof(sregs_ext->vxrs_high))) |
| return -EFAULT; |
| } |
| return 0; |
| } |
| |
| static int restore_sigregs_ext(struct pt_regs *regs, |
| _sigregs_ext __user *sregs_ext) |
| { |
| __u64 vxrs[__NUM_VXRS_LOW]; |
| int i; |
| |
| /* Restore vector registers from signal stack */ |
| if (MACHINE_HAS_VX) { |
| if (__copy_from_user(vxrs, &sregs_ext->vxrs_low, |
| sizeof(sregs_ext->vxrs_low)) || |
| __copy_from_user(current->thread.fpu.vxrs + __NUM_VXRS_LOW, |
| &sregs_ext->vxrs_high, |
| sizeof(sregs_ext->vxrs_high))) |
| return -EFAULT; |
| for (i = 0; i < __NUM_VXRS_LOW; i++) |
| *((__u64 *)(current->thread.fpu.vxrs + i) + 1) = vxrs[i]; |
| } |
| return 0; |
| } |
| |
| SYSCALL_DEFINE0(sigreturn) |
| { |
| struct pt_regs *regs = task_pt_regs(current); |
| struct sigframe __user *frame = |
| (struct 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); |
| save_fpu_regs(); |
| if (restore_sigregs(regs, &frame->sregs)) |
| goto badframe; |
| if (restore_sigregs_ext(regs, &frame->sregs_ext)) |
| goto badframe; |
| load_sigregs(); |
| return regs->gprs[2]; |
| badframe: |
| force_sig(SIGSEGV, current); |
| return 0; |
| } |
| |
| SYSCALL_DEFINE0(rt_sigreturn) |
| { |
| struct pt_regs *regs = task_pt_regs(current); |
| struct rt_sigframe __user *frame = |
| (struct 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_altstack(&frame->uc.uc_stack)) |
| goto badframe; |
| save_fpu_regs(); |
| if (restore_sigregs(regs, &frame->uc.uc_mcontext)) |
| goto badframe; |
| if (restore_sigregs_ext(regs, &frame->uc.uc_mcontext_ext)) |
| goto badframe; |
| load_sigregs(); |
| return regs->gprs[2]; |
| badframe: |
| force_sig(SIGSEGV, current); |
| return 0; |
| } |
| |
| /* |
| * 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 int setup_frame(int sig, struct k_sigaction *ka, |
| sigset_t *set, struct pt_regs * regs) |
| { |
| struct sigframe __user *frame; |
| struct sigcontext sc; |
| unsigned long restorer; |
| size_t frame_size; |
| |
| /* |
| * gprs_high are only present for a 31-bit task running on |
| * a 64-bit kernel (see compat_signal.c) but the space for |
| * gprs_high need to be allocated if vector registers are |
| * included in the signal frame on a 31-bit system. |
| */ |
| frame_size = sizeof(*frame) - sizeof(frame->sregs_ext); |
| if (MACHINE_HAS_VX) |
| frame_size += sizeof(frame->sregs_ext); |
| frame = get_sigframe(ka, regs, frame_size); |
| if (frame == (void __user *) -1UL) |
| return -EFAULT; |
| |
| /* Set up backchain. */ |
| if (__put_user(regs->gprs[15], (addr_t __user *) frame)) |
| return -EFAULT; |
| |
| /* Create struct sigcontext on the signal stack */ |
| memcpy(&sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE); |
| sc.sregs = (_sigregs __user __force *) &frame->sregs; |
| if (__copy_to_user(&frame->sc, &sc, sizeof(frame->sc))) |
| return -EFAULT; |
| |
| /* Store registers needed to create the signal frame */ |
| store_sigregs(); |
| |
| /* Create _sigregs on the signal stack */ |
| if (save_sigregs(regs, &frame->sregs)) |
| return -EFAULT; |
| |
| /* Place signal number on stack to allow backtrace from handler. */ |
| if (__put_user(regs->gprs[2], (int __user *) &frame->signo)) |
| return -EFAULT; |
| |
| /* Create _sigregs_ext on the signal stack */ |
| if (save_sigregs_ext(regs, &frame->sregs_ext)) |
| return -EFAULT; |
| |
| /* Set up to return from userspace. If provided, use a stub |
| already in userspace. */ |
| if (ka->sa.sa_flags & SA_RESTORER) { |
| restorer = (unsigned long) ka->sa.sa_restorer | PSW_ADDR_AMODE; |
| } else { |
| /* Signal frame without vector registers are short ! */ |
| __u16 __user *svc = (void __user *) frame + frame_size - 2; |
| if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn, svc)) |
| return -EFAULT; |
| restorer = (unsigned long) svc | PSW_ADDR_AMODE; |
| } |
| |
| /* Set up registers for signal handler */ |
| regs->gprs[14] = restorer; |
| 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] = 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; |
| } |
| return 0; |
| } |
| |
| static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, |
| struct pt_regs *regs) |
| { |
| struct rt_sigframe __user *frame; |
| unsigned long uc_flags, restorer; |
| size_t frame_size; |
| |
| frame_size = sizeof(struct rt_sigframe) - sizeof(_sigregs_ext); |
| /* |
| * gprs_high are only present for a 31-bit task running on |
| * a 64-bit kernel (see compat_signal.c) but the space for |
| * gprs_high need to be allocated if vector registers are |
| * included in the signal frame on a 31-bit system. |
| */ |
| uc_flags = 0; |
| if (MACHINE_HAS_VX) { |
| frame_size += sizeof(_sigregs_ext); |
| uc_flags |= UC_VXRS; |
| } |
| frame = get_sigframe(&ksig->ka, regs, frame_size); |
| if (frame == (void __user *) -1UL) |
| return -EFAULT; |
| |
| /* Set up backchain. */ |
| if (__put_user(regs->gprs[15], (addr_t __user *) frame)) |
| return -EFAULT; |
| |
| /* Set up to return from userspace. If provided, use a stub |
| already in userspace. */ |
| if (ksig->ka.sa.sa_flags & SA_RESTORER) { |
| restorer = (unsigned long) |
| ksig->ka.sa.sa_restorer | PSW_ADDR_AMODE; |
| } else { |
| __u16 __user *svc = &frame->svc_insn; |
| if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn, svc)) |
| return -EFAULT; |
| restorer = (unsigned long) svc | PSW_ADDR_AMODE; |
| } |
| |
| /* Create siginfo on the signal stack */ |
| if (copy_siginfo_to_user(&frame->info, &ksig->info)) |
| return -EFAULT; |
| |
| /* Store registers needed to create the signal frame */ |
| store_sigregs(); |
| |
| /* Create ucontext on the signal stack. */ |
| if (__put_user(uc_flags, &frame->uc.uc_flags) || |
| __put_user(NULL, &frame->uc.uc_link) || |
| __save_altstack(&frame->uc.uc_stack, regs->gprs[15]) || |
| save_sigregs(regs, &frame->uc.uc_mcontext) || |
| __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)) || |
| save_sigregs_ext(regs, &frame->uc.uc_mcontext_ext)) |
| return -EFAULT; |
| |
| /* Set up registers for signal handler */ |
| regs->gprs[14] = restorer; |
| 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) ksig->ka.sa.sa_handler | PSW_ADDR_AMODE; |
| |
| regs->gprs[2] = ksig->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; |
| } |
| |
| static void handle_signal(struct ksignal *ksig, sigset_t *oldset, |
| struct pt_regs *regs) |
| { |
| int ret; |
| |
| /* Set up the stack frame */ |
| if (ksig->ka.sa.sa_flags & SA_SIGINFO) |
| ret = setup_rt_frame(ksig, oldset, regs); |
| else |
| ret = setup_frame(ksig->sig, &ksig->ka, oldset, regs); |
| |
| signal_setup_done(ret, ksig, 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) |
| { |
| struct ksignal ksig; |
| 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_pt_regs_flag(regs, PIF_SYSCALL) ? regs->int_code : 0; |
| |
| if (get_signal(&ksig)) { |
| /* 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 (!(ksig.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_pt_regs_flag(regs, PIF_SYSCALL); |
| |
| if (is_compat_task()) |
| handle_signal32(&ksig, oldset, regs); |
| else |
| handle_signal(&ksig, oldset, regs); |
| return; |
| } |
| |
| /* No handlers present - check for system call restart */ |
| clear_pt_regs_flag(regs, PIF_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_pt_regs_flag(regs, PIF_SYSCALL); |
| if (test_thread_flag(TIF_SINGLE_STEP)) |
| clear_pt_regs_flag(regs, PIF_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); |
| } |
