| /* |
| * Copyright (C) 2003, Axis Communications AB. |
| */ |
| |
| #include <linux/sched.h> |
| #include <linux/mm.h> |
| #include <linux/slab.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/syscalls.h> |
| #include <linux/vmalloc.h> |
| |
| #include <asm/io.h> |
| #include <asm/processor.h> |
| #include <asm/ucontext.h> |
| #include <asm/uaccess.h> |
| #include <arch/ptrace.h> |
| #include <arch/hwregs/cpu_vect.h> |
| |
| extern unsigned long cris_signal_return_page; |
| |
| /* |
| * A syscall in CRIS is really a "break 13" instruction, which is 2 |
| * bytes. The registers is manipulated so upon return the instruction |
| * will be executed again. |
| * |
| * This relies on that PC points to the instruction after the break call. |
| */ |
| #define RESTART_CRIS_SYS(regs) regs->r10 = regs->orig_r10; regs->erp -= 2; |
| |
| /* Signal frames. */ |
| struct signal_frame { |
| struct sigcontext sc; |
| unsigned long extramask[_NSIG_WORDS - 1]; |
| unsigned char retcode[8]; /* Trampoline code. */ |
| }; |
| |
| struct rt_signal_frame { |
| struct siginfo *pinfo; |
| void *puc; |
| struct siginfo info; |
| struct ucontext uc; |
| unsigned char retcode[8]; /* Trampoline code. */ |
| }; |
| |
| void do_signal(int restart, struct pt_regs *regs); |
| void keep_debug_flags(unsigned long oldccs, unsigned long oldspc, |
| struct pt_regs *regs); |
| |
| static int |
| restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) |
| { |
| unsigned int err = 0; |
| unsigned long old_usp; |
| |
| /* Always make any pending restarted system calls return -EINTR */ |
| current->restart_block.fn = do_no_restart_syscall; |
| |
| /* |
| * Restore the registers from &sc->regs. sc is already checked |
| * for VERIFY_READ since the signal_frame was previously |
| * checked in sys_sigreturn(). |
| */ |
| if (__copy_from_user(regs, sc, sizeof(struct pt_regs))) |
| goto badframe; |
| |
| /* Make that the user-mode flag is set. */ |
| regs->ccs |= (1 << (U_CCS_BITNR + CCS_SHIFT)); |
| |
| /* Don't perform syscall restarting */ |
| regs->exs = -1; |
| |
| /* Restore the old USP. */ |
| err |= __get_user(old_usp, &sc->usp); |
| wrusp(old_usp); |
| |
| return err; |
| |
| badframe: |
| return 1; |
| } |
| |
| asmlinkage int sys_sigreturn(void) |
| { |
| struct pt_regs *regs = current_pt_regs(); |
| sigset_t set; |
| struct signal_frame __user *frame; |
| unsigned long oldspc = regs->spc; |
| unsigned long oldccs = regs->ccs; |
| |
| frame = (struct signal_frame *) rdusp(); |
| |
| /* |
| * Since the signal is stacked on a dword boundary, the frame |
| * should be dword aligned here as well. It it's not, then the |
| * user is trying some funny business. |
| */ |
| if (((long)frame) & 3) |
| goto badframe; |
| |
| 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; |
| |
| set_current_blocked(&set); |
| |
| if (restore_sigcontext(regs, &frame->sc)) |
| goto badframe; |
| |
| keep_debug_flags(oldccs, oldspc, regs); |
| |
| return regs->r10; |
| |
| badframe: |
| force_sig(SIGSEGV, current); |
| return 0; |
| } |
| |
| asmlinkage int sys_rt_sigreturn(void) |
| { |
| struct pt_regs *regs = current_pt_regs(); |
| sigset_t set; |
| struct rt_signal_frame __user *frame; |
| unsigned long oldspc = regs->spc; |
| unsigned long oldccs = regs->ccs; |
| |
| frame = (struct rt_signal_frame *) rdusp(); |
| |
| /* |
| * Since the signal is stacked on a dword boundary, the frame |
| * should be dword aligned here as well. It it's not, then the |
| * user is trying some funny business. |
| */ |
| if (((long)frame) & 3) |
| goto badframe; |
| |
| if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) |
| goto badframe; |
| |
| if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) |
| goto badframe; |
| |
| set_current_blocked(&set); |
| |
| if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) |
| goto badframe; |
| |
| if (restore_altstack(&frame->uc.uc_stack)) |
| goto badframe; |
| |
| keep_debug_flags(oldccs, oldspc, regs); |
| |
| return regs->r10; |
| |
| badframe: |
| force_sig(SIGSEGV, current); |
| return 0; |
| } |
| |
| /* Setup a signal frame. */ |
| static int |
| setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, |
| unsigned long mask) |
| { |
| int err; |
| unsigned long usp; |
| |
| err = 0; |
| usp = rdusp(); |
| |
| /* |
| * Copy the registers. They are located first in sc, so it's |
| * possible to use sc directly. |
| */ |
| err |= __copy_to_user(sc, regs, sizeof(struct pt_regs)); |
| |
| err |= __put_user(mask, &sc->oldmask); |
| err |= __put_user(usp, &sc->usp); |
| |
| return err; |
| } |
| |
| /* Figure out where to put the new signal frame - usually on the stack. */ |
| static inline void __user * |
| get_sigframe(struct ksignal *ksig, size_t frame_size) |
| { |
| unsigned long sp = sigsp(rdusp(), ksig); |
| |
| /* Make sure the frame is dword-aligned. */ |
| sp &= ~3; |
| |
| return (void __user *)(sp - frame_size); |
| } |
| |
| /* Grab and setup a signal frame. |
| * |
| * Basically a lot of state-info is stacked, and arranged for the |
| * user-mode program to return to the kernel using either a trampiline |
| * which performs the syscall sigreturn(), or a provided user-mode |
| * trampoline. |
| */ |
| static int |
| setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs) |
| { |
| int err; |
| unsigned long return_ip; |
| struct signal_frame __user *frame; |
| |
| err = 0; |
| frame = get_sigframe(ksig, sizeof(*frame)); |
| |
| if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) |
| return -EFAULT; |
| |
| err |= setup_sigcontext(&frame->sc, regs, set->sig[0]); |
| |
| if (err) |
| return -EFAULT; |
| |
| if (_NSIG_WORDS > 1) { |
| err |= __copy_to_user(frame->extramask, &set->sig[1], |
| sizeof(frame->extramask)); |
| } |
| |
| if (err) |
| return -EFAULT; |
| |
| /* |
| * Set up to return from user-space. If provided, use a stub |
| * already located in user-space. |
| */ |
| if (ksig->ka.sa.sa_flags & SA_RESTORER) { |
| return_ip = (unsigned long)ksig->ka.sa.sa_restorer; |
| } else { |
| /* Trampoline - the desired return ip is in the signal return page. */ |
| return_ip = cris_signal_return_page; |
| |
| /* |
| * This is movu.w __NR_sigreturn, r9; break 13; |
| * |
| * 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(0x9c5f, (short __user*)(frame->retcode+0)); |
| err |= __put_user(__NR_sigreturn, (short __user*)(frame->retcode+2)); |
| err |= __put_user(0xe93d, (short __user*)(frame->retcode+4)); |
| } |
| |
| if (err) |
| return -EFAULT; |
| |
| /* |
| * Set up registers for signal handler. |
| * |
| * Where the code enters now. |
| * Where the code enter later. |
| * First argument, signo. |
| */ |
| regs->erp = (unsigned long) ksig->ka.sa.sa_handler; |
| regs->srp = return_ip; |
| regs->r10 = ksig->sig; |
| |
| /* Actually move the USP to reflect the stacked frame. */ |
| wrusp((unsigned long)frame); |
| |
| return 0; |
| } |
| |
| static int |
| setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs) |
| { |
| int err; |
| unsigned long return_ip; |
| struct rt_signal_frame __user *frame; |
| |
| err = 0; |
| frame = get_sigframe(ksig, sizeof(*frame)); |
| |
| if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) |
| return -EFAULT; |
| |
| err |= __put_user(&frame->info, &frame->pinfo); |
| err |= __put_user(&frame->uc, &frame->puc); |
| err |= copy_siginfo_to_user(&frame->info, &ksig->info); |
| |
| if (err) |
| return -EFAULT; |
| |
| /* Clear all the bits of the ucontext we don't use. */ |
| err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext)); |
| err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]); |
| err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); |
| err |= __save_altstack(&frame->uc.uc_stack, rdusp()); |
| |
| if (err) |
| return -EFAULT; |
| |
| /* |
| * Set up to return from user-space. If provided, use a stub |
| * already located in user-space. |
| */ |
| if (ksig->ka.sa.sa_flags & SA_RESTORER) { |
| return_ip = (unsigned long) ksig->ka.sa.sa_restorer; |
| } else { |
| /* Trampoline - the desired return ip is in the signal return page. */ |
| return_ip = cris_signal_return_page + 6; |
| |
| /* |
| * This is movu.w __NR_rt_sigreturn, r9; break 13; |
| * |
| * 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(0x9c5f, (short __user*)(frame->retcode+0)); |
| |
| err |= __put_user(__NR_rt_sigreturn, |
| (short __user*)(frame->retcode+2)); |
| |
| err |= __put_user(0xe93d, (short __user*)(frame->retcode+4)); |
| } |
| |
| if (err) |
| return -EFAULT; |
| |
| /* |
| * Set up registers for signal handler. |
| * |
| * Where the code enters now. |
| * Where the code enters later. |
| * First argument is signo. |
| * Second argument is (siginfo_t *). |
| * Third argument is unused. |
| */ |
| regs->erp = (unsigned long) ksig->ka.sa.sa_handler; |
| regs->srp = return_ip; |
| regs->r10 = ksig->sig; |
| regs->r11 = (unsigned long) &frame->info; |
| regs->r12 = 0; |
| |
| /* Actually move the usp to reflect the stacked frame. */ |
| wrusp((unsigned long)frame); |
| |
| return 0; |
| } |
| |
| /* Invoke a signal handler to, well, handle the signal. */ |
| static inline void |
| handle_signal(int canrestart, struct ksignal *ksig, struct pt_regs *regs) |
| { |
| sigset_t *oldset = sigmask_to_save(); |
| int ret; |
| |
| /* Check if this got called from a system call. */ |
| if (canrestart) { |
| /* If so, check system call restarting. */ |
| switch (regs->r10) { |
| case -ERESTART_RESTARTBLOCK: |
| case -ERESTARTNOHAND: |
| /* |
| * This means that the syscall should |
| * only be restarted if there was no |
| * handler for the signal, and since |
| * this point isn't reached unless |
| * there is a handler, there's no need |
| * to restart. |
| */ |
| regs->r10 = -EINTR; |
| break; |
| |
| case -ERESTARTSYS: |
| /* |
| * This means restart the syscall if |
| * there is no handler, or the handler |
| * was registered with SA_RESTART. |
| */ |
| if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { |
| regs->r10 = -EINTR; |
| break; |
| } |
| |
| /* Fall through. */ |
| |
| case -ERESTARTNOINTR: |
| /* |
| * This means that the syscall should |
| * be called again after the signal |
| * handler returns. |
| */ |
| RESTART_CRIS_SYS(regs); |
| break; |
| } |
| } |
| |
| /* 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, oldset, regs); |
| |
| signal_setup_done(ret, ksig, 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. |
| * |
| * Also note that the regs structure given here as an argument, is the latest |
| * pushed pt_regs. It may or may not be the same as the first pushed registers |
| * when the initial usermode->kernelmode transition took place. Therefore |
| * we can use user_mode(regs) to see if we came directly from kernel or user |
| * mode below. |
| */ |
| void |
| do_signal(int canrestart, struct pt_regs *regs) |
| { |
| struct ksignal ksig; |
| |
| canrestart = canrestart && ((int)regs->exs >= 0); |
| |
| /* |
| * The common case should go fast, which is why this point is |
| * reached from kernel-mode. If that's the case, just return |
| * without doing anything. |
| */ |
| if (!user_mode(regs)) |
| return; |
| |
| if (get_signal(&ksig)) { |
| /* Whee! Actually deliver the signal. */ |
| handle_signal(canrestart, &ksig, regs); |
| return; |
| } |
| |
| /* Got here from a system call? */ |
| if (canrestart) { |
| /* Restart the system call - no handlers present. */ |
| if (regs->r10 == -ERESTARTNOHAND || |
| regs->r10 == -ERESTARTSYS || |
| regs->r10 == -ERESTARTNOINTR) { |
| RESTART_CRIS_SYS(regs); |
| } |
| |
| if (regs->r10 == -ERESTART_RESTARTBLOCK){ |
| regs->r9 = __NR_restart_syscall; |
| regs->erp -= 2; |
| } |
| } |
| |
| /* if there's no signal to deliver, we just put the saved sigmask |
| * back */ |
| restore_saved_sigmask(); |
| } |
| |
| asmlinkage void |
| ugdb_trap_user(struct thread_info *ti, int sig) |
| { |
| if (((user_regs(ti)->exs & 0xff00) >> 8) != SINGLE_STEP_INTR_VECT) { |
| /* Zero single-step PC if the reason we stopped wasn't a single |
| step exception. This is to avoid relying on it when it isn't |
| reliable. */ |
| user_regs(ti)->spc = 0; |
| } |
| /* FIXME: Filter out false h/w breakpoint hits (i.e. EDA |
| not within any configured h/w breakpoint range). Synchronize with |
| what already exists for kernel debugging. */ |
| if (((user_regs(ti)->exs & 0xff00) >> 8) == BREAK_8_INTR_VECT) { |
| /* Break 8: subtract 2 from ERP unless in a delay slot. */ |
| if (!(user_regs(ti)->erp & 0x1)) |
| user_regs(ti)->erp -= 2; |
| } |
| sys_kill(ti->task->pid, sig); |
| } |
| |
| void |
| keep_debug_flags(unsigned long oldccs, unsigned long oldspc, |
| struct pt_regs *regs) |
| { |
| if (oldccs & (1 << Q_CCS_BITNR)) { |
| /* Pending single step due to single-stepping the break 13 |
| in the signal trampoline: keep the Q flag. */ |
| regs->ccs |= (1 << Q_CCS_BITNR); |
| /* S flag should be set - complain if it's not. */ |
| if (!(oldccs & (1 << (S_CCS_BITNR + CCS_SHIFT)))) { |
| printk("Q flag but no S flag?"); |
| } |
| regs->ccs |= (1 << (S_CCS_BITNR + CCS_SHIFT)); |
| /* Assume the SPC is valid and interesting. */ |
| regs->spc = oldspc; |
| |
| } else if (oldccs & (1 << (S_CCS_BITNR + CCS_SHIFT))) { |
| /* If a h/w bp was set in the signal handler we need |
| to keep the S flag. */ |
| regs->ccs |= (1 << (S_CCS_BITNR + CCS_SHIFT)); |
| /* Don't keep the old SPC though; if we got here due to |
| a single-step, the Q flag should have been set. */ |
| } else if (regs->spc) { |
| /* If we were single-stepping *before* the signal was taken, |
| we don't want to restore that state now, because GDB will |
| have forgotten all about it. */ |
| regs->spc = 0; |
| regs->ccs &= ~(1 << (S_CCS_BITNR + CCS_SHIFT)); |
| } |
| } |
| |
| /* Set up the trampolines on the signal return page. */ |
| int __init |
| cris_init_signal(void) |
| { |
| u16* data = kmalloc(PAGE_SIZE, GFP_KERNEL); |
| |
| /* This is movu.w __NR_sigreturn, r9; break 13; */ |
| data[0] = 0x9c5f; |
| data[1] = __NR_sigreturn; |
| data[2] = 0xe93d; |
| /* This is movu.w __NR_rt_sigreturn, r9; break 13; */ |
| data[3] = 0x9c5f; |
| data[4] = __NR_rt_sigreturn; |
| data[5] = 0xe93d; |
| |
| /* Map to userspace with appropriate permissions (no write access...) */ |
| cris_signal_return_page = (unsigned long) |
| __ioremap_prot(virt_to_phys(data), PAGE_SIZE, PAGE_SIGNAL_TRAMPOLINE); |
| |
| return 0; |
| } |
| |
| __initcall(cris_init_signal); |