| /* |
| * Copyright (C) 1991,1992 Linus Torvalds |
| * Copyright (C) 2005-2012 Imagination Technologies Ltd. |
| * |
| * 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/personality.h> |
| #include <linux/uaccess.h> |
| #include <linux/tracehook.h> |
| |
| #include <asm/ucontext.h> |
| #include <asm/cacheflush.h> |
| #include <asm/switch.h> |
| #include <asm/syscall.h> |
| #include <asm/syscalls.h> |
| |
| #define REG_FLAGS ctx.SaveMask |
| #define REG_RETVAL ctx.DX[0].U0 |
| #define REG_SYSCALL ctx.DX[0].U1 |
| #define REG_SP ctx.AX[0].U0 |
| #define REG_ARG1 ctx.DX[3].U1 |
| #define REG_ARG2 ctx.DX[3].U0 |
| #define REG_ARG3 ctx.DX[2].U1 |
| #define REG_PC ctx.CurrPC |
| #define REG_RTP ctx.DX[4].U1 |
| |
| struct rt_sigframe { |
| struct siginfo info; |
| struct ucontext uc; |
| unsigned long retcode[2]; |
| }; |
| |
| static int restore_sigcontext(struct pt_regs *regs, |
| struct sigcontext __user *sc) |
| { |
| int err; |
| |
| /* Always make any pending restarted system calls return -EINTR */ |
| current_thread_info()->restart_block.fn = do_no_restart_syscall; |
| |
| err = metag_gp_regs_copyin(regs, 0, sizeof(struct user_gp_regs), NULL, |
| &sc->regs); |
| if (!err) |
| err = metag_cb_regs_copyin(regs, 0, |
| sizeof(struct user_cb_regs), NULL, |
| &sc->cb); |
| if (!err) |
| err = metag_rp_state_copyin(regs, 0, |
| sizeof(struct user_rp_state), NULL, |
| &sc->rp); |
| |
| /* This is a user-mode context. */ |
| regs->REG_FLAGS |= TBICTX_PRIV_BIT; |
| |
| return err; |
| } |
| |
| long sys_rt_sigreturn(void) |
| { |
| /* NOTE - Meta stack goes UPWARDS - so we wind the stack back */ |
| struct pt_regs *regs = current_pt_regs(); |
| struct rt_sigframe __user *frame; |
| sigset_t set; |
| |
| frame = (__force struct rt_sigframe __user *)(regs->REG_SP - |
| sizeof(*frame)); |
| |
| 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; |
| |
| return regs->REG_RETVAL; |
| |
| badframe: |
| force_sig(SIGSEGV, current); |
| |
| return 0; |
| } |
| |
| static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, |
| unsigned long mask) |
| { |
| int err; |
| |
| err = metag_gp_regs_copyout(regs, 0, sizeof(struct user_gp_regs), NULL, |
| &sc->regs); |
| |
| if (!err) |
| err = metag_cb_regs_copyout(regs, 0, |
| sizeof(struct user_cb_regs), NULL, |
| &sc->cb); |
| if (!err) |
| err = metag_rp_state_copyout(regs, 0, |
| sizeof(struct user_rp_state), NULL, |
| &sc->rp); |
| |
| /* OK, clear that cbuf flag in the old context, or our stored |
| * catch buffer will be restored when we go to call the signal |
| * handler. Also clear out the CBRP RA/RD pipe bit incase |
| * that is pending as well! |
| * Note that as we have already stored this context, these |
| * flags will get restored on sigreturn to their original |
| * state. |
| */ |
| regs->REG_FLAGS &= ~(TBICTX_XCBF_BIT | TBICTX_CBUF_BIT | |
| TBICTX_CBRP_BIT); |
| |
| /* Clear out the LSM_STEP bits in case we are in the middle of |
| * and MSET/MGET. |
| */ |
| regs->ctx.Flags &= ~TXSTATUS_LSM_STEP_BITS; |
| |
| err |= __put_user(mask, &sc->oldmask); |
| |
| return err; |
| } |
| |
| /* |
| * Determine which stack to use.. |
| */ |
| static void __user *get_sigframe(struct k_sigaction *ka, unsigned long sp, |
| size_t frame_size) |
| { |
| /* Meta stacks grows upwards */ |
| if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0)) |
| sp = current->sas_ss_sp; |
| |
| sp = (sp + 7) & ~7; /* 8byte align stack */ |
| |
| return (void __user *)sp; |
| } |
| |
| static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, |
| struct pt_regs *regs) |
| { |
| struct rt_sigframe __user *frame; |
| int err; |
| unsigned long code; |
| |
| frame = get_sigframe(&ksig->ka, regs->REG_SP, sizeof(*frame)); |
| if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) |
| return -EFAULT; |
| |
| err = copy_siginfo_to_user(&frame->info, &ksig->info); |
| |
| /* Create the ucontext. */ |
| err |= __put_user(0, &frame->uc.uc_flags); |
| err |= __put_user(0, (unsigned long __user *)&frame->uc.uc_link); |
| err |= __save_altstack(&frame->uc.uc_stack, regs->REG_SP); |
| err |= setup_sigcontext(&frame->uc.uc_mcontext, |
| regs, set->sig[0]); |
| err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); |
| |
| if (err) |
| return -EFAULT; |
| |
| /* Set up to return from userspace. */ |
| |
| /* MOV D1Re0 (D1.0), #__NR_rt_sigreturn */ |
| code = 0x03000004 | (__NR_rt_sigreturn << 3); |
| err |= __put_user(code, (unsigned long __user *)(&frame->retcode[0])); |
| |
| /* SWITCH #__METAG_SW_SYS */ |
| code = __METAG_SW_ENCODING(SYS); |
| err |= __put_user(code, (unsigned long __user *)(&frame->retcode[1])); |
| |
| if (err) |
| return -EFAULT; |
| |
| /* Set up registers for signal handler */ |
| regs->REG_RTP = (unsigned long) frame->retcode; |
| regs->REG_SP = (unsigned long) frame + sizeof(*frame); |
| regs->REG_ARG1 = ksig->sig; |
| regs->REG_ARG2 = (unsigned long) &frame->info; |
| regs->REG_ARG3 = (unsigned long) &frame->uc; |
| regs->REG_PC = (unsigned long) ksig->ka.sa.sa_handler; |
| |
| pr_debug("SIG deliver (%s:%d): sp=%p pc=%08x pr=%08x\n", |
| current->comm, current->pid, frame, regs->REG_PC, |
| regs->REG_RTP); |
| |
| /* Now pass size of 'new code' into sigtramp so we can do a more |
| * effective cache flush - directed rather than 'full flush'. |
| */ |
| flush_cache_sigtramp(regs->REG_RTP, sizeof(frame->retcode)); |
| |
| return 0; |
| } |
| |
| static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) |
| { |
| sigset_t *oldset = sigmask_to_save(); |
| int ret; |
| |
| /* Set up the stack frame */ |
| ret = setup_rt_frame(ksig, oldset, regs); |
| |
| signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); |
| } |
| |
| /* |
| * Notes for Meta. |
| * We have moved from the old 2.4.9 SH way of using syscall_nr (in the stored |
| * context) to passing in the syscall flag on the stack. |
| * This is because having syscall_nr in our context does not fit with TBX, and |
| * corrupted the stack. |
| */ |
| static int do_signal(struct pt_regs *regs, int syscall) |
| { |
| unsigned int retval = 0, continue_addr = 0, restart_addr = 0; |
| int restart = 0; |
| struct ksignal ksig; |
| |
| /* |
| * By the end of rt_sigreturn the context describes the point that the |
| * signal was taken (which may happen to be just before a syscall if |
| * it's already been restarted). This should *never* be mistaken for a |
| * system call in need of restarting. |
| */ |
| if (syscall == __NR_rt_sigreturn) |
| syscall = -1; |
| |
| /* Did we come from a system call? */ |
| if (syscall >= 0) { |
| continue_addr = regs->REG_PC; |
| restart_addr = continue_addr - 4; |
| retval = regs->REG_RETVAL; |
| |
| /* |
| * Prepare for system call restart. We do this here so that a |
| * debugger will see the already changed PC. |
| */ |
| switch (retval) { |
| case -ERESTART_RESTARTBLOCK: |
| restart = -2; |
| case -ERESTARTNOHAND: |
| case -ERESTARTSYS: |
| case -ERESTARTNOINTR: |
| ++restart; |
| regs->REG_PC = restart_addr; |
| break; |
| } |
| } |
| |
| /* |
| * Get the signal to deliver. When running under ptrace, at this point |
| * the debugger may change all our registers ... |
| */ |
| get_signal(&ksig); |
| |
| /* |
| * Depending on the signal settings we may need to revert the decision |
| * to restart the system call. But skip this if a debugger has chosen to |
| * restart at a different PC. |
| */ |
| if (regs->REG_PC != restart_addr) |
| restart = 0; |
| if (ksig.sig > 0) { |
| if (unlikely(restart)) { |
| if (retval == -ERESTARTNOHAND |
| || retval == -ERESTART_RESTARTBLOCK |
| || (retval == -ERESTARTSYS |
| && !(ksig.ka.sa.sa_flags & SA_RESTART))) { |
| regs->REG_RETVAL = -EINTR; |
| regs->REG_PC = continue_addr; |
| } |
| } |
| |
| /* Whee! Actually deliver the signal. */ |
| handle_signal(&ksig, regs); |
| return 0; |
| } |
| |
| /* Handlerless -ERESTART_RESTARTBLOCK re-enters via restart_syscall */ |
| if (unlikely(restart < 0)) |
| regs->REG_SYSCALL = __NR_restart_syscall; |
| |
| /* |
| * If there's no signal to deliver, we just put the saved sigmask back. |
| */ |
| restore_saved_sigmask(); |
| |
| return restart; |
| } |
| |
| int do_work_pending(struct pt_regs *regs, unsigned int thread_flags, |
| int syscall) |
| { |
| do { |
| if (likely(thread_flags & _TIF_NEED_RESCHED)) { |
| schedule(); |
| } else { |
| if (unlikely(!user_mode(regs))) |
| return 0; |
| local_irq_enable(); |
| if (thread_flags & _TIF_SIGPENDING) { |
| int restart = do_signal(regs, syscall); |
| if (unlikely(restart)) { |
| /* |
| * Restart without handlers. |
| * Deal with it without leaving |
| * the kernel space. |
| */ |
| return restart; |
| } |
| syscall = -1; |
| } else { |
| clear_thread_flag(TIF_NOTIFY_RESUME); |
| tracehook_notify_resume(regs); |
| } |
| } |
| local_irq_disable(); |
| thread_flags = current_thread_info()->flags; |
| } while (thread_flags & _TIF_WORK_MASK); |
| return 0; |
| } |