From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- arch/cris/arch-v10/kernel/signal.c | 438 +++++++++++++++++++++++++++++++++++++ 1 file changed, 438 insertions(+) create mode 100644 arch/cris/arch-v10/kernel/signal.c (limited to 'arch/cris/arch-v10/kernel/signal.c') diff --git a/arch/cris/arch-v10/kernel/signal.c b/arch/cris/arch-v10/kernel/signal.c new file mode 100644 index 000000000..7122d9773 --- /dev/null +++ b/arch/cris/arch-v10/kernel/signal.c @@ -0,0 +1,438 @@ +/* + * linux/arch/cris/kernel/signal.c + * + * Based on arch/i386/kernel/signal.c by + * Copyright (C) 1991, 1992 Linus Torvalds + * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson * + * + * Ideas also taken from arch/arm. + * + * Copyright (C) 2000-2007 Axis Communications AB + * + * Authors: Bjorn Wesen (bjornw@axis.com) + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +#define DEBUG_SIG 0 + +/* a syscall in Linux/CRIS is a break 13 instruction which is 2 bytes */ +/* manipulate regs so that upon return, it will be re-executed */ + +/* We rely on that pc points to the instruction after "break 13", so the + * library must never do strange things like putting it in a delay slot. + */ +#define RESTART_CRIS_SYS(regs) regs->r10 = regs->orig_r10; regs->irp -= 2; + +void do_signal(int canrestart, struct pt_regs *regs); + +/* + * Do a signal return; undo the signal stack. + */ + +struct sigframe { + struct sigcontext sc; + unsigned long extramask[_NSIG_WORDS-1]; + unsigned char retcode[8]; /* trampoline code */ +}; + +struct rt_sigframe { + struct siginfo *pinfo; + void *puc; + struct siginfo info; + struct ucontext uc; + unsigned char retcode[8]; /* trampoline code */ +}; + + +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 regs from &sc->regs (same as sc, since regs is first) + * (sc is already checked for VERIFY_READ since the sigframe was + * checked in sys_sigreturn previously) + */ + + if (__copy_from_user(regs, sc, sizeof(struct pt_regs))) + goto badframe; + + /* make sure the U-flag is set so user-mode cannot fool us */ + + regs->dccr |= 1 << 8; + + /* restore the old USP as it was before we stacked the sc etc. + * (we cannot just pop the sigcontext since we aligned the sp and + * stuff after pushing it) + */ + + err |= __get_user(old_usp, &sc->usp); + + wrusp(old_usp); + + /* TODO: the other ports use regs->orig_XX to disable syscall checks + * after this completes, but we don't use that mechanism. maybe we can + * use it now ? + */ + + return err; + +badframe: + return 1; +} + +asmlinkage int sys_sigreturn(void) +{ + struct pt_regs *regs = current_pt_regs(); + struct sigframe __user *frame = (struct sigframe *)rdusp(); + sigset_t set; + + /* + * Since we stacked the signal on a dword boundary, + * then frame should be dword aligned here. If it's + * not, then the user is trying to mess with us. + */ + 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; + + /* TODO: SIGTRAP when single-stepping as in arm ? */ + + return regs->r10; + +badframe: + force_sig(SIGSEGV, current); + return 0; +} + +asmlinkage int sys_rt_sigreturn(void) +{ + struct pt_regs *regs = current_pt_regs(); + struct rt_sigframe __user *frame = (struct rt_sigframe *)rdusp(); + sigset_t set; + + /* + * Since we stacked the signal on a dword boundary, + * then frame should be dword aligned here. If it's + * not, then the user is trying to mess with us. + */ + 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; + + return regs->r10; + +badframe: + force_sig(SIGSEGV, current); + return 0; +} + +/* + * Set up a signal frame. + */ + +static int setup_sigcontext(struct sigcontext __user *sc, + struct pt_regs *regs, unsigned long mask) +{ + int err = 0; + unsigned long usp = rdusp(); + + /* copy the regs. they are first in sc so we can use sc directly */ + + err |= __copy_to_user(sc, regs, sizeof(struct pt_regs)); + + /* Set the frametype to CRIS_FRAME_NORMAL for the execution of + the signal handler. The frametype will be restored to its previous + value in restore_sigcontext. */ + regs->frametype = CRIS_FRAME_NORMAL; + + /* then some other stuff */ + + err |= __put_user(mask, &sc->oldmask); + + err |= __put_user(usp, &sc->usp); + + return err; +} + +/* Figure out where we want 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 we stack a lot of state info, and arrange for the + * user-mode program to return to the kernel using either a + * trampoline 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) +{ + struct sigframe __user *frame; + unsigned long return_ip; + int 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 userspace. If provided, use a stub + already in userspace. */ + if (ksig->ka.sa.sa_flags & SA_RESTORER) { + return_ip = (unsigned long)ksig->ka.sa.sa_restorer; + } else { + /* trampoline - the desired return ip is the retcode itself */ + return_ip = (unsigned long)&frame->retcode; + /* This is movu.w __NR_sigreturn, r9; break 13; */ + 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 */ + + regs->irp = (unsigned long) ksig->ka.sa.sa_handler; /* what we enter NOW */ + regs->srp = return_ip; /* what we enter LATER */ + regs->r10 = ksig->sig; /* first argument is signo */ + + /* 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) +{ + struct rt_sigframe __user *frame; + unsigned long return_ip; + int 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 userspace. If provided, use a stub + already in userspace. */ + if (ksig->ka.sa.sa_flags & SA_RESTORER) { + return_ip = (unsigned long)ksig->ka.sa.sa_restorer; + } else { + /* trampoline - the desired return ip is the retcode itself */ + return_ip = (unsigned long)&frame->retcode; + /* This is movu.w __NR_rt_sigreturn, r9; break 13; */ + 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 */ + + /* What we enter NOW */ + regs->irp = (unsigned long) ksig->ka.sa.sa_handler; + /* What we enter LATER */ + regs->srp = return_ip; + /* First argument is signo */ + regs->r10 = ksig->sig; + /* Second argument is (siginfo_t *) */ + regs->r11 = (unsigned long)&frame->info; + /* Third argument is unused */ + regs->r12 = 0; + + /* Actually move the usp to reflect the stacked frame */ + wrusp((unsigned long)frame); + + return 0; +} + +/* + * OK, we're invoking a handler + */ + +static inline void handle_signal(int canrestart, struct ksignal *ksig, + struct pt_regs *regs) +{ + sigset_t *oldset = sigmask_to_save(); + int ret; + + /* Are we from a system call? */ + if (canrestart) { + /* If so, check system call restarting.. */ + switch (regs->r10) { + case -ERESTART_RESTARTBLOCK: + case -ERESTARTNOHAND: + /* ERESTARTNOHAND means that the syscall should + * only be restarted if there was no handler for + * the signal, and since we only get here if there + * is a handler, we don't restart */ + regs->r10 = -EINTR; + break; + case -ERESTARTSYS: + /* ERESTARTSYS means to 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; + } + /* fallthrough */ + case -ERESTARTNOINTR: + /* ERESTARTNOINTR means that the syscall should + * be called again after the signal handler returns. */ + RESTART_CRIS_SYS(regs); + } + } + + /* 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; + + /* + * 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 (get_signal(&ksig)) { + /* Whee! Actually deliver the signal. */ + handle_signal(canrestart, &ksig, regs); + return; + } + + /* Did we come 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->irp -= 2; + } + } + + /* if there's no signal to deliver, we just put the saved sigmask + * back */ + restore_saved_sigmask(); +} -- cgit v1.2.3-54-g00ecf