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Diffstat (limited to 'arch/cris/arch-v32/kernel/signal.c')
-rw-r--r--arch/cris/arch-v32/kernel/signal.c540
1 files changed, 540 insertions, 0 deletions
diff --git a/arch/cris/arch-v32/kernel/signal.c b/arch/cris/arch-v32/kernel/signal.c
new file mode 100644
index 000000000..3a36ae6b7
--- /dev/null
+++ b/arch/cris/arch-v32/kernel/signal.c
@@ -0,0 +1,540 @@
+/*
+ * 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);
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-05 20:46:07 +0000