Initial import

1 files changed, 673 insertions, 0 deletions

diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
new file mode 100644
index 000000000..6a28c792d
--- /dev/null
+++ b/arch/mips/kernel/signal.c
@@ -0,0 +1,673 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1991, 1992  Linus Torvalds
+ * Copyright (C) 1994 - 2000  Ralf Baechle
+ * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
+ * Copyright (C) 2014, Imagination Technologies Ltd.
+ */
+#include <linux/cache.h>
+#include <linux/context_tracking.h>
+#include <linux/irqflags.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/personality.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/compiler.h>
+#include <linux/syscalls.h>
+#include <linux/uaccess.h>
+#include <linux/tracehook.h>
+
+#include <asm/abi.h>
+#include <asm/asm.h>
+#include <linux/bitops.h>
+#include <asm/cacheflush.h>
+#include <asm/fpu.h>
+#include <asm/sim.h>
+#include <asm/ucontext.h>
+#include <asm/cpu-features.h>
+#include <asm/war.h>
+#include <asm/vdso.h>
+#include <asm/dsp.h>
+#include <asm/inst.h>
+
+#include "signal-common.h"
+
+static int (*save_fp_context)(struct sigcontext __user *sc);
+static int (*restore_fp_context)(struct sigcontext __user *sc);
+
+extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
+extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
+
+struct sigframe {
+	u32 sf_ass[4];		/* argument save space for o32 */
+	u32 sf_pad[2];		/* Was: signal trampoline */
+	struct sigcontext sf_sc;
+	sigset_t sf_mask;
+};
+
+struct rt_sigframe {
+	u32 rs_ass[4];		/* argument save space for o32 */
+	u32 rs_pad[2];		/* Was: signal trampoline */
+	struct siginfo rs_info;
+	struct ucontext rs_uc;
+};
+
+/*
+ * Thread saved context copy to/from a signal context presumed to be on the
+ * user stack, and therefore accessed with appropriate macros from uaccess.h.
+ */
+static int copy_fp_to_sigcontext(struct sigcontext __user *sc)
+{
+	int i;
+	int err = 0;
+
+	for (i = 0; i < NUM_FPU_REGS; i++) {
+		err |=
+		    __put_user(get_fpr64(&current->thread.fpu.fpr[i], 0),
+			       &sc->sc_fpregs[i]);
+	}
+	err |= __put_user(current->thread.fpu.fcr31, &sc->sc_fpc_csr);
+
+	return err;
+}
+
+static int copy_fp_from_sigcontext(struct sigcontext __user *sc)
+{
+	int i;
+	int err = 0;
+	u64 fpr_val;
+
+	for (i = 0; i < NUM_FPU_REGS; i++) {
+		err |= __get_user(fpr_val, &sc->sc_fpregs[i]);
+		set_fpr64(&current->thread.fpu.fpr[i], 0, fpr_val);
+	}
+	err |= __get_user(current->thread.fpu.fcr31, &sc->sc_fpc_csr);
+
+	return err;
+}
+
+/*
+ * Helper routines
+ */
+static int protected_save_fp_context(struct sigcontext __user *sc)
+{
+	int err;
+#ifndef CONFIG_EVA
+	while (1) {
+		lock_fpu_owner();
+		if (is_fpu_owner()) {
+			err = save_fp_context(sc);
+			unlock_fpu_owner();
+		} else {
+			unlock_fpu_owner();
+			err = copy_fp_to_sigcontext(sc);
+		}
+		if (likely(!err))
+			break;
+		/* touch the sigcontext and try again */
+		err = __put_user(0, &sc->sc_fpregs[0]) |
+			__put_user(0, &sc->sc_fpregs[31]) |
+			__put_user(0, &sc->sc_fpc_csr);
+		if (err)
+			break;	/* really bad sigcontext */
+	}
+#else
+	/*
+	 * EVA does not have FPU EVA instructions so saving fpu context directly
+	 * does not work.
+	 */
+	lose_fpu(1);
+	err = save_fp_context(sc); /* this might fail */
+#endif
+	return err;
+}
+
+static int protected_restore_fp_context(struct sigcontext __user *sc)
+{
+	int err, tmp __maybe_unused;
+#ifndef CONFIG_EVA
+	while (1) {
+		lock_fpu_owner();
+		if (is_fpu_owner()) {
+			err = restore_fp_context(sc);
+			unlock_fpu_owner();
+		} else {
+			unlock_fpu_owner();
+			err = copy_fp_from_sigcontext(sc);
+		}
+		if (likely(!err))
+			break;
+		/* touch the sigcontext and try again */
+		err = __get_user(tmp, &sc->sc_fpregs[0]) |
+			__get_user(tmp, &sc->sc_fpregs[31]) |
+			__get_user(tmp, &sc->sc_fpc_csr);
+		if (err)
+			break;	/* really bad sigcontext */
+	}
+#else
+	/*
+	 * EVA does not have FPU EVA instructions so restoring fpu context
+	 * directly does not work.
+	 */
+	lose_fpu(0);
+	err = restore_fp_context(sc); /* this might fail */
+#endif
+	return err;
+}
+
+int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
+{
+	int err = 0;
+	int i;
+	unsigned int used_math;
+
+	err |= __put_user(regs->cp0_epc, &sc->sc_pc);
+
+	err |= __put_user(0, &sc->sc_regs[0]);
+	for (i = 1; i < 32; i++)
+		err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
+
+#ifdef CONFIG_CPU_HAS_SMARTMIPS
+	err |= __put_user(regs->acx, &sc->sc_acx);
+#endif
+	err |= __put_user(regs->hi, &sc->sc_mdhi);
+	err |= __put_user(regs->lo, &sc->sc_mdlo);
+	if (cpu_has_dsp) {
+		err |= __put_user(mfhi1(), &sc->sc_hi1);
+		err |= __put_user(mflo1(), &sc->sc_lo1);
+		err |= __put_user(mfhi2(), &sc->sc_hi2);
+		err |= __put_user(mflo2(), &sc->sc_lo2);
+		err |= __put_user(mfhi3(), &sc->sc_hi3);
+		err |= __put_user(mflo3(), &sc->sc_lo3);
+		err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
+	}
+
+	used_math = !!used_math();
+	err |= __put_user(used_math, &sc->sc_used_math);
+
+	if (used_math) {
+		/*
+		 * Save FPU state to signal context. Signal handler
+		 * will "inherit" current FPU state.
+		 */
+		err |= protected_save_fp_context(sc);
+	}
+	return err;
+}
+
+int fpcsr_pending(unsigned int __user *fpcsr)
+{
+	int err, sig = 0;
+	unsigned int csr, enabled;
+
+	err = __get_user(csr, fpcsr);
+	enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
+	/*
+	 * If the signal handler set some FPU exceptions, clear it and
+	 * send SIGFPE.
+	 */
+	if (csr & enabled) {
+		csr &= ~enabled;
+		err |= __put_user(csr, fpcsr);
+		sig = SIGFPE;
+	}
+	return err ?: sig;
+}
+
+static int
+check_and_restore_fp_context(struct sigcontext __user *sc)
+{
+	int err, sig;
+
+	err = sig = fpcsr_pending(&sc->sc_fpc_csr);
+	if (err > 0)
+		err = 0;
+	err |= protected_restore_fp_context(sc);
+	return err ?: sig;
+}
+
+int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
+{
+	unsigned int used_math;
+	unsigned long treg;
+	int err = 0;
+	int i;
+
+	/* Always make any pending restarted system calls return -EINTR */
+	current->restart_block.fn = do_no_restart_syscall;
+
+	err |= __get_user(regs->cp0_epc, &sc->sc_pc);
+
+#ifdef CONFIG_CPU_HAS_SMARTMIPS
+	err |= __get_user(regs->acx, &sc->sc_acx);
+#endif
+	err |= __get_user(regs->hi, &sc->sc_mdhi);
+	err |= __get_user(regs->lo, &sc->sc_mdlo);
+	if (cpu_has_dsp) {
+		err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
+		err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
+		err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
+		err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
+		err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
+		err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
+		err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
+	}
+
+	for (i = 1; i < 32; i++)
+		err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
+
+	err |= __get_user(used_math, &sc->sc_used_math);
+	conditional_used_math(used_math);
+
+	if (used_math) {
+		/* restore fpu context if we have used it before */
+		if (!err)
+			err = check_and_restore_fp_context(sc);
+	} else {
+		/* signal handler may have used FPU.  Give it up. */
+		lose_fpu(0);
+	}
+
+	return err;
+}
+
+void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
+			  size_t frame_size)
+{
+	unsigned long sp;
+
+	/* Default to using normal stack */
+	sp = regs->regs[29];
+
+	/*
+	 * FPU emulator may have it's own trampoline active just
+	 * above the user stack, 16-bytes before the next lowest
+	 * 16 byte boundary.  Try to avoid trashing it.
+	 */
+	sp -= 32;
+
+	sp = sigsp(sp, ksig);
+
+	return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK));
+}
+
+/*
+ * Atomically swap in the new signal mask, and wait for a signal.
+ */
+
+#ifdef CONFIG_TRAD_SIGNALS
+SYSCALL_DEFINE1(sigsuspend, sigset_t __user *, uset)
+{
+	return sys_rt_sigsuspend(uset, sizeof(sigset_t));
+}
+#endif
+
+#ifdef CONFIG_TRAD_SIGNALS
+SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act,
+	struct sigaction __user *, oact)
+{
+	struct k_sigaction new_ka, old_ka;
+	int ret;
+	int err = 0;
+
+	if (act) {
+		old_sigset_t mask;
+
+		if (!access_ok(VERIFY_READ, act, sizeof(*act)))
+			return -EFAULT;
+		err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
+		err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
+		err |= __get_user(mask, &act->sa_mask.sig[0]);
+		if (err)
+			return -EFAULT;
+
+		siginitset(&new_ka.sa.sa_mask, mask);
+	}
+
+	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
+
+	if (!ret && oact) {
+		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
+			return -EFAULT;
+		err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
+		err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
+		err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
+		err |= __put_user(0, &oact->sa_mask.sig[1]);
+		err |= __put_user(0, &oact->sa_mask.sig[2]);
+		err |= __put_user(0, &oact->sa_mask.sig[3]);
+		if (err)
+			return -EFAULT;
+	}
+
+	return ret;
+}
+#endif
+
+#ifdef CONFIG_TRAD_SIGNALS
+asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
+{
+	struct sigframe __user *frame;
+	sigset_t blocked;
+	int sig;
+
+	frame = (struct sigframe __user *) regs.regs[29];
+	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
+		goto badframe;
+	if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
+		goto badframe;
+
+	set_current_blocked(&blocked);
+
+	sig = restore_sigcontext(&regs, &frame->sf_sc);
+	if (sig < 0)
+		goto badframe;
+	else if (sig)
+		force_sig(sig, current);
+
+	/*
+	 * Don't let your children do this ...
+	 */
+	__asm__ __volatile__(
+		"move\t$29, %0\n\t"
+		"j\tsyscall_exit"
+		:/* no outputs */
+		:"r" (&regs));
+	/* Unreached */
+
+badframe:
+	force_sig(SIGSEGV, current);
+}
+#endif /* CONFIG_TRAD_SIGNALS */
+
+asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
+{
+	struct rt_sigframe __user *frame;
+	sigset_t set;
+	int sig;
+
+	frame = (struct rt_sigframe __user *) regs.regs[29];
+	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
+		goto badframe;
+	if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
+		goto badframe;
+
+	set_current_blocked(&set);
+
+	sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
+	if (sig < 0)
+		goto badframe;
+	else if (sig)
+		force_sig(sig, current);
+
+	if (restore_altstack(&frame->rs_uc.uc_stack))
+		goto badframe;
+
+	/*
+	 * Don't let your children do this ...
+	 */
+	__asm__ __volatile__(
+		"move\t$29, %0\n\t"
+		"j\tsyscall_exit"
+		:/* no outputs */
+		:"r" (&regs));
+	/* Unreached */
+
+badframe:
+	force_sig(SIGSEGV, current);
+}
+
+#ifdef CONFIG_TRAD_SIGNALS
+static int setup_frame(void *sig_return, struct ksignal *ksig,
+		       struct pt_regs *regs, sigset_t *set)
+{
+	struct sigframe __user *frame;
+	int err = 0;
+
+	frame = get_sigframe(ksig, regs, sizeof(*frame));
+	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
+		return -EFAULT;
+
+	err |= setup_sigcontext(regs, &frame->sf_sc);
+	err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
+	if (err)
+		return -EFAULT;
+
+	/*
+	 * Arguments to signal handler:
+	 *
+	 *   a0 = signal number
+	 *   a1 = 0 (should be cause)
+	 *   a2 = pointer to struct sigcontext
+	 *
+	 * $25 and c0_epc point to the signal handler, $29 points to the
+	 * struct sigframe.
+	 */
+	regs->regs[ 4] = ksig->sig;
+	regs->regs[ 5] = 0;
+	regs->regs[ 6] = (unsigned long) &frame->sf_sc;
+	regs->regs[29] = (unsigned long) frame;
+	regs->regs[31] = (unsigned long) sig_return;
+	regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
+
+	DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
+	       current->comm, current->pid,
+	       frame, regs->cp0_epc, regs->regs[31]);
+	return 0;
+}
+#endif
+
+static int setup_rt_frame(void *sig_return, struct ksignal *ksig,
+			  struct pt_regs *regs, sigset_t *set)
+{
+	struct rt_sigframe __user *frame;
+	int err = 0;
+
+	frame = get_sigframe(ksig, regs, sizeof(*frame));
+	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
+		return -EFAULT;
+
+	/* Create siginfo.  */
+	err |= copy_siginfo_to_user(&frame->rs_info, &ksig->info);
+
+	/* Create the ucontext.	 */
+	err |= __put_user(0, &frame->rs_uc.uc_flags);
+	err |= __put_user(NULL, &frame->rs_uc.uc_link);
+	err |= __save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
+	err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
+	err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
+
+	if (err)
+		return -EFAULT;
+
+	/*
+	 * Arguments to signal handler:
+	 *
+	 *   a0 = signal number
+	 *   a1 = 0 (should be cause)
+	 *   a2 = pointer to ucontext
+	 *
+	 * $25 and c0_epc point to the signal handler, $29 points to
+	 * the struct rt_sigframe.
+	 */
+	regs->regs[ 4] = ksig->sig;
+	regs->regs[ 5] = (unsigned long) &frame->rs_info;
+	regs->regs[ 6] = (unsigned long) &frame->rs_uc;
+	regs->regs[29] = (unsigned long) frame;
+	regs->regs[31] = (unsigned long) sig_return;
+	regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
+
+	DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
+	       current->comm, current->pid,
+	       frame, regs->cp0_epc, regs->regs[31]);
+
+	return 0;
+}
+
+struct mips_abi mips_abi = {
+#ifdef CONFIG_TRAD_SIGNALS
+	.setup_frame	= setup_frame,
+	.signal_return_offset = offsetof(struct mips_vdso, signal_trampoline),
+#endif
+	.setup_rt_frame = setup_rt_frame,
+	.rt_signal_return_offset =
+		offsetof(struct mips_vdso, rt_signal_trampoline),
+	.restart	= __NR_restart_syscall
+};
+
+static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
+{
+	sigset_t *oldset = sigmask_to_save();
+	int ret;
+	struct mips_abi *abi = current->thread.abi;
+#ifdef CONFIG_CPU_MICROMIPS
+	void *vdso;
+	unsigned long tmp = (unsigned long)current->mm->context.vdso;
+
+	set_isa16_mode(tmp);
+	vdso = (void *)tmp;
+#else
+	void *vdso = current->mm->context.vdso;
+#endif
+
+	if (regs->regs[0]) {
+		switch(regs->regs[2]) {
+		case ERESTART_RESTARTBLOCK:
+		case ERESTARTNOHAND:
+			regs->regs[2] = EINTR;
+			break;
+		case ERESTARTSYS:
+			if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
+				regs->regs[2] = EINTR;
+				break;
+			}
+		/* fallthrough */
+		case ERESTARTNOINTR:
+			regs->regs[7] = regs->regs[26];
+			regs->regs[2] = regs->regs[0];
+			regs->cp0_epc -= 4;
+		}
+
+		regs->regs[0] = 0;		/* Don't deal with this again.	*/
+	}
+
+	if (sig_uses_siginfo(&ksig->ka))
+		ret = abi->setup_rt_frame(vdso + abi->rt_signal_return_offset,
+					  ksig, regs, oldset);
+	else
+		ret = abi->setup_frame(vdso + abi->signal_return_offset, ksig,
+				       regs, oldset);
+
+	signal_setup_done(ret, ksig, 0);
+}
+
+static void do_signal(struct pt_regs *regs)
+{
+	struct ksignal ksig;
+
+	if (get_signal(&ksig)) {
+		/* Whee!  Actually deliver the signal.	*/
+		handle_signal(&ksig, regs);
+		return;
+	}
+
+	if (regs->regs[0]) {
+		switch (regs->regs[2]) {
+		case ERESTARTNOHAND:
+		case ERESTARTSYS:
+		case ERESTARTNOINTR:
+			regs->regs[2] = regs->regs[0];
+			regs->regs[7] = regs->regs[26];
+			regs->cp0_epc -= 4;
+			break;
+
+		case ERESTART_RESTARTBLOCK:
+			regs->regs[2] = current->thread.abi->restart;
+			regs->regs[7] = regs->regs[26];
+			regs->cp0_epc -= 4;
+			break;
+		}
+		regs->regs[0] = 0;	/* Don't deal with this again.	*/
+	}
+
+	/*
+	 * If there's no signal to deliver, we just put the saved sigmask
+	 * back
+	 */
+	restore_saved_sigmask();
+}
+
+/*
+ * notification of userspace execution resumption
+ * - triggered by the TIF_WORK_MASK flags
+ */
+asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
+	__u32 thread_info_flags)
+{
+	local_irq_enable();
+
+	user_exit();
+
+	/* deal with pending signal delivery */
+	if (thread_info_flags & _TIF_SIGPENDING)
+		do_signal(regs);
+
+	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
+		clear_thread_flag(TIF_NOTIFY_RESUME);
+		tracehook_notify_resume(regs);
+	}
+
+	user_enter();
+}
+
+#ifdef CONFIG_SMP
+#ifndef CONFIG_EVA
+static int smp_save_fp_context(struct sigcontext __user *sc)
+{
+	return raw_cpu_has_fpu
+	       ? _save_fp_context(sc)
+	       : copy_fp_to_sigcontext(sc);
+}
+
+static int smp_restore_fp_context(struct sigcontext __user *sc)
+{
+	return raw_cpu_has_fpu
+	       ? _restore_fp_context(sc)
+	       : copy_fp_from_sigcontext(sc);
+}
+#endif /* CONFIG_EVA */
+#endif
+
+static int signal_setup(void)
+{
+#ifndef CONFIG_EVA
+#ifdef CONFIG_SMP
+	/* For now just do the cpu_has_fpu check when the functions are invoked */
+	save_fp_context = smp_save_fp_context;
+	restore_fp_context = smp_restore_fp_context;
+#else
+	if (cpu_has_fpu) {
+		save_fp_context = _save_fp_context;
+		restore_fp_context = _restore_fp_context;
+	} else {
+		save_fp_context = copy_fp_to_sigcontext;
+		restore_fp_context = copy_fp_from_sigcontext;
+	}
+#endif /* CONFIG_SMP */
+#else
+	save_fp_context = copy_fp_to_sigcontext;
+	restore_fp_context = copy_fp_from_sigcontext;
+#endif
+
+	return 0;
+}
+
+arch_initcall(signal_setup);