Merge Qualcom Hexagon architecture

This is the fifth version of the patchset (with one tiny whitespace fix)
to the Linux kernel to support the Qualcomm Hexagon architecture.

Between now and the next pull requests, Richard Kuo should have his key
signed, etc., and should be back on kernel.org.  In the meantime, this
got merged as a emailed patch-series.

* Hexagon: (36 commits)
  Add extra arch overrides to asm-generic/checksum.h
  Hexagon: Add self to MAINTAINERS
  Hexagon: Add basic stacktrace functionality for Hexagon architecture.
  Hexagon: Add configuration and makefiles for the Hexagon architecture.
  Hexagon: Comet platform support
  Hexagon: kgdb support files
  Hexagon: Add page-fault support.
  Hexagon: Add page table header files & etc.
  Hexagon: Add ioremap support
  Hexagon: Provide DMA implementation
  Hexagon: Implement basic TLB management routines for Hexagon.
  Hexagon: Implement basic cache-flush support
  Hexagon: Provide basic implementation and/or stubs for I/O routines.
  Hexagon: Add user access functions
  Hexagon: Add locking types and functions
  Hexagon: Add SMP support
  Hexagon: Provide basic debugging and system trap support.
  Hexagon: Add ptrace support
  Hexagon: Add time and timer functions
  Hexagon: Add interrupts
  ...

1 files changed, 345 insertions, 0 deletions

diff --git a/arch/hexagon/kernel/signal.c b/arch/hexagon/kernel/signal.c
new file mode 100644
index 000000000000..b45be3181193
--- /dev/null
+++ b/arch/hexagon/kernel/signal.c
@@ -0,0 +1,345 @@
+/*
+ * Signal support for Hexagon processor
+ *
+ * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <linux/linkage.h>
+#include <linux/syscalls.h>
+#include <linux/freezer.h>
+#include <linux/tracehook.h>
+#include <asm/registers.h>
+#include <asm/thread_info.h>
+#include <asm/unistd.h>
+#include <asm/uaccess.h>
+#include <asm/ucontext.h>
+#include <asm/cacheflush.h>
+#include <asm/signal.h>
+#include <asm/vdso.h>
+
+#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
+
+struct rt_sigframe {
+	unsigned long tramp[2];
+	struct siginfo info;
+	struct ucontext uc;
+};
+
+static void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
+			  size_t frame_size)
+{
+	unsigned long sp = regs->r29;
+
+	/* Switch to signal stack if appropriate */
+	if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
+		sp = current->sas_ss_sp + current->sas_ss_size;
+
+	return (void __user *)((sp - frame_size) & ~(sizeof(long long) - 1));
+}
+
+static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
+{
+	unsigned long tmp;
+	int err = 0;
+
+	err |= copy_to_user(&sc->sc_regs.r0, &regs->r00,
+			    32*sizeof(unsigned long));
+
+	err |= __put_user(regs->sa0, &sc->sc_regs.sa0);
+	err |= __put_user(regs->lc0, &sc->sc_regs.lc0);
+	err |= __put_user(regs->sa1, &sc->sc_regs.sa1);
+	err |= __put_user(regs->lc1, &sc->sc_regs.lc1);
+	err |= __put_user(regs->m0, &sc->sc_regs.m0);
+	err |= __put_user(regs->m1, &sc->sc_regs.m1);
+	err |= __put_user(regs->usr, &sc->sc_regs.usr);
+	err |= __put_user(regs->preds, &sc->sc_regs.p3_0);
+	err |= __put_user(regs->gp, &sc->sc_regs.gp);
+	err |= __put_user(regs->ugp, &sc->sc_regs.ugp);
+
+	tmp = pt_elr(regs); err |= __put_user(tmp, &sc->sc_regs.pc);
+	tmp = pt_cause(regs); err |= __put_user(tmp, &sc->sc_regs.cause);
+	tmp = pt_badva(regs); err |= __put_user(tmp, &sc->sc_regs.badva);
+
+	return err;
+}
+
+static int restore_sigcontext(struct pt_regs *regs,
+			      struct sigcontext __user *sc)
+{
+	unsigned long tmp;
+	int err = 0;
+
+	err |= copy_from_user(&regs->r00, &sc->sc_regs.r0,
+			      32 * sizeof(unsigned long));
+
+	err |= __get_user(regs->sa0, &sc->sc_regs.sa0);
+	err |= __get_user(regs->lc0, &sc->sc_regs.lc0);
+	err |= __get_user(regs->sa1, &sc->sc_regs.sa1);
+	err |= __get_user(regs->lc1, &sc->sc_regs.lc1);
+	err |= __get_user(regs->m0, &sc->sc_regs.m0);
+	err |= __get_user(regs->m1, &sc->sc_regs.m1);
+	err |= __get_user(regs->usr, &sc->sc_regs.usr);
+	err |= __get_user(regs->preds, &sc->sc_regs.p3_0);
+	err |= __get_user(regs->gp, &sc->sc_regs.gp);
+	err |= __get_user(regs->ugp, &sc->sc_regs.ugp);
+
+	err |= __get_user(tmp, &sc->sc_regs.pc); pt_set_elr(regs, tmp);
+
+	return err;
+}
+
+/*
+ * Setup signal stack frame with siginfo structure
+ */
+static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info,
+			  sigset_t *set,  struct pt_regs *regs)
+{
+	int err = 0;
+	struct rt_sigframe __user *frame;
+	struct hexagon_vdso *vdso = current->mm->context.vdso;
+
+	frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe));
+
+	if (!access_ok(VERIFY_WRITE, frame, sizeof(struct rt_sigframe)))
+		goto	sigsegv;
+
+	if (copy_siginfo_to_user(&frame->info, info))
+		goto	sigsegv;
+
+	/* The on-stack signal trampoline is no longer executed;
+	 * however, the libgcc signal frame unwinding code checks for
+	 * the presence of these two numeric magic values.
+	 */
+	err |= __put_user(0x7800d166, &frame->tramp[0]);
+	err |= __put_user(0x5400c004, &frame->tramp[1]);
+	err |= setup_sigcontext(regs, &frame->uc.uc_mcontext);
+	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+	if (err)
+		goto sigsegv;
+
+	/* Load r0/r1 pair with signumber/siginfo pointer... */
+	regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32)
+		| (unsigned long long)signr;
+	regs->r02 = (unsigned long) &frame->uc;
+	regs->r31 = (unsigned long) vdso->rt_signal_trampoline;
+	pt_psp(regs) = (unsigned long) frame;
+	pt_set_elr(regs, (unsigned long)ka->sa.sa_handler);
+
+	return 0;
+
+sigsegv:
+	force_sigsegv(signr, current);
+	return -EFAULT;
+}
+
+/*
+ * Setup invocation of signal handler
+ */
+static int handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka,
+			 sigset_t *oldset, struct pt_regs *regs)
+{
+	int rc;
+
+	/*
+	 * If we're handling a signal that aborted a system call,
+	 * set up the error return value before adding the signal
+	 * frame to the stack.
+	 */
+
+	if (regs->syscall_nr >= 0) {
+		switch (regs->r00) {
+		case -ERESTART_RESTARTBLOCK:
+		case -ERESTARTNOHAND:
+			regs->r00 = -EINTR;
+			break;
+		case -ERESTARTSYS:
+			if (!(ka->sa.sa_flags & SA_RESTART)) {
+				regs->r00 = -EINTR;
+				break;
+			}
+			/* Fall through */
+		case -ERESTARTNOINTR:
+			regs->r06 = regs->syscall_nr;
+			pt_set_elr(regs, pt_elr(regs) - 4);
+			regs->r00 = regs->restart_r0;
+			break;
+		default:
+			break;
+		}
+	}
+
+	/*
+	 * Set up the stack frame; not doing the SA_SIGINFO thing.  We
+	 * only set up the rt_frame flavor.
+	 */
+	rc = setup_rt_frame(sig, ka, info, oldset, regs);
+
+	/* If there was an error on setup, no signal was delivered. */
+	if (rc)
+		return rc;
+
+	spin_lock_irq(&current->sighand->siglock);
+	sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
+	if (!(ka->sa.sa_flags & SA_NODEFER))
+		sigaddset(&current->blocked, sig);
+	recalc_sigpending();
+	spin_unlock_irq(&current->sighand->siglock);
+
+	return 0;
+}
+
+/*
+ * Called from return-from-event code.
+ */
+static void do_signal(struct pt_regs *regs)
+{
+	struct k_sigaction sigact;
+	siginfo_t info;
+	int signo;
+
+	if (!user_mode(regs))
+		return;
+
+	if (try_to_freeze())
+		goto no_signal;
+
+	signo = get_signal_to_deliver(&info, &sigact, regs, NULL);
+
+	if (signo > 0) {
+		sigset_t *oldset;
+
+		if (test_thread_flag(TIF_RESTORE_SIGMASK))
+			oldset = &current->saved_sigmask;
+		else
+			oldset = &current->blocked;
+
+		if (handle_signal(signo, &info, &sigact, oldset, regs) == 0) {
+			/*
+			 * Successful delivery case.  The saved sigmask is
+			 * stored in the signal frame, and will be restored
+			 * by sigreturn.  We can clear the TIF flag.
+			 */
+			clear_thread_flag(TIF_RESTORE_SIGMASK);
+
+			tracehook_signal_handler(signo, &info, &sigact, regs,
+				test_thread_flag(TIF_SINGLESTEP));
+		}
+		return;
+	}
+
+no_signal:
+	/*
+	 * If we came from a system call, handle the restart.
+	 */
+	if (regs->syscall_nr >= 0) {
+		switch (regs->r00) {
+		case -ERESTARTNOHAND:
+		case -ERESTARTSYS:
+		case -ERESTARTNOINTR:
+			regs->r06 = regs->syscall_nr;
+			break;
+		case -ERESTART_RESTARTBLOCK:
+			regs->r06 = __NR_restart_syscall;
+			break;
+		default:
+			goto no_restart;
+		}
+		pt_set_elr(regs, pt_elr(regs) - 4);
+		regs->r00 = regs->restart_r0;
+	}
+
+no_restart:
+	/* If there's no signal to deliver, put the saved sigmask back */
+	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
+		clear_thread_flag(TIF_RESTORE_SIGMASK);
+		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
+	}
+}
+
+void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
+{
+	if (thread_info_flags & _TIF_SIGPENDING)
+		do_signal(regs);
+
+	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
+		clear_thread_flag(TIF_NOTIFY_RESUME);
+		if (current->replacement_session_keyring)
+			key_replace_session_keyring();
+	}
+}
+
+/*
+ * Architecture-specific wrappers for signal-related system calls
+ */
+asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
+{
+	struct pt_regs *regs = current_thread_info()->regs;
+
+	return do_sigaltstack(uss, uoss, regs->r29);
+}
+
+asmlinkage int sys_rt_sigreturn(void)
+{
+	struct pt_regs *regs = current_thread_info()->regs;
+	struct rt_sigframe __user *frame;
+	sigset_t blocked;
+
+	frame = (struct rt_sigframe __user *)pt_psp(regs);
+	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
+		goto badframe;
+	if (__copy_from_user(&blocked, &frame->uc.uc_sigmask, sizeof(blocked)))
+		goto badframe;
+
+	sigdelsetmask(&blocked, ~_BLOCKABLE);
+	spin_lock_irq(&current->sighand->siglock);
+	current->blocked = blocked;
+	recalc_sigpending();
+	spin_unlock_irq(&current->sighand->siglock);
+
+	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
+		goto badframe;
+
+	/* Restore the user's stack as well */
+	pt_psp(regs) = regs->r29;
+
+	/*
+	 * Leave a trace in the stack frame that this was a sigreturn.
+	 * If the system call is to replay, we've already restored the
+	 * number in the GPR slot and it will be regenerated on the
+	 * new system call trap entry. Note that if restore_sigcontext()
+	 * did something other than a bulk copy of the pt_regs struct,
+	 * we could avoid this assignment by simply not overwriting
+	 * regs->syscall_nr.
+	 */
+	regs->syscall_nr = __NR_rt_sigreturn;
+
+	/*
+	 * If we were meticulous, we'd only call this if we knew that
+	 * we were actually going to use an alternate stack, and we'd
+	 * consider any error to be fatal.  What we do here, in common
+	 * with many other architectures, is call it blindly and only
+	 * consider the -EFAULT return case to be proof of a problem.
+	 */
+	if (do_sigaltstack(&frame->uc.uc_stack, NULL, pt_psp(regs)) == -EFAULT)
+		goto badframe;
+
+	return 0;
+
+badframe:
+	force_sig(SIGSEGV, current);
+	return 0;
+}