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, 454 insertions, 0 deletions

diff --git a/arch/hexagon/kernel/traps.c b/arch/hexagon/kernel/traps.c
new file mode 100644
index 000000000000..f08857d0715b
--- /dev/null
+++ b/arch/hexagon/kernel/traps.c
@@ -0,0 +1,454 @@
+/*
+ * Kernel traps/events 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/init.h>
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/kdebug.h>
+#include <linux/syscalls.h>
+#include <linux/signal.h>
+#include <linux/tracehook.h>
+#include <asm/traps.h>
+#include <asm/vm_fault.h>
+#include <asm/syscall.h>
+#include <asm/registers.h>
+#include <asm/unistd.h>
+#include <asm/sections.h>
+#ifdef CONFIG_KGDB
+# include <linux/kgdb.h>
+#endif
+
+#define TRAP_SYSCALL	1
+#define TRAP_DEBUG	0xdb
+
+void __init trap_init(void)
+{
+}
+
+#ifdef CONFIG_GENERIC_BUG
+/* Maybe should resemble arch/sh/kernel/traps.c ?? */
+int is_valid_bugaddr(unsigned long addr)
+{
+	return 1;
+}
+#endif /* CONFIG_GENERIC_BUG */
+
+static const char *ex_name(int ex)
+{
+	switch (ex) {
+	case HVM_GE_C_XPROT:
+	case HVM_GE_C_XUSER:
+		return "Execute protection fault";
+	case HVM_GE_C_RPROT:
+	case HVM_GE_C_RUSER:
+		return "Read protection fault";
+	case HVM_GE_C_WPROT:
+	case HVM_GE_C_WUSER:
+		return "Write protection fault";
+	case HVM_GE_C_XMAL:
+		return "Misaligned instruction";
+	case HVM_GE_C_RMAL:
+		return "Misaligned data load";
+	case HVM_GE_C_WMAL:
+		return "Misaligned data store";
+	case HVM_GE_C_INVI:
+	case HVM_GE_C_PRIVI:
+		return "Illegal instruction";
+	case HVM_GE_C_BUS:
+		return "Precise bus error";
+	case HVM_GE_C_CACHE:
+		return "Cache error";
+
+	case 0xdb:
+		return "Debugger trap";
+
+	default:
+		return "Unrecognized exception";
+	}
+}
+
+static void do_show_stack(struct task_struct *task, unsigned long *fp,
+			  unsigned long ip)
+{
+	int kstack_depth_to_print = 24;
+	unsigned long offset, size;
+	const char *name = NULL;
+	unsigned long *newfp;
+	unsigned long low, high;
+	char tmpstr[128];
+	char *modname;
+	int i;
+
+	if (task == NULL)
+		task = current;
+
+	printk(KERN_INFO "CPU#%d, %s/%d, Call Trace:\n",
+	       raw_smp_processor_id(), task->comm,
+	       task_pid_nr(task));
+
+	if (fp == NULL) {
+		if (task == current) {
+			asm("%0 = r30" : "=r" (fp));
+		} else {
+			fp = (unsigned long *)
+			     ((struct hexagon_switch_stack *)
+			     task->thread.switch_sp)->fp;
+		}
+	}
+
+	if ((((unsigned long) fp) & 0x3) || ((unsigned long) fp < 0x1000)) {
+		printk(KERN_INFO "-- Corrupt frame pointer %p\n", fp);
+		return;
+	}
+
+	/* Saved link reg is one word above FP */
+	if (!ip)
+		ip = *(fp+1);
+
+	/* Expect kernel stack to be in-bounds */
+	low = (unsigned long)task_stack_page(task);
+	high = low + THREAD_SIZE - 8;
+	low += sizeof(struct thread_info);
+
+	for (i = 0; i < kstack_depth_to_print; i++) {
+
+		name = kallsyms_lookup(ip, &size, &offset, &modname, tmpstr);
+
+		printk(KERN_INFO "[%p] 0x%lx: %s + 0x%lx", fp, ip, name,
+			offset);
+		if (((unsigned long) fp < low) || (high < (unsigned long) fp))
+			printk(KERN_CONT " (FP out of bounds!)");
+		if (modname)
+			printk(KERN_CONT " [%s] ", modname);
+		printk(KERN_CONT "\n");
+
+		newfp = (unsigned long *) *fp;
+
+		if (((unsigned long) newfp) & 0x3) {
+			printk(KERN_INFO "-- Corrupt frame pointer %p\n",
+				newfp);
+			break;
+		}
+
+		/* Attempt to continue past exception. */
+		if (0 == newfp) {
+			struct pt_regs *regs = (struct pt_regs *) (((void *)fp)
+						+ 8);
+
+			if (regs->syscall_nr != -1) {
+				printk(KERN_INFO "-- trap0 -- syscall_nr: %ld",
+					regs->syscall_nr);
+				printk(KERN_CONT "  psp: %lx  elr: %lx\n",
+					 pt_psp(regs), pt_elr(regs));
+				break;
+			} else {
+				/* really want to see more ... */
+				kstack_depth_to_print += 6;
+				printk(KERN_INFO "-- %s (0x%lx)  badva: %lx\n",
+					ex_name(pt_cause(regs)), pt_cause(regs),
+					pt_badva(regs));
+			}
+
+			newfp = (unsigned long *) regs->r30;
+			ip = pt_elr(regs);
+		} else {
+			ip = *(newfp + 1);
+		}
+
+		/* If link reg is null, we are done. */
+		if (ip == 0x0)
+			break;
+
+		/* If newfp isn't larger, we're tracing garbage. */
+		if (newfp > fp)
+			fp = newfp;
+		else
+			break;
+	}
+}
+
+void show_stack(struct task_struct *task, unsigned long *fp)
+{
+	/* Saved link reg is one word above FP */
+	do_show_stack(task, fp, 0);
+}
+
+void dump_stack(void)
+{
+	unsigned long *fp;
+	asm("%0 = r30" : "=r" (fp));
+	show_stack(current, fp);
+}
+EXPORT_SYMBOL(dump_stack);
+
+int die(const char *str, struct pt_regs *regs, long err)
+{
+	static struct {
+		spinlock_t lock;
+		int counter;
+	} die = {
+		.lock = __SPIN_LOCK_UNLOCKED(die.lock),
+		.counter = 0
+	};
+
+	console_verbose();
+	oops_enter();
+
+	spin_lock_irq(&die.lock);
+	bust_spinlocks(1);
+	printk(KERN_EMERG "Oops: %s[#%d]:\n", str, ++die.counter);
+
+	if (notify_die(DIE_OOPS, str, regs, err, pt_cause(regs), SIGSEGV) ==
+	    NOTIFY_STOP)
+		return 1;
+
+	print_modules();
+	show_regs(regs);
+	do_show_stack(current, &regs->r30, pt_elr(regs));
+
+	bust_spinlocks(0);
+	add_taint(TAINT_DIE);
+
+	spin_unlock_irq(&die.lock);
+
+	if (in_interrupt())
+		panic("Fatal exception in interrupt");
+
+	if (panic_on_oops)
+		panic("Fatal exception");
+
+	oops_exit();
+	do_exit(err);
+	return 0;
+}
+
+int die_if_kernel(char *str, struct pt_regs *regs, long err)
+{
+	if (!user_mode(regs))
+		return die(str, regs, err);
+	else
+		return 0;
+}
+
+/*
+ * It's not clear that misaligned fetches are ever recoverable.
+ */
+static void misaligned_instruction(struct pt_regs *regs)
+{
+	die_if_kernel("Misaligned Instruction", regs, 0);
+	force_sig(SIGBUS, current);
+}
+
+/*
+ * Misaligned loads and stores, on the other hand, can be
+ * emulated, and probably should be, some day.  But for now
+ * they will be considered fatal.
+ */
+static void misaligned_data_load(struct pt_regs *regs)
+{
+	die_if_kernel("Misaligned Data Load", regs, 0);
+	force_sig(SIGBUS, current);
+}
+
+static void misaligned_data_store(struct pt_regs *regs)
+{
+	die_if_kernel("Misaligned Data Store", regs, 0);
+	force_sig(SIGBUS, current);
+}
+
+static void illegal_instruction(struct pt_regs *regs)
+{
+	die_if_kernel("Illegal Instruction", regs, 0);
+	force_sig(SIGILL, current);
+}
+
+/*
+ * Precise bus errors may be recoverable with a a retry,
+ * but for now, treat them as irrecoverable.
+ */
+static void precise_bus_error(struct pt_regs *regs)
+{
+	die_if_kernel("Precise Bus Error", regs, 0);
+	force_sig(SIGBUS, current);
+}
+
+/*
+ * If anything is to be done here other than panic,
+ * it will probably be complex and migrate to another
+ * source module.  For now, just die.
+ */
+static void cache_error(struct pt_regs *regs)
+{
+	die("Cache Error", regs, 0);
+}
+
+/*
+ * General exception handler
+ */
+void do_genex(struct pt_regs *regs)
+{
+	/*
+	 * Decode Cause and Dispatch
+	 */
+	switch (pt_cause(regs)) {
+	case HVM_GE_C_XPROT:
+	case HVM_GE_C_XUSER:
+		execute_protection_fault(regs);
+		break;
+	case HVM_GE_C_RPROT:
+	case HVM_GE_C_RUSER:
+		read_protection_fault(regs);
+		break;
+	case HVM_GE_C_WPROT:
+	case HVM_GE_C_WUSER:
+		write_protection_fault(regs);
+		break;
+	case HVM_GE_C_XMAL:
+		misaligned_instruction(regs);
+		break;
+	case HVM_GE_C_RMAL:
+		misaligned_data_load(regs);
+		break;
+	case HVM_GE_C_WMAL:
+		misaligned_data_store(regs);
+		break;
+	case HVM_GE_C_INVI:
+	case HVM_GE_C_PRIVI:
+		illegal_instruction(regs);
+		break;
+	case HVM_GE_C_BUS:
+		precise_bus_error(regs);
+		break;
+	case HVM_GE_C_CACHE:
+		cache_error(regs);
+		break;
+	default:
+		/* Halt and catch fire */
+		panic("Unrecognized exception 0x%lx\n", pt_cause(regs));
+		break;
+	}
+}
+
+/* Indirect system call dispatch */
+long sys_syscall(void)
+{
+	printk(KERN_ERR "sys_syscall invoked!\n");
+	return -ENOSYS;
+}
+
+void do_trap0(struct pt_regs *regs)
+{
+	unsigned long syscallret = 0;
+	syscall_fn syscall;
+
+	switch (pt_cause(regs)) {
+	case TRAP_SYSCALL:
+		/* System call is trap0 #1 */
+
+		/* allow strace to catch syscall args  */
+		if (unlikely(test_thread_flag(TIF_SYSCALL_TRACE) &&
+			tracehook_report_syscall_entry(regs)))
+			return;  /*  return -ENOSYS somewhere?  */
+
+		/* Interrupts should be re-enabled for syscall processing */
+		__vmsetie(VM_INT_ENABLE);
+
+		/*
+		 * System call number is in r6, arguments in r0..r5.
+		 * Fortunately, no Linux syscall has more than 6 arguments,
+		 * and Hexagon ABI passes first 6 arguments in registers.
+		 * 64-bit arguments are passed in odd/even register pairs.
+		 * Fortunately, we have no system calls that take more
+		 * than three arguments with more than one 64-bit value.
+		 * Should that change, we'd need to redesign to copy
+		 * between user and kernel stacks.
+		 */
+		regs->syscall_nr = regs->r06;
+
+		/*
+		 * GPR R0 carries the first parameter, and is also used
+		 * to report the return value.  We need a backup of
+		 * the user's value in case we need to do a late restart
+		 * of the system call.
+		 */
+		regs->restart_r0 = regs->r00;
+
+		if ((unsigned long) regs->syscall_nr >= __NR_syscalls) {
+			regs->r00 = -1;
+		} else {
+			syscall = (syscall_fn)
+				  (sys_call_table[regs->syscall_nr]);
+			syscallret = syscall(regs->r00, regs->r01,
+				   regs->r02, regs->r03,
+				   regs->r04, regs->r05);
+		}
+
+		/*
+		 * If it was a sigreturn system call, don't overwrite
+		 * r0 value in stack frame with return value.
+		 *
+		 * __NR_sigreturn doesn't seem to exist in new unistd.h
+		 */
+
+		if (regs->syscall_nr != __NR_rt_sigreturn)
+			regs->r00 = syscallret;
+
+		/* allow strace to get the syscall return state  */
+		if (unlikely(test_thread_flag(TIF_SYSCALL_TRACE)))
+			tracehook_report_syscall_exit(regs, 0);
+
+		break;
+	case TRAP_DEBUG:
+		/* Trap0 0xdb is debug breakpoint */
+		if (user_mode(regs)) {
+			struct siginfo info;
+
+			info.si_signo = SIGTRAP;
+			info.si_errno = 0;
+			/*
+			 * Some architecures add some per-thread state
+			 * to distinguish between breakpoint traps and
+			 * trace traps.  We may want to do that, and
+			 * set the si_code value appropriately, or we
+			 * may want to use a different trap0 flavor.
+			 */
+			info.si_code = TRAP_BRKPT;
+			info.si_addr = (void __user *) pt_elr(regs);
+			send_sig_info(SIGTRAP, &info, current);
+		} else {
+#ifdef CONFIG_KGDB
+			kgdb_handle_exception(pt_cause(regs), SIGTRAP,
+					      TRAP_BRKPT, regs);
+#endif
+		}
+		break;
+	}
+	/* Ignore other trap0 codes for now, especially 0 (Angel calls) */
+}
+
+/*
+ * Machine check exception handler
+ */
+void do_machcheck(struct pt_regs *regs)
+{
+	/* Halt and catch fire */
+	__vmstop();
+}