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, 187 insertions, 0 deletions

diff --git a/arch/hexagon/mm/vm_fault.c b/arch/hexagon/mm/vm_fault.c
new file mode 100644
index 000000000000..c10b76ff9d65
--- /dev/null
+++ b/arch/hexagon/mm/vm_fault.c
@@ -0,0 +1,187 @@
+/*
+ * Memory fault handling for Hexagon
+ *
+ * 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.
+ */
+
+/*
+ * Page fault handling for the Hexagon Virtual Machine.
+ * Can also be called by a native port emulating the HVM
+ * execptions.
+ */
+
+#include <asm/pgtable.h>
+#include <asm/traps.h>
+#include <asm/uaccess.h>
+#include <linux/mm.h>
+#include <linux/signal.h>
+#include <linux/module.h>
+#include <linux/hardirq.h>
+
+/*
+ * Decode of hardware exception sends us to one of several
+ * entry points.  At each, we generate canonical arguments
+ * for handling by the abstract memory management code.
+ */
+#define FLT_IFETCH     -1
+#define FLT_LOAD        0
+#define FLT_STORE       1
+
+
+/*
+ * Canonical page fault handler
+ */
+void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
+{
+	struct vm_area_struct *vma;
+	struct mm_struct *mm = current->mm;
+	siginfo_t info;
+	int si_code = SEGV_MAPERR;
+	int fault;
+	const struct exception_table_entry *fixup;
+
+	/*
+	 * If we're in an interrupt or have no user context,
+	 * then must not take the fault.
+	 */
+	if (unlikely(in_interrupt() || !mm))
+		goto no_context;
+
+	local_irq_enable();
+
+	down_read(&mm->mmap_sem);
+	vma = find_vma(mm, address);
+	if (!vma)
+		goto bad_area;
+
+	if (vma->vm_start <= address)
+		goto good_area;
+
+	if (!(vma->vm_flags & VM_GROWSDOWN))
+		goto bad_area;
+
+	if (expand_stack(vma, address))
+		goto bad_area;
+
+good_area:
+	/* Address space is OK.  Now check access rights. */
+	si_code = SEGV_ACCERR;
+
+	switch (cause) {
+	case FLT_IFETCH:
+		if (!(vma->vm_flags & VM_EXEC))
+			goto bad_area;
+		break;
+	case FLT_LOAD:
+		if (!(vma->vm_flags & VM_READ))
+			goto bad_area;
+		break;
+	case FLT_STORE:
+		if (!(vma->vm_flags & VM_WRITE))
+			goto bad_area;
+		break;
+	}
+
+	fault = handle_mm_fault(mm, vma, address, (cause > 0));
+
+	/* The most common case -- we are done. */
+	if (likely(!(fault & VM_FAULT_ERROR))) {
+		if (fault & VM_FAULT_MAJOR)
+			current->maj_flt++;
+		else
+			current->min_flt++;
+
+		up_read(&mm->mmap_sem);
+		return;
+	}
+
+	up_read(&mm->mmap_sem);
+
+	/* Handle copyin/out exception cases */
+	if (!user_mode(regs))
+		goto no_context;
+
+	if (fault & VM_FAULT_OOM) {
+		pagefault_out_of_memory();
+		return;
+	}
+
+	/* User-mode address is in the memory map, but we are
+	 * unable to fix up the page fault.
+	 */
+	if (fault & VM_FAULT_SIGBUS) {
+		info.si_signo = SIGBUS;
+		info.si_code = BUS_ADRERR;
+	}
+	/* Address is not in the memory map */
+	else {
+		info.si_signo = SIGSEGV;
+		info.si_code = SEGV_ACCERR;
+	}
+	info.si_errno = 0;
+	info.si_addr = (void __user *)address;
+	force_sig_info(info.si_code, &info, current);
+	return;
+
+bad_area:
+	up_read(&mm->mmap_sem);
+
+	if (user_mode(regs)) {
+		info.si_signo = SIGSEGV;
+		info.si_errno = 0;
+		info.si_code = si_code;
+		info.si_addr = (void *)address;
+		force_sig_info(SIGSEGV, &info, current);
+		return;
+	}
+	/* Kernel-mode fault falls through */
+
+no_context:
+	fixup = search_exception_tables(pt_elr(regs));
+	if (fixup) {
+		pt_set_elr(regs, fixup->fixup);
+		return;
+	}
+
+	/* Things are looking very, very bad now */
+	bust_spinlocks(1);
+	printk(KERN_EMERG "Unable to handle kernel paging request at "
+		"virtual address 0x%08lx, regs %p\n", address, regs);
+	die("Bad Kernel VA", regs, SIGKILL);
+}
+
+
+void read_protection_fault(struct pt_regs *regs)
+{
+	unsigned long badvadr = pt_badva(regs);
+
+	do_page_fault(badvadr, FLT_LOAD, regs);
+}
+
+void write_protection_fault(struct pt_regs *regs)
+{
+	unsigned long badvadr = pt_badva(regs);
+
+	do_page_fault(badvadr, FLT_STORE, regs);
+}
+
+void execute_protection_fault(struct pt_regs *regs)
+{
+	unsigned long badvadr = pt_badva(regs);
+
+	do_page_fault(badvadr, FLT_IFETCH, regs);
+}