Date:	Wed, 26 Aug 2009 14:38:54 +0800
From:	Chen Liqin <liqin.chen@...plusct.com>
To:	linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:	Arnd Bergmann <arnd@...db.de>, torvalds@...ux-foundation.org
Subject: Subject: [PATCH 32/33] score: create mm/ files extable.c fault.c

>>From 9a983ba502045e6ed9ac8055f10717df9db100cb Mon Sep 17 00:00:00 2001
From: Chen Liqin <liqin.chen@...plusct.com>
Date: Wed, 26 Aug 2009 10:05:12 +0800
Subject: [PATCH 32/33] score: create mm/ files extable.c fault.c


Signed-off-by: Chen Liqin <liqin.chen@...plusct.com>
---
 arch/score/mm/extable.c |   38 ++++++++
 arch/score/mm/fault.c   |  235 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 273 insertions(+), 0 deletions(-)
 create mode 100644 arch/score/mm/extable.c
 create mode 100644 arch/score/mm/fault.c

diff --git a/arch/score/mm/extable.c b/arch/score/mm/extable.c
new file mode 100644
index 0000000..01ff644
--- /dev/null
+++ b/arch/score/mm/extable.c
@@ -0,0 +1,38 @@
+/*
+ * arch/score/mm/extable.c
+ *
+ * Score Processor version.
+ *
+ * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
+ *  Lennox Wu <lennox.wu@...plusct.com>
+ *  Chen Liqin <liqin.chen@...plusct.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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, see the file COPYING, or write
+ * to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <linux/module.h>
+
+int fixup_exception(struct pt_regs *regs)
+{
+	const struct exception_table_entry *fixup;
+
+	fixup = search_exception_tables(regs->cp0_epc);
+	if (fixup) {
+		regs->cp0_epc = fixup->fixup;
+		return 1;
+	}
+	return 0;
+}
diff --git a/arch/score/mm/fault.c b/arch/score/mm/fault.c
new file mode 100644
index 0000000..47b600e
--- /dev/null
+++ b/arch/score/mm/fault.c
@@ -0,0 +1,235 @@
+/*
+ * arch/score/mm/fault.c
+ *
+ * Score Processor version.
+ *
+ * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
+ *  Lennox Wu <lennox.wu@...plusct.com>
+ *  Chen Liqin <liqin.chen@...plusct.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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, see the file COPYING, or write
+ * to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/module.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+
+/*
+ * This routine handles page faults.  It determines the address,
+ * and the problem, and then passes it off to one of the appropriate
+ * routines.
+ */
+asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
+				unsigned long address)
+{
+	struct vm_area_struct *vma = NULL;
+	struct task_struct *tsk = current;
+	struct mm_struct *mm = tsk->mm;
+	const int field = sizeof(unsigned long) * 2;
+	siginfo_t info;
+	int fault;
+
+	info.si_code = SEGV_MAPERR;
+
+	/*
+	* We fault-in kernel-space virtual memory on-demand. The
+	* 'reference' page table is init_mm.pgd.
+	*
+	* NOTE! We MUST NOT take any locks for this case. We may
+	* be in an interrupt or a critical region, and should
+	* only copy the information from the master page table,
+	* nothing more.
+	*/
+	if (unlikely(address >= VMALLOC_START && address <= VMALLOC_END))
+		goto vmalloc_fault;
+#ifdef MODULE_START
+	if (unlikely(address >= MODULE_START && address < MODULE_END))
+		goto vmalloc_fault;
+#endif
+
+	/*
+	* If we're in an interrupt or have no user
+	* context, we must not take the fault..
+	*/
+	if (in_atomic() || !mm)
+		goto bad_area_nosemaphore;
+
+	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;
+	/*
+	* Ok, we have a good vm_area for this memory access, so
+	* we can handle it..
+	 */
+good_area:
+	info.si_code = SEGV_ACCERR;
+
+	if (write) {
+		if (!(vma->vm_flags & VM_WRITE))
+			goto bad_area;
+	} else {
+		if (!(vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)))
+			goto bad_area;
+	}
+
+survive:
+	/*
+	* If for any reason at all we couldn't handle the fault,
+	* make sure we exit gracefully rather than endlessly redo
+	* the fault.
+	*/
+	fault = handle_mm_fault(mm, vma, address, write);
+	if (unlikely(fault & VM_FAULT_ERROR)) {
+		if (fault & VM_FAULT_OOM)
+			goto out_of_memory;
+		else if (fault & VM_FAULT_SIGBUS)
+			goto do_sigbus;
+		BUG();
+	}
+	if (fault & VM_FAULT_MAJOR)
+		tsk->maj_flt++;
+	else
+		tsk->min_flt++;
+
+	up_read(&mm->mmap_sem);
+	return;
+
+	/*
+	* Something tried to access memory that isn't in our memory map..
+	* Fix it, but check if it's kernel or user first..
+	 */
+bad_area:
+	up_read(&mm->mmap_sem);
+
+bad_area_nosemaphore:
+	/* User mode accesses just cause a SIGSEGV */
+	if (user_mode(regs)) {
+		tsk->thread.cp0_badvaddr = address;
+		tsk->thread.error_code = write;
+		info.si_signo = SIGSEGV;
+		info.si_errno = 0;
+		/* info.si_code has been set above */
+		info.si_addr = (void __user *) address;
+		force_sig_info(SIGSEGV, &info, tsk);
+		return;
+	}
+
+no_context:
+	/* Are we prepared to handle this kernel fault? */
+	if (fixup_exception(regs)) {
+		current->thread.cp0_baduaddr = address;
+		return;
+	}
+
+	/*
+	* Oops. The kernel tried to access some bad page. We'll have to
+	* terminate things with extreme prejudice.
+	*/
+	bust_spinlocks(1);
+
+	printk(KERN_ALERT "CPU %d Unable to handle kernel paging request at "
+			"virtual address %0*lx, epc == %0*lx, ra == %0*lx\n",
+			0, field, address, field, regs->cp0_epc,
+			field, regs->regs[3]);
+	die("Oops", regs);
+
+	/*
+	* We ran out of memory, or some other thing happened to us that made
+	* us unable to handle the page fault gracefully.
+	*/
+out_of_memory:
+	up_read(&mm->mmap_sem);
+	if (is_global_init(tsk)) {
+		yield();
+		down_read(&mm->mmap_sem);
+		goto survive;
+	}
+	printk("VM: killing process %s\n", tsk->comm);
+	if (user_mode(regs))
+		do_group_exit(SIGKILL);
+	goto no_context;
+
+do_sigbus:
+	up_read(&mm->mmap_sem);
+	/* Kernel mode? Handle exceptions or die */
+	if (!user_mode(regs))
+		goto no_context;
+	else
+	/*
+	* Send a sigbus, regardless of whether we were in kernel
+	* or user mode.
+	*/
+	tsk->thread.cp0_badvaddr = address;
+	info.si_signo = SIGBUS;
+	info.si_errno = 0;
+	info.si_code = BUS_ADRERR;
+	info.si_addr = (void __user *) address;
+	force_sig_info(SIGBUS, &info, tsk);
+	return;
+vmalloc_fault:
+	{
+		/*
+		* Synchronize this task's top level page-table
+		* with the 'reference' page table.
+		*
+		* Do _not_ use "tsk" here. We might be inside
+		* an interrupt in the middle of a task switch..
+		*/
+		int offset = __pgd_offset(address);
+		pgd_t *pgd, *pgd_k;
+		pud_t *pud, *pud_k;
+		pmd_t *pmd, *pmd_k;
+		pte_t *pte_k;
+
+		pgd = (pgd_t *) pgd_current + offset;
+		pgd_k = init_mm.pgd + offset;
+
+		if (!pgd_present(*pgd_k))
+			goto no_context;
+		set_pgd(pgd, *pgd_k);
+
+		pud = pud_offset(pgd, address);
+		pud_k = pud_offset(pgd_k, address);
+		if (!pud_present(*pud_k))
+			goto no_context;
+
+		pmd = pmd_offset(pud, address);
+		pmd_k = pmd_offset(pud_k, address);
+		if (!pmd_present(*pmd_k))
+			goto no_context;
+		set_pmd(pmd, *pmd_k);
+
+		pte_k = pte_offset_kernel(pmd_k, address);
+		if (!pte_present(*pte_k))
+			goto no_context;
+		return;
+	}
+}
-- 
1.6.2



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