* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
-#include <linux/config.h>
#include <linux/module.h>
#include <linux/signal.h>
#include <linux/ptrace.h>
force_sig_info(sig, &si, tsk);
}
-void
-do_bad_area(struct task_struct *tsk, struct mm_struct *mm, unsigned long addr,
- unsigned int fsr, struct pt_regs *regs)
+void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
+ struct task_struct *tsk = current;
+ struct mm_struct *mm = tsk->active_mm;
+
/*
* If we are in kernel mode at this point, we
* have no context to handle this fault with.
if (fsr & (1 << 11)) /* write? */
mask = VM_WRITE;
else
- mask = VM_READ|VM_EXEC;
+ mask = VM_READ|VM_EXEC|VM_WRITE;
fault = VM_FAULT_BADACCESS;
if (!(vma->vm_flags & mask))
return fault;
}
- if (tsk->pid != 1)
+ if (!is_init(tsk))
goto out;
/*
* If we're in an interrupt or have no user
* context, we must not take the fault..
*/
- if (in_interrupt() || !mm)
+ if (in_atomic() || !mm)
goto no_context;
- down_read(&mm->mmap_sem);
+ /*
+ * As per x86, we may deadlock here. However, since the kernel only
+ * validly references user space from well defined areas of the code,
+ * we can bug out early if this is from code which shouldn't.
+ */
+ if (!down_read_trylock(&mm->mmap_sem)) {
+ if (!user_mode(regs) && !search_exception_tables(regs->ARM_pc))
+ goto no_context;
+ down_read(&mm->mmap_sem);
+ }
+
fault = __do_page_fault(mm, addr, fsr, tsk);
up_read(&mm->mmap_sem);
do_translation_fault(unsigned long addr, unsigned int fsr,
struct pt_regs *regs)
{
- struct task_struct *tsk;
unsigned int index;
pgd_t *pgd, *pgd_k;
pmd_t *pmd, *pmd_k;
return 0;
bad_area:
- tsk = current;
-
- do_bad_area(tsk, tsk->active_mm, addr, fsr, regs);
+ do_bad_area(addr, fsr, regs);
return 0;
}
static int
do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
- struct task_struct *tsk = current;
- do_bad_area(tsk, tsk->active_mm, addr, fsr, regs);
+ do_bad_area(addr, fsr, regs);
return 0;
}