nios2: MMU Fault handling
This patch adds support for the handling of the MMU faults (exception entry code introduced by a previous patch, kernel/entry.S). Signed-off-by: Ley Foon Tan <lftan@altera.com>
This commit is contained in:
Ley Foon Tan
parent
6b8baec4d6
commit
862674d424
25
arch/nios2/mm/extable.c
Normal file
25
arch/nios2/mm/extable.c
Normal file
@ -0,0 +1,25 @@
|
||||
/*
|
||||
* Copyright (C) 2010, Tobias Klauser <tklauser@distanz.ch>
|
||||
* Copyright (C) 2009, Wind River Systems Inc
|
||||
* Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
|
||||
*
|
||||
* This file is subject to the terms and conditions of the GNU General Public
|
||||
* License. See the file "COPYING" in the main directory of this archive
|
||||
* for more details.
|
||||
*/
|
||||
|
||||
#include <linux/module.h>
|
||||
#include <linux/uaccess.h>
|
||||
|
||||
int fixup_exception(struct pt_regs *regs)
|
||||
{
|
||||
const struct exception_table_entry *fixup;
|
||||
|
||||
fixup = search_exception_tables(regs->ea);
|
||||
if (fixup) {
|
||||
regs->ea = fixup->fixup;
|
||||
return 1;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
251
arch/nios2/mm/fault.c
Normal file
251
arch/nios2/mm/fault.c
Normal file
@ -0,0 +1,251 @@
|
||||
/*
|
||||
* Copyright (C) 2009 Wind River Systems Inc
|
||||
* Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
|
||||
*
|
||||
* based on arch/mips/mm/fault.c which is:
|
||||
*
|
||||
* Copyright (C) 1995-2000 Ralf Baechle
|
||||
*
|
||||
* This file is subject to the terms and conditions of the GNU General Public
|
||||
* License. See the file "COPYING" in the main directory of this archive
|
||||
* for more details.
|
||||
*/
|
||||
|
||||
#include <linux/signal.h>
|
||||
#include <linux/sched.h>
|
||||
#include <linux/interrupt.h>
|
||||
#include <linux/kernel.h>
|
||||
#include <linux/errno.h>
|
||||
#include <linux/string.h>
|
||||
#include <linux/types.h>
|
||||
#include <linux/ptrace.h>
|
||||
#include <linux/mman.h>
|
||||
#include <linux/mm.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/uaccess.h>
|
||||
#include <linux/ptrace.h>
|
||||
|
||||
#include <asm/mmu_context.h>
|
||||
#include <asm/traps.h>
|
||||
|
||||
#define EXC_SUPERV_INSN_ACCESS 9 /* Supervisor only instruction address */
|
||||
#define EXC_SUPERV_DATA_ACCESS 11 /* Supervisor only data address */
|
||||
#define EXC_X_PROTECTION_FAULT 13 /* TLB permission violation (x) */
|
||||
#define EXC_R_PROTECTION_FAULT 14 /* TLB permission violation (r) */
|
||||
#define EXC_W_PROTECTION_FAULT 15 /* TLB permission violation (w) */
|
||||
|
||||
/*
|
||||
* 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 cause,
|
||||
unsigned long address)
|
||||
{
|
||||
struct vm_area_struct *vma = NULL;
|
||||
struct task_struct *tsk = current;
|
||||
struct mm_struct *mm = tsk->mm;
|
||||
int code = SEGV_MAPERR;
|
||||
int fault;
|
||||
unsigned int flags = 0;
|
||||
|
||||
cause >>= 2;
|
||||
|
||||
/* Restart the instruction */
|
||||
regs->ea -= 4;
|
||||
|
||||
/*
|
||||
* 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)) {
|
||||
if (user_mode(regs))
|
||||
goto bad_area_nosemaphore;
|
||||
else
|
||||
goto vmalloc_fault;
|
||||
}
|
||||
|
||||
if (unlikely(address >= TASK_SIZE))
|
||||
goto bad_area_nosemaphore;
|
||||
|
||||
/*
|
||||
* 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;
|
||||
|
||||
if (user_mode(regs))
|
||||
flags |= FAULT_FLAG_USER;
|
||||
|
||||
if (!down_read_trylock(&mm->mmap_sem)) {
|
||||
if (!user_mode(regs) && !search_exception_tables(regs->ea))
|
||||
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:
|
||||
code = SEGV_ACCERR;
|
||||
|
||||
switch (cause) {
|
||||
case EXC_SUPERV_INSN_ACCESS:
|
||||
goto bad_area;
|
||||
case EXC_SUPERV_DATA_ACCESS:
|
||||
goto bad_area;
|
||||
case EXC_X_PROTECTION_FAULT:
|
||||
if (!(vma->vm_flags & VM_EXEC))
|
||||
goto bad_area;
|
||||
break;
|
||||
case EXC_R_PROTECTION_FAULT:
|
||||
if (!(vma->vm_flags & VM_READ))
|
||||
goto bad_area;
|
||||
break;
|
||||
case EXC_W_PROTECTION_FAULT:
|
||||
if (!(vma->vm_flags & VM_WRITE))
|
||||
goto bad_area;
|
||||
flags = FAULT_FLAG_WRITE;
|
||||
break;
|
||||
}
|
||||
|
||||
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, flags);
|
||||
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)) {
|
||||
pr_alert("%s: unhandled page fault (%d) at 0x%08lx, "
|
||||
"cause %ld\n", current->comm, SIGSEGV, address, cause);
|
||||
show_regs(regs);
|
||||
_exception(SIGSEGV, regs, code, address);
|
||||
return;
|
||||
}
|
||||
|
||||
no_context:
|
||||
/* Are we prepared to handle this kernel fault? */
|
||||
if (fixup_exception(regs))
|
||||
return;
|
||||
|
||||
/*
|
||||
* Oops. The kernel tried to access some bad page. We'll have to
|
||||
* terminate things with extreme prejudice.
|
||||
*/
|
||||
bust_spinlocks(1);
|
||||
|
||||
pr_alert("Unable to handle kernel %s at virtual address %08lx",
|
||||
address < PAGE_SIZE ? "NULL pointer dereference" :
|
||||
"paging request", address);
|
||||
pr_alert("ea = %08lx, ra = %08lx, cause = %ld\n", regs->ea, regs->ra,
|
||||
cause);
|
||||
panic("Oops");
|
||||
return;
|
||||
|
||||
/*
|
||||
* 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;
|
||||
}
|
||||
if (!user_mode(regs))
|
||||
goto no_context;
|
||||
pagefault_out_of_memory();
|
||||
return;
|
||||
|
||||
do_sigbus:
|
||||
up_read(&mm->mmap_sem);
|
||||
|
||||
/* Kernel mode? Handle exceptions or die */
|
||||
if (!user_mode(regs))
|
||||
goto no_context;
|
||||
|
||||
_exception(SIGBUS, regs, BUS_ADRERR, address);
|
||||
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_index(address);
|
||||
pgd_t *pgd, *pgd_k;
|
||||
pud_t *pud, *pud_k;
|
||||
pmd_t *pmd, *pmd_k;
|
||||
pte_t *pte_k;
|
||||
|
||||
pgd = 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;
|
||||
|
||||
flush_tlb_one(address);
|
||||
return;
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user