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sh: Tidy up vmalloc fault handling.

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This rewrites the vmalloc fault handling as per x86, which subsequently
allows for easy future tie-in for vmalloc_sync_all().

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Paul Mundt 2009-07-05 03:18:47 +09:00
parent c63c3105e4
commit 0f60bb25b4
1 changed files with 97 additions and 56 deletions
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153
arch/sh/mm/fault_32.c
View file

@ -2,7 +2,7 @@
* Page fault handler for SH with an MMU.
*
* Copyright (C) 1999 Niibe Yutaka
* Copyright (C) 2003 - 2008 Paul Mundt
* Copyright (C) 2003 - 2009 Paul Mundt
*
* Based on linux/arch/i386/mm/fault.c:
* Copyright (C) 1995 Linus Torvalds
@ -35,6 +35,74 @@ static inline int notify_page_fault(struct pt_regs *regs, int trap)
return ret;
}
static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
{
unsigned index = pgd_index(address);
pgd_t *pgd_k;
pud_t *pud, *pud_k;
pmd_t *pmd, *pmd_k;
pgd += index;
pgd_k = init_mm.pgd + index;
if (!pgd_present(*pgd_k))
return NULL;
pud = pud_offset(pgd, address);
pud_k = pud_offset(pgd_k, address);
if (!pud_present(*pud_k))
return NULL;
pmd = pmd_offset(pud, address);
pmd_k = pmd_offset(pud_k, address);
if (!pmd_present(*pmd_k))
return NULL;
if (!pmd_present(*pmd))
set_pmd(pmd, *pmd_k);
else
BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k));
return pmd_k;
}
/*
* Handle a fault on the vmalloc or module mapping area
*/
static noinline int vmalloc_fault(unsigned long address)
{
pgd_t *pgd_k;
pmd_t *pmd_k;
pte_t *pte_k;
/* Make sure we are in vmalloc area: */
if (!(address >= VMALLOC_START && address < VMALLOC_END))
return -1;
/*
* Synchronize this task's top level page-table
* with the 'reference' page table.
*
* Do _not_ use "current" here. We might be inside
* an interrupt in the middle of a task switch..
*/
pgd_k = get_TTB();
pmd_k = vmalloc_sync_one(__va((unsigned long)pgd_k), address);
if (!pmd_k)
return -1;
pte_k = pte_offset_kernel(pmd_k, address);
if (!pte_present(*pte_k))
return -1;
return 0;
}
static int fault_in_kernel_space(unsigned long address)
{
return address >= TASK_SIZE;
}
/*
* This routine handles page faults. It determines the address,
* and the problem, and then passes it off to one of the appropriate
@ -44,6 +112,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
unsigned long writeaccess,
unsigned long address)
{
unsigned long vec;
struct task_struct *tsk;
struct mm_struct *mm;
struct vm_area_struct * vma;
@ -51,59 +120,30 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
int fault;
siginfo_t info;
/*
* We don't bother with any notifier callbacks here, as they are
* all handled through the __do_page_fault() fast-path.
*/
tsk = current;
mm = tsk->mm;
si_code = SEGV_MAPERR;
vec = lookup_exception_vector();
if (unlikely(address >= TASK_SIZE)) {
/*
* 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;
pgd = get_TTB() + offset;
pgd_k = swapper_pg_dir + offset;
if (!pgd_present(*pgd)) {
if (!pgd_present(*pgd_k))
goto bad_area_nosemaphore;
set_pgd(pgd, *pgd_k);
/*
* 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(fault_in_kernel_space(address))) {
if (vmalloc_fault(address) >= 0)
return;
}
pud = pud_offset(pgd, address);
pud_k = pud_offset(pgd_k, address);
if (!pud_present(*pud)) {
if (!pud_present(*pud_k))
goto bad_area_nosemaphore;
set_pud(pud, *pud_k);
if (notify_page_fault(regs, vec))
return;
}
pmd = pmd_offset(pud, address);
pmd_k = pmd_offset(pud_k, address);
if (pmd_present(*pmd) || !pmd_present(*pmd_k))
goto bad_area_nosemaphore;
set_pmd(pmd, *pmd_k);
return;
goto bad_area_nosemaphore;
}
mm = tsk->mm;
if (unlikely(notify_page_fault(regs, lookup_exception_vector())))
if (unlikely(notify_page_fault(regs, vec)))
return;
/* Only enable interrupts if they were on before the fault */
@ -113,8 +153,8 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
perf_swcounter_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, address);
/*
* If we're in an interrupt or have no user
* context, we must not take the fault..
* If we're in an interrupt, have no user context or are running
* in an atomic region then we must not take the fault:
*/
if (in_atomic() || !mm)
goto no_context;
@ -130,10 +170,11 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
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..
*/
/*
* Ok, we have a good vm_area for this memory access, so
* we can handle it..
*/
good_area:
si_code = SEGV_ACCERR;
if (writeaccess) {
@ -171,10 +212,10 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
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..
*/
/*
* 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);