diff options
Diffstat (limited to 'arch/nios2/mm/fault.c')
| -rw-r--r-- | arch/nios2/mm/fault.c | 84 |
1 files changed, 36 insertions, 48 deletions
diff --git a/arch/nios2/mm/fault.c b/arch/nios2/mm/fault.c index 6a2e716b959f..e3fa9c15181d 100644 --- a/arch/nios2/mm/fault.c +++ b/arch/nios2/mm/fault.c @@ -24,6 +24,7 @@ #include <linux/mm.h> #include <linux/extable.h> #include <linux/uaccess.h> +#include <linux/perf_event.h> #include <asm/mmu_context.h> #include <asm/traps.h> @@ -47,7 +48,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long cause, struct mm_struct *mm = tsk->mm; int code = SEGV_MAPERR; vm_fault_t fault; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; cause >>= 2; @@ -83,27 +84,16 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long cause, 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; -retry: - down_read(&mm->mmap_sem); - } + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); - vma = find_vma(mm, address); +retry: + vma = lock_mm_and_find_vma(mm, address, regs); 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; + goto bad_area_nosemaphore; /* * Ok, we have a good vm_area for this memory access, so * we can handle it.. */ -good_area: code = SEGV_ACCERR; switch (cause) { @@ -131,9 +121,16 @@ good_area: * make sure we exit gracefully rather than endlessly redo * the fault. */ - fault = handle_mm_fault(vma, address, flags); + fault = handle_mm_fault(vma, address, flags, regs); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if (fault_signal_pending(fault, regs)) { + if (!user_mode(regs)) + goto no_context; + return; + } + + /* The fault is fully completed (including releasing mmap lock) */ + if (fault & VM_FAULT_COMPLETED) return; if (unlikely(fault & VM_FAULT_ERROR)) { @@ -146,33 +143,19 @@ good_area: BUG(); } - /* - * Major/minor page fault accounting is only done on the - * initial attempt. If we go through a retry, it is extremely - * likely that the page will be found in page cache at that point. - */ - if (flags & FAULT_FLAG_ALLOW_RETRY) { - if (fault & VM_FAULT_MAJOR) - current->maj_flt++; - else - current->min_flt++; - if (fault & VM_FAULT_RETRY) { - /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk - * of starvation. */ - flags &= ~FAULT_FLAG_ALLOW_RETRY; - flags |= FAULT_FLAG_TRIED; - - /* - * No need to up_read(&mm->mmap_sem) as we would - * have already released it in __lock_page_or_retry - * in mm/filemap.c. - */ - - goto retry; - } + if (fault & VM_FAULT_RETRY) { + flags |= FAULT_FLAG_TRIED; + + /* + * No need to mmap_read_unlock(mm) as we would + * have already released it in __lock_page_or_retry + * in mm/filemap.c. + */ + + goto retry; } - up_read(&mm->mmap_sem); + mmap_read_unlock(mm); return; /* @@ -180,7 +163,7 @@ good_area: * Fix it, but check if it's kernel or user first.. */ bad_area: - up_read(&mm->mmap_sem); + mmap_read_unlock(mm); bad_area_nosemaphore: /* User mode accesses just cause a SIGSEGV */ @@ -218,14 +201,14 @@ no_context: * us unable to handle the page fault gracefully. */ out_of_memory: - up_read(&mm->mmap_sem); + mmap_read_unlock(mm); if (!user_mode(regs)) goto no_context; pagefault_out_of_memory(); return; do_sigbus: - up_read(&mm->mmap_sem); + mmap_read_unlock(mm); /* Kernel mode? Handle exceptions or die */ if (!user_mode(regs)) @@ -245,6 +228,7 @@ vmalloc_fault: */ int offset = pgd_index(address); pgd_t *pgd, *pgd_k; + p4d_t *p4d, *p4d_k; pud_t *pud, *pud_k; pmd_t *pmd, *pmd_k; pte_t *pte_k; @@ -256,8 +240,12 @@ vmalloc_fault: goto no_context; set_pgd(pgd, *pgd_k); - pud = pud_offset(pgd, address); - pud_k = pud_offset(pgd_k, address); + p4d = p4d_offset(pgd, address); + p4d_k = p4d_offset(pgd_k, address); + if (!p4d_present(*p4d_k)) + goto no_context; + pud = pud_offset(p4d, address); + pud_k = pud_offset(p4d_k, address); if (!pud_present(*pud_k)) goto no_context; pmd = pmd_offset(pud, address); |