diff options
Diffstat (limited to 'arch/loongarch/mm/fault.c')
| -rw-r--r-- | arch/loongarch/mm/fault.c | 99 |
1 files changed, 96 insertions, 3 deletions
diff --git a/arch/loongarch/mm/fault.c b/arch/loongarch/mm/fault.c index 97b40defde06..2c93d33356e5 100644 --- a/arch/loongarch/mm/fault.c +++ b/arch/loongarch/mm/fault.c @@ -31,11 +31,52 @@ int show_unhandled_signals = 1; +static int __kprobes spurious_fault(unsigned long write, unsigned long address) +{ + pgd_t *pgd; + p4d_t *p4d; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + + if (!(address & __UA_LIMIT)) + return 0; + + pgd = pgd_offset_k(address); + if (!pgd_present(pgdp_get(pgd))) + return 0; + + p4d = p4d_offset(pgd, address); + if (!p4d_present(p4dp_get(p4d))) + return 0; + + pud = pud_offset(p4d, address); + if (!pud_present(pudp_get(pud))) + return 0; + + pmd = pmd_offset(pud, address); + if (!pmd_present(pmdp_get(pmd))) + return 0; + + if (pmd_leaf(*pmd)) { + return write ? pmd_write(pmdp_get(pmd)) : 1; + } else { + pte = pte_offset_kernel(pmd, address); + if (!pte_present(ptep_get(pte))) + return 0; + + return write ? pte_write(ptep_get(pte)) : 1; + } +} + static void __kprobes no_context(struct pt_regs *regs, unsigned long write, unsigned long address) { const int field = sizeof(unsigned long) * 2; + if (spurious_fault(write, address)) + return; + /* Are we prepared to handle this kernel fault? */ if (fixup_exception(regs)) return; @@ -174,6 +215,58 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, flags |= FAULT_FLAG_USER; perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); + + if (!(flags & FAULT_FLAG_USER)) + goto lock_mmap; + + vma = lock_vma_under_rcu(mm, address); + if (!vma) + goto lock_mmap; + + if (write) { + flags |= FAULT_FLAG_WRITE; + if (!(vma->vm_flags & VM_WRITE)) { + vma_end_read(vma); + si_code = SEGV_ACCERR; + count_vm_vma_lock_event(VMA_LOCK_SUCCESS); + goto bad_area_nosemaphore; + } + } else { + if (!(vma->vm_flags & VM_EXEC) && address == exception_era(regs)) { + vma_end_read(vma); + si_code = SEGV_ACCERR; + count_vm_vma_lock_event(VMA_LOCK_SUCCESS); + goto bad_area_nosemaphore; + } + if (!(vma->vm_flags & (VM_READ | VM_WRITE)) && address != exception_era(regs)) { + vma_end_read(vma); + si_code = SEGV_ACCERR; + count_vm_vma_lock_event(VMA_LOCK_SUCCESS); + goto bad_area_nosemaphore; + } + } + + fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, regs); + if (!(fault & (VM_FAULT_RETRY | VM_FAULT_COMPLETED))) + vma_end_read(vma); + + if (!(fault & VM_FAULT_RETRY)) { + count_vm_vma_lock_event(VMA_LOCK_SUCCESS); + goto done; + } + + count_vm_vma_lock_event(VMA_LOCK_RETRY); + if (fault & VM_FAULT_MAJOR) + flags |= FAULT_FLAG_TRIED; + + /* Quick path to respond to signals */ + if (fault_signal_pending(fault, regs)) { + if (!user_mode(regs)) + no_context(regs, write, address); + return; + } +lock_mmap: + retry: vma = lock_mm_and_find_vma(mm, address, regs); if (unlikely(!vma)) @@ -235,8 +328,10 @@ good_area: */ goto retry; } + mmap_read_unlock(mm); + +done: if (unlikely(fault & VM_FAULT_ERROR)) { - mmap_read_unlock(mm); if (fault & VM_FAULT_OOM) { do_out_of_memory(regs, write, address); return; @@ -249,8 +344,6 @@ good_area: } BUG(); } - - mmap_read_unlock(mm); } asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, |