diff options
| -rw-r--r-- | arch/arm/mm/fault.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c index 192c8ab196db..0e5b4bc7b217 100644 --- a/arch/arm/mm/fault.c +++ b/arch/arm/mm/fault.c @@ -262,6 +262,35 @@ static inline bool ttbr0_usermode_access_allowed(struct pt_regs *regs) #endif static int __kprobes +do_kernel_address_page_fault(struct mm_struct *mm, unsigned long addr, + unsigned int fsr, struct pt_regs *regs) +{ + if (user_mode(regs)) { + /* + * Fault from user mode for a kernel space address. User mode + * should not be faulting in kernel space, which includes the + * vector/khelper page. Send a SIGSEGV. + */ + __do_user_fault(addr, fsr, SIGSEGV, SEGV_MAPERR, regs); + } else { + /* + * Fault from kernel mode. Enable interrupts if they were + * enabled in the parent context. Section (upper page table) + * translation faults are handled via do_translation_fault(), + * so we will only get here for a non-present kernel space + * PTE or PTE permission fault. This may happen in exceptional + * circumstances and need the fixup tables to be walked. + */ + if (interrupts_enabled(regs)) + local_irq_enable(); + + __do_kernel_fault(mm, addr, fsr, regs); + } + + return 0; +} + +static int __kprobes do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs) { struct mm_struct *mm = current->mm; @@ -274,6 +303,12 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs) if (kprobe_page_fault(regs, fsr)) return 0; + /* + * Handle kernel addresses faults separately, which avoids touching + * the mmap lock from contexts that are not able to sleep. + */ + if (addr >= TASK_SIZE) + return do_kernel_address_page_fault(mm, addr, fsr, regs); /* Enable interrupts if they were enabled in the parent context. */ if (interrupts_enabled(regs)) |