diff options
Diffstat (limited to 'arch/arm64/mm/fault.c')
| -rw-r--r-- | arch/arm64/mm/fault.c | 84 |
1 files changed, 35 insertions, 49 deletions
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 1426468b77f3..c23751b06120 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -130,7 +130,7 @@ static void __do_user_fault(struct task_struct *tsk, unsigned long addr, force_sig_info(sig, &si, tsk); } -void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *regs) +static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *regs) { struct task_struct *tsk = current; struct mm_struct *mm = tsk->active_mm; @@ -152,25 +152,8 @@ void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *regs) #define ESR_CM (1 << 8) #define ESR_LNX_EXEC (1 << 24) -/* - * Check that the permissions on the VMA allow for the fault which occurred. - * If we encountered a write fault, we must have write permission, otherwise - * we allow any permission. - */ -static inline bool access_error(unsigned int esr, struct vm_area_struct *vma) -{ - unsigned int mask = VM_READ | VM_WRITE | VM_EXEC; - - if (esr & ESR_WRITE) - mask = VM_WRITE; - if (esr & ESR_LNX_EXEC) - mask = VM_EXEC; - - return vma->vm_flags & mask ? false : true; -} - static int __do_page_fault(struct mm_struct *mm, unsigned long addr, - unsigned int esr, unsigned int flags, + unsigned int mm_flags, unsigned long vm_flags, struct task_struct *tsk) { struct vm_area_struct *vma; @@ -188,12 +171,17 @@ static int __do_page_fault(struct mm_struct *mm, unsigned long addr, * it. */ good_area: - if (access_error(esr, vma)) { + /* + * Check that the permissions on the VMA allow for the fault which + * occurred. If we encountered a write or exec fault, we must have + * appropriate permissions, otherwise we allow any permission. + */ + if (!(vma->vm_flags & vm_flags)) { fault = VM_FAULT_BADACCESS; goto out; } - return handle_mm_fault(mm, vma, addr & PAGE_MASK, flags); + return handle_mm_fault(mm, vma, addr & PAGE_MASK, mm_flags); check_stack: if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr)) @@ -208,9 +196,8 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, struct task_struct *tsk; struct mm_struct *mm; int fault, sig, code; - bool write = (esr & ESR_WRITE) && !(esr & ESR_CM); - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE | - (write ? FAULT_FLAG_WRITE : 0); + unsigned long vm_flags = VM_READ | VM_WRITE | VM_EXEC; + unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; tsk = current; mm = tsk->mm; @@ -226,6 +213,16 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, if (in_atomic() || !mm) goto no_context; + if (user_mode(regs)) + mm_flags |= FAULT_FLAG_USER; + + if (esr & ESR_LNX_EXEC) { + vm_flags = VM_EXEC; + } else if ((esr & ESR_WRITE) && !(esr & ESR_CM)) { + vm_flags = VM_WRITE; + mm_flags |= FAULT_FLAG_WRITE; + } + /* * As per x86, we may deadlock here. However, since the kernel only * validly references user space from well defined areas of the code, @@ -248,7 +245,7 @@ retry: #endif } - fault = __do_page_fault(mm, addr, esr, flags, tsk); + fault = __do_page_fault(mm, addr, mm_flags, vm_flags, tsk); /* * If we need to retry but a fatal signal is pending, handle the @@ -265,7 +262,7 @@ retry: */ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr); - if (flags & FAULT_FLAG_ALLOW_RETRY) { + if (mm_flags & FAULT_FLAG_ALLOW_RETRY) { if (fault & VM_FAULT_MAJOR) { tsk->maj_flt++; perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, @@ -280,7 +277,7 @@ retry: * Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk of * starvation. */ - flags &= ~FAULT_FLAG_ALLOW_RETRY; + mm_flags &= ~FAULT_FLAG_ALLOW_RETRY; goto retry; } } @@ -294,6 +291,13 @@ retry: VM_FAULT_BADACCESS)))) return 0; + /* + * If we are in kernel mode at this point, we have no context to + * handle this fault with. + */ + if (!user_mode(regs)) + goto no_context; + if (fault & VM_FAULT_OOM) { /* * We ran out of memory, call the OOM killer, and return to @@ -304,13 +308,6 @@ retry: return 0; } - /* - * If we are in kernel mode at this point, we have no context to - * handle this fault with. - */ - if (!user_mode(regs)) - goto no_context; - if (fault & VM_FAULT_SIGBUS) { /* * We had some memory, but were unable to successfully fix up @@ -365,17 +362,6 @@ static int __kprobes do_translation_fault(unsigned long addr, } /* - * Some section permission faults need to be handled gracefully. They can - * happen due to a __{get,put}_user during an oops. - */ -static int do_sect_fault(unsigned long addr, unsigned int esr, - struct pt_regs *regs) -{ - do_bad_area(addr, esr, regs); - return 0; -} - -/* * This abort handler always returns "fault". */ static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs) @@ -398,12 +384,12 @@ static struct fault_info { { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 2 translation fault" }, { do_page_fault, SIGSEGV, SEGV_MAPERR, "level 3 translation fault" }, { do_bad, SIGBUS, 0, "reserved access flag fault" }, - { do_bad, SIGSEGV, SEGV_ACCERR, "level 1 access flag fault" }, - { do_bad, SIGSEGV, SEGV_ACCERR, "level 2 access flag fault" }, + { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 access flag fault" }, + { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 access flag fault" }, { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 access flag fault" }, { do_bad, SIGBUS, 0, "reserved permission fault" }, - { do_bad, SIGSEGV, SEGV_ACCERR, "level 1 permission fault" }, - { do_sect_fault, SIGSEGV, SEGV_ACCERR, "level 2 permission fault" }, + { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 permission fault" }, + { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 permission fault" }, { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 permission fault" }, { do_bad, SIGBUS, 0, "synchronous external abort" }, { do_bad, SIGBUS, 0, "asynchronous external abort" }, |