11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * arch/s390/mm/fault.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * S390 version 51da177e4SLinus Torvalds * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation 61da177e4SLinus Torvalds * Author(s): Hartmut Penner (hp@de.ibm.com) 71da177e4SLinus Torvalds * Ulrich Weigand (uweigand@de.ibm.com) 81da177e4SLinus Torvalds * 91da177e4SLinus Torvalds * Derived from "arch/i386/mm/fault.c" 101da177e4SLinus Torvalds * Copyright (C) 1995 Linus Torvalds 111da177e4SLinus Torvalds */ 121da177e4SLinus Torvalds 13052ff461SHeiko Carstens #include <linux/kernel_stat.h> 14cdd6c482SIngo Molnar #include <linux/perf_event.h> 151da177e4SLinus Torvalds #include <linux/signal.h> 161da177e4SLinus Torvalds #include <linux/sched.h> 171da177e4SLinus Torvalds #include <linux/kernel.h> 181da177e4SLinus Torvalds #include <linux/errno.h> 191da177e4SLinus Torvalds #include <linux/string.h> 201da177e4SLinus Torvalds #include <linux/types.h> 211da177e4SLinus Torvalds #include <linux/ptrace.h> 221da177e4SLinus Torvalds #include <linux/mman.h> 231da177e4SLinus Torvalds #include <linux/mm.h> 247757591aSHeiko Carstens #include <linux/compat.h> 251da177e4SLinus Torvalds #include <linux/smp.h> 261eeb66a1SChristoph Hellwig #include <linux/kdebug.h> 271da177e4SLinus Torvalds #include <linux/init.h> 281da177e4SLinus Torvalds #include <linux/console.h> 291da177e4SLinus Torvalds #include <linux/module.h> 301da177e4SLinus Torvalds #include <linux/hardirq.h> 314ba069b8SMichael Grundy #include <linux/kprobes.h> 32be5ec363SMartin Schwidefsky #include <linux/uaccess.h> 3353492b1dSGerald Schaefer #include <linux/hugetlb.h> 34cbb870c8SHeiko Carstens #include <asm/asm-offsets.h> 351da177e4SLinus Torvalds #include <asm/system.h> 361da177e4SLinus Torvalds #include <asm/pgtable.h> 37d7b250e2SHeiko Carstens #include <asm/irq.h> 386252d702SMartin Schwidefsky #include <asm/mmu_context.h> 3950d7280dSMartin Schwidefsky #include <asm/compat.h> 40a806170eSHeiko Carstens #include "../kernel/entry.h" 411da177e4SLinus Torvalds 42347a8dc3SMartin Schwidefsky #ifndef CONFIG_64BIT 431da177e4SLinus Torvalds #define __FAIL_ADDR_MASK 0x7ffff000 441da177e4SLinus Torvalds #define __SUBCODE_MASK 0x0200 451da177e4SLinus Torvalds #define __PF_RES_FIELD 0ULL 46347a8dc3SMartin Schwidefsky #else /* CONFIG_64BIT */ 471da177e4SLinus Torvalds #define __FAIL_ADDR_MASK -4096L 481da177e4SLinus Torvalds #define __SUBCODE_MASK 0x0600 491da177e4SLinus Torvalds #define __PF_RES_FIELD 0x8000000000000000ULL 50347a8dc3SMartin Schwidefsky #endif /* CONFIG_64BIT */ 511da177e4SLinus Torvalds 5250d7280dSMartin Schwidefsky #define VM_FAULT_BADCONTEXT 0x010000 5350d7280dSMartin Schwidefsky #define VM_FAULT_BADMAP 0x020000 5450d7280dSMartin Schwidefsky #define VM_FAULT_BADACCESS 0x040000 5550d7280dSMartin Schwidefsky 5692f842eaSMartin Schwidefsky static unsigned long store_indication; 5792f842eaSMartin Schwidefsky 5892f842eaSMartin Schwidefsky void fault_init(void) 5992f842eaSMartin Schwidefsky { 6014375bc4SMartin Schwidefsky if (test_facility(2) && test_facility(75)) 6192f842eaSMartin Schwidefsky store_indication = 0xc00; 6292f842eaSMartin Schwidefsky } 6392f842eaSMartin Schwidefsky 647ecb344aSMartin Schwidefsky static inline int notify_page_fault(struct pt_regs *regs) 6510c1031fSMartin Schwidefsky { 6633464e3bSChristoph Hellwig int ret = 0; 6733464e3bSChristoph Hellwig 6833464e3bSChristoph Hellwig /* kprobe_running() needs smp_processor_id() */ 6922e0a046SHeiko Carstens if (kprobes_built_in() && !user_mode(regs)) { 7033464e3bSChristoph Hellwig preempt_disable(); 7133464e3bSChristoph Hellwig if (kprobe_running() && kprobe_fault_handler(regs, 14)) 7233464e3bSChristoph Hellwig ret = 1; 7333464e3bSChristoph Hellwig preempt_enable(); 7433464e3bSChristoph Hellwig } 7533464e3bSChristoph Hellwig return ret; 764ba069b8SMichael Grundy } 774ba069b8SMichael Grundy 781da177e4SLinus Torvalds 791da177e4SLinus Torvalds /* 801da177e4SLinus Torvalds * Unlock any spinlocks which will prevent us from getting the 81cefc8be8SKirill Korotaev * message out. 821da177e4SLinus Torvalds */ 831da177e4SLinus Torvalds void bust_spinlocks(int yes) 841da177e4SLinus Torvalds { 851da177e4SLinus Torvalds if (yes) { 861da177e4SLinus Torvalds oops_in_progress = 1; 871da177e4SLinus Torvalds } else { 881da177e4SLinus Torvalds int loglevel_save = console_loglevel; 891da177e4SLinus Torvalds console_unblank(); 901da177e4SLinus Torvalds oops_in_progress = 0; 911da177e4SLinus Torvalds /* 921da177e4SLinus Torvalds * OK, the message is on the console. Now we call printk() 931da177e4SLinus Torvalds * without oops_in_progress set so that printk will give klogd 941da177e4SLinus Torvalds * a poke. Hold onto your hats... 951da177e4SLinus Torvalds */ 961da177e4SLinus Torvalds console_loglevel = 15; 971da177e4SLinus Torvalds printk(" "); 981da177e4SLinus Torvalds console_loglevel = loglevel_save; 991da177e4SLinus Torvalds } 1001da177e4SLinus Torvalds } 1011da177e4SLinus Torvalds 1021da177e4SLinus Torvalds /* 103482b05ddSGerald Schaefer * Returns the address space associated with the fault. 10461365e13SMartin Schwidefsky * Returns 0 for kernel space and 1 for user space. 1051da177e4SLinus Torvalds */ 10661365e13SMartin Schwidefsky static inline int user_space_fault(unsigned long trans_exc_code) 1071da177e4SLinus Torvalds { 1081da177e4SLinus Torvalds /* 10961365e13SMartin Schwidefsky * The lowest two bits of the translation exception 11061365e13SMartin Schwidefsky * identification indicate which paging table was used. 1111da177e4SLinus Torvalds */ 11261365e13SMartin Schwidefsky trans_exc_code &= 3; 11361365e13SMartin Schwidefsky if (trans_exc_code == 2) 11461365e13SMartin Schwidefsky /* Access via secondary space, set_fs setting decides */ 11561365e13SMartin Schwidefsky return current->thread.mm_segment.ar4; 116b11b5334SMartin Schwidefsky if (user_mode == HOME_SPACE_MODE) 11761365e13SMartin Schwidefsky /* User space if the access has been done via home space. */ 11861365e13SMartin Schwidefsky return trans_exc_code == 3; 119482b05ddSGerald Schaefer /* 12061365e13SMartin Schwidefsky * If the user space is not the home space the kernel runs in home 12161365e13SMartin Schwidefsky * space. Access via secondary space has already been covered, 12261365e13SMartin Schwidefsky * access via primary space or access register is from user space 12361365e13SMartin Schwidefsky * and access via home space is from the kernel. 124482b05ddSGerald Schaefer */ 12561365e13SMartin Schwidefsky return trans_exc_code != 3; 1261da177e4SLinus Torvalds } 1271da177e4SLinus Torvalds 128ab3c68eeSHeiko Carstens static inline void report_user_fault(struct pt_regs *regs, long int_code, 129ab3c68eeSHeiko Carstens int signr, unsigned long address) 130ab3c68eeSHeiko Carstens { 131ab3c68eeSHeiko Carstens if ((task_pid_nr(current) > 1) && !show_unhandled_signals) 132ab3c68eeSHeiko Carstens return; 133ab3c68eeSHeiko Carstens if (!unhandled_signal(current, signr)) 134ab3c68eeSHeiko Carstens return; 135ab3c68eeSHeiko Carstens if (!printk_ratelimit()) 136ab3c68eeSHeiko Carstens return; 137ab3c68eeSHeiko Carstens printk("User process fault: interruption code 0x%lX ", int_code); 138ab3c68eeSHeiko Carstens print_vma_addr(KERN_CONT "in ", regs->psw.addr & PSW_ADDR_INSN); 139ab3c68eeSHeiko Carstens printk("\n"); 140ab3c68eeSHeiko Carstens printk("failing address: %lX\n", address); 141ab3c68eeSHeiko Carstens show_regs(regs); 142ab3c68eeSHeiko Carstens } 143ab3c68eeSHeiko Carstens 1441da177e4SLinus Torvalds /* 1451da177e4SLinus Torvalds * Send SIGSEGV to task. This is an external routine 1461da177e4SLinus Torvalds * to keep the stack usage of do_page_fault small. 1471da177e4SLinus Torvalds */ 14850d7280dSMartin Schwidefsky static noinline void do_sigsegv(struct pt_regs *regs, long int_code, 14950d7280dSMartin Schwidefsky int si_code, unsigned long trans_exc_code) 1501da177e4SLinus Torvalds { 1511da177e4SLinus Torvalds struct siginfo si; 15250d7280dSMartin Schwidefsky unsigned long address; 1531da177e4SLinus Torvalds 15450d7280dSMartin Schwidefsky address = trans_exc_code & __FAIL_ADDR_MASK; 15550d7280dSMartin Schwidefsky current->thread.prot_addr = address; 15650d7280dSMartin Schwidefsky current->thread.trap_no = int_code; 157ab3c68eeSHeiko Carstens report_user_fault(regs, int_code, SIGSEGV, address); 1581da177e4SLinus Torvalds si.si_signo = SIGSEGV; 1591da177e4SLinus Torvalds si.si_code = si_code; 160d2c993d8SHeiko Carstens si.si_addr = (void __user *) address; 1611da177e4SLinus Torvalds force_sig_info(SIGSEGV, &si, current); 1621da177e4SLinus Torvalds } 1631da177e4SLinus Torvalds 16450d7280dSMartin Schwidefsky static noinline void do_no_context(struct pt_regs *regs, long int_code, 16561365e13SMartin Schwidefsky unsigned long trans_exc_code) 16610c1031fSMartin Schwidefsky { 16710c1031fSMartin Schwidefsky const struct exception_table_entry *fixup; 16861365e13SMartin Schwidefsky unsigned long address; 16910c1031fSMartin Schwidefsky 17010c1031fSMartin Schwidefsky /* Are we prepared to handle this kernel fault? */ 17150d7280dSMartin Schwidefsky fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN); 17210c1031fSMartin Schwidefsky if (fixup) { 17310c1031fSMartin Schwidefsky regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE; 17410c1031fSMartin Schwidefsky return; 17510c1031fSMartin Schwidefsky } 17610c1031fSMartin Schwidefsky 17710c1031fSMartin Schwidefsky /* 17810c1031fSMartin Schwidefsky * Oops. The kernel tried to access some bad page. We'll have to 17910c1031fSMartin Schwidefsky * terminate things with extreme prejudice. 18010c1031fSMartin Schwidefsky */ 18161365e13SMartin Schwidefsky address = trans_exc_code & __FAIL_ADDR_MASK; 182b11b5334SMartin Schwidefsky if (!user_space_fault(trans_exc_code)) 18310c1031fSMartin Schwidefsky printk(KERN_ALERT "Unable to handle kernel pointer dereference" 18410c1031fSMartin Schwidefsky " at virtual kernel address %p\n", (void *)address); 18510c1031fSMartin Schwidefsky else 18610c1031fSMartin Schwidefsky printk(KERN_ALERT "Unable to handle kernel paging request" 18710c1031fSMartin Schwidefsky " at virtual user address %p\n", (void *)address); 18810c1031fSMartin Schwidefsky 18950d7280dSMartin Schwidefsky die("Oops", regs, int_code); 19010c1031fSMartin Schwidefsky do_exit(SIGKILL); 19110c1031fSMartin Schwidefsky } 19210c1031fSMartin Schwidefsky 19350d7280dSMartin Schwidefsky static noinline void do_low_address(struct pt_regs *regs, long int_code, 19461365e13SMartin Schwidefsky unsigned long trans_exc_code) 19510c1031fSMartin Schwidefsky { 19610c1031fSMartin Schwidefsky /* Low-address protection hit in kernel mode means 19710c1031fSMartin Schwidefsky NULL pointer write access in kernel mode. */ 19810c1031fSMartin Schwidefsky if (regs->psw.mask & PSW_MASK_PSTATE) { 19910c1031fSMartin Schwidefsky /* Low-address protection hit in user mode 'cannot happen'. */ 20050d7280dSMartin Schwidefsky die ("Low-address protection", regs, int_code); 20110c1031fSMartin Schwidefsky do_exit(SIGKILL); 20210c1031fSMartin Schwidefsky } 20310c1031fSMartin Schwidefsky 20450d7280dSMartin Schwidefsky do_no_context(regs, int_code, trans_exc_code); 20510c1031fSMartin Schwidefsky } 20610c1031fSMartin Schwidefsky 20750d7280dSMartin Schwidefsky static noinline void do_sigbus(struct pt_regs *regs, long int_code, 20861365e13SMartin Schwidefsky unsigned long trans_exc_code) 20910c1031fSMartin Schwidefsky { 21010c1031fSMartin Schwidefsky struct task_struct *tsk = current; 21136bf9680SMartin Schwidefsky unsigned long address; 21236bf9680SMartin Schwidefsky struct siginfo si; 21310c1031fSMartin Schwidefsky 21410c1031fSMartin Schwidefsky /* 21510c1031fSMartin Schwidefsky * Send a sigbus, regardless of whether we were in kernel 21610c1031fSMartin Schwidefsky * or user mode. 21710c1031fSMartin Schwidefsky */ 21836bf9680SMartin Schwidefsky address = trans_exc_code & __FAIL_ADDR_MASK; 21936bf9680SMartin Schwidefsky tsk->thread.prot_addr = address; 22050d7280dSMartin Schwidefsky tsk->thread.trap_no = int_code; 22136bf9680SMartin Schwidefsky si.si_signo = SIGBUS; 22236bf9680SMartin Schwidefsky si.si_errno = 0; 22336bf9680SMartin Schwidefsky si.si_code = BUS_ADRERR; 22436bf9680SMartin Schwidefsky si.si_addr = (void __user *) address; 22536bf9680SMartin Schwidefsky force_sig_info(SIGBUS, &si, tsk); 22610c1031fSMartin Schwidefsky } 22710c1031fSMartin Schwidefsky 22850d7280dSMartin Schwidefsky static noinline void do_fault_error(struct pt_regs *regs, long int_code, 22950d7280dSMartin Schwidefsky unsigned long trans_exc_code, int fault) 23050d7280dSMartin Schwidefsky { 23150d7280dSMartin Schwidefsky int si_code; 23250d7280dSMartin Schwidefsky 23350d7280dSMartin Schwidefsky switch (fault) { 23450d7280dSMartin Schwidefsky case VM_FAULT_BADACCESS: 23550d7280dSMartin Schwidefsky case VM_FAULT_BADMAP: 23650d7280dSMartin Schwidefsky /* Bad memory access. Check if it is kernel or user space. */ 23750d7280dSMartin Schwidefsky if (regs->psw.mask & PSW_MASK_PSTATE) { 23850d7280dSMartin Schwidefsky /* User mode accesses just cause a SIGSEGV */ 23950d7280dSMartin Schwidefsky si_code = (fault == VM_FAULT_BADMAP) ? 24050d7280dSMartin Schwidefsky SEGV_MAPERR : SEGV_ACCERR; 24150d7280dSMartin Schwidefsky do_sigsegv(regs, int_code, si_code, trans_exc_code); 24250d7280dSMartin Schwidefsky return; 24350d7280dSMartin Schwidefsky } 24450d7280dSMartin Schwidefsky case VM_FAULT_BADCONTEXT: 24550d7280dSMartin Schwidefsky do_no_context(regs, int_code, trans_exc_code); 24650d7280dSMartin Schwidefsky break; 24750d7280dSMartin Schwidefsky default: /* fault & VM_FAULT_ERROR */ 24899583181SHeiko Carstens if (fault & VM_FAULT_OOM) { 24999583181SHeiko Carstens if (!(regs->psw.mask & PSW_MASK_PSTATE)) 25099583181SHeiko Carstens do_no_context(regs, int_code, trans_exc_code); 25199583181SHeiko Carstens else 25250d7280dSMartin Schwidefsky pagefault_out_of_memory(); 25399583181SHeiko Carstens } else if (fault & VM_FAULT_SIGBUS) { 25450d7280dSMartin Schwidefsky /* Kernel mode? Handle exceptions or die */ 25550d7280dSMartin Schwidefsky if (!(regs->psw.mask & PSW_MASK_PSTATE)) 25650d7280dSMartin Schwidefsky do_no_context(regs, int_code, trans_exc_code); 25736bf9680SMartin Schwidefsky else 25836bf9680SMartin Schwidefsky do_sigbus(regs, int_code, trans_exc_code); 25950d7280dSMartin Schwidefsky } else 26050d7280dSMartin Schwidefsky BUG(); 26150d7280dSMartin Schwidefsky break; 26250d7280dSMartin Schwidefsky } 26350d7280dSMartin Schwidefsky } 26450d7280dSMartin Schwidefsky 2651da177e4SLinus Torvalds /* 2661da177e4SLinus Torvalds * This routine handles page faults. It determines the address, 2671da177e4SLinus Torvalds * and the problem, and then passes it off to one of the appropriate 2681da177e4SLinus Torvalds * routines. 2691da177e4SLinus Torvalds * 27050d7280dSMartin Schwidefsky * interruption code (int_code): 2711da177e4SLinus Torvalds * 04 Protection -> Write-Protection (suprression) 2721da177e4SLinus Torvalds * 10 Segment translation -> Not present (nullification) 2731da177e4SLinus Torvalds * 11 Page translation -> Not present (nullification) 2741da177e4SLinus Torvalds * 3b Region third trans. -> Not present (nullification) 2751da177e4SLinus Torvalds */ 2761ab947deSMartin Schwidefsky static inline int do_exception(struct pt_regs *regs, int access, 27761365e13SMartin Schwidefsky unsigned long trans_exc_code) 2781da177e4SLinus Torvalds { 2791da177e4SLinus Torvalds struct task_struct *tsk; 2801da177e4SLinus Torvalds struct mm_struct *mm; 2811da177e4SLinus Torvalds struct vm_area_struct *vma; 2821da177e4SLinus Torvalds unsigned long address; 28333ce6140SHeiko Carstens unsigned int flags; 28433ce6140SHeiko Carstens int fault; 28510c1031fSMartin Schwidefsky 2867ecb344aSMartin Schwidefsky if (notify_page_fault(regs)) 28750d7280dSMartin Schwidefsky return 0; 2881da177e4SLinus Torvalds 2891da177e4SLinus Torvalds tsk = current; 2901da177e4SLinus Torvalds mm = tsk->mm; 2911da177e4SLinus Torvalds 2921da177e4SLinus Torvalds /* 2931da177e4SLinus Torvalds * Verify that the fault happened in user space, that 2941da177e4SLinus Torvalds * we are not in an interrupt and that there is a 2951da177e4SLinus Torvalds * user context. 2961da177e4SLinus Torvalds */ 29750d7280dSMartin Schwidefsky fault = VM_FAULT_BADCONTEXT; 29861365e13SMartin Schwidefsky if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm)) 29950d7280dSMartin Schwidefsky goto out; 3001da177e4SLinus Torvalds 30161365e13SMartin Schwidefsky address = trans_exc_code & __FAIL_ADDR_MASK; 302a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); 30333ce6140SHeiko Carstens flags = FAULT_FLAG_ALLOW_RETRY; 30433ce6140SHeiko Carstens if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400) 30533ce6140SHeiko Carstens flags |= FAULT_FLAG_WRITE; 3061da177e4SLinus Torvalds down_read(&mm->mmap_sem); 3071da177e4SLinus Torvalds 308e5992f2eSMartin Schwidefsky #ifdef CONFIG_PGSTE 309e5992f2eSMartin Schwidefsky if (test_tsk_thread_flag(current, TIF_SIE) && S390_lowcore.gmap) { 310e5992f2eSMartin Schwidefsky address = gmap_fault(address, 311e5992f2eSMartin Schwidefsky (struct gmap *) S390_lowcore.gmap); 312e5992f2eSMartin Schwidefsky if (address == -EFAULT) { 313e5992f2eSMartin Schwidefsky fault = VM_FAULT_BADMAP; 314e5992f2eSMartin Schwidefsky goto out_up; 315e5992f2eSMartin Schwidefsky } 316e5992f2eSMartin Schwidefsky if (address == -ENOMEM) { 317e5992f2eSMartin Schwidefsky fault = VM_FAULT_OOM; 318e5992f2eSMartin Schwidefsky goto out_up; 319e5992f2eSMartin Schwidefsky } 320e5992f2eSMartin Schwidefsky } 321e5992f2eSMartin Schwidefsky #endif 322e5992f2eSMartin Schwidefsky 323e5992f2eSMartin Schwidefsky retry: 32450d7280dSMartin Schwidefsky fault = VM_FAULT_BADMAP; 3251da177e4SLinus Torvalds vma = find_vma(mm, address); 3261da177e4SLinus Torvalds if (!vma) 32750d7280dSMartin Schwidefsky goto out_up; 328c1821c2eSGerald Schaefer 32950d7280dSMartin Schwidefsky if (unlikely(vma->vm_start > address)) { 3301da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 33150d7280dSMartin Schwidefsky goto out_up; 3321da177e4SLinus Torvalds if (expand_stack(vma, address)) 33350d7280dSMartin Schwidefsky goto out_up; 33450d7280dSMartin Schwidefsky } 33550d7280dSMartin Schwidefsky 3361da177e4SLinus Torvalds /* 3371da177e4SLinus Torvalds * Ok, we have a good vm_area for this memory access, so 3381da177e4SLinus Torvalds * we can handle it.. 3391da177e4SLinus Torvalds */ 34050d7280dSMartin Schwidefsky fault = VM_FAULT_BADACCESS; 3411ab947deSMartin Schwidefsky if (unlikely(!(vma->vm_flags & access))) 34250d7280dSMartin Schwidefsky goto out_up; 3431da177e4SLinus Torvalds 34453492b1dSGerald Schaefer if (is_vm_hugetlb_page(vma)) 34553492b1dSGerald Schaefer address &= HPAGE_MASK; 3461da177e4SLinus Torvalds /* 3471da177e4SLinus Torvalds * If for any reason at all we couldn't handle the fault, 3481da177e4SLinus Torvalds * make sure we exit gracefully rather than endlessly redo 3491da177e4SLinus Torvalds * the fault. 3501da177e4SLinus Torvalds */ 35133ce6140SHeiko Carstens fault = handle_mm_fault(mm, vma, address, flags); 35250d7280dSMartin Schwidefsky if (unlikely(fault & VM_FAULT_ERROR)) 35350d7280dSMartin Schwidefsky goto out_up; 35450d7280dSMartin Schwidefsky 35533ce6140SHeiko Carstens /* 35633ce6140SHeiko Carstens * Major/minor page fault accounting is only done on the 35733ce6140SHeiko Carstens * initial attempt. If we go through a retry, it is extremely 35833ce6140SHeiko Carstens * likely that the page will be found in page cache at that point. 35933ce6140SHeiko Carstens */ 36033ce6140SHeiko Carstens if (flags & FAULT_FLAG_ALLOW_RETRY) { 361bde69af2SHeiko Carstens if (fault & VM_FAULT_MAJOR) { 36283c54070SNick Piggin tsk->maj_flt++; 363a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 364bde69af2SHeiko Carstens regs, address); 365bde69af2SHeiko Carstens } else { 36683c54070SNick Piggin tsk->min_flt++; 367a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 368bde69af2SHeiko Carstens regs, address); 369bde69af2SHeiko Carstens } 37033ce6140SHeiko Carstens if (fault & VM_FAULT_RETRY) { 37133ce6140SHeiko Carstens /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk 37233ce6140SHeiko Carstens * of starvation. */ 37333ce6140SHeiko Carstens flags &= ~FAULT_FLAG_ALLOW_RETRY; 374e5992f2eSMartin Schwidefsky down_read(&mm->mmap_sem); 37533ce6140SHeiko Carstens goto retry; 37633ce6140SHeiko Carstens } 37733ce6140SHeiko Carstens } 3781da177e4SLinus Torvalds /* 3791da177e4SLinus Torvalds * The instruction that caused the program check will 3801da177e4SLinus Torvalds * be repeated. Don't signal single step via SIGTRAP. 3811da177e4SLinus Torvalds */ 3825e9a2692SMartin Schwidefsky clear_tsk_thread_flag(tsk, TIF_PER_TRAP); 38350d7280dSMartin Schwidefsky fault = 0; 38450d7280dSMartin Schwidefsky out_up: 3851da177e4SLinus Torvalds up_read(&mm->mmap_sem); 38650d7280dSMartin Schwidefsky out: 38750d7280dSMartin Schwidefsky return fault; 3881da177e4SLinus Torvalds } 3891da177e4SLinus Torvalds 3901e54622eSMartin Schwidefsky void __kprobes do_protection_exception(struct pt_regs *regs, long pgm_int_code, 3911e54622eSMartin Schwidefsky unsigned long trans_exc_code) 3921da177e4SLinus Torvalds { 39350d7280dSMartin Schwidefsky int fault; 39461365e13SMartin Schwidefsky 39525985edcSLucas De Marchi /* Protection exception is suppressing, decrement psw address. */ 396ccf45cafSMartin Schwidefsky regs->psw.addr = __rewind_psw(regs->psw, pgm_int_code >> 16); 39710c1031fSMartin Schwidefsky /* 39810c1031fSMartin Schwidefsky * Check for low-address protection. This needs to be treated 39910c1031fSMartin Schwidefsky * as a special case because the translation exception code 40010c1031fSMartin Schwidefsky * field is not guaranteed to contain valid data in this case. 40110c1031fSMartin Schwidefsky */ 40261365e13SMartin Schwidefsky if (unlikely(!(trans_exc_code & 4))) { 4031e54622eSMartin Schwidefsky do_low_address(regs, pgm_int_code, trans_exc_code); 40410c1031fSMartin Schwidefsky return; 40510c1031fSMartin Schwidefsky } 4061ab947deSMartin Schwidefsky fault = do_exception(regs, VM_WRITE, trans_exc_code); 40750d7280dSMartin Schwidefsky if (unlikely(fault)) 40850d7280dSMartin Schwidefsky do_fault_error(regs, 4, trans_exc_code, fault); 4091da177e4SLinus Torvalds } 4101da177e4SLinus Torvalds 4111e54622eSMartin Schwidefsky void __kprobes do_dat_exception(struct pt_regs *regs, long pgm_int_code, 4121e54622eSMartin Schwidefsky unsigned long trans_exc_code) 4131da177e4SLinus Torvalds { 4141ab947deSMartin Schwidefsky int access, fault; 41550d7280dSMartin Schwidefsky 4161ab947deSMartin Schwidefsky access = VM_READ | VM_EXEC | VM_WRITE; 4171ab947deSMartin Schwidefsky fault = do_exception(regs, access, trans_exc_code); 41850d7280dSMartin Schwidefsky if (unlikely(fault)) 4191e54622eSMartin Schwidefsky do_fault_error(regs, pgm_int_code & 255, trans_exc_code, fault); 4201da177e4SLinus Torvalds } 4211da177e4SLinus Torvalds 4226252d702SMartin Schwidefsky #ifdef CONFIG_64BIT 4231e54622eSMartin Schwidefsky void __kprobes do_asce_exception(struct pt_regs *regs, long pgm_int_code, 4241e54622eSMartin Schwidefsky unsigned long trans_exc_code) 4256252d702SMartin Schwidefsky { 42650d7280dSMartin Schwidefsky struct mm_struct *mm = current->mm; 4276252d702SMartin Schwidefsky struct vm_area_struct *vma; 4286252d702SMartin Schwidefsky 42961365e13SMartin Schwidefsky if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm)) 4306252d702SMartin Schwidefsky goto no_context; 4316252d702SMartin Schwidefsky 4326252d702SMartin Schwidefsky down_read(&mm->mmap_sem); 43350d7280dSMartin Schwidefsky vma = find_vma(mm, trans_exc_code & __FAIL_ADDR_MASK); 4346252d702SMartin Schwidefsky up_read(&mm->mmap_sem); 4356252d702SMartin Schwidefsky 4366252d702SMartin Schwidefsky if (vma) { 4376252d702SMartin Schwidefsky update_mm(mm, current); 4386252d702SMartin Schwidefsky return; 4396252d702SMartin Schwidefsky } 4406252d702SMartin Schwidefsky 4416252d702SMartin Schwidefsky /* User mode accesses just cause a SIGSEGV */ 4426252d702SMartin Schwidefsky if (regs->psw.mask & PSW_MASK_PSTATE) { 4431e54622eSMartin Schwidefsky do_sigsegv(regs, pgm_int_code, SEGV_MAPERR, trans_exc_code); 4446252d702SMartin Schwidefsky return; 4456252d702SMartin Schwidefsky } 4466252d702SMartin Schwidefsky 4476252d702SMartin Schwidefsky no_context: 4481e54622eSMartin Schwidefsky do_no_context(regs, pgm_int_code, trans_exc_code); 4496252d702SMartin Schwidefsky } 4506252d702SMartin Schwidefsky #endif 4516252d702SMartin Schwidefsky 4521e54622eSMartin Schwidefsky int __handle_fault(unsigned long uaddr, unsigned long pgm_int_code, int write) 4536c1e3e79SGerald Schaefer { 4546c1e3e79SGerald Schaefer struct pt_regs regs; 4556c1e3e79SGerald Schaefer int access, fault; 4566c1e3e79SGerald Schaefer 457b50511e4SMartin Schwidefsky regs.psw.mask = psw_kernel_bits | PSW_MASK_DAT | PSW_MASK_MCHECK; 4586c1e3e79SGerald Schaefer if (!irqs_disabled()) 4596c1e3e79SGerald Schaefer regs.psw.mask |= PSW_MASK_IO | PSW_MASK_EXT; 4606c1e3e79SGerald Schaefer regs.psw.addr = (unsigned long) __builtin_return_address(0); 4616c1e3e79SGerald Schaefer regs.psw.addr |= PSW_ADDR_AMODE; 4626c1e3e79SGerald Schaefer uaddr &= PAGE_MASK; 4631e54622eSMartin Schwidefsky access = write ? VM_WRITE : VM_READ; 4646c1e3e79SGerald Schaefer fault = do_exception(®s, access, uaddr | 2); 4656c1e3e79SGerald Schaefer if (unlikely(fault)) { 46699583181SHeiko Carstens if (fault & VM_FAULT_OOM) 46799583181SHeiko Carstens return -EFAULT; 46899583181SHeiko Carstens else if (fault & VM_FAULT_SIGBUS) 4691e54622eSMartin Schwidefsky do_sigbus(®s, pgm_int_code, uaddr); 4706c1e3e79SGerald Schaefer } 4716c1e3e79SGerald Schaefer return fault ? -EFAULT : 0; 4726c1e3e79SGerald Schaefer } 4736c1e3e79SGerald Schaefer 4741da177e4SLinus Torvalds #ifdef CONFIG_PFAULT 4751da177e4SLinus Torvalds /* 4761da177e4SLinus Torvalds * 'pfault' pseudo page faults routines. 4771da177e4SLinus Torvalds */ 478fb0a9d7eSHeiko Carstens static int pfault_disable; 4791da177e4SLinus Torvalds 4801da177e4SLinus Torvalds static int __init nopfault(char *str) 4811da177e4SLinus Torvalds { 4821da177e4SLinus Torvalds pfault_disable = 1; 4831da177e4SLinus Torvalds return 1; 4841da177e4SLinus Torvalds } 4851da177e4SLinus Torvalds 4861da177e4SLinus Torvalds __setup("nopfault", nopfault); 4871da177e4SLinus Torvalds 4887dd8fe1fSHeiko Carstens struct pfault_refbk { 4897dd8fe1fSHeiko Carstens u16 refdiagc; 4907dd8fe1fSHeiko Carstens u16 reffcode; 4917dd8fe1fSHeiko Carstens u16 refdwlen; 4927dd8fe1fSHeiko Carstens u16 refversn; 4937dd8fe1fSHeiko Carstens u64 refgaddr; 4947dd8fe1fSHeiko Carstens u64 refselmk; 4957dd8fe1fSHeiko Carstens u64 refcmpmk; 4967dd8fe1fSHeiko Carstens u64 reserved; 4977dd8fe1fSHeiko Carstens } __attribute__ ((packed, aligned(8))); 4981da177e4SLinus Torvalds 4991da177e4SLinus Torvalds int pfault_init(void) 5001da177e4SLinus Torvalds { 5017dd8fe1fSHeiko Carstens struct pfault_refbk refbk = { 5027dd8fe1fSHeiko Carstens .refdiagc = 0x258, 5037dd8fe1fSHeiko Carstens .reffcode = 0, 5047dd8fe1fSHeiko Carstens .refdwlen = 5, 5057dd8fe1fSHeiko Carstens .refversn = 2, 5067dd8fe1fSHeiko Carstens .refgaddr = __LC_CURRENT_PID, 5077dd8fe1fSHeiko Carstens .refselmk = 1ULL << 48, 5087dd8fe1fSHeiko Carstens .refcmpmk = 1ULL << 48, 5097dd8fe1fSHeiko Carstens .reserved = __PF_RES_FIELD }; 5101da177e4SLinus Torvalds int rc; 5111da177e4SLinus Torvalds 51229b08d2bSHeiko Carstens if (!MACHINE_IS_VM || pfault_disable) 5131da177e4SLinus Torvalds return -1; 51494c12cc7SMartin Schwidefsky asm volatile( 5151da177e4SLinus Torvalds " diag %1,%0,0x258\n" 5161da177e4SLinus Torvalds "0: j 2f\n" 5171da177e4SLinus Torvalds "1: la %0,8\n" 5181da177e4SLinus Torvalds "2:\n" 51994c12cc7SMartin Schwidefsky EX_TABLE(0b,1b) 520d4b68996SMartin Schwidefsky : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); 5211da177e4SLinus Torvalds return rc; 5221da177e4SLinus Torvalds } 5231da177e4SLinus Torvalds 5241da177e4SLinus Torvalds void pfault_fini(void) 5251da177e4SLinus Torvalds { 5267dd8fe1fSHeiko Carstens struct pfault_refbk refbk = { 5277dd8fe1fSHeiko Carstens .refdiagc = 0x258, 5287dd8fe1fSHeiko Carstens .reffcode = 1, 5297dd8fe1fSHeiko Carstens .refdwlen = 5, 5307dd8fe1fSHeiko Carstens .refversn = 2, 5317dd8fe1fSHeiko Carstens }; 5321da177e4SLinus Torvalds 53329b08d2bSHeiko Carstens if (!MACHINE_IS_VM || pfault_disable) 5341da177e4SLinus Torvalds return; 53594c12cc7SMartin Schwidefsky asm volatile( 5361da177e4SLinus Torvalds " diag %0,0,0x258\n" 5371da177e4SLinus Torvalds "0:\n" 53894c12cc7SMartin Schwidefsky EX_TABLE(0b,0b) 539d4b68996SMartin Schwidefsky : : "a" (&refbk), "m" (refbk) : "cc"); 5401da177e4SLinus Torvalds } 5411da177e4SLinus Torvalds 542f2db2e6cSHeiko Carstens static DEFINE_SPINLOCK(pfault_lock); 543f2db2e6cSHeiko Carstens static LIST_HEAD(pfault_list); 544f2db2e6cSHeiko Carstens 545f6649a7eSMartin Schwidefsky static void pfault_interrupt(unsigned int ext_int_code, 546f6649a7eSMartin Schwidefsky unsigned int param32, unsigned long param64) 5471da177e4SLinus Torvalds { 5481da177e4SLinus Torvalds struct task_struct *tsk; 5491da177e4SLinus Torvalds __u16 subcode; 550f2db2e6cSHeiko Carstens pid_t pid; 5511da177e4SLinus Torvalds 5521da177e4SLinus Torvalds /* 5531da177e4SLinus Torvalds * Get the external interruption subcode & pfault 5541da177e4SLinus Torvalds * initial/completion signal bit. VM stores this 5551da177e4SLinus Torvalds * in the 'cpu address' field associated with the 5561da177e4SLinus Torvalds * external interrupt. 5571da177e4SLinus Torvalds */ 558f6649a7eSMartin Schwidefsky subcode = ext_int_code >> 16; 5591da177e4SLinus Torvalds if ((subcode & 0xff00) != __SUBCODE_MASK) 5601da177e4SLinus Torvalds return; 561a9851832SHeiko Carstens kstat_cpu(smp_processor_id()).irqs[EXTINT_PFL]++; 562f2db2e6cSHeiko Carstens if (subcode & 0x0080) { 563f2db2e6cSHeiko Carstens /* Get the token (= pid of the affected task). */ 564f2db2e6cSHeiko Carstens pid = sizeof(void *) == 4 ? param32 : param64; 565f2db2e6cSHeiko Carstens rcu_read_lock(); 566f2db2e6cSHeiko Carstens tsk = find_task_by_pid_ns(pid, &init_pid_ns); 567f2db2e6cSHeiko Carstens if (tsk) 568f2db2e6cSHeiko Carstens get_task_struct(tsk); 569f2db2e6cSHeiko Carstens rcu_read_unlock(); 570f2db2e6cSHeiko Carstens if (!tsk) 571f2db2e6cSHeiko Carstens return; 572f2db2e6cSHeiko Carstens } else { 573f2db2e6cSHeiko Carstens tsk = current; 574f2db2e6cSHeiko Carstens } 575f2db2e6cSHeiko Carstens spin_lock(&pfault_lock); 5761da177e4SLinus Torvalds if (subcode & 0x0080) { 5771da177e4SLinus Torvalds /* signal bit is set -> a page has been swapped in by VM */ 578f2db2e6cSHeiko Carstens if (tsk->thread.pfault_wait == 1) { 5791da177e4SLinus Torvalds /* Initial interrupt was faster than the completion 5801da177e4SLinus Torvalds * interrupt. pfault_wait is valid. Set pfault_wait 5811da177e4SLinus Torvalds * back to zero and wake up the process. This can 5821da177e4SLinus Torvalds * safely be done because the task is still sleeping 583b6d09449SMartin Schwidefsky * and can't produce new pfaults. */ 5841da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 585f2db2e6cSHeiko Carstens list_del(&tsk->thread.list); 5861da177e4SLinus Torvalds wake_up_process(tsk); 587f2db2e6cSHeiko Carstens } else { 588f2db2e6cSHeiko Carstens /* Completion interrupt was faster than initial 589f2db2e6cSHeiko Carstens * interrupt. Set pfault_wait to -1 so the initial 590f2db2e6cSHeiko Carstens * interrupt doesn't put the task to sleep. */ 591f2db2e6cSHeiko Carstens tsk->thread.pfault_wait = -1; 5921da177e4SLinus Torvalds } 593f2db2e6cSHeiko Carstens put_task_struct(tsk); 5941da177e4SLinus Torvalds } else { 5951da177e4SLinus Torvalds /* signal bit not set -> a real page is missing. */ 596f2db2e6cSHeiko Carstens if (tsk->thread.pfault_wait == -1) { 5971da177e4SLinus Torvalds /* Completion interrupt was faster than the initial 598f2db2e6cSHeiko Carstens * interrupt (pfault_wait == -1). Set pfault_wait 599f2db2e6cSHeiko Carstens * back to zero and exit. */ 6001da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 601f2db2e6cSHeiko Carstens } else { 602f2db2e6cSHeiko Carstens /* Initial interrupt arrived before completion 603f2db2e6cSHeiko Carstens * interrupt. Let the task sleep. */ 604f2db2e6cSHeiko Carstens tsk->thread.pfault_wait = 1; 605f2db2e6cSHeiko Carstens list_add(&tsk->thread.list, &pfault_list); 606f2db2e6cSHeiko Carstens set_task_state(tsk, TASK_UNINTERRUPTIBLE); 6071da177e4SLinus Torvalds set_tsk_need_resched(tsk); 6081da177e4SLinus Torvalds } 6091da177e4SLinus Torvalds } 610f2db2e6cSHeiko Carstens spin_unlock(&pfault_lock); 611f2db2e6cSHeiko Carstens } 612f2db2e6cSHeiko Carstens 613f2db2e6cSHeiko Carstens static int __cpuinit pfault_cpu_notify(struct notifier_block *self, 614f2db2e6cSHeiko Carstens unsigned long action, void *hcpu) 615f2db2e6cSHeiko Carstens { 616f2db2e6cSHeiko Carstens struct thread_struct *thread, *next; 617f2db2e6cSHeiko Carstens struct task_struct *tsk; 618f2db2e6cSHeiko Carstens 619f2db2e6cSHeiko Carstens switch (action) { 620f2db2e6cSHeiko Carstens case CPU_DEAD: 621f2db2e6cSHeiko Carstens case CPU_DEAD_FROZEN: 622f2db2e6cSHeiko Carstens spin_lock_irq(&pfault_lock); 623f2db2e6cSHeiko Carstens list_for_each_entry_safe(thread, next, &pfault_list, list) { 624f2db2e6cSHeiko Carstens thread->pfault_wait = 0; 625f2db2e6cSHeiko Carstens list_del(&thread->list); 626f2db2e6cSHeiko Carstens tsk = container_of(thread, struct task_struct, thread); 627f2db2e6cSHeiko Carstens wake_up_process(tsk); 628f2db2e6cSHeiko Carstens } 629f2db2e6cSHeiko Carstens spin_unlock_irq(&pfault_lock); 630f2db2e6cSHeiko Carstens break; 631f2db2e6cSHeiko Carstens default: 632f2db2e6cSHeiko Carstens break; 633f2db2e6cSHeiko Carstens } 634f2db2e6cSHeiko Carstens return NOTIFY_OK; 635f2db2e6cSHeiko Carstens } 6361da177e4SLinus Torvalds 637fb0a9d7eSHeiko Carstens static int __init pfault_irq_init(void) 63829b08d2bSHeiko Carstens { 639fb0a9d7eSHeiko Carstens int rc; 64029b08d2bSHeiko Carstens 641fb0a9d7eSHeiko Carstens if (!MACHINE_IS_VM) 642fb0a9d7eSHeiko Carstens return 0; 643fb0a9d7eSHeiko Carstens rc = register_external_interrupt(0x2603, pfault_interrupt); 6447dd8fe1fSHeiko Carstens if (rc) 6457dd8fe1fSHeiko Carstens goto out_extint; 6467dd8fe1fSHeiko Carstens rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP; 6477dd8fe1fSHeiko Carstens if (rc) 6487dd8fe1fSHeiko Carstens goto out_pfault; 649df7997abSHeiko Carstens service_subclass_irq_register(); 6507dd8fe1fSHeiko Carstens hotcpu_notifier(pfault_cpu_notify, 0); 6517dd8fe1fSHeiko Carstens return 0; 6527dd8fe1fSHeiko Carstens 6537dd8fe1fSHeiko Carstens out_pfault: 6547dd8fe1fSHeiko Carstens unregister_external_interrupt(0x2603, pfault_interrupt); 6557dd8fe1fSHeiko Carstens out_extint: 656fb0a9d7eSHeiko Carstens pfault_disable = 1; 657fb0a9d7eSHeiko Carstens return rc; 658fb0a9d7eSHeiko Carstens } 659fb0a9d7eSHeiko Carstens early_initcall(pfault_irq_init); 660fb0a9d7eSHeiko Carstens 6617dd8fe1fSHeiko Carstens #endif /* CONFIG_PFAULT */ 662