11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * S390 version 3a53c8fabSHeiko Carstens * Copyright IBM Corp. 1999 41da177e4SLinus Torvalds * Author(s): Hartmut Penner (hp@de.ibm.com) 51da177e4SLinus Torvalds * Ulrich Weigand (uweigand@de.ibm.com) 61da177e4SLinus Torvalds * 71da177e4SLinus Torvalds * Derived from "arch/i386/mm/fault.c" 81da177e4SLinus Torvalds * Copyright (C) 1995 Linus Torvalds 91da177e4SLinus Torvalds */ 101da177e4SLinus Torvalds 11052ff461SHeiko Carstens #include <linux/kernel_stat.h> 12cdd6c482SIngo Molnar #include <linux/perf_event.h> 131da177e4SLinus Torvalds #include <linux/signal.h> 141da177e4SLinus Torvalds #include <linux/sched.h> 151da177e4SLinus Torvalds #include <linux/kernel.h> 161da177e4SLinus Torvalds #include <linux/errno.h> 171da177e4SLinus Torvalds #include <linux/string.h> 181da177e4SLinus Torvalds #include <linux/types.h> 191da177e4SLinus Torvalds #include <linux/ptrace.h> 201da177e4SLinus Torvalds #include <linux/mman.h> 211da177e4SLinus Torvalds #include <linux/mm.h> 227757591aSHeiko Carstens #include <linux/compat.h> 231da177e4SLinus Torvalds #include <linux/smp.h> 241eeb66a1SChristoph Hellwig #include <linux/kdebug.h> 251da177e4SLinus Torvalds #include <linux/init.h> 261da177e4SLinus Torvalds #include <linux/console.h> 271da177e4SLinus Torvalds #include <linux/module.h> 281da177e4SLinus Torvalds #include <linux/hardirq.h> 294ba069b8SMichael Grundy #include <linux/kprobes.h> 30be5ec363SMartin Schwidefsky #include <linux/uaccess.h> 3153492b1dSGerald Schaefer #include <linux/hugetlb.h> 32cbb870c8SHeiko Carstens #include <asm/asm-offsets.h> 331da177e4SLinus Torvalds #include <asm/pgtable.h> 34d7b250e2SHeiko Carstens #include <asm/irq.h> 356252d702SMartin Schwidefsky #include <asm/mmu_context.h> 36a0616cdeSDavid Howells #include <asm/facility.h> 37a806170eSHeiko Carstens #include "../kernel/entry.h" 381da177e4SLinus Torvalds 39347a8dc3SMartin Schwidefsky #ifndef CONFIG_64BIT 401da177e4SLinus Torvalds #define __FAIL_ADDR_MASK 0x7ffff000 411da177e4SLinus Torvalds #define __SUBCODE_MASK 0x0200 421da177e4SLinus Torvalds #define __PF_RES_FIELD 0ULL 43347a8dc3SMartin Schwidefsky #else /* CONFIG_64BIT */ 441da177e4SLinus Torvalds #define __FAIL_ADDR_MASK -4096L 451da177e4SLinus Torvalds #define __SUBCODE_MASK 0x0600 461da177e4SLinus Torvalds #define __PF_RES_FIELD 0x8000000000000000ULL 47347a8dc3SMartin Schwidefsky #endif /* CONFIG_64BIT */ 481da177e4SLinus Torvalds 4950d7280dSMartin Schwidefsky #define VM_FAULT_BADCONTEXT 0x010000 5050d7280dSMartin Schwidefsky #define VM_FAULT_BADMAP 0x020000 5150d7280dSMartin Schwidefsky #define VM_FAULT_BADACCESS 0x040000 52f2c76e3bSHeiko Carstens #define VM_FAULT_SIGNAL 0x080000 5324eb3a82SDominik Dingel #define VM_FAULT_PFAULT 0x100000 5450d7280dSMartin Schwidefsky 55a4f32bdbSHeiko Carstens static unsigned long store_indication __read_mostly; 5692f842eaSMartin Schwidefsky 57a4f32bdbSHeiko Carstens #ifdef CONFIG_64BIT 58a4f32bdbSHeiko Carstens static int __init fault_init(void) 5992f842eaSMartin Schwidefsky { 60a4f32bdbSHeiko Carstens if (test_facility(75)) 6192f842eaSMartin Schwidefsky store_indication = 0xc00; 62a4f32bdbSHeiko Carstens return 0; 6392f842eaSMartin Schwidefsky } 64a4f32bdbSHeiko Carstens early_initcall(fault_init); 65a4f32bdbSHeiko Carstens #endif 6692f842eaSMartin Schwidefsky 677ecb344aSMartin Schwidefsky static inline int notify_page_fault(struct pt_regs *regs) 6810c1031fSMartin Schwidefsky { 6933464e3bSChristoph Hellwig int ret = 0; 7033464e3bSChristoph Hellwig 7133464e3bSChristoph Hellwig /* kprobe_running() needs smp_processor_id() */ 7222e0a046SHeiko Carstens if (kprobes_built_in() && !user_mode(regs)) { 7333464e3bSChristoph Hellwig preempt_disable(); 7433464e3bSChristoph Hellwig if (kprobe_running() && kprobe_fault_handler(regs, 14)) 7533464e3bSChristoph Hellwig ret = 1; 7633464e3bSChristoph Hellwig preempt_enable(); 7733464e3bSChristoph Hellwig } 7833464e3bSChristoph Hellwig return ret; 794ba069b8SMichael Grundy } 804ba069b8SMichael Grundy 811da177e4SLinus Torvalds 821da177e4SLinus Torvalds /* 831da177e4SLinus Torvalds * Unlock any spinlocks which will prevent us from getting the 84cefc8be8SKirill Korotaev * message out. 851da177e4SLinus Torvalds */ 861da177e4SLinus Torvalds void bust_spinlocks(int yes) 871da177e4SLinus Torvalds { 881da177e4SLinus Torvalds if (yes) { 891da177e4SLinus Torvalds oops_in_progress = 1; 901da177e4SLinus Torvalds } else { 911da177e4SLinus Torvalds int loglevel_save = console_loglevel; 921da177e4SLinus Torvalds console_unblank(); 931da177e4SLinus Torvalds oops_in_progress = 0; 941da177e4SLinus Torvalds /* 951da177e4SLinus Torvalds * OK, the message is on the console. Now we call printk() 961da177e4SLinus Torvalds * without oops_in_progress set so that printk will give klogd 971da177e4SLinus Torvalds * a poke. Hold onto your hats... 981da177e4SLinus Torvalds */ 991da177e4SLinus Torvalds console_loglevel = 15; 1001da177e4SLinus Torvalds printk(" "); 1011da177e4SLinus Torvalds console_loglevel = loglevel_save; 1021da177e4SLinus Torvalds } 1031da177e4SLinus Torvalds } 1041da177e4SLinus Torvalds 1051da177e4SLinus Torvalds /* 106482b05ddSGerald Schaefer * Returns the address space associated with the fault. 10761365e13SMartin Schwidefsky * Returns 0 for kernel space and 1 for user space. 1081da177e4SLinus Torvalds */ 10961365e13SMartin Schwidefsky static inline int user_space_fault(unsigned long trans_exc_code) 1101da177e4SLinus Torvalds { 1111da177e4SLinus Torvalds /* 11261365e13SMartin Schwidefsky * The lowest two bits of the translation exception 11361365e13SMartin Schwidefsky * identification indicate which paging table was used. 1141da177e4SLinus Torvalds */ 11561365e13SMartin Schwidefsky trans_exc_code &= 3; 11661365e13SMartin Schwidefsky if (trans_exc_code == 2) 11761365e13SMartin Schwidefsky /* Access via secondary space, set_fs setting decides */ 11861365e13SMartin Schwidefsky return current->thread.mm_segment.ar4; 119482b05ddSGerald Schaefer /* 120e258d719SMartin Schwidefsky * Access via primary space or access register is from user space 12161365e13SMartin Schwidefsky * and access via home space is from the kernel. 122482b05ddSGerald Schaefer */ 12361365e13SMartin Schwidefsky return trans_exc_code != 3; 1241da177e4SLinus Torvalds } 1251da177e4SLinus Torvalds 126aa33c8cbSMartin Schwidefsky static inline void report_user_fault(struct pt_regs *regs, long signr) 127ab3c68eeSHeiko Carstens { 128ab3c68eeSHeiko Carstens if ((task_pid_nr(current) > 1) && !show_unhandled_signals) 129ab3c68eeSHeiko Carstens return; 130ab3c68eeSHeiko Carstens if (!unhandled_signal(current, signr)) 131ab3c68eeSHeiko Carstens return; 132ab3c68eeSHeiko Carstens if (!printk_ratelimit()) 133ab3c68eeSHeiko Carstens return; 134aa33c8cbSMartin Schwidefsky printk(KERN_ALERT "User process fault: interruption code 0x%X ", 135aa33c8cbSMartin Schwidefsky regs->int_code); 136ab3c68eeSHeiko Carstens print_vma_addr(KERN_CONT "in ", regs->psw.addr & PSW_ADDR_INSN); 137aa33c8cbSMartin Schwidefsky printk(KERN_CONT "\n"); 138aa33c8cbSMartin Schwidefsky printk(KERN_ALERT "failing address: %lX\n", 139aa33c8cbSMartin Schwidefsky regs->int_parm_long & __FAIL_ADDR_MASK); 140ab3c68eeSHeiko Carstens show_regs(regs); 141ab3c68eeSHeiko Carstens } 142ab3c68eeSHeiko Carstens 1431da177e4SLinus Torvalds /* 1441da177e4SLinus Torvalds * Send SIGSEGV to task. This is an external routine 1451da177e4SLinus Torvalds * to keep the stack usage of do_page_fault small. 1461da177e4SLinus Torvalds */ 147aa33c8cbSMartin Schwidefsky static noinline void do_sigsegv(struct pt_regs *regs, int si_code) 1481da177e4SLinus Torvalds { 1491da177e4SLinus Torvalds struct siginfo si; 1501da177e4SLinus Torvalds 151aa33c8cbSMartin Schwidefsky report_user_fault(regs, SIGSEGV); 1521da177e4SLinus Torvalds si.si_signo = SIGSEGV; 1531da177e4SLinus Torvalds si.si_code = si_code; 154aa33c8cbSMartin Schwidefsky si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); 1551da177e4SLinus Torvalds force_sig_info(SIGSEGV, &si, current); 1561da177e4SLinus Torvalds } 1571da177e4SLinus Torvalds 158aa33c8cbSMartin Schwidefsky static noinline void do_no_context(struct pt_regs *regs) 15910c1031fSMartin Schwidefsky { 16010c1031fSMartin Schwidefsky const struct exception_table_entry *fixup; 16161365e13SMartin Schwidefsky unsigned long address; 16210c1031fSMartin Schwidefsky 16310c1031fSMartin Schwidefsky /* Are we prepared to handle this kernel fault? */ 16450d7280dSMartin Schwidefsky fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN); 16510c1031fSMartin Schwidefsky if (fixup) { 166eb608fb3SHeiko Carstens regs->psw.addr = extable_fixup(fixup) | PSW_ADDR_AMODE; 16710c1031fSMartin Schwidefsky return; 16810c1031fSMartin Schwidefsky } 16910c1031fSMartin Schwidefsky 17010c1031fSMartin Schwidefsky /* 17110c1031fSMartin Schwidefsky * Oops. The kernel tried to access some bad page. We'll have to 17210c1031fSMartin Schwidefsky * terminate things with extreme prejudice. 17310c1031fSMartin Schwidefsky */ 174aa33c8cbSMartin Schwidefsky address = regs->int_parm_long & __FAIL_ADDR_MASK; 175aa33c8cbSMartin Schwidefsky if (!user_space_fault(regs->int_parm_long)) 17610c1031fSMartin Schwidefsky printk(KERN_ALERT "Unable to handle kernel pointer dereference" 17710c1031fSMartin Schwidefsky " at virtual kernel address %p\n", (void *)address); 17810c1031fSMartin Schwidefsky else 17910c1031fSMartin Schwidefsky printk(KERN_ALERT "Unable to handle kernel paging request" 18010c1031fSMartin Schwidefsky " at virtual user address %p\n", (void *)address); 18110c1031fSMartin Schwidefsky 182aa33c8cbSMartin Schwidefsky die(regs, "Oops"); 18310c1031fSMartin Schwidefsky do_exit(SIGKILL); 18410c1031fSMartin Schwidefsky } 18510c1031fSMartin Schwidefsky 186aa33c8cbSMartin Schwidefsky static noinline void do_low_address(struct pt_regs *regs) 18710c1031fSMartin Schwidefsky { 18810c1031fSMartin Schwidefsky /* Low-address protection hit in kernel mode means 18910c1031fSMartin Schwidefsky NULL pointer write access in kernel mode. */ 19010c1031fSMartin Schwidefsky if (regs->psw.mask & PSW_MASK_PSTATE) { 19110c1031fSMartin Schwidefsky /* Low-address protection hit in user mode 'cannot happen'. */ 192aa33c8cbSMartin Schwidefsky die (regs, "Low-address protection"); 19310c1031fSMartin Schwidefsky do_exit(SIGKILL); 19410c1031fSMartin Schwidefsky } 19510c1031fSMartin Schwidefsky 196aa33c8cbSMartin Schwidefsky do_no_context(regs); 19710c1031fSMartin Schwidefsky } 19810c1031fSMartin Schwidefsky 199aa33c8cbSMartin Schwidefsky static noinline void do_sigbus(struct pt_regs *regs) 20010c1031fSMartin Schwidefsky { 20110c1031fSMartin Schwidefsky struct task_struct *tsk = current; 20236bf9680SMartin Schwidefsky struct siginfo si; 20310c1031fSMartin Schwidefsky 20410c1031fSMartin Schwidefsky /* 20510c1031fSMartin Schwidefsky * Send a sigbus, regardless of whether we were in kernel 20610c1031fSMartin Schwidefsky * or user mode. 20710c1031fSMartin Schwidefsky */ 20836bf9680SMartin Schwidefsky si.si_signo = SIGBUS; 20936bf9680SMartin Schwidefsky si.si_errno = 0; 21036bf9680SMartin Schwidefsky si.si_code = BUS_ADRERR; 211aa33c8cbSMartin Schwidefsky si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); 21236bf9680SMartin Schwidefsky force_sig_info(SIGBUS, &si, tsk); 21310c1031fSMartin Schwidefsky } 21410c1031fSMartin Schwidefsky 215aa33c8cbSMartin Schwidefsky static noinline void do_fault_error(struct pt_regs *regs, int fault) 21650d7280dSMartin Schwidefsky { 21750d7280dSMartin Schwidefsky int si_code; 21850d7280dSMartin Schwidefsky 21950d7280dSMartin Schwidefsky switch (fault) { 22050d7280dSMartin Schwidefsky case VM_FAULT_BADACCESS: 22150d7280dSMartin Schwidefsky case VM_FAULT_BADMAP: 22250d7280dSMartin Schwidefsky /* Bad memory access. Check if it is kernel or user space. */ 2237d256175SHeiko Carstens if (user_mode(regs)) { 22450d7280dSMartin Schwidefsky /* User mode accesses just cause a SIGSEGV */ 22550d7280dSMartin Schwidefsky si_code = (fault == VM_FAULT_BADMAP) ? 22650d7280dSMartin Schwidefsky SEGV_MAPERR : SEGV_ACCERR; 227aa33c8cbSMartin Schwidefsky do_sigsegv(regs, si_code); 22850d7280dSMartin Schwidefsky return; 22950d7280dSMartin Schwidefsky } 23050d7280dSMartin Schwidefsky case VM_FAULT_BADCONTEXT: 23124eb3a82SDominik Dingel case VM_FAULT_PFAULT: 232aa33c8cbSMartin Schwidefsky do_no_context(regs); 23350d7280dSMartin Schwidefsky break; 234f2c76e3bSHeiko Carstens case VM_FAULT_SIGNAL: 235f2c76e3bSHeiko Carstens if (!user_mode(regs)) 236f2c76e3bSHeiko Carstens do_no_context(regs); 237f2c76e3bSHeiko Carstens break; 23850d7280dSMartin Schwidefsky default: /* fault & VM_FAULT_ERROR */ 23999583181SHeiko Carstens if (fault & VM_FAULT_OOM) { 2407d256175SHeiko Carstens if (!user_mode(regs)) 241aa33c8cbSMartin Schwidefsky do_no_context(regs); 24299583181SHeiko Carstens else 24350d7280dSMartin Schwidefsky pagefault_out_of_memory(); 24499583181SHeiko Carstens } else if (fault & VM_FAULT_SIGBUS) { 24550d7280dSMartin Schwidefsky /* Kernel mode? Handle exceptions or die */ 2467d256175SHeiko Carstens if (!user_mode(regs)) 247aa33c8cbSMartin Schwidefsky do_no_context(regs); 24836bf9680SMartin Schwidefsky else 249aa33c8cbSMartin Schwidefsky do_sigbus(regs); 25050d7280dSMartin Schwidefsky } else 25150d7280dSMartin Schwidefsky BUG(); 25250d7280dSMartin Schwidefsky break; 25350d7280dSMartin Schwidefsky } 25450d7280dSMartin Schwidefsky } 25550d7280dSMartin Schwidefsky 2561da177e4SLinus Torvalds /* 2571da177e4SLinus Torvalds * This routine handles page faults. It determines the address, 2581da177e4SLinus Torvalds * and the problem, and then passes it off to one of the appropriate 2591da177e4SLinus Torvalds * routines. 2601da177e4SLinus Torvalds * 26150d7280dSMartin Schwidefsky * interruption code (int_code): 2621da177e4SLinus Torvalds * 04 Protection -> Write-Protection (suprression) 2631da177e4SLinus Torvalds * 10 Segment translation -> Not present (nullification) 2641da177e4SLinus Torvalds * 11 Page translation -> Not present (nullification) 2651da177e4SLinus Torvalds * 3b Region third trans. -> Not present (nullification) 2661da177e4SLinus Torvalds */ 267aa33c8cbSMartin Schwidefsky static inline int do_exception(struct pt_regs *regs, int access) 2681da177e4SLinus Torvalds { 26924eb3a82SDominik Dingel #ifdef CONFIG_PGSTE 27024eb3a82SDominik Dingel struct gmap *gmap; 27124eb3a82SDominik Dingel #endif 2721da177e4SLinus Torvalds struct task_struct *tsk; 2731da177e4SLinus Torvalds struct mm_struct *mm; 2741da177e4SLinus Torvalds struct vm_area_struct *vma; 275aa33c8cbSMartin Schwidefsky unsigned long trans_exc_code; 2761da177e4SLinus Torvalds unsigned long address; 27733ce6140SHeiko Carstens unsigned int flags; 27833ce6140SHeiko Carstens int fault; 27910c1031fSMartin Schwidefsky 28039efd4ecSMartin Schwidefsky tsk = current; 28139efd4ecSMartin Schwidefsky /* 28239efd4ecSMartin Schwidefsky * The instruction that caused the program check has 28339efd4ecSMartin Schwidefsky * been nullified. Don't signal single step via SIGTRAP. 28439efd4ecSMartin Schwidefsky */ 28539efd4ecSMartin Schwidefsky clear_tsk_thread_flag(tsk, TIF_PER_TRAP); 28639efd4ecSMartin Schwidefsky 2877ecb344aSMartin Schwidefsky if (notify_page_fault(regs)) 28850d7280dSMartin Schwidefsky return 0; 2891da177e4SLinus Torvalds 2901da177e4SLinus Torvalds mm = tsk->mm; 291aa33c8cbSMartin Schwidefsky trans_exc_code = regs->int_parm_long; 2921da177e4SLinus Torvalds 2931da177e4SLinus Torvalds /* 2941da177e4SLinus Torvalds * Verify that the fault happened in user space, that 2951da177e4SLinus Torvalds * we are not in an interrupt and that there is a 2961da177e4SLinus Torvalds * user context. 2971da177e4SLinus Torvalds */ 29850d7280dSMartin Schwidefsky fault = VM_FAULT_BADCONTEXT; 29961365e13SMartin Schwidefsky if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm)) 30050d7280dSMartin Schwidefsky goto out; 3011da177e4SLinus Torvalds 30261365e13SMartin Schwidefsky address = trans_exc_code & __FAIL_ADDR_MASK; 303a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); 304f2c76e3bSHeiko Carstens flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; 305759496baSJohannes Weiner if (user_mode(regs)) 306759496baSJohannes Weiner flags |= FAULT_FLAG_USER; 30733ce6140SHeiko Carstens if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400) 30833ce6140SHeiko Carstens flags |= FAULT_FLAG_WRITE; 3091da177e4SLinus Torvalds down_read(&mm->mmap_sem); 3101da177e4SLinus Torvalds 311e5992f2eSMartin Schwidefsky #ifdef CONFIG_PGSTE 31224eb3a82SDominik Dingel gmap = (struct gmap *) 31324eb3a82SDominik Dingel ((current->flags & PF_VCPU) ? S390_lowcore.gmap : 0); 31424eb3a82SDominik Dingel if (gmap) { 31524eb3a82SDominik Dingel address = __gmap_fault(address, gmap); 316e5992f2eSMartin Schwidefsky if (address == -EFAULT) { 317e5992f2eSMartin Schwidefsky fault = VM_FAULT_BADMAP; 318e5992f2eSMartin Schwidefsky goto out_up; 319e5992f2eSMartin Schwidefsky } 320e5992f2eSMartin Schwidefsky if (address == -ENOMEM) { 321e5992f2eSMartin Schwidefsky fault = VM_FAULT_OOM; 322e5992f2eSMartin Schwidefsky goto out_up; 323e5992f2eSMartin Schwidefsky } 32424eb3a82SDominik Dingel if (gmap->pfault_enabled) 32524eb3a82SDominik Dingel flags |= FAULT_FLAG_RETRY_NOWAIT; 326e5992f2eSMartin Schwidefsky } 327e5992f2eSMartin Schwidefsky #endif 328e5992f2eSMartin Schwidefsky 329e5992f2eSMartin Schwidefsky retry: 33050d7280dSMartin Schwidefsky fault = VM_FAULT_BADMAP; 3311da177e4SLinus Torvalds vma = find_vma(mm, address); 3321da177e4SLinus Torvalds if (!vma) 33350d7280dSMartin Schwidefsky goto out_up; 334c1821c2eSGerald Schaefer 33550d7280dSMartin Schwidefsky if (unlikely(vma->vm_start > address)) { 3361da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 33750d7280dSMartin Schwidefsky goto out_up; 3381da177e4SLinus Torvalds if (expand_stack(vma, address)) 33950d7280dSMartin Schwidefsky goto out_up; 34050d7280dSMartin Schwidefsky } 34150d7280dSMartin Schwidefsky 3421da177e4SLinus Torvalds /* 3431da177e4SLinus Torvalds * Ok, we have a good vm_area for this memory access, so 3441da177e4SLinus Torvalds * we can handle it.. 3451da177e4SLinus Torvalds */ 34650d7280dSMartin Schwidefsky fault = VM_FAULT_BADACCESS; 3471ab947deSMartin Schwidefsky if (unlikely(!(vma->vm_flags & access))) 34850d7280dSMartin Schwidefsky goto out_up; 3491da177e4SLinus Torvalds 35053492b1dSGerald Schaefer if (is_vm_hugetlb_page(vma)) 35153492b1dSGerald Schaefer address &= HPAGE_MASK; 3521da177e4SLinus Torvalds /* 3531da177e4SLinus Torvalds * If for any reason at all we couldn't handle the fault, 3541da177e4SLinus Torvalds * make sure we exit gracefully rather than endlessly redo 3551da177e4SLinus Torvalds * the fault. 3561da177e4SLinus Torvalds */ 35733ce6140SHeiko Carstens fault = handle_mm_fault(mm, vma, address, flags); 358f2c76e3bSHeiko Carstens /* No reason to continue if interrupted by SIGKILL. */ 359f2c76e3bSHeiko Carstens if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { 360f2c76e3bSHeiko Carstens fault = VM_FAULT_SIGNAL; 361f2c76e3bSHeiko Carstens goto out; 362f2c76e3bSHeiko Carstens } 36350d7280dSMartin Schwidefsky if (unlikely(fault & VM_FAULT_ERROR)) 36450d7280dSMartin Schwidefsky goto out_up; 36550d7280dSMartin Schwidefsky 36633ce6140SHeiko Carstens /* 36733ce6140SHeiko Carstens * Major/minor page fault accounting is only done on the 36833ce6140SHeiko Carstens * initial attempt. If we go through a retry, it is extremely 36933ce6140SHeiko Carstens * likely that the page will be found in page cache at that point. 37033ce6140SHeiko Carstens */ 37133ce6140SHeiko Carstens if (flags & FAULT_FLAG_ALLOW_RETRY) { 372bde69af2SHeiko Carstens if (fault & VM_FAULT_MAJOR) { 37383c54070SNick Piggin tsk->maj_flt++; 374a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 375bde69af2SHeiko Carstens regs, address); 376bde69af2SHeiko Carstens } else { 37783c54070SNick Piggin tsk->min_flt++; 378a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 379bde69af2SHeiko Carstens regs, address); 380bde69af2SHeiko Carstens } 38133ce6140SHeiko Carstens if (fault & VM_FAULT_RETRY) { 38224eb3a82SDominik Dingel #ifdef CONFIG_PGSTE 38324eb3a82SDominik Dingel if (gmap && (flags & FAULT_FLAG_RETRY_NOWAIT)) { 38424eb3a82SDominik Dingel /* FAULT_FLAG_RETRY_NOWAIT has been set, 38524eb3a82SDominik Dingel * mmap_sem has not been released */ 38624eb3a82SDominik Dingel current->thread.gmap_pfault = 1; 38724eb3a82SDominik Dingel fault = VM_FAULT_PFAULT; 38824eb3a82SDominik Dingel goto out_up; 38924eb3a82SDominik Dingel } 39024eb3a82SDominik Dingel #endif 39133ce6140SHeiko Carstens /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk 39233ce6140SHeiko Carstens * of starvation. */ 39324eb3a82SDominik Dingel flags &= ~(FAULT_FLAG_ALLOW_RETRY | 39424eb3a82SDominik Dingel FAULT_FLAG_RETRY_NOWAIT); 39545cac65bSShaohua Li flags |= FAULT_FLAG_TRIED; 396e5992f2eSMartin Schwidefsky down_read(&mm->mmap_sem); 39733ce6140SHeiko Carstens goto retry; 39833ce6140SHeiko Carstens } 39933ce6140SHeiko Carstens } 40050d7280dSMartin Schwidefsky fault = 0; 40150d7280dSMartin Schwidefsky out_up: 4021da177e4SLinus Torvalds up_read(&mm->mmap_sem); 40350d7280dSMartin Schwidefsky out: 40450d7280dSMartin Schwidefsky return fault; 4051da177e4SLinus Torvalds } 4061da177e4SLinus Torvalds 407aa33c8cbSMartin Schwidefsky void __kprobes do_protection_exception(struct pt_regs *regs) 4081da177e4SLinus Torvalds { 409aa33c8cbSMartin Schwidefsky unsigned long trans_exc_code; 41050d7280dSMartin Schwidefsky int fault; 41161365e13SMartin Schwidefsky 412aa33c8cbSMartin Schwidefsky trans_exc_code = regs->int_parm_long; 413f752ac4dSMartin Schwidefsky /* 414f752ac4dSMartin Schwidefsky * Protection exceptions are suppressing, decrement psw address. 415f752ac4dSMartin Schwidefsky * The exception to this rule are aborted transactions, for these 416f752ac4dSMartin Schwidefsky * the PSW already points to the correct location. 417f752ac4dSMartin Schwidefsky */ 418f752ac4dSMartin Schwidefsky if (!(regs->int_code & 0x200)) 419aa33c8cbSMartin Schwidefsky regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16); 42010c1031fSMartin Schwidefsky /* 42110c1031fSMartin Schwidefsky * Check for low-address protection. This needs to be treated 42210c1031fSMartin Schwidefsky * as a special case because the translation exception code 42310c1031fSMartin Schwidefsky * field is not guaranteed to contain valid data in this case. 42410c1031fSMartin Schwidefsky */ 42561365e13SMartin Schwidefsky if (unlikely(!(trans_exc_code & 4))) { 426aa33c8cbSMartin Schwidefsky do_low_address(regs); 42710c1031fSMartin Schwidefsky return; 42810c1031fSMartin Schwidefsky } 429aa33c8cbSMartin Schwidefsky fault = do_exception(regs, VM_WRITE); 43050d7280dSMartin Schwidefsky if (unlikely(fault)) 431aa33c8cbSMartin Schwidefsky do_fault_error(regs, fault); 4321da177e4SLinus Torvalds } 4331da177e4SLinus Torvalds 434aa33c8cbSMartin Schwidefsky void __kprobes do_dat_exception(struct pt_regs *regs) 4351da177e4SLinus Torvalds { 4361ab947deSMartin Schwidefsky int access, fault; 43750d7280dSMartin Schwidefsky 4381ab947deSMartin Schwidefsky access = VM_READ | VM_EXEC | VM_WRITE; 439aa33c8cbSMartin Schwidefsky fault = do_exception(regs, access); 44050d7280dSMartin Schwidefsky if (unlikely(fault)) 441aa33c8cbSMartin Schwidefsky do_fault_error(regs, fault); 4421da177e4SLinus Torvalds } 4431da177e4SLinus Torvalds 4441e54622eSMartin Schwidefsky int __handle_fault(unsigned long uaddr, unsigned long pgm_int_code, int write) 4456c1e3e79SGerald Schaefer { 4466c1e3e79SGerald Schaefer struct pt_regs regs; 4476c1e3e79SGerald Schaefer int access, fault; 4486c1e3e79SGerald Schaefer 449008c2e8fSHeiko Carstens /* Emulate a uaccess fault from kernel mode. */ 450e258d719SMartin Schwidefsky regs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT | PSW_MASK_MCHECK; 4516c1e3e79SGerald Schaefer if (!irqs_disabled()) 4526c1e3e79SGerald Schaefer regs.psw.mask |= PSW_MASK_IO | PSW_MASK_EXT; 4536c1e3e79SGerald Schaefer regs.psw.addr = (unsigned long) __builtin_return_address(0); 4546c1e3e79SGerald Schaefer regs.psw.addr |= PSW_ADDR_AMODE; 455aa33c8cbSMartin Schwidefsky regs.int_code = pgm_int_code; 456aa33c8cbSMartin Schwidefsky regs.int_parm_long = (uaddr & PAGE_MASK) | 2; 4571e54622eSMartin Schwidefsky access = write ? VM_WRITE : VM_READ; 458aa33c8cbSMartin Schwidefsky fault = do_exception(®s, access); 459008c2e8fSHeiko Carstens /* 460008c2e8fSHeiko Carstens * Since the fault happened in kernel mode while performing a uaccess 461008c2e8fSHeiko Carstens * all we need to do now is emulating a fixup in case "fault" is not 462008c2e8fSHeiko Carstens * zero. 463008c2e8fSHeiko Carstens * For the calling uaccess functions this results always in -EFAULT. 464008c2e8fSHeiko Carstens */ 4656c1e3e79SGerald Schaefer return fault ? -EFAULT : 0; 4666c1e3e79SGerald Schaefer } 4676c1e3e79SGerald Schaefer 4681da177e4SLinus Torvalds #ifdef CONFIG_PFAULT 4691da177e4SLinus Torvalds /* 4701da177e4SLinus Torvalds * 'pfault' pseudo page faults routines. 4711da177e4SLinus Torvalds */ 472fb0a9d7eSHeiko Carstens static int pfault_disable; 4731da177e4SLinus Torvalds 4741da177e4SLinus Torvalds static int __init nopfault(char *str) 4751da177e4SLinus Torvalds { 4761da177e4SLinus Torvalds pfault_disable = 1; 4771da177e4SLinus Torvalds return 1; 4781da177e4SLinus Torvalds } 4791da177e4SLinus Torvalds 4801da177e4SLinus Torvalds __setup("nopfault", nopfault); 4811da177e4SLinus Torvalds 4827dd8fe1fSHeiko Carstens struct pfault_refbk { 4837dd8fe1fSHeiko Carstens u16 refdiagc; 4847dd8fe1fSHeiko Carstens u16 reffcode; 4857dd8fe1fSHeiko Carstens u16 refdwlen; 4867dd8fe1fSHeiko Carstens u16 refversn; 4877dd8fe1fSHeiko Carstens u64 refgaddr; 4887dd8fe1fSHeiko Carstens u64 refselmk; 4897dd8fe1fSHeiko Carstens u64 refcmpmk; 4907dd8fe1fSHeiko Carstens u64 reserved; 4917dd8fe1fSHeiko Carstens } __attribute__ ((packed, aligned(8))); 4921da177e4SLinus Torvalds 4931da177e4SLinus Torvalds int pfault_init(void) 4941da177e4SLinus Torvalds { 4957dd8fe1fSHeiko Carstens struct pfault_refbk refbk = { 4967dd8fe1fSHeiko Carstens .refdiagc = 0x258, 4977dd8fe1fSHeiko Carstens .reffcode = 0, 4987dd8fe1fSHeiko Carstens .refdwlen = 5, 4997dd8fe1fSHeiko Carstens .refversn = 2, 5007dd8fe1fSHeiko Carstens .refgaddr = __LC_CURRENT_PID, 5017dd8fe1fSHeiko Carstens .refselmk = 1ULL << 48, 5027dd8fe1fSHeiko Carstens .refcmpmk = 1ULL << 48, 5037dd8fe1fSHeiko Carstens .reserved = __PF_RES_FIELD }; 5041da177e4SLinus Torvalds int rc; 5051da177e4SLinus Torvalds 506f32269a0SCarsten Otte if (pfault_disable) 5071da177e4SLinus Torvalds return -1; 50894c12cc7SMartin Schwidefsky asm volatile( 5091da177e4SLinus Torvalds " diag %1,%0,0x258\n" 5101da177e4SLinus Torvalds "0: j 2f\n" 5111da177e4SLinus Torvalds "1: la %0,8\n" 5121da177e4SLinus Torvalds "2:\n" 51394c12cc7SMartin Schwidefsky EX_TABLE(0b,1b) 514d4b68996SMartin Schwidefsky : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); 5151da177e4SLinus Torvalds return rc; 5161da177e4SLinus Torvalds } 5171da177e4SLinus Torvalds 5181da177e4SLinus Torvalds void pfault_fini(void) 5191da177e4SLinus Torvalds { 5207dd8fe1fSHeiko Carstens struct pfault_refbk refbk = { 5217dd8fe1fSHeiko Carstens .refdiagc = 0x258, 5227dd8fe1fSHeiko Carstens .reffcode = 1, 5237dd8fe1fSHeiko Carstens .refdwlen = 5, 5247dd8fe1fSHeiko Carstens .refversn = 2, 5257dd8fe1fSHeiko Carstens }; 5261da177e4SLinus Torvalds 527f32269a0SCarsten Otte if (pfault_disable) 5281da177e4SLinus Torvalds return; 52994c12cc7SMartin Schwidefsky asm volatile( 5301da177e4SLinus Torvalds " diag %0,0,0x258\n" 5311da177e4SLinus Torvalds "0:\n" 53294c12cc7SMartin Schwidefsky EX_TABLE(0b,0b) 533d4b68996SMartin Schwidefsky : : "a" (&refbk), "m" (refbk) : "cc"); 5341da177e4SLinus Torvalds } 5351da177e4SLinus Torvalds 536f2db2e6cSHeiko Carstens static DEFINE_SPINLOCK(pfault_lock); 537f2db2e6cSHeiko Carstens static LIST_HEAD(pfault_list); 538f2db2e6cSHeiko Carstens 539fde15c3aSHeiko Carstens static void pfault_interrupt(struct ext_code ext_code, 540f6649a7eSMartin Schwidefsky unsigned int param32, unsigned long param64) 5411da177e4SLinus Torvalds { 5421da177e4SLinus Torvalds struct task_struct *tsk; 5431da177e4SLinus Torvalds __u16 subcode; 544f2db2e6cSHeiko Carstens pid_t pid; 5451da177e4SLinus Torvalds 5461da177e4SLinus Torvalds /* 5471da177e4SLinus Torvalds * Get the external interruption subcode & pfault 5481da177e4SLinus Torvalds * initial/completion signal bit. VM stores this 5491da177e4SLinus Torvalds * in the 'cpu address' field associated with the 5501da177e4SLinus Torvalds * external interrupt. 5511da177e4SLinus Torvalds */ 552fde15c3aSHeiko Carstens subcode = ext_code.subcode; 5531da177e4SLinus Torvalds if ((subcode & 0xff00) != __SUBCODE_MASK) 5541da177e4SLinus Torvalds return; 555420f42ecSHeiko Carstens inc_irq_stat(IRQEXT_PFL); 556f2db2e6cSHeiko Carstens /* Get the token (= pid of the affected task). */ 557f2db2e6cSHeiko Carstens pid = sizeof(void *) == 4 ? param32 : param64; 558f2db2e6cSHeiko Carstens rcu_read_lock(); 559f2db2e6cSHeiko Carstens tsk = find_task_by_pid_ns(pid, &init_pid_ns); 560f2db2e6cSHeiko Carstens if (tsk) 561f2db2e6cSHeiko Carstens get_task_struct(tsk); 562f2db2e6cSHeiko Carstens rcu_read_unlock(); 563f2db2e6cSHeiko Carstens if (!tsk) 564f2db2e6cSHeiko Carstens return; 565f2db2e6cSHeiko Carstens spin_lock(&pfault_lock); 5661da177e4SLinus Torvalds if (subcode & 0x0080) { 5671da177e4SLinus Torvalds /* signal bit is set -> a page has been swapped in by VM */ 568f2db2e6cSHeiko Carstens if (tsk->thread.pfault_wait == 1) { 5691da177e4SLinus Torvalds /* Initial interrupt was faster than the completion 5701da177e4SLinus Torvalds * interrupt. pfault_wait is valid. Set pfault_wait 5711da177e4SLinus Torvalds * back to zero and wake up the process. This can 5721da177e4SLinus Torvalds * safely be done because the task is still sleeping 573b6d09449SMartin Schwidefsky * and can't produce new pfaults. */ 5741da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 575f2db2e6cSHeiko Carstens list_del(&tsk->thread.list); 5761da177e4SLinus Torvalds wake_up_process(tsk); 577d5e50a51SHeiko Carstens put_task_struct(tsk); 578f2db2e6cSHeiko Carstens } else { 579f2db2e6cSHeiko Carstens /* Completion interrupt was faster than initial 580f2db2e6cSHeiko Carstens * interrupt. Set pfault_wait to -1 so the initial 581fa2fb2f4SHeiko Carstens * interrupt doesn't put the task to sleep. 582fa2fb2f4SHeiko Carstens * If the task is not running, ignore the completion 583fa2fb2f4SHeiko Carstens * interrupt since it must be a leftover of a PFAULT 584fa2fb2f4SHeiko Carstens * CANCEL operation which didn't remove all pending 585fa2fb2f4SHeiko Carstens * completion interrupts. */ 586fa2fb2f4SHeiko Carstens if (tsk->state == TASK_RUNNING) 587f2db2e6cSHeiko Carstens tsk->thread.pfault_wait = -1; 5881da177e4SLinus Torvalds } 5891da177e4SLinus Torvalds } else { 5901da177e4SLinus Torvalds /* signal bit not set -> a real page is missing. */ 591d49f47f8SHeiko Carstens if (WARN_ON_ONCE(tsk != current)) 592d49f47f8SHeiko Carstens goto out; 593d5e50a51SHeiko Carstens if (tsk->thread.pfault_wait == 1) { 594d5e50a51SHeiko Carstens /* Already on the list with a reference: put to sleep */ 5950a16ba78SHeiko Carstens __set_task_state(tsk, TASK_UNINTERRUPTIBLE); 596d5e50a51SHeiko Carstens set_tsk_need_resched(tsk); 597d5e50a51SHeiko Carstens } else if (tsk->thread.pfault_wait == -1) { 5981da177e4SLinus Torvalds /* Completion interrupt was faster than the initial 599f2db2e6cSHeiko Carstens * interrupt (pfault_wait == -1). Set pfault_wait 600f2db2e6cSHeiko Carstens * back to zero and exit. */ 6011da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 602f2db2e6cSHeiko Carstens } else { 603f2db2e6cSHeiko Carstens /* Initial interrupt arrived before completion 604d5e50a51SHeiko Carstens * interrupt. Let the task sleep. 605d5e50a51SHeiko Carstens * An extra task reference is needed since a different 606d5e50a51SHeiko Carstens * cpu may set the task state to TASK_RUNNING again 607d5e50a51SHeiko Carstens * before the scheduler is reached. */ 608d5e50a51SHeiko Carstens get_task_struct(tsk); 609f2db2e6cSHeiko Carstens tsk->thread.pfault_wait = 1; 610f2db2e6cSHeiko Carstens list_add(&tsk->thread.list, &pfault_list); 6110a16ba78SHeiko Carstens __set_task_state(tsk, TASK_UNINTERRUPTIBLE); 6121da177e4SLinus Torvalds set_tsk_need_resched(tsk); 6131da177e4SLinus Torvalds } 6141da177e4SLinus Torvalds } 615d49f47f8SHeiko Carstens out: 616f2db2e6cSHeiko Carstens spin_unlock(&pfault_lock); 61754c27791SHeiko Carstens put_task_struct(tsk); 618f2db2e6cSHeiko Carstens } 619f2db2e6cSHeiko Carstens 620e2741f17SPaul Gortmaker static int pfault_cpu_notify(struct notifier_block *self, unsigned long action, 621e2741f17SPaul Gortmaker void *hcpu) 622f2db2e6cSHeiko Carstens { 623f2db2e6cSHeiko Carstens struct thread_struct *thread, *next; 624f2db2e6cSHeiko Carstens struct task_struct *tsk; 625f2db2e6cSHeiko Carstens 6261c725922SHeiko Carstens switch (action & ~CPU_TASKS_FROZEN) { 627f2db2e6cSHeiko Carstens case CPU_DEAD: 628f2db2e6cSHeiko Carstens spin_lock_irq(&pfault_lock); 629f2db2e6cSHeiko Carstens list_for_each_entry_safe(thread, next, &pfault_list, list) { 630f2db2e6cSHeiko Carstens thread->pfault_wait = 0; 631f2db2e6cSHeiko Carstens list_del(&thread->list); 632f2db2e6cSHeiko Carstens tsk = container_of(thread, struct task_struct, thread); 633f2db2e6cSHeiko Carstens wake_up_process(tsk); 634d5e50a51SHeiko Carstens put_task_struct(tsk); 635f2db2e6cSHeiko Carstens } 636f2db2e6cSHeiko Carstens spin_unlock_irq(&pfault_lock); 637f2db2e6cSHeiko Carstens break; 638f2db2e6cSHeiko Carstens default: 639f2db2e6cSHeiko Carstens break; 640f2db2e6cSHeiko Carstens } 641f2db2e6cSHeiko Carstens return NOTIFY_OK; 642f2db2e6cSHeiko Carstens } 6431da177e4SLinus Torvalds 644fb0a9d7eSHeiko Carstens static int __init pfault_irq_init(void) 64529b08d2bSHeiko Carstens { 646fb0a9d7eSHeiko Carstens int rc; 64729b08d2bSHeiko Carstens 648fb0a9d7eSHeiko Carstens rc = register_external_interrupt(0x2603, pfault_interrupt); 6497dd8fe1fSHeiko Carstens if (rc) 6507dd8fe1fSHeiko Carstens goto out_extint; 6517dd8fe1fSHeiko Carstens rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP; 6527dd8fe1fSHeiko Carstens if (rc) 6537dd8fe1fSHeiko Carstens goto out_pfault; 65482003c3eSHeiko Carstens irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL); 6557dd8fe1fSHeiko Carstens hotcpu_notifier(pfault_cpu_notify, 0); 6567dd8fe1fSHeiko Carstens return 0; 6577dd8fe1fSHeiko Carstens 6587dd8fe1fSHeiko Carstens out_pfault: 6597dd8fe1fSHeiko Carstens unregister_external_interrupt(0x2603, pfault_interrupt); 6607dd8fe1fSHeiko Carstens out_extint: 661fb0a9d7eSHeiko Carstens pfault_disable = 1; 662fb0a9d7eSHeiko Carstens return rc; 663fb0a9d7eSHeiko Carstens } 664fb0a9d7eSHeiko Carstens early_initcall(pfault_irq_init); 665fb0a9d7eSHeiko Carstens 6667dd8fe1fSHeiko Carstens #endif /* CONFIG_PFAULT */ 667