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 5350d7280dSMartin Schwidefsky 54a4f32bdbSHeiko Carstens static unsigned long store_indication __read_mostly; 5592f842eaSMartin Schwidefsky 56a4f32bdbSHeiko Carstens #ifdef CONFIG_64BIT 57a4f32bdbSHeiko Carstens static int __init fault_init(void) 5892f842eaSMartin Schwidefsky { 59a4f32bdbSHeiko Carstens if (test_facility(75)) 6092f842eaSMartin Schwidefsky store_indication = 0xc00; 61a4f32bdbSHeiko Carstens return 0; 6292f842eaSMartin Schwidefsky } 63a4f32bdbSHeiko Carstens early_initcall(fault_init); 64a4f32bdbSHeiko Carstens #endif 6592f842eaSMartin Schwidefsky 667ecb344aSMartin Schwidefsky static inline int notify_page_fault(struct pt_regs *regs) 6710c1031fSMartin Schwidefsky { 6833464e3bSChristoph Hellwig int ret = 0; 6933464e3bSChristoph Hellwig 7033464e3bSChristoph Hellwig /* kprobe_running() needs smp_processor_id() */ 7122e0a046SHeiko Carstens if (kprobes_built_in() && !user_mode(regs)) { 7233464e3bSChristoph Hellwig preempt_disable(); 7333464e3bSChristoph Hellwig if (kprobe_running() && kprobe_fault_handler(regs, 14)) 7433464e3bSChristoph Hellwig ret = 1; 7533464e3bSChristoph Hellwig preempt_enable(); 7633464e3bSChristoph Hellwig } 7733464e3bSChristoph Hellwig return ret; 784ba069b8SMichael Grundy } 794ba069b8SMichael Grundy 801da177e4SLinus Torvalds 811da177e4SLinus Torvalds /* 821da177e4SLinus Torvalds * Unlock any spinlocks which will prevent us from getting the 83cefc8be8SKirill Korotaev * message out. 841da177e4SLinus Torvalds */ 851da177e4SLinus Torvalds void bust_spinlocks(int yes) 861da177e4SLinus Torvalds { 871da177e4SLinus Torvalds if (yes) { 881da177e4SLinus Torvalds oops_in_progress = 1; 891da177e4SLinus Torvalds } else { 901da177e4SLinus Torvalds int loglevel_save = console_loglevel; 911da177e4SLinus Torvalds console_unblank(); 921da177e4SLinus Torvalds oops_in_progress = 0; 931da177e4SLinus Torvalds /* 941da177e4SLinus Torvalds * OK, the message is on the console. Now we call printk() 951da177e4SLinus Torvalds * without oops_in_progress set so that printk will give klogd 961da177e4SLinus Torvalds * a poke. Hold onto your hats... 971da177e4SLinus Torvalds */ 981da177e4SLinus Torvalds console_loglevel = 15; 991da177e4SLinus Torvalds printk(" "); 1001da177e4SLinus Torvalds console_loglevel = loglevel_save; 1011da177e4SLinus Torvalds } 1021da177e4SLinus Torvalds } 1031da177e4SLinus Torvalds 1041da177e4SLinus Torvalds /* 105482b05ddSGerald Schaefer * Returns the address space associated with the fault. 10661365e13SMartin Schwidefsky * Returns 0 for kernel space and 1 for user space. 1071da177e4SLinus Torvalds */ 10861365e13SMartin Schwidefsky static inline int user_space_fault(unsigned long trans_exc_code) 1091da177e4SLinus Torvalds { 1101da177e4SLinus Torvalds /* 11161365e13SMartin Schwidefsky * The lowest two bits of the translation exception 11261365e13SMartin Schwidefsky * identification indicate which paging table was used. 1131da177e4SLinus Torvalds */ 11461365e13SMartin Schwidefsky trans_exc_code &= 3; 11561365e13SMartin Schwidefsky if (trans_exc_code == 2) 11661365e13SMartin Schwidefsky /* Access via secondary space, set_fs setting decides */ 11761365e13SMartin Schwidefsky return current->thread.mm_segment.ar4; 118482b05ddSGerald Schaefer /* 119e258d719SMartin Schwidefsky * Access via primary space or access register is from user space 12061365e13SMartin Schwidefsky * and access via home space is from the kernel. 121482b05ddSGerald Schaefer */ 12261365e13SMartin Schwidefsky return trans_exc_code != 3; 1231da177e4SLinus Torvalds } 1241da177e4SLinus Torvalds 125aa33c8cbSMartin Schwidefsky static inline void report_user_fault(struct pt_regs *regs, long signr) 126ab3c68eeSHeiko Carstens { 127ab3c68eeSHeiko Carstens if ((task_pid_nr(current) > 1) && !show_unhandled_signals) 128ab3c68eeSHeiko Carstens return; 129ab3c68eeSHeiko Carstens if (!unhandled_signal(current, signr)) 130ab3c68eeSHeiko Carstens return; 131ab3c68eeSHeiko Carstens if (!printk_ratelimit()) 132ab3c68eeSHeiko Carstens return; 133aa33c8cbSMartin Schwidefsky printk(KERN_ALERT "User process fault: interruption code 0x%X ", 134aa33c8cbSMartin Schwidefsky regs->int_code); 135ab3c68eeSHeiko Carstens print_vma_addr(KERN_CONT "in ", regs->psw.addr & PSW_ADDR_INSN); 136aa33c8cbSMartin Schwidefsky printk(KERN_CONT "\n"); 137aa33c8cbSMartin Schwidefsky printk(KERN_ALERT "failing address: %lX\n", 138aa33c8cbSMartin Schwidefsky regs->int_parm_long & __FAIL_ADDR_MASK); 139ab3c68eeSHeiko Carstens show_regs(regs); 140ab3c68eeSHeiko Carstens } 141ab3c68eeSHeiko Carstens 1421da177e4SLinus Torvalds /* 1431da177e4SLinus Torvalds * Send SIGSEGV to task. This is an external routine 1441da177e4SLinus Torvalds * to keep the stack usage of do_page_fault small. 1451da177e4SLinus Torvalds */ 146aa33c8cbSMartin Schwidefsky static noinline void do_sigsegv(struct pt_regs *regs, int si_code) 1471da177e4SLinus Torvalds { 1481da177e4SLinus Torvalds struct siginfo si; 1491da177e4SLinus Torvalds 150aa33c8cbSMartin Schwidefsky report_user_fault(regs, SIGSEGV); 1511da177e4SLinus Torvalds si.si_signo = SIGSEGV; 1521da177e4SLinus Torvalds si.si_code = si_code; 153aa33c8cbSMartin Schwidefsky si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); 1541da177e4SLinus Torvalds force_sig_info(SIGSEGV, &si, current); 1551da177e4SLinus Torvalds } 1561da177e4SLinus Torvalds 157aa33c8cbSMartin Schwidefsky static noinline void do_no_context(struct pt_regs *regs) 15810c1031fSMartin Schwidefsky { 15910c1031fSMartin Schwidefsky const struct exception_table_entry *fixup; 16061365e13SMartin Schwidefsky unsigned long address; 16110c1031fSMartin Schwidefsky 16210c1031fSMartin Schwidefsky /* Are we prepared to handle this kernel fault? */ 16350d7280dSMartin Schwidefsky fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN); 16410c1031fSMartin Schwidefsky if (fixup) { 165eb608fb3SHeiko Carstens regs->psw.addr = extable_fixup(fixup) | PSW_ADDR_AMODE; 16610c1031fSMartin Schwidefsky return; 16710c1031fSMartin Schwidefsky } 16810c1031fSMartin Schwidefsky 16910c1031fSMartin Schwidefsky /* 17010c1031fSMartin Schwidefsky * Oops. The kernel tried to access some bad page. We'll have to 17110c1031fSMartin Schwidefsky * terminate things with extreme prejudice. 17210c1031fSMartin Schwidefsky */ 173aa33c8cbSMartin Schwidefsky address = regs->int_parm_long & __FAIL_ADDR_MASK; 174aa33c8cbSMartin Schwidefsky if (!user_space_fault(regs->int_parm_long)) 17510c1031fSMartin Schwidefsky printk(KERN_ALERT "Unable to handle kernel pointer dereference" 17610c1031fSMartin Schwidefsky " at virtual kernel address %p\n", (void *)address); 17710c1031fSMartin Schwidefsky else 17810c1031fSMartin Schwidefsky printk(KERN_ALERT "Unable to handle kernel paging request" 17910c1031fSMartin Schwidefsky " at virtual user address %p\n", (void *)address); 18010c1031fSMartin Schwidefsky 181aa33c8cbSMartin Schwidefsky die(regs, "Oops"); 18210c1031fSMartin Schwidefsky do_exit(SIGKILL); 18310c1031fSMartin Schwidefsky } 18410c1031fSMartin Schwidefsky 185aa33c8cbSMartin Schwidefsky static noinline void do_low_address(struct pt_regs *regs) 18610c1031fSMartin Schwidefsky { 18710c1031fSMartin Schwidefsky /* Low-address protection hit in kernel mode means 18810c1031fSMartin Schwidefsky NULL pointer write access in kernel mode. */ 18910c1031fSMartin Schwidefsky if (regs->psw.mask & PSW_MASK_PSTATE) { 19010c1031fSMartin Schwidefsky /* Low-address protection hit in user mode 'cannot happen'. */ 191aa33c8cbSMartin Schwidefsky die (regs, "Low-address protection"); 19210c1031fSMartin Schwidefsky do_exit(SIGKILL); 19310c1031fSMartin Schwidefsky } 19410c1031fSMartin Schwidefsky 195aa33c8cbSMartin Schwidefsky do_no_context(regs); 19610c1031fSMartin Schwidefsky } 19710c1031fSMartin Schwidefsky 198aa33c8cbSMartin Schwidefsky static noinline void do_sigbus(struct pt_regs *regs) 19910c1031fSMartin Schwidefsky { 20010c1031fSMartin Schwidefsky struct task_struct *tsk = current; 20136bf9680SMartin Schwidefsky struct siginfo si; 20210c1031fSMartin Schwidefsky 20310c1031fSMartin Schwidefsky /* 20410c1031fSMartin Schwidefsky * Send a sigbus, regardless of whether we were in kernel 20510c1031fSMartin Schwidefsky * or user mode. 20610c1031fSMartin Schwidefsky */ 20736bf9680SMartin Schwidefsky si.si_signo = SIGBUS; 20836bf9680SMartin Schwidefsky si.si_errno = 0; 20936bf9680SMartin Schwidefsky si.si_code = BUS_ADRERR; 210aa33c8cbSMartin Schwidefsky si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); 21136bf9680SMartin Schwidefsky force_sig_info(SIGBUS, &si, tsk); 21210c1031fSMartin Schwidefsky } 21310c1031fSMartin Schwidefsky 214aa33c8cbSMartin Schwidefsky static noinline void do_fault_error(struct pt_regs *regs, int fault) 21550d7280dSMartin Schwidefsky { 21650d7280dSMartin Schwidefsky int si_code; 21750d7280dSMartin Schwidefsky 21850d7280dSMartin Schwidefsky switch (fault) { 21950d7280dSMartin Schwidefsky case VM_FAULT_BADACCESS: 22050d7280dSMartin Schwidefsky case VM_FAULT_BADMAP: 22150d7280dSMartin Schwidefsky /* Bad memory access. Check if it is kernel or user space. */ 2227d256175SHeiko Carstens if (user_mode(regs)) { 22350d7280dSMartin Schwidefsky /* User mode accesses just cause a SIGSEGV */ 22450d7280dSMartin Schwidefsky si_code = (fault == VM_FAULT_BADMAP) ? 22550d7280dSMartin Schwidefsky SEGV_MAPERR : SEGV_ACCERR; 226aa33c8cbSMartin Schwidefsky do_sigsegv(regs, si_code); 22750d7280dSMartin Schwidefsky return; 22850d7280dSMartin Schwidefsky } 22950d7280dSMartin Schwidefsky case VM_FAULT_BADCONTEXT: 230aa33c8cbSMartin Schwidefsky do_no_context(regs); 23150d7280dSMartin Schwidefsky break; 232f2c76e3bSHeiko Carstens case VM_FAULT_SIGNAL: 233f2c76e3bSHeiko Carstens if (!user_mode(regs)) 234f2c76e3bSHeiko Carstens do_no_context(regs); 235f2c76e3bSHeiko Carstens break; 23650d7280dSMartin Schwidefsky default: /* fault & VM_FAULT_ERROR */ 23799583181SHeiko Carstens if (fault & VM_FAULT_OOM) { 2387d256175SHeiko Carstens if (!user_mode(regs)) 239aa33c8cbSMartin Schwidefsky do_no_context(regs); 24099583181SHeiko Carstens else 24150d7280dSMartin Schwidefsky pagefault_out_of_memory(); 24299583181SHeiko Carstens } else if (fault & VM_FAULT_SIGBUS) { 24350d7280dSMartin Schwidefsky /* Kernel mode? Handle exceptions or die */ 2447d256175SHeiko Carstens if (!user_mode(regs)) 245aa33c8cbSMartin Schwidefsky do_no_context(regs); 24636bf9680SMartin Schwidefsky else 247aa33c8cbSMartin Schwidefsky do_sigbus(regs); 24850d7280dSMartin Schwidefsky } else 24950d7280dSMartin Schwidefsky BUG(); 25050d7280dSMartin Schwidefsky break; 25150d7280dSMartin Schwidefsky } 25250d7280dSMartin Schwidefsky } 25350d7280dSMartin Schwidefsky 2541da177e4SLinus Torvalds /* 2551da177e4SLinus Torvalds * This routine handles page faults. It determines the address, 2561da177e4SLinus Torvalds * and the problem, and then passes it off to one of the appropriate 2571da177e4SLinus Torvalds * routines. 2581da177e4SLinus Torvalds * 25950d7280dSMartin Schwidefsky * interruption code (int_code): 2601da177e4SLinus Torvalds * 04 Protection -> Write-Protection (suprression) 2611da177e4SLinus Torvalds * 10 Segment translation -> Not present (nullification) 2621da177e4SLinus Torvalds * 11 Page translation -> Not present (nullification) 2631da177e4SLinus Torvalds * 3b Region third trans. -> Not present (nullification) 2641da177e4SLinus Torvalds */ 265aa33c8cbSMartin Schwidefsky static inline int do_exception(struct pt_regs *regs, int access) 2661da177e4SLinus Torvalds { 2671da177e4SLinus Torvalds struct task_struct *tsk; 2681da177e4SLinus Torvalds struct mm_struct *mm; 2691da177e4SLinus Torvalds struct vm_area_struct *vma; 270aa33c8cbSMartin Schwidefsky unsigned long trans_exc_code; 2711da177e4SLinus Torvalds unsigned long address; 27233ce6140SHeiko Carstens unsigned int flags; 27333ce6140SHeiko Carstens int fault; 27410c1031fSMartin Schwidefsky 27539efd4ecSMartin Schwidefsky tsk = current; 27639efd4ecSMartin Schwidefsky /* 27739efd4ecSMartin Schwidefsky * The instruction that caused the program check has 27839efd4ecSMartin Schwidefsky * been nullified. Don't signal single step via SIGTRAP. 27939efd4ecSMartin Schwidefsky */ 28039efd4ecSMartin Schwidefsky clear_tsk_thread_flag(tsk, TIF_PER_TRAP); 28139efd4ecSMartin Schwidefsky 2827ecb344aSMartin Schwidefsky if (notify_page_fault(regs)) 28350d7280dSMartin Schwidefsky return 0; 2841da177e4SLinus Torvalds 2851da177e4SLinus Torvalds mm = tsk->mm; 286aa33c8cbSMartin Schwidefsky trans_exc_code = regs->int_parm_long; 2871da177e4SLinus Torvalds 2881da177e4SLinus Torvalds /* 2891da177e4SLinus Torvalds * Verify that the fault happened in user space, that 2901da177e4SLinus Torvalds * we are not in an interrupt and that there is a 2911da177e4SLinus Torvalds * user context. 2921da177e4SLinus Torvalds */ 29350d7280dSMartin Schwidefsky fault = VM_FAULT_BADCONTEXT; 29461365e13SMartin Schwidefsky if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm)) 29550d7280dSMartin Schwidefsky goto out; 2961da177e4SLinus Torvalds 29761365e13SMartin Schwidefsky address = trans_exc_code & __FAIL_ADDR_MASK; 298a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); 299f2c76e3bSHeiko Carstens flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; 300759496baSJohannes Weiner if (user_mode(regs)) 301759496baSJohannes Weiner flags |= FAULT_FLAG_USER; 30233ce6140SHeiko Carstens if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400) 30333ce6140SHeiko Carstens flags |= FAULT_FLAG_WRITE; 3041da177e4SLinus Torvalds down_read(&mm->mmap_sem); 3051da177e4SLinus Torvalds 306e5992f2eSMartin Schwidefsky #ifdef CONFIG_PGSTE 3075e8010cbSMartin Schwidefsky if ((current->flags & PF_VCPU) && S390_lowcore.gmap) { 308499069e1SCarsten Otte address = __gmap_fault(address, 309e5992f2eSMartin Schwidefsky (struct gmap *) S390_lowcore.gmap); 310e5992f2eSMartin Schwidefsky if (address == -EFAULT) { 311e5992f2eSMartin Schwidefsky fault = VM_FAULT_BADMAP; 312e5992f2eSMartin Schwidefsky goto out_up; 313e5992f2eSMartin Schwidefsky } 314e5992f2eSMartin Schwidefsky if (address == -ENOMEM) { 315e5992f2eSMartin Schwidefsky fault = VM_FAULT_OOM; 316e5992f2eSMartin Schwidefsky goto out_up; 317e5992f2eSMartin Schwidefsky } 318e5992f2eSMartin Schwidefsky } 319e5992f2eSMartin Schwidefsky #endif 320e5992f2eSMartin Schwidefsky 321e5992f2eSMartin Schwidefsky retry: 32250d7280dSMartin Schwidefsky fault = VM_FAULT_BADMAP; 3231da177e4SLinus Torvalds vma = find_vma(mm, address); 3241da177e4SLinus Torvalds if (!vma) 32550d7280dSMartin Schwidefsky goto out_up; 326c1821c2eSGerald Schaefer 32750d7280dSMartin Schwidefsky if (unlikely(vma->vm_start > address)) { 3281da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 32950d7280dSMartin Schwidefsky goto out_up; 3301da177e4SLinus Torvalds if (expand_stack(vma, address)) 33150d7280dSMartin Schwidefsky goto out_up; 33250d7280dSMartin Schwidefsky } 33350d7280dSMartin Schwidefsky 3341da177e4SLinus Torvalds /* 3351da177e4SLinus Torvalds * Ok, we have a good vm_area for this memory access, so 3361da177e4SLinus Torvalds * we can handle it.. 3371da177e4SLinus Torvalds */ 33850d7280dSMartin Schwidefsky fault = VM_FAULT_BADACCESS; 3391ab947deSMartin Schwidefsky if (unlikely(!(vma->vm_flags & access))) 34050d7280dSMartin Schwidefsky goto out_up; 3411da177e4SLinus Torvalds 34253492b1dSGerald Schaefer if (is_vm_hugetlb_page(vma)) 34353492b1dSGerald Schaefer address &= HPAGE_MASK; 3441da177e4SLinus Torvalds /* 3451da177e4SLinus Torvalds * If for any reason at all we couldn't handle the fault, 3461da177e4SLinus Torvalds * make sure we exit gracefully rather than endlessly redo 3471da177e4SLinus Torvalds * the fault. 3481da177e4SLinus Torvalds */ 34933ce6140SHeiko Carstens fault = handle_mm_fault(mm, vma, address, flags); 350f2c76e3bSHeiko Carstens /* No reason to continue if interrupted by SIGKILL. */ 351f2c76e3bSHeiko Carstens if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { 352f2c76e3bSHeiko Carstens fault = VM_FAULT_SIGNAL; 353f2c76e3bSHeiko Carstens goto out; 354f2c76e3bSHeiko Carstens } 35550d7280dSMartin Schwidefsky if (unlikely(fault & VM_FAULT_ERROR)) 35650d7280dSMartin Schwidefsky goto out_up; 35750d7280dSMartin Schwidefsky 35833ce6140SHeiko Carstens /* 35933ce6140SHeiko Carstens * Major/minor page fault accounting is only done on the 36033ce6140SHeiko Carstens * initial attempt. If we go through a retry, it is extremely 36133ce6140SHeiko Carstens * likely that the page will be found in page cache at that point. 36233ce6140SHeiko Carstens */ 36333ce6140SHeiko Carstens if (flags & FAULT_FLAG_ALLOW_RETRY) { 364bde69af2SHeiko Carstens if (fault & VM_FAULT_MAJOR) { 36583c54070SNick Piggin tsk->maj_flt++; 366a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 367bde69af2SHeiko Carstens regs, address); 368bde69af2SHeiko Carstens } else { 36983c54070SNick Piggin tsk->min_flt++; 370a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 371bde69af2SHeiko Carstens regs, address); 372bde69af2SHeiko Carstens } 37333ce6140SHeiko Carstens if (fault & VM_FAULT_RETRY) { 37433ce6140SHeiko Carstens /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk 37533ce6140SHeiko Carstens * of starvation. */ 37633ce6140SHeiko Carstens flags &= ~FAULT_FLAG_ALLOW_RETRY; 37745cac65bSShaohua Li flags |= FAULT_FLAG_TRIED; 378e5992f2eSMartin Schwidefsky down_read(&mm->mmap_sem); 37933ce6140SHeiko Carstens goto retry; 38033ce6140SHeiko Carstens } 38133ce6140SHeiko Carstens } 38250d7280dSMartin Schwidefsky fault = 0; 38350d7280dSMartin Schwidefsky out_up: 3841da177e4SLinus Torvalds up_read(&mm->mmap_sem); 38550d7280dSMartin Schwidefsky out: 38650d7280dSMartin Schwidefsky return fault; 3871da177e4SLinus Torvalds } 3881da177e4SLinus Torvalds 389aa33c8cbSMartin Schwidefsky void __kprobes do_protection_exception(struct pt_regs *regs) 3901da177e4SLinus Torvalds { 391aa33c8cbSMartin Schwidefsky unsigned long trans_exc_code; 39250d7280dSMartin Schwidefsky int fault; 39361365e13SMartin Schwidefsky 394aa33c8cbSMartin Schwidefsky trans_exc_code = regs->int_parm_long; 395f752ac4dSMartin Schwidefsky /* 396f752ac4dSMartin Schwidefsky * Protection exceptions are suppressing, decrement psw address. 397f752ac4dSMartin Schwidefsky * The exception to this rule are aborted transactions, for these 398f752ac4dSMartin Schwidefsky * the PSW already points to the correct location. 399f752ac4dSMartin Schwidefsky */ 400f752ac4dSMartin Schwidefsky if (!(regs->int_code & 0x200)) 401aa33c8cbSMartin Schwidefsky regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16); 40210c1031fSMartin Schwidefsky /* 40310c1031fSMartin Schwidefsky * Check for low-address protection. This needs to be treated 40410c1031fSMartin Schwidefsky * as a special case because the translation exception code 40510c1031fSMartin Schwidefsky * field is not guaranteed to contain valid data in this case. 40610c1031fSMartin Schwidefsky */ 40761365e13SMartin Schwidefsky if (unlikely(!(trans_exc_code & 4))) { 408aa33c8cbSMartin Schwidefsky do_low_address(regs); 40910c1031fSMartin Schwidefsky return; 41010c1031fSMartin Schwidefsky } 411aa33c8cbSMartin Schwidefsky fault = do_exception(regs, VM_WRITE); 41250d7280dSMartin Schwidefsky if (unlikely(fault)) 413aa33c8cbSMartin Schwidefsky do_fault_error(regs, fault); 4141da177e4SLinus Torvalds } 4151da177e4SLinus Torvalds 416aa33c8cbSMartin Schwidefsky void __kprobes do_dat_exception(struct pt_regs *regs) 4171da177e4SLinus Torvalds { 4181ab947deSMartin Schwidefsky int access, fault; 41950d7280dSMartin Schwidefsky 4201ab947deSMartin Schwidefsky access = VM_READ | VM_EXEC | VM_WRITE; 421aa33c8cbSMartin Schwidefsky fault = do_exception(regs, access); 42250d7280dSMartin Schwidefsky if (unlikely(fault)) 423aa33c8cbSMartin Schwidefsky do_fault_error(regs, fault); 4241da177e4SLinus Torvalds } 4251da177e4SLinus Torvalds 4261e54622eSMartin Schwidefsky int __handle_fault(unsigned long uaddr, unsigned long pgm_int_code, int write) 4276c1e3e79SGerald Schaefer { 4286c1e3e79SGerald Schaefer struct pt_regs regs; 4296c1e3e79SGerald Schaefer int access, fault; 4306c1e3e79SGerald Schaefer 431008c2e8fSHeiko Carstens /* Emulate a uaccess fault from kernel mode. */ 432e258d719SMartin Schwidefsky regs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT | PSW_MASK_MCHECK; 4336c1e3e79SGerald Schaefer if (!irqs_disabled()) 4346c1e3e79SGerald Schaefer regs.psw.mask |= PSW_MASK_IO | PSW_MASK_EXT; 4356c1e3e79SGerald Schaefer regs.psw.addr = (unsigned long) __builtin_return_address(0); 4366c1e3e79SGerald Schaefer regs.psw.addr |= PSW_ADDR_AMODE; 437aa33c8cbSMartin Schwidefsky regs.int_code = pgm_int_code; 438aa33c8cbSMartin Schwidefsky regs.int_parm_long = (uaddr & PAGE_MASK) | 2; 4391e54622eSMartin Schwidefsky access = write ? VM_WRITE : VM_READ; 440aa33c8cbSMartin Schwidefsky fault = do_exception(®s, access); 441008c2e8fSHeiko Carstens /* 442008c2e8fSHeiko Carstens * Since the fault happened in kernel mode while performing a uaccess 443008c2e8fSHeiko Carstens * all we need to do now is emulating a fixup in case "fault" is not 444008c2e8fSHeiko Carstens * zero. 445008c2e8fSHeiko Carstens * For the calling uaccess functions this results always in -EFAULT. 446008c2e8fSHeiko Carstens */ 4476c1e3e79SGerald Schaefer return fault ? -EFAULT : 0; 4486c1e3e79SGerald Schaefer } 4496c1e3e79SGerald Schaefer 4501da177e4SLinus Torvalds #ifdef CONFIG_PFAULT 4511da177e4SLinus Torvalds /* 4521da177e4SLinus Torvalds * 'pfault' pseudo page faults routines. 4531da177e4SLinus Torvalds */ 454fb0a9d7eSHeiko Carstens static int pfault_disable; 4551da177e4SLinus Torvalds 4561da177e4SLinus Torvalds static int __init nopfault(char *str) 4571da177e4SLinus Torvalds { 4581da177e4SLinus Torvalds pfault_disable = 1; 4591da177e4SLinus Torvalds return 1; 4601da177e4SLinus Torvalds } 4611da177e4SLinus Torvalds 4621da177e4SLinus Torvalds __setup("nopfault", nopfault); 4631da177e4SLinus Torvalds 4647dd8fe1fSHeiko Carstens struct pfault_refbk { 4657dd8fe1fSHeiko Carstens u16 refdiagc; 4667dd8fe1fSHeiko Carstens u16 reffcode; 4677dd8fe1fSHeiko Carstens u16 refdwlen; 4687dd8fe1fSHeiko Carstens u16 refversn; 4697dd8fe1fSHeiko Carstens u64 refgaddr; 4707dd8fe1fSHeiko Carstens u64 refselmk; 4717dd8fe1fSHeiko Carstens u64 refcmpmk; 4727dd8fe1fSHeiko Carstens u64 reserved; 4737dd8fe1fSHeiko Carstens } __attribute__ ((packed, aligned(8))); 4741da177e4SLinus Torvalds 4751da177e4SLinus Torvalds int pfault_init(void) 4761da177e4SLinus Torvalds { 4777dd8fe1fSHeiko Carstens struct pfault_refbk refbk = { 4787dd8fe1fSHeiko Carstens .refdiagc = 0x258, 4797dd8fe1fSHeiko Carstens .reffcode = 0, 4807dd8fe1fSHeiko Carstens .refdwlen = 5, 4817dd8fe1fSHeiko Carstens .refversn = 2, 4827dd8fe1fSHeiko Carstens .refgaddr = __LC_CURRENT_PID, 4837dd8fe1fSHeiko Carstens .refselmk = 1ULL << 48, 4847dd8fe1fSHeiko Carstens .refcmpmk = 1ULL << 48, 4857dd8fe1fSHeiko Carstens .reserved = __PF_RES_FIELD }; 4861da177e4SLinus Torvalds int rc; 4871da177e4SLinus Torvalds 488f32269a0SCarsten Otte if (pfault_disable) 4891da177e4SLinus Torvalds return -1; 49094c12cc7SMartin Schwidefsky asm volatile( 4911da177e4SLinus Torvalds " diag %1,%0,0x258\n" 4921da177e4SLinus Torvalds "0: j 2f\n" 4931da177e4SLinus Torvalds "1: la %0,8\n" 4941da177e4SLinus Torvalds "2:\n" 49594c12cc7SMartin Schwidefsky EX_TABLE(0b,1b) 496d4b68996SMartin Schwidefsky : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); 4971da177e4SLinus Torvalds return rc; 4981da177e4SLinus Torvalds } 4991da177e4SLinus Torvalds 5001da177e4SLinus Torvalds void pfault_fini(void) 5011da177e4SLinus Torvalds { 5027dd8fe1fSHeiko Carstens struct pfault_refbk refbk = { 5037dd8fe1fSHeiko Carstens .refdiagc = 0x258, 5047dd8fe1fSHeiko Carstens .reffcode = 1, 5057dd8fe1fSHeiko Carstens .refdwlen = 5, 5067dd8fe1fSHeiko Carstens .refversn = 2, 5077dd8fe1fSHeiko Carstens }; 5081da177e4SLinus Torvalds 509f32269a0SCarsten Otte if (pfault_disable) 5101da177e4SLinus Torvalds return; 51194c12cc7SMartin Schwidefsky asm volatile( 5121da177e4SLinus Torvalds " diag %0,0,0x258\n" 5131da177e4SLinus Torvalds "0:\n" 51494c12cc7SMartin Schwidefsky EX_TABLE(0b,0b) 515d4b68996SMartin Schwidefsky : : "a" (&refbk), "m" (refbk) : "cc"); 5161da177e4SLinus Torvalds } 5171da177e4SLinus Torvalds 518f2db2e6cSHeiko Carstens static DEFINE_SPINLOCK(pfault_lock); 519f2db2e6cSHeiko Carstens static LIST_HEAD(pfault_list); 520f2db2e6cSHeiko Carstens 521fde15c3aSHeiko Carstens static void pfault_interrupt(struct ext_code ext_code, 522f6649a7eSMartin Schwidefsky unsigned int param32, unsigned long param64) 5231da177e4SLinus Torvalds { 5241da177e4SLinus Torvalds struct task_struct *tsk; 5251da177e4SLinus Torvalds __u16 subcode; 526f2db2e6cSHeiko Carstens pid_t pid; 5271da177e4SLinus Torvalds 5281da177e4SLinus Torvalds /* 5291da177e4SLinus Torvalds * Get the external interruption subcode & pfault 5301da177e4SLinus Torvalds * initial/completion signal bit. VM stores this 5311da177e4SLinus Torvalds * in the 'cpu address' field associated with the 5321da177e4SLinus Torvalds * external interrupt. 5331da177e4SLinus Torvalds */ 534fde15c3aSHeiko Carstens subcode = ext_code.subcode; 5351da177e4SLinus Torvalds if ((subcode & 0xff00) != __SUBCODE_MASK) 5361da177e4SLinus Torvalds return; 537420f42ecSHeiko Carstens inc_irq_stat(IRQEXT_PFL); 538f2db2e6cSHeiko Carstens /* Get the token (= pid of the affected task). */ 539f2db2e6cSHeiko Carstens pid = sizeof(void *) == 4 ? param32 : param64; 540f2db2e6cSHeiko Carstens rcu_read_lock(); 541f2db2e6cSHeiko Carstens tsk = find_task_by_pid_ns(pid, &init_pid_ns); 542f2db2e6cSHeiko Carstens if (tsk) 543f2db2e6cSHeiko Carstens get_task_struct(tsk); 544f2db2e6cSHeiko Carstens rcu_read_unlock(); 545f2db2e6cSHeiko Carstens if (!tsk) 546f2db2e6cSHeiko Carstens return; 547f2db2e6cSHeiko Carstens spin_lock(&pfault_lock); 5481da177e4SLinus Torvalds if (subcode & 0x0080) { 5491da177e4SLinus Torvalds /* signal bit is set -> a page has been swapped in by VM */ 550f2db2e6cSHeiko Carstens if (tsk->thread.pfault_wait == 1) { 5511da177e4SLinus Torvalds /* Initial interrupt was faster than the completion 5521da177e4SLinus Torvalds * interrupt. pfault_wait is valid. Set pfault_wait 5531da177e4SLinus Torvalds * back to zero and wake up the process. This can 5541da177e4SLinus Torvalds * safely be done because the task is still sleeping 555b6d09449SMartin Schwidefsky * and can't produce new pfaults. */ 5561da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 557f2db2e6cSHeiko Carstens list_del(&tsk->thread.list); 5581da177e4SLinus Torvalds wake_up_process(tsk); 559d5e50a51SHeiko Carstens put_task_struct(tsk); 560f2db2e6cSHeiko Carstens } else { 561f2db2e6cSHeiko Carstens /* Completion interrupt was faster than initial 562f2db2e6cSHeiko Carstens * interrupt. Set pfault_wait to -1 so the initial 563fa2fb2f4SHeiko Carstens * interrupt doesn't put the task to sleep. 564fa2fb2f4SHeiko Carstens * If the task is not running, ignore the completion 565fa2fb2f4SHeiko Carstens * interrupt since it must be a leftover of a PFAULT 566fa2fb2f4SHeiko Carstens * CANCEL operation which didn't remove all pending 567fa2fb2f4SHeiko Carstens * completion interrupts. */ 568fa2fb2f4SHeiko Carstens if (tsk->state == TASK_RUNNING) 569f2db2e6cSHeiko Carstens tsk->thread.pfault_wait = -1; 5701da177e4SLinus Torvalds } 5711da177e4SLinus Torvalds } else { 5721da177e4SLinus Torvalds /* signal bit not set -> a real page is missing. */ 573d49f47f8SHeiko Carstens if (WARN_ON_ONCE(tsk != current)) 574d49f47f8SHeiko Carstens goto out; 575d5e50a51SHeiko Carstens if (tsk->thread.pfault_wait == 1) { 576d5e50a51SHeiko Carstens /* Already on the list with a reference: put to sleep */ 5770a16ba78SHeiko Carstens __set_task_state(tsk, TASK_UNINTERRUPTIBLE); 578d5e50a51SHeiko Carstens set_tsk_need_resched(tsk); 579d5e50a51SHeiko Carstens } else if (tsk->thread.pfault_wait == -1) { 5801da177e4SLinus Torvalds /* Completion interrupt was faster than the initial 581f2db2e6cSHeiko Carstens * interrupt (pfault_wait == -1). Set pfault_wait 582f2db2e6cSHeiko Carstens * back to zero and exit. */ 5831da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 584f2db2e6cSHeiko Carstens } else { 585f2db2e6cSHeiko Carstens /* Initial interrupt arrived before completion 586d5e50a51SHeiko Carstens * interrupt. Let the task sleep. 587d5e50a51SHeiko Carstens * An extra task reference is needed since a different 588d5e50a51SHeiko Carstens * cpu may set the task state to TASK_RUNNING again 589d5e50a51SHeiko Carstens * before the scheduler is reached. */ 590d5e50a51SHeiko Carstens get_task_struct(tsk); 591f2db2e6cSHeiko Carstens tsk->thread.pfault_wait = 1; 592f2db2e6cSHeiko Carstens list_add(&tsk->thread.list, &pfault_list); 5930a16ba78SHeiko Carstens __set_task_state(tsk, TASK_UNINTERRUPTIBLE); 5941da177e4SLinus Torvalds set_tsk_need_resched(tsk); 5951da177e4SLinus Torvalds } 5961da177e4SLinus Torvalds } 597d49f47f8SHeiko Carstens out: 598f2db2e6cSHeiko Carstens spin_unlock(&pfault_lock); 59954c27791SHeiko Carstens put_task_struct(tsk); 600f2db2e6cSHeiko Carstens } 601f2db2e6cSHeiko Carstens 602e2741f17SPaul Gortmaker static int pfault_cpu_notify(struct notifier_block *self, unsigned long action, 603e2741f17SPaul Gortmaker void *hcpu) 604f2db2e6cSHeiko Carstens { 605f2db2e6cSHeiko Carstens struct thread_struct *thread, *next; 606f2db2e6cSHeiko Carstens struct task_struct *tsk; 607f2db2e6cSHeiko Carstens 6081c725922SHeiko Carstens switch (action & ~CPU_TASKS_FROZEN) { 609f2db2e6cSHeiko Carstens case CPU_DEAD: 610f2db2e6cSHeiko Carstens spin_lock_irq(&pfault_lock); 611f2db2e6cSHeiko Carstens list_for_each_entry_safe(thread, next, &pfault_list, list) { 612f2db2e6cSHeiko Carstens thread->pfault_wait = 0; 613f2db2e6cSHeiko Carstens list_del(&thread->list); 614f2db2e6cSHeiko Carstens tsk = container_of(thread, struct task_struct, thread); 615f2db2e6cSHeiko Carstens wake_up_process(tsk); 616d5e50a51SHeiko Carstens put_task_struct(tsk); 617f2db2e6cSHeiko Carstens } 618f2db2e6cSHeiko Carstens spin_unlock_irq(&pfault_lock); 619f2db2e6cSHeiko Carstens break; 620f2db2e6cSHeiko Carstens default: 621f2db2e6cSHeiko Carstens break; 622f2db2e6cSHeiko Carstens } 623f2db2e6cSHeiko Carstens return NOTIFY_OK; 624f2db2e6cSHeiko Carstens } 6251da177e4SLinus Torvalds 626fb0a9d7eSHeiko Carstens static int __init pfault_irq_init(void) 62729b08d2bSHeiko Carstens { 628fb0a9d7eSHeiko Carstens int rc; 62929b08d2bSHeiko Carstens 6301dad093bSThomas Huth rc = register_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt); 6317dd8fe1fSHeiko Carstens if (rc) 6327dd8fe1fSHeiko Carstens goto out_extint; 6337dd8fe1fSHeiko Carstens rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP; 6347dd8fe1fSHeiko Carstens if (rc) 6357dd8fe1fSHeiko Carstens goto out_pfault; 63682003c3eSHeiko Carstens irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL); 6377dd8fe1fSHeiko Carstens hotcpu_notifier(pfault_cpu_notify, 0); 6387dd8fe1fSHeiko Carstens return 0; 6397dd8fe1fSHeiko Carstens 6407dd8fe1fSHeiko Carstens out_pfault: 6411dad093bSThomas Huth unregister_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt); 6427dd8fe1fSHeiko Carstens out_extint: 643fb0a9d7eSHeiko Carstens pfault_disable = 1; 644fb0a9d7eSHeiko Carstens return rc; 645fb0a9d7eSHeiko Carstens } 646fb0a9d7eSHeiko Carstens early_initcall(pfault_irq_init); 647fb0a9d7eSHeiko Carstens 6487dd8fe1fSHeiko Carstens #endif /* CONFIG_PFAULT */ 649