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 5250d7280dSMartin Schwidefsky 5392f842eaSMartin Schwidefsky static unsigned long store_indication; 5492f842eaSMartin Schwidefsky 5592f842eaSMartin Schwidefsky void fault_init(void) 5692f842eaSMartin Schwidefsky { 5714375bc4SMartin Schwidefsky if (test_facility(2) && test_facility(75)) 5892f842eaSMartin Schwidefsky store_indication = 0xc00; 5992f842eaSMartin Schwidefsky } 6092f842eaSMartin Schwidefsky 617ecb344aSMartin Schwidefsky static inline int notify_page_fault(struct pt_regs *regs) 6210c1031fSMartin Schwidefsky { 6333464e3bSChristoph Hellwig int ret = 0; 6433464e3bSChristoph Hellwig 6533464e3bSChristoph Hellwig /* kprobe_running() needs smp_processor_id() */ 6622e0a046SHeiko Carstens if (kprobes_built_in() && !user_mode(regs)) { 6733464e3bSChristoph Hellwig preempt_disable(); 6833464e3bSChristoph Hellwig if (kprobe_running() && kprobe_fault_handler(regs, 14)) 6933464e3bSChristoph Hellwig ret = 1; 7033464e3bSChristoph Hellwig preempt_enable(); 7133464e3bSChristoph Hellwig } 7233464e3bSChristoph Hellwig return ret; 734ba069b8SMichael Grundy } 744ba069b8SMichael Grundy 751da177e4SLinus Torvalds 761da177e4SLinus Torvalds /* 771da177e4SLinus Torvalds * Unlock any spinlocks which will prevent us from getting the 78cefc8be8SKirill Korotaev * message out. 791da177e4SLinus Torvalds */ 801da177e4SLinus Torvalds void bust_spinlocks(int yes) 811da177e4SLinus Torvalds { 821da177e4SLinus Torvalds if (yes) { 831da177e4SLinus Torvalds oops_in_progress = 1; 841da177e4SLinus Torvalds } else { 851da177e4SLinus Torvalds int loglevel_save = console_loglevel; 861da177e4SLinus Torvalds console_unblank(); 871da177e4SLinus Torvalds oops_in_progress = 0; 881da177e4SLinus Torvalds /* 891da177e4SLinus Torvalds * OK, the message is on the console. Now we call printk() 901da177e4SLinus Torvalds * without oops_in_progress set so that printk will give klogd 911da177e4SLinus Torvalds * a poke. Hold onto your hats... 921da177e4SLinus Torvalds */ 931da177e4SLinus Torvalds console_loglevel = 15; 941da177e4SLinus Torvalds printk(" "); 951da177e4SLinus Torvalds console_loglevel = loglevel_save; 961da177e4SLinus Torvalds } 971da177e4SLinus Torvalds } 981da177e4SLinus Torvalds 991da177e4SLinus Torvalds /* 100482b05ddSGerald Schaefer * Returns the address space associated with the fault. 10161365e13SMartin Schwidefsky * Returns 0 for kernel space and 1 for user space. 1021da177e4SLinus Torvalds */ 10361365e13SMartin Schwidefsky static inline int user_space_fault(unsigned long trans_exc_code) 1041da177e4SLinus Torvalds { 1051da177e4SLinus Torvalds /* 10661365e13SMartin Schwidefsky * The lowest two bits of the translation exception 10761365e13SMartin Schwidefsky * identification indicate which paging table was used. 1081da177e4SLinus Torvalds */ 10961365e13SMartin Schwidefsky trans_exc_code &= 3; 11061365e13SMartin Schwidefsky if (trans_exc_code == 2) 11161365e13SMartin Schwidefsky /* Access via secondary space, set_fs setting decides */ 11261365e13SMartin Schwidefsky return current->thread.mm_segment.ar4; 113b11b5334SMartin Schwidefsky if (user_mode == HOME_SPACE_MODE) 11461365e13SMartin Schwidefsky /* User space if the access has been done via home space. */ 11561365e13SMartin Schwidefsky return trans_exc_code == 3; 116482b05ddSGerald Schaefer /* 11761365e13SMartin Schwidefsky * If the user space is not the home space the kernel runs in home 11861365e13SMartin Schwidefsky * space. Access via secondary space has already been covered, 11961365e13SMartin 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) { 16510c1031fSMartin Schwidefsky regs->psw.addr = 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. */ 22250d7280dSMartin Schwidefsky if (regs->psw.mask & PSW_MASK_PSTATE) { 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; 23250d7280dSMartin Schwidefsky default: /* fault & VM_FAULT_ERROR */ 23399583181SHeiko Carstens if (fault & VM_FAULT_OOM) { 23499583181SHeiko Carstens if (!(regs->psw.mask & PSW_MASK_PSTATE)) 235aa33c8cbSMartin Schwidefsky do_no_context(regs); 23699583181SHeiko Carstens else 23750d7280dSMartin Schwidefsky pagefault_out_of_memory(); 23899583181SHeiko Carstens } else if (fault & VM_FAULT_SIGBUS) { 23950d7280dSMartin Schwidefsky /* Kernel mode? Handle exceptions or die */ 24050d7280dSMartin Schwidefsky if (!(regs->psw.mask & PSW_MASK_PSTATE)) 241aa33c8cbSMartin Schwidefsky do_no_context(regs); 24236bf9680SMartin Schwidefsky else 243aa33c8cbSMartin Schwidefsky do_sigbus(regs); 24450d7280dSMartin Schwidefsky } else 24550d7280dSMartin Schwidefsky BUG(); 24650d7280dSMartin Schwidefsky break; 24750d7280dSMartin Schwidefsky } 24850d7280dSMartin Schwidefsky } 24950d7280dSMartin Schwidefsky 2501da177e4SLinus Torvalds /* 2511da177e4SLinus Torvalds * This routine handles page faults. It determines the address, 2521da177e4SLinus Torvalds * and the problem, and then passes it off to one of the appropriate 2531da177e4SLinus Torvalds * routines. 2541da177e4SLinus Torvalds * 25550d7280dSMartin Schwidefsky * interruption code (int_code): 2561da177e4SLinus Torvalds * 04 Protection -> Write-Protection (suprression) 2571da177e4SLinus Torvalds * 10 Segment translation -> Not present (nullification) 2581da177e4SLinus Torvalds * 11 Page translation -> Not present (nullification) 2591da177e4SLinus Torvalds * 3b Region third trans. -> Not present (nullification) 2601da177e4SLinus Torvalds */ 261aa33c8cbSMartin Schwidefsky static inline int do_exception(struct pt_regs *regs, int access) 2621da177e4SLinus Torvalds { 2631da177e4SLinus Torvalds struct task_struct *tsk; 2641da177e4SLinus Torvalds struct mm_struct *mm; 2651da177e4SLinus Torvalds struct vm_area_struct *vma; 266aa33c8cbSMartin Schwidefsky unsigned long trans_exc_code; 2671da177e4SLinus Torvalds unsigned long address; 26833ce6140SHeiko Carstens unsigned int flags; 26933ce6140SHeiko Carstens int fault; 27010c1031fSMartin Schwidefsky 2717ecb344aSMartin Schwidefsky if (notify_page_fault(regs)) 27250d7280dSMartin Schwidefsky return 0; 2731da177e4SLinus Torvalds 2741da177e4SLinus Torvalds tsk = current; 2751da177e4SLinus Torvalds mm = tsk->mm; 276aa33c8cbSMartin Schwidefsky trans_exc_code = regs->int_parm_long; 2771da177e4SLinus Torvalds 2781da177e4SLinus Torvalds /* 2791da177e4SLinus Torvalds * Verify that the fault happened in user space, that 2801da177e4SLinus Torvalds * we are not in an interrupt and that there is a 2811da177e4SLinus Torvalds * user context. 2821da177e4SLinus Torvalds */ 28350d7280dSMartin Schwidefsky fault = VM_FAULT_BADCONTEXT; 28461365e13SMartin Schwidefsky if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm)) 28550d7280dSMartin Schwidefsky goto out; 2861da177e4SLinus Torvalds 28761365e13SMartin Schwidefsky address = trans_exc_code & __FAIL_ADDR_MASK; 288a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); 28933ce6140SHeiko Carstens flags = FAULT_FLAG_ALLOW_RETRY; 29033ce6140SHeiko Carstens if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400) 29133ce6140SHeiko Carstens flags |= FAULT_FLAG_WRITE; 2921da177e4SLinus Torvalds down_read(&mm->mmap_sem); 2931da177e4SLinus Torvalds 294e5992f2eSMartin Schwidefsky #ifdef CONFIG_PGSTE 2955e8010cbSMartin Schwidefsky if ((current->flags & PF_VCPU) && S390_lowcore.gmap) { 296499069e1SCarsten Otte address = __gmap_fault(address, 297e5992f2eSMartin Schwidefsky (struct gmap *) S390_lowcore.gmap); 298e5992f2eSMartin Schwidefsky if (address == -EFAULT) { 299e5992f2eSMartin Schwidefsky fault = VM_FAULT_BADMAP; 300e5992f2eSMartin Schwidefsky goto out_up; 301e5992f2eSMartin Schwidefsky } 302e5992f2eSMartin Schwidefsky if (address == -ENOMEM) { 303e5992f2eSMartin Schwidefsky fault = VM_FAULT_OOM; 304e5992f2eSMartin Schwidefsky goto out_up; 305e5992f2eSMartin Schwidefsky } 306e5992f2eSMartin Schwidefsky } 307e5992f2eSMartin Schwidefsky #endif 308e5992f2eSMartin Schwidefsky 309e5992f2eSMartin Schwidefsky retry: 31050d7280dSMartin Schwidefsky fault = VM_FAULT_BADMAP; 3111da177e4SLinus Torvalds vma = find_vma(mm, address); 3121da177e4SLinus Torvalds if (!vma) 31350d7280dSMartin Schwidefsky goto out_up; 314c1821c2eSGerald Schaefer 31550d7280dSMartin Schwidefsky if (unlikely(vma->vm_start > address)) { 3161da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 31750d7280dSMartin Schwidefsky goto out_up; 3181da177e4SLinus Torvalds if (expand_stack(vma, address)) 31950d7280dSMartin Schwidefsky goto out_up; 32050d7280dSMartin Schwidefsky } 32150d7280dSMartin Schwidefsky 3221da177e4SLinus Torvalds /* 3231da177e4SLinus Torvalds * Ok, we have a good vm_area for this memory access, so 3241da177e4SLinus Torvalds * we can handle it.. 3251da177e4SLinus Torvalds */ 32650d7280dSMartin Schwidefsky fault = VM_FAULT_BADACCESS; 3271ab947deSMartin Schwidefsky if (unlikely(!(vma->vm_flags & access))) 32850d7280dSMartin Schwidefsky goto out_up; 3291da177e4SLinus Torvalds 33053492b1dSGerald Schaefer if (is_vm_hugetlb_page(vma)) 33153492b1dSGerald Schaefer address &= HPAGE_MASK; 3321da177e4SLinus Torvalds /* 3331da177e4SLinus Torvalds * If for any reason at all we couldn't handle the fault, 3341da177e4SLinus Torvalds * make sure we exit gracefully rather than endlessly redo 3351da177e4SLinus Torvalds * the fault. 3361da177e4SLinus Torvalds */ 33733ce6140SHeiko Carstens fault = handle_mm_fault(mm, vma, address, flags); 33850d7280dSMartin Schwidefsky if (unlikely(fault & VM_FAULT_ERROR)) 33950d7280dSMartin Schwidefsky goto out_up; 34050d7280dSMartin Schwidefsky 34133ce6140SHeiko Carstens /* 34233ce6140SHeiko Carstens * Major/minor page fault accounting is only done on the 34333ce6140SHeiko Carstens * initial attempt. If we go through a retry, it is extremely 34433ce6140SHeiko Carstens * likely that the page will be found in page cache at that point. 34533ce6140SHeiko Carstens */ 34633ce6140SHeiko Carstens if (flags & FAULT_FLAG_ALLOW_RETRY) { 347bde69af2SHeiko Carstens if (fault & VM_FAULT_MAJOR) { 34883c54070SNick Piggin tsk->maj_flt++; 349a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 350bde69af2SHeiko Carstens regs, address); 351bde69af2SHeiko Carstens } else { 35283c54070SNick Piggin tsk->min_flt++; 353a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 354bde69af2SHeiko Carstens regs, address); 355bde69af2SHeiko Carstens } 35633ce6140SHeiko Carstens if (fault & VM_FAULT_RETRY) { 35733ce6140SHeiko Carstens /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk 35833ce6140SHeiko Carstens * of starvation. */ 35933ce6140SHeiko Carstens flags &= ~FAULT_FLAG_ALLOW_RETRY; 360e5992f2eSMartin Schwidefsky down_read(&mm->mmap_sem); 36133ce6140SHeiko Carstens goto retry; 36233ce6140SHeiko Carstens } 36333ce6140SHeiko Carstens } 3641da177e4SLinus Torvalds /* 3651da177e4SLinus Torvalds * The instruction that caused the program check will 3661da177e4SLinus Torvalds * be repeated. Don't signal single step via SIGTRAP. 3671da177e4SLinus Torvalds */ 3685e9a2692SMartin Schwidefsky clear_tsk_thread_flag(tsk, TIF_PER_TRAP); 36950d7280dSMartin Schwidefsky fault = 0; 37050d7280dSMartin Schwidefsky out_up: 3711da177e4SLinus Torvalds up_read(&mm->mmap_sem); 37250d7280dSMartin Schwidefsky out: 37350d7280dSMartin Schwidefsky return fault; 3741da177e4SLinus Torvalds } 3751da177e4SLinus Torvalds 376aa33c8cbSMartin Schwidefsky void __kprobes do_protection_exception(struct pt_regs *regs) 3771da177e4SLinus Torvalds { 378aa33c8cbSMartin Schwidefsky unsigned long trans_exc_code; 37950d7280dSMartin Schwidefsky int fault; 38061365e13SMartin Schwidefsky 381aa33c8cbSMartin Schwidefsky trans_exc_code = regs->int_parm_long; 38225985edcSLucas De Marchi /* Protection exception is suppressing, decrement psw address. */ 383aa33c8cbSMartin Schwidefsky regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16); 38410c1031fSMartin Schwidefsky /* 38510c1031fSMartin Schwidefsky * Check for low-address protection. This needs to be treated 38610c1031fSMartin Schwidefsky * as a special case because the translation exception code 38710c1031fSMartin Schwidefsky * field is not guaranteed to contain valid data in this case. 38810c1031fSMartin Schwidefsky */ 38961365e13SMartin Schwidefsky if (unlikely(!(trans_exc_code & 4))) { 390aa33c8cbSMartin Schwidefsky do_low_address(regs); 39110c1031fSMartin Schwidefsky return; 39210c1031fSMartin Schwidefsky } 393aa33c8cbSMartin Schwidefsky fault = do_exception(regs, VM_WRITE); 39450d7280dSMartin Schwidefsky if (unlikely(fault)) 395aa33c8cbSMartin Schwidefsky do_fault_error(regs, fault); 3961da177e4SLinus Torvalds } 3971da177e4SLinus Torvalds 398aa33c8cbSMartin Schwidefsky void __kprobes do_dat_exception(struct pt_regs *regs) 3991da177e4SLinus Torvalds { 4001ab947deSMartin Schwidefsky int access, fault; 40150d7280dSMartin Schwidefsky 4021ab947deSMartin Schwidefsky access = VM_READ | VM_EXEC | VM_WRITE; 403aa33c8cbSMartin Schwidefsky fault = do_exception(regs, access); 40450d7280dSMartin Schwidefsky if (unlikely(fault)) 405aa33c8cbSMartin Schwidefsky do_fault_error(regs, fault); 4061da177e4SLinus Torvalds } 4071da177e4SLinus Torvalds 4086252d702SMartin Schwidefsky #ifdef CONFIG_64BIT 409aa33c8cbSMartin Schwidefsky void __kprobes do_asce_exception(struct pt_regs *regs) 4106252d702SMartin Schwidefsky { 41150d7280dSMartin Schwidefsky struct mm_struct *mm = current->mm; 4126252d702SMartin Schwidefsky struct vm_area_struct *vma; 413aa33c8cbSMartin Schwidefsky unsigned long trans_exc_code; 4146252d702SMartin Schwidefsky 415aa33c8cbSMartin Schwidefsky trans_exc_code = regs->int_parm_long; 41661365e13SMartin Schwidefsky if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm)) 4176252d702SMartin Schwidefsky goto no_context; 4186252d702SMartin Schwidefsky 4196252d702SMartin Schwidefsky down_read(&mm->mmap_sem); 42050d7280dSMartin Schwidefsky vma = find_vma(mm, trans_exc_code & __FAIL_ADDR_MASK); 4216252d702SMartin Schwidefsky up_read(&mm->mmap_sem); 4226252d702SMartin Schwidefsky 4236252d702SMartin Schwidefsky if (vma) { 4246252d702SMartin Schwidefsky update_mm(mm, current); 4256252d702SMartin Schwidefsky return; 4266252d702SMartin Schwidefsky } 4276252d702SMartin Schwidefsky 4286252d702SMartin Schwidefsky /* User mode accesses just cause a SIGSEGV */ 4296252d702SMartin Schwidefsky if (regs->psw.mask & PSW_MASK_PSTATE) { 430aa33c8cbSMartin Schwidefsky do_sigsegv(regs, SEGV_MAPERR); 4316252d702SMartin Schwidefsky return; 4326252d702SMartin Schwidefsky } 4336252d702SMartin Schwidefsky 4346252d702SMartin Schwidefsky no_context: 435aa33c8cbSMartin Schwidefsky do_no_context(regs); 4366252d702SMartin Schwidefsky } 4376252d702SMartin Schwidefsky #endif 4386252d702SMartin Schwidefsky 4391e54622eSMartin Schwidefsky int __handle_fault(unsigned long uaddr, unsigned long pgm_int_code, int write) 4406c1e3e79SGerald Schaefer { 4416c1e3e79SGerald Schaefer struct pt_regs regs; 4426c1e3e79SGerald Schaefer int access, fault; 4436c1e3e79SGerald Schaefer 444b50511e4SMartin Schwidefsky regs.psw.mask = psw_kernel_bits | PSW_MASK_DAT | PSW_MASK_MCHECK; 4456c1e3e79SGerald Schaefer if (!irqs_disabled()) 4466c1e3e79SGerald Schaefer regs.psw.mask |= PSW_MASK_IO | PSW_MASK_EXT; 4476c1e3e79SGerald Schaefer regs.psw.addr = (unsigned long) __builtin_return_address(0); 4486c1e3e79SGerald Schaefer regs.psw.addr |= PSW_ADDR_AMODE; 449aa33c8cbSMartin Schwidefsky regs.int_code = pgm_int_code; 450aa33c8cbSMartin Schwidefsky regs.int_parm_long = (uaddr & PAGE_MASK) | 2; 4511e54622eSMartin Schwidefsky access = write ? VM_WRITE : VM_READ; 452aa33c8cbSMartin Schwidefsky fault = do_exception(®s, access); 4536c1e3e79SGerald Schaefer if (unlikely(fault)) { 45499583181SHeiko Carstens if (fault & VM_FAULT_OOM) 45599583181SHeiko Carstens return -EFAULT; 45699583181SHeiko Carstens else if (fault & VM_FAULT_SIGBUS) 457aa33c8cbSMartin Schwidefsky do_sigbus(®s); 4586c1e3e79SGerald Schaefer } 4596c1e3e79SGerald Schaefer return fault ? -EFAULT : 0; 4606c1e3e79SGerald Schaefer } 4616c1e3e79SGerald Schaefer 4621da177e4SLinus Torvalds #ifdef CONFIG_PFAULT 4631da177e4SLinus Torvalds /* 4641da177e4SLinus Torvalds * 'pfault' pseudo page faults routines. 4651da177e4SLinus Torvalds */ 466fb0a9d7eSHeiko Carstens static int pfault_disable; 4671da177e4SLinus Torvalds 4681da177e4SLinus Torvalds static int __init nopfault(char *str) 4691da177e4SLinus Torvalds { 4701da177e4SLinus Torvalds pfault_disable = 1; 4711da177e4SLinus Torvalds return 1; 4721da177e4SLinus Torvalds } 4731da177e4SLinus Torvalds 4741da177e4SLinus Torvalds __setup("nopfault", nopfault); 4751da177e4SLinus Torvalds 4767dd8fe1fSHeiko Carstens struct pfault_refbk { 4777dd8fe1fSHeiko Carstens u16 refdiagc; 4787dd8fe1fSHeiko Carstens u16 reffcode; 4797dd8fe1fSHeiko Carstens u16 refdwlen; 4807dd8fe1fSHeiko Carstens u16 refversn; 4817dd8fe1fSHeiko Carstens u64 refgaddr; 4827dd8fe1fSHeiko Carstens u64 refselmk; 4837dd8fe1fSHeiko Carstens u64 refcmpmk; 4847dd8fe1fSHeiko Carstens u64 reserved; 4857dd8fe1fSHeiko Carstens } __attribute__ ((packed, aligned(8))); 4861da177e4SLinus Torvalds 4871da177e4SLinus Torvalds int pfault_init(void) 4881da177e4SLinus Torvalds { 4897dd8fe1fSHeiko Carstens struct pfault_refbk refbk = { 4907dd8fe1fSHeiko Carstens .refdiagc = 0x258, 4917dd8fe1fSHeiko Carstens .reffcode = 0, 4927dd8fe1fSHeiko Carstens .refdwlen = 5, 4937dd8fe1fSHeiko Carstens .refversn = 2, 4947dd8fe1fSHeiko Carstens .refgaddr = __LC_CURRENT_PID, 4957dd8fe1fSHeiko Carstens .refselmk = 1ULL << 48, 4967dd8fe1fSHeiko Carstens .refcmpmk = 1ULL << 48, 4977dd8fe1fSHeiko Carstens .reserved = __PF_RES_FIELD }; 4981da177e4SLinus Torvalds int rc; 4991da177e4SLinus Torvalds 500f32269a0SCarsten Otte if (pfault_disable) 5011da177e4SLinus Torvalds return -1; 50294c12cc7SMartin Schwidefsky asm volatile( 5031da177e4SLinus Torvalds " diag %1,%0,0x258\n" 5041da177e4SLinus Torvalds "0: j 2f\n" 5051da177e4SLinus Torvalds "1: la %0,8\n" 5061da177e4SLinus Torvalds "2:\n" 50794c12cc7SMartin Schwidefsky EX_TABLE(0b,1b) 508d4b68996SMartin Schwidefsky : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); 5091da177e4SLinus Torvalds return rc; 5101da177e4SLinus Torvalds } 5111da177e4SLinus Torvalds 5121da177e4SLinus Torvalds void pfault_fini(void) 5131da177e4SLinus Torvalds { 5147dd8fe1fSHeiko Carstens struct pfault_refbk refbk = { 5157dd8fe1fSHeiko Carstens .refdiagc = 0x258, 5167dd8fe1fSHeiko Carstens .reffcode = 1, 5177dd8fe1fSHeiko Carstens .refdwlen = 5, 5187dd8fe1fSHeiko Carstens .refversn = 2, 5197dd8fe1fSHeiko Carstens }; 5201da177e4SLinus Torvalds 521f32269a0SCarsten Otte if (pfault_disable) 5221da177e4SLinus Torvalds return; 52394c12cc7SMartin Schwidefsky asm volatile( 5241da177e4SLinus Torvalds " diag %0,0,0x258\n" 5251da177e4SLinus Torvalds "0:\n" 52694c12cc7SMartin Schwidefsky EX_TABLE(0b,0b) 527d4b68996SMartin Schwidefsky : : "a" (&refbk), "m" (refbk) : "cc"); 5281da177e4SLinus Torvalds } 5291da177e4SLinus Torvalds 530f2db2e6cSHeiko Carstens static DEFINE_SPINLOCK(pfault_lock); 531f2db2e6cSHeiko Carstens static LIST_HEAD(pfault_list); 532f2db2e6cSHeiko Carstens 533fde15c3aSHeiko Carstens static void pfault_interrupt(struct ext_code ext_code, 534f6649a7eSMartin Schwidefsky unsigned int param32, unsigned long param64) 5351da177e4SLinus Torvalds { 5361da177e4SLinus Torvalds struct task_struct *tsk; 5371da177e4SLinus Torvalds __u16 subcode; 538f2db2e6cSHeiko Carstens pid_t pid; 5391da177e4SLinus Torvalds 5401da177e4SLinus Torvalds /* 5411da177e4SLinus Torvalds * Get the external interruption subcode & pfault 5421da177e4SLinus Torvalds * initial/completion signal bit. VM stores this 5431da177e4SLinus Torvalds * in the 'cpu address' field associated with the 5441da177e4SLinus Torvalds * external interrupt. 5451da177e4SLinus Torvalds */ 546fde15c3aSHeiko Carstens subcode = ext_code.subcode; 5471da177e4SLinus Torvalds if ((subcode & 0xff00) != __SUBCODE_MASK) 5481da177e4SLinus Torvalds return; 549a9851832SHeiko Carstens kstat_cpu(smp_processor_id()).irqs[EXTINT_PFL]++; 550f2db2e6cSHeiko Carstens /* Get the token (= pid of the affected task). */ 551f2db2e6cSHeiko Carstens pid = sizeof(void *) == 4 ? param32 : param64; 552f2db2e6cSHeiko Carstens rcu_read_lock(); 553f2db2e6cSHeiko Carstens tsk = find_task_by_pid_ns(pid, &init_pid_ns); 554f2db2e6cSHeiko Carstens if (tsk) 555f2db2e6cSHeiko Carstens get_task_struct(tsk); 556f2db2e6cSHeiko Carstens rcu_read_unlock(); 557f2db2e6cSHeiko Carstens if (!tsk) 558f2db2e6cSHeiko Carstens return; 559f2db2e6cSHeiko Carstens spin_lock(&pfault_lock); 5601da177e4SLinus Torvalds if (subcode & 0x0080) { 5611da177e4SLinus Torvalds /* signal bit is set -> a page has been swapped in by VM */ 562f2db2e6cSHeiko Carstens if (tsk->thread.pfault_wait == 1) { 5631da177e4SLinus Torvalds /* Initial interrupt was faster than the completion 5641da177e4SLinus Torvalds * interrupt. pfault_wait is valid. Set pfault_wait 5651da177e4SLinus Torvalds * back to zero and wake up the process. This can 5661da177e4SLinus Torvalds * safely be done because the task is still sleeping 567b6d09449SMartin Schwidefsky * and can't produce new pfaults. */ 5681da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 569f2db2e6cSHeiko Carstens list_del(&tsk->thread.list); 5701da177e4SLinus Torvalds wake_up_process(tsk); 571d5e50a51SHeiko Carstens put_task_struct(tsk); 572f2db2e6cSHeiko Carstens } else { 573f2db2e6cSHeiko Carstens /* Completion interrupt was faster than initial 574f2db2e6cSHeiko Carstens * interrupt. Set pfault_wait to -1 so the initial 575fa2fb2f4SHeiko Carstens * interrupt doesn't put the task to sleep. 576fa2fb2f4SHeiko Carstens * If the task is not running, ignore the completion 577fa2fb2f4SHeiko Carstens * interrupt since it must be a leftover of a PFAULT 578fa2fb2f4SHeiko Carstens * CANCEL operation which didn't remove all pending 579fa2fb2f4SHeiko Carstens * completion interrupts. */ 580fa2fb2f4SHeiko Carstens if (tsk->state == TASK_RUNNING) 581f2db2e6cSHeiko Carstens tsk->thread.pfault_wait = -1; 5821da177e4SLinus Torvalds } 5831da177e4SLinus Torvalds } else { 5841da177e4SLinus Torvalds /* signal bit not set -> a real page is missing. */ 585d49f47f8SHeiko Carstens if (WARN_ON_ONCE(tsk != current)) 586d49f47f8SHeiko Carstens goto out; 587d5e50a51SHeiko Carstens if (tsk->thread.pfault_wait == 1) { 588d5e50a51SHeiko Carstens /* Already on the list with a reference: put to sleep */ 5890a16ba78SHeiko Carstens __set_task_state(tsk, TASK_UNINTERRUPTIBLE); 590d5e50a51SHeiko Carstens set_tsk_need_resched(tsk); 591d5e50a51SHeiko Carstens } else if (tsk->thread.pfault_wait == -1) { 5921da177e4SLinus Torvalds /* Completion interrupt was faster than the initial 593f2db2e6cSHeiko Carstens * interrupt (pfault_wait == -1). Set pfault_wait 594f2db2e6cSHeiko Carstens * back to zero and exit. */ 5951da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 596f2db2e6cSHeiko Carstens } else { 597f2db2e6cSHeiko Carstens /* Initial interrupt arrived before completion 598d5e50a51SHeiko Carstens * interrupt. Let the task sleep. 599d5e50a51SHeiko Carstens * An extra task reference is needed since a different 600d5e50a51SHeiko Carstens * cpu may set the task state to TASK_RUNNING again 601d5e50a51SHeiko Carstens * before the scheduler is reached. */ 602d5e50a51SHeiko Carstens get_task_struct(tsk); 603f2db2e6cSHeiko Carstens tsk->thread.pfault_wait = 1; 604f2db2e6cSHeiko Carstens list_add(&tsk->thread.list, &pfault_list); 6050a16ba78SHeiko Carstens __set_task_state(tsk, TASK_UNINTERRUPTIBLE); 6061da177e4SLinus Torvalds set_tsk_need_resched(tsk); 6071da177e4SLinus Torvalds } 6081da177e4SLinus Torvalds } 609d49f47f8SHeiko Carstens out: 610f2db2e6cSHeiko Carstens spin_unlock(&pfault_lock); 61154c27791SHeiko Carstens put_task_struct(tsk); 612f2db2e6cSHeiko Carstens } 613f2db2e6cSHeiko Carstens 614f2db2e6cSHeiko Carstens static int __cpuinit pfault_cpu_notify(struct notifier_block *self, 615f2db2e6cSHeiko Carstens unsigned long action, void *hcpu) 616f2db2e6cSHeiko Carstens { 617f2db2e6cSHeiko Carstens struct thread_struct *thread, *next; 618f2db2e6cSHeiko Carstens struct task_struct *tsk; 619f2db2e6cSHeiko Carstens 620f2db2e6cSHeiko Carstens switch (action) { 621f2db2e6cSHeiko Carstens case CPU_DEAD: 622f2db2e6cSHeiko Carstens case CPU_DEAD_FROZEN: 623f2db2e6cSHeiko Carstens spin_lock_irq(&pfault_lock); 624f2db2e6cSHeiko Carstens list_for_each_entry_safe(thread, next, &pfault_list, list) { 625f2db2e6cSHeiko Carstens thread->pfault_wait = 0; 626f2db2e6cSHeiko Carstens list_del(&thread->list); 627f2db2e6cSHeiko Carstens tsk = container_of(thread, struct task_struct, thread); 628f2db2e6cSHeiko Carstens wake_up_process(tsk); 629d5e50a51SHeiko Carstens put_task_struct(tsk); 630f2db2e6cSHeiko Carstens } 631f2db2e6cSHeiko Carstens spin_unlock_irq(&pfault_lock); 632f2db2e6cSHeiko Carstens break; 633f2db2e6cSHeiko Carstens default: 634f2db2e6cSHeiko Carstens break; 635f2db2e6cSHeiko Carstens } 636f2db2e6cSHeiko Carstens return NOTIFY_OK; 637f2db2e6cSHeiko Carstens } 6381da177e4SLinus Torvalds 639fb0a9d7eSHeiko Carstens static int __init pfault_irq_init(void) 64029b08d2bSHeiko Carstens { 641fb0a9d7eSHeiko Carstens int rc; 64229b08d2bSHeiko Carstens 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