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 5492f842eaSMartin Schwidefsky static unsigned long store_indication; 5592f842eaSMartin Schwidefsky 5692f842eaSMartin Schwidefsky void fault_init(void) 5792f842eaSMartin Schwidefsky { 5814375bc4SMartin Schwidefsky if (test_facility(2) && test_facility(75)) 5992f842eaSMartin Schwidefsky store_indication = 0xc00; 6092f842eaSMartin Schwidefsky } 6192f842eaSMartin Schwidefsky 627ecb344aSMartin Schwidefsky static inline int notify_page_fault(struct pt_regs *regs) 6310c1031fSMartin Schwidefsky { 6433464e3bSChristoph Hellwig int ret = 0; 6533464e3bSChristoph Hellwig 6633464e3bSChristoph Hellwig /* kprobe_running() needs smp_processor_id() */ 6722e0a046SHeiko Carstens if (kprobes_built_in() && !user_mode(regs)) { 6833464e3bSChristoph Hellwig preempt_disable(); 6933464e3bSChristoph Hellwig if (kprobe_running() && kprobe_fault_handler(regs, 14)) 7033464e3bSChristoph Hellwig ret = 1; 7133464e3bSChristoph Hellwig preempt_enable(); 7233464e3bSChristoph Hellwig } 7333464e3bSChristoph Hellwig return ret; 744ba069b8SMichael Grundy } 754ba069b8SMichael Grundy 761da177e4SLinus Torvalds 771da177e4SLinus Torvalds /* 781da177e4SLinus Torvalds * Unlock any spinlocks which will prevent us from getting the 79cefc8be8SKirill Korotaev * message out. 801da177e4SLinus Torvalds */ 811da177e4SLinus Torvalds void bust_spinlocks(int yes) 821da177e4SLinus Torvalds { 831da177e4SLinus Torvalds if (yes) { 841da177e4SLinus Torvalds oops_in_progress = 1; 851da177e4SLinus Torvalds } else { 861da177e4SLinus Torvalds int loglevel_save = console_loglevel; 871da177e4SLinus Torvalds console_unblank(); 881da177e4SLinus Torvalds oops_in_progress = 0; 891da177e4SLinus Torvalds /* 901da177e4SLinus Torvalds * OK, the message is on the console. Now we call printk() 911da177e4SLinus Torvalds * without oops_in_progress set so that printk will give klogd 921da177e4SLinus Torvalds * a poke. Hold onto your hats... 931da177e4SLinus Torvalds */ 941da177e4SLinus Torvalds console_loglevel = 15; 951da177e4SLinus Torvalds printk(" "); 961da177e4SLinus Torvalds console_loglevel = loglevel_save; 971da177e4SLinus Torvalds } 981da177e4SLinus Torvalds } 991da177e4SLinus Torvalds 1001da177e4SLinus Torvalds /* 101482b05ddSGerald Schaefer * Returns the address space associated with the fault. 10261365e13SMartin Schwidefsky * Returns 0 for kernel space and 1 for user space. 1031da177e4SLinus Torvalds */ 10461365e13SMartin Schwidefsky static inline int user_space_fault(unsigned long trans_exc_code) 1051da177e4SLinus Torvalds { 1061da177e4SLinus Torvalds /* 10761365e13SMartin Schwidefsky * The lowest two bits of the translation exception 10861365e13SMartin Schwidefsky * identification indicate which paging table was used. 1091da177e4SLinus Torvalds */ 11061365e13SMartin Schwidefsky trans_exc_code &= 3; 11161365e13SMartin Schwidefsky if (trans_exc_code == 2) 11261365e13SMartin Schwidefsky /* Access via secondary space, set_fs setting decides */ 11361365e13SMartin Schwidefsky return current->thread.mm_segment.ar4; 114*d1b0d842SHeiko Carstens if (s390_user_mode == HOME_SPACE_MODE) 11561365e13SMartin Schwidefsky /* User space if the access has been done via home space. */ 11661365e13SMartin Schwidefsky return trans_exc_code == 3; 117482b05ddSGerald Schaefer /* 11861365e13SMartin Schwidefsky * If the user space is not the home space the kernel runs in home 11961365e13SMartin Schwidefsky * space. Access via secondary space has already been covered, 12061365e13SMartin 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) { 16610c1031fSMartin Schwidefsky regs->psw.addr = 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: 231aa33c8cbSMartin Schwidefsky do_no_context(regs); 23250d7280dSMartin Schwidefsky break; 233f2c76e3bSHeiko Carstens case VM_FAULT_SIGNAL: 234f2c76e3bSHeiko Carstens if (!user_mode(regs)) 235f2c76e3bSHeiko Carstens do_no_context(regs); 236f2c76e3bSHeiko Carstens break; 23750d7280dSMartin Schwidefsky default: /* fault & VM_FAULT_ERROR */ 23899583181SHeiko Carstens if (fault & VM_FAULT_OOM) { 2397d256175SHeiko Carstens if (!user_mode(regs)) 240aa33c8cbSMartin Schwidefsky do_no_context(regs); 24199583181SHeiko Carstens else 24250d7280dSMartin Schwidefsky pagefault_out_of_memory(); 24399583181SHeiko Carstens } else if (fault & VM_FAULT_SIGBUS) { 24450d7280dSMartin Schwidefsky /* Kernel mode? Handle exceptions or die */ 2457d256175SHeiko Carstens if (!user_mode(regs)) 246aa33c8cbSMartin Schwidefsky do_no_context(regs); 24736bf9680SMartin Schwidefsky else 248aa33c8cbSMartin Schwidefsky do_sigbus(regs); 24950d7280dSMartin Schwidefsky } else 25050d7280dSMartin Schwidefsky BUG(); 25150d7280dSMartin Schwidefsky break; 25250d7280dSMartin Schwidefsky } 25350d7280dSMartin Schwidefsky } 25450d7280dSMartin Schwidefsky 2551da177e4SLinus Torvalds /* 2561da177e4SLinus Torvalds * This routine handles page faults. It determines the address, 2571da177e4SLinus Torvalds * and the problem, and then passes it off to one of the appropriate 2581da177e4SLinus Torvalds * routines. 2591da177e4SLinus Torvalds * 26050d7280dSMartin Schwidefsky * interruption code (int_code): 2611da177e4SLinus Torvalds * 04 Protection -> Write-Protection (suprression) 2621da177e4SLinus Torvalds * 10 Segment translation -> Not present (nullification) 2631da177e4SLinus Torvalds * 11 Page translation -> Not present (nullification) 2641da177e4SLinus Torvalds * 3b Region third trans. -> Not present (nullification) 2651da177e4SLinus Torvalds */ 266aa33c8cbSMartin Schwidefsky static inline int do_exception(struct pt_regs *regs, int access) 2671da177e4SLinus Torvalds { 2681da177e4SLinus Torvalds struct task_struct *tsk; 2691da177e4SLinus Torvalds struct mm_struct *mm; 2701da177e4SLinus Torvalds struct vm_area_struct *vma; 271aa33c8cbSMartin Schwidefsky unsigned long trans_exc_code; 2721da177e4SLinus Torvalds unsigned long address; 27333ce6140SHeiko Carstens unsigned int flags; 27433ce6140SHeiko Carstens int fault; 27510c1031fSMartin Schwidefsky 2767ecb344aSMartin Schwidefsky if (notify_page_fault(regs)) 27750d7280dSMartin Schwidefsky return 0; 2781da177e4SLinus Torvalds 2791da177e4SLinus Torvalds tsk = current; 2801da177e4SLinus Torvalds mm = tsk->mm; 281aa33c8cbSMartin Schwidefsky trans_exc_code = regs->int_parm_long; 2821da177e4SLinus Torvalds 2831da177e4SLinus Torvalds /* 2841da177e4SLinus Torvalds * Verify that the fault happened in user space, that 2851da177e4SLinus Torvalds * we are not in an interrupt and that there is a 2861da177e4SLinus Torvalds * user context. 2871da177e4SLinus Torvalds */ 28850d7280dSMartin Schwidefsky fault = VM_FAULT_BADCONTEXT; 28961365e13SMartin Schwidefsky if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm)) 29050d7280dSMartin Schwidefsky goto out; 2911da177e4SLinus Torvalds 29261365e13SMartin Schwidefsky address = trans_exc_code & __FAIL_ADDR_MASK; 293a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); 294f2c76e3bSHeiko Carstens flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; 29533ce6140SHeiko Carstens if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400) 29633ce6140SHeiko Carstens flags |= FAULT_FLAG_WRITE; 2971da177e4SLinus Torvalds down_read(&mm->mmap_sem); 2981da177e4SLinus Torvalds 299e5992f2eSMartin Schwidefsky #ifdef CONFIG_PGSTE 3005e8010cbSMartin Schwidefsky if ((current->flags & PF_VCPU) && S390_lowcore.gmap) { 301499069e1SCarsten Otte address = __gmap_fault(address, 302e5992f2eSMartin Schwidefsky (struct gmap *) S390_lowcore.gmap); 303e5992f2eSMartin Schwidefsky if (address == -EFAULT) { 304e5992f2eSMartin Schwidefsky fault = VM_FAULT_BADMAP; 305e5992f2eSMartin Schwidefsky goto out_up; 306e5992f2eSMartin Schwidefsky } 307e5992f2eSMartin Schwidefsky if (address == -ENOMEM) { 308e5992f2eSMartin Schwidefsky fault = VM_FAULT_OOM; 309e5992f2eSMartin Schwidefsky goto out_up; 310e5992f2eSMartin Schwidefsky } 311e5992f2eSMartin Schwidefsky } 312e5992f2eSMartin Schwidefsky #endif 313e5992f2eSMartin Schwidefsky 314e5992f2eSMartin Schwidefsky retry: 31550d7280dSMartin Schwidefsky fault = VM_FAULT_BADMAP; 3161da177e4SLinus Torvalds vma = find_vma(mm, address); 3171da177e4SLinus Torvalds if (!vma) 31850d7280dSMartin Schwidefsky goto out_up; 319c1821c2eSGerald Schaefer 32050d7280dSMartin Schwidefsky if (unlikely(vma->vm_start > address)) { 3211da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 32250d7280dSMartin Schwidefsky goto out_up; 3231da177e4SLinus Torvalds if (expand_stack(vma, address)) 32450d7280dSMartin Schwidefsky goto out_up; 32550d7280dSMartin Schwidefsky } 32650d7280dSMartin Schwidefsky 3271da177e4SLinus Torvalds /* 3281da177e4SLinus Torvalds * Ok, we have a good vm_area for this memory access, so 3291da177e4SLinus Torvalds * we can handle it.. 3301da177e4SLinus Torvalds */ 33150d7280dSMartin Schwidefsky fault = VM_FAULT_BADACCESS; 3321ab947deSMartin Schwidefsky if (unlikely(!(vma->vm_flags & access))) 33350d7280dSMartin Schwidefsky goto out_up; 3341da177e4SLinus Torvalds 33553492b1dSGerald Schaefer if (is_vm_hugetlb_page(vma)) 33653492b1dSGerald Schaefer address &= HPAGE_MASK; 3371da177e4SLinus Torvalds /* 3381da177e4SLinus Torvalds * If for any reason at all we couldn't handle the fault, 3391da177e4SLinus Torvalds * make sure we exit gracefully rather than endlessly redo 3401da177e4SLinus Torvalds * the fault. 3411da177e4SLinus Torvalds */ 34233ce6140SHeiko Carstens fault = handle_mm_fault(mm, vma, address, flags); 343f2c76e3bSHeiko Carstens /* No reason to continue if interrupted by SIGKILL. */ 344f2c76e3bSHeiko Carstens if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { 345f2c76e3bSHeiko Carstens fault = VM_FAULT_SIGNAL; 346f2c76e3bSHeiko Carstens goto out; 347f2c76e3bSHeiko Carstens } 34850d7280dSMartin Schwidefsky if (unlikely(fault & VM_FAULT_ERROR)) 34950d7280dSMartin Schwidefsky goto out_up; 35050d7280dSMartin Schwidefsky 35133ce6140SHeiko Carstens /* 35233ce6140SHeiko Carstens * Major/minor page fault accounting is only done on the 35333ce6140SHeiko Carstens * initial attempt. If we go through a retry, it is extremely 35433ce6140SHeiko Carstens * likely that the page will be found in page cache at that point. 35533ce6140SHeiko Carstens */ 35633ce6140SHeiko Carstens if (flags & FAULT_FLAG_ALLOW_RETRY) { 357bde69af2SHeiko Carstens if (fault & VM_FAULT_MAJOR) { 35883c54070SNick Piggin tsk->maj_flt++; 359a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 360bde69af2SHeiko Carstens regs, address); 361bde69af2SHeiko Carstens } else { 36283c54070SNick Piggin tsk->min_flt++; 363a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 364bde69af2SHeiko Carstens regs, address); 365bde69af2SHeiko Carstens } 36633ce6140SHeiko Carstens if (fault & VM_FAULT_RETRY) { 36733ce6140SHeiko Carstens /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk 36833ce6140SHeiko Carstens * of starvation. */ 36933ce6140SHeiko Carstens flags &= ~FAULT_FLAG_ALLOW_RETRY; 370e5992f2eSMartin Schwidefsky down_read(&mm->mmap_sem); 37133ce6140SHeiko Carstens goto retry; 37233ce6140SHeiko Carstens } 37333ce6140SHeiko Carstens } 3741da177e4SLinus Torvalds /* 3751da177e4SLinus Torvalds * The instruction that caused the program check will 3761da177e4SLinus Torvalds * be repeated. Don't signal single step via SIGTRAP. 3771da177e4SLinus Torvalds */ 3785e9a2692SMartin Schwidefsky clear_tsk_thread_flag(tsk, TIF_PER_TRAP); 37950d7280dSMartin Schwidefsky fault = 0; 38050d7280dSMartin Schwidefsky out_up: 3811da177e4SLinus Torvalds up_read(&mm->mmap_sem); 38250d7280dSMartin Schwidefsky out: 38350d7280dSMartin Schwidefsky return fault; 3841da177e4SLinus Torvalds } 3851da177e4SLinus Torvalds 386aa33c8cbSMartin Schwidefsky void __kprobes do_protection_exception(struct pt_regs *regs) 3871da177e4SLinus Torvalds { 388aa33c8cbSMartin Schwidefsky unsigned long trans_exc_code; 38950d7280dSMartin Schwidefsky int fault; 39061365e13SMartin Schwidefsky 391aa33c8cbSMartin Schwidefsky trans_exc_code = regs->int_parm_long; 39225985edcSLucas De Marchi /* Protection exception is suppressing, decrement psw address. */ 393aa33c8cbSMartin Schwidefsky regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16); 39410c1031fSMartin Schwidefsky /* 39510c1031fSMartin Schwidefsky * Check for low-address protection. This needs to be treated 39610c1031fSMartin Schwidefsky * as a special case because the translation exception code 39710c1031fSMartin Schwidefsky * field is not guaranteed to contain valid data in this case. 39810c1031fSMartin Schwidefsky */ 39961365e13SMartin Schwidefsky if (unlikely(!(trans_exc_code & 4))) { 400aa33c8cbSMartin Schwidefsky do_low_address(regs); 40110c1031fSMartin Schwidefsky return; 40210c1031fSMartin Schwidefsky } 403aa33c8cbSMartin Schwidefsky fault = do_exception(regs, VM_WRITE); 40450d7280dSMartin Schwidefsky if (unlikely(fault)) 405aa33c8cbSMartin Schwidefsky do_fault_error(regs, fault); 4061da177e4SLinus Torvalds } 4071da177e4SLinus Torvalds 408aa33c8cbSMartin Schwidefsky void __kprobes do_dat_exception(struct pt_regs *regs) 4091da177e4SLinus Torvalds { 4101ab947deSMartin Schwidefsky int access, fault; 41150d7280dSMartin Schwidefsky 4121ab947deSMartin Schwidefsky access = VM_READ | VM_EXEC | VM_WRITE; 413aa33c8cbSMartin Schwidefsky fault = do_exception(regs, access); 41450d7280dSMartin Schwidefsky if (unlikely(fault)) 415aa33c8cbSMartin Schwidefsky do_fault_error(regs, fault); 4161da177e4SLinus Torvalds } 4171da177e4SLinus Torvalds 4186252d702SMartin Schwidefsky #ifdef CONFIG_64BIT 419aa33c8cbSMartin Schwidefsky void __kprobes do_asce_exception(struct pt_regs *regs) 4206252d702SMartin Schwidefsky { 42150d7280dSMartin Schwidefsky struct mm_struct *mm = current->mm; 4226252d702SMartin Schwidefsky struct vm_area_struct *vma; 423aa33c8cbSMartin Schwidefsky unsigned long trans_exc_code; 4246252d702SMartin Schwidefsky 425aa33c8cbSMartin Schwidefsky trans_exc_code = regs->int_parm_long; 42661365e13SMartin Schwidefsky if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm)) 4276252d702SMartin Schwidefsky goto no_context; 4286252d702SMartin Schwidefsky 4296252d702SMartin Schwidefsky down_read(&mm->mmap_sem); 43050d7280dSMartin Schwidefsky vma = find_vma(mm, trans_exc_code & __FAIL_ADDR_MASK); 4316252d702SMartin Schwidefsky up_read(&mm->mmap_sem); 4326252d702SMartin Schwidefsky 4336252d702SMartin Schwidefsky if (vma) { 4346252d702SMartin Schwidefsky update_mm(mm, current); 4356252d702SMartin Schwidefsky return; 4366252d702SMartin Schwidefsky } 4376252d702SMartin Schwidefsky 4386252d702SMartin Schwidefsky /* User mode accesses just cause a SIGSEGV */ 4397d256175SHeiko Carstens if (user_mode(regs)) { 440aa33c8cbSMartin Schwidefsky do_sigsegv(regs, SEGV_MAPERR); 4416252d702SMartin Schwidefsky return; 4426252d702SMartin Schwidefsky } 4436252d702SMartin Schwidefsky 4446252d702SMartin Schwidefsky no_context: 445aa33c8cbSMartin Schwidefsky do_no_context(regs); 4466252d702SMartin Schwidefsky } 4476252d702SMartin Schwidefsky #endif 4486252d702SMartin Schwidefsky 4491e54622eSMartin Schwidefsky int __handle_fault(unsigned long uaddr, unsigned long pgm_int_code, int write) 4506c1e3e79SGerald Schaefer { 4516c1e3e79SGerald Schaefer struct pt_regs regs; 4526c1e3e79SGerald Schaefer int access, fault; 4536c1e3e79SGerald Schaefer 454008c2e8fSHeiko Carstens /* Emulate a uaccess fault from kernel mode. */ 455b50511e4SMartin Schwidefsky regs.psw.mask = psw_kernel_bits | PSW_MASK_DAT | PSW_MASK_MCHECK; 4566c1e3e79SGerald Schaefer if (!irqs_disabled()) 4576c1e3e79SGerald Schaefer regs.psw.mask |= PSW_MASK_IO | PSW_MASK_EXT; 4586c1e3e79SGerald Schaefer regs.psw.addr = (unsigned long) __builtin_return_address(0); 4596c1e3e79SGerald Schaefer regs.psw.addr |= PSW_ADDR_AMODE; 460aa33c8cbSMartin Schwidefsky regs.int_code = pgm_int_code; 461aa33c8cbSMartin Schwidefsky regs.int_parm_long = (uaddr & PAGE_MASK) | 2; 4621e54622eSMartin Schwidefsky access = write ? VM_WRITE : VM_READ; 463aa33c8cbSMartin Schwidefsky fault = do_exception(®s, access); 464008c2e8fSHeiko Carstens /* 465008c2e8fSHeiko Carstens * Since the fault happened in kernel mode while performing a uaccess 466008c2e8fSHeiko Carstens * all we need to do now is emulating a fixup in case "fault" is not 467008c2e8fSHeiko Carstens * zero. 468008c2e8fSHeiko Carstens * For the calling uaccess functions this results always in -EFAULT. 469008c2e8fSHeiko Carstens */ 4706c1e3e79SGerald Schaefer return fault ? -EFAULT : 0; 4716c1e3e79SGerald Schaefer } 4726c1e3e79SGerald Schaefer 4731da177e4SLinus Torvalds #ifdef CONFIG_PFAULT 4741da177e4SLinus Torvalds /* 4751da177e4SLinus Torvalds * 'pfault' pseudo page faults routines. 4761da177e4SLinus Torvalds */ 477fb0a9d7eSHeiko Carstens static int pfault_disable; 4781da177e4SLinus Torvalds 4791da177e4SLinus Torvalds static int __init nopfault(char *str) 4801da177e4SLinus Torvalds { 4811da177e4SLinus Torvalds pfault_disable = 1; 4821da177e4SLinus Torvalds return 1; 4831da177e4SLinus Torvalds } 4841da177e4SLinus Torvalds 4851da177e4SLinus Torvalds __setup("nopfault", nopfault); 4861da177e4SLinus Torvalds 4877dd8fe1fSHeiko Carstens struct pfault_refbk { 4887dd8fe1fSHeiko Carstens u16 refdiagc; 4897dd8fe1fSHeiko Carstens u16 reffcode; 4907dd8fe1fSHeiko Carstens u16 refdwlen; 4917dd8fe1fSHeiko Carstens u16 refversn; 4927dd8fe1fSHeiko Carstens u64 refgaddr; 4937dd8fe1fSHeiko Carstens u64 refselmk; 4947dd8fe1fSHeiko Carstens u64 refcmpmk; 4957dd8fe1fSHeiko Carstens u64 reserved; 4967dd8fe1fSHeiko Carstens } __attribute__ ((packed, aligned(8))); 4971da177e4SLinus Torvalds 4981da177e4SLinus Torvalds int pfault_init(void) 4991da177e4SLinus Torvalds { 5007dd8fe1fSHeiko Carstens struct pfault_refbk refbk = { 5017dd8fe1fSHeiko Carstens .refdiagc = 0x258, 5027dd8fe1fSHeiko Carstens .reffcode = 0, 5037dd8fe1fSHeiko Carstens .refdwlen = 5, 5047dd8fe1fSHeiko Carstens .refversn = 2, 5057dd8fe1fSHeiko Carstens .refgaddr = __LC_CURRENT_PID, 5067dd8fe1fSHeiko Carstens .refselmk = 1ULL << 48, 5077dd8fe1fSHeiko Carstens .refcmpmk = 1ULL << 48, 5087dd8fe1fSHeiko Carstens .reserved = __PF_RES_FIELD }; 5091da177e4SLinus Torvalds int rc; 5101da177e4SLinus Torvalds 511f32269a0SCarsten Otte if (pfault_disable) 5121da177e4SLinus Torvalds return -1; 51394c12cc7SMartin Schwidefsky asm volatile( 5141da177e4SLinus Torvalds " diag %1,%0,0x258\n" 5151da177e4SLinus Torvalds "0: j 2f\n" 5161da177e4SLinus Torvalds "1: la %0,8\n" 5171da177e4SLinus Torvalds "2:\n" 51894c12cc7SMartin Schwidefsky EX_TABLE(0b,1b) 519d4b68996SMartin Schwidefsky : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); 5201da177e4SLinus Torvalds return rc; 5211da177e4SLinus Torvalds } 5221da177e4SLinus Torvalds 5231da177e4SLinus Torvalds void pfault_fini(void) 5241da177e4SLinus Torvalds { 5257dd8fe1fSHeiko Carstens struct pfault_refbk refbk = { 5267dd8fe1fSHeiko Carstens .refdiagc = 0x258, 5277dd8fe1fSHeiko Carstens .reffcode = 1, 5287dd8fe1fSHeiko Carstens .refdwlen = 5, 5297dd8fe1fSHeiko Carstens .refversn = 2, 5307dd8fe1fSHeiko Carstens }; 5311da177e4SLinus Torvalds 532f32269a0SCarsten Otte if (pfault_disable) 5331da177e4SLinus Torvalds return; 53494c12cc7SMartin Schwidefsky asm volatile( 5351da177e4SLinus Torvalds " diag %0,0,0x258\n" 5361da177e4SLinus Torvalds "0:\n" 53794c12cc7SMartin Schwidefsky EX_TABLE(0b,0b) 538d4b68996SMartin Schwidefsky : : "a" (&refbk), "m" (refbk) : "cc"); 5391da177e4SLinus Torvalds } 5401da177e4SLinus Torvalds 541f2db2e6cSHeiko Carstens static DEFINE_SPINLOCK(pfault_lock); 542f2db2e6cSHeiko Carstens static LIST_HEAD(pfault_list); 543f2db2e6cSHeiko Carstens 544fde15c3aSHeiko Carstens static void pfault_interrupt(struct ext_code ext_code, 545f6649a7eSMartin Schwidefsky unsigned int param32, unsigned long param64) 5461da177e4SLinus Torvalds { 5471da177e4SLinus Torvalds struct task_struct *tsk; 5481da177e4SLinus Torvalds __u16 subcode; 549f2db2e6cSHeiko Carstens pid_t pid; 5501da177e4SLinus Torvalds 5511da177e4SLinus Torvalds /* 5521da177e4SLinus Torvalds * Get the external interruption subcode & pfault 5531da177e4SLinus Torvalds * initial/completion signal bit. VM stores this 5541da177e4SLinus Torvalds * in the 'cpu address' field associated with the 5551da177e4SLinus Torvalds * external interrupt. 5561da177e4SLinus Torvalds */ 557fde15c3aSHeiko Carstens subcode = ext_code.subcode; 5581da177e4SLinus Torvalds if ((subcode & 0xff00) != __SUBCODE_MASK) 5591da177e4SLinus Torvalds return; 560a9851832SHeiko Carstens kstat_cpu(smp_processor_id()).irqs[EXTINT_PFL]++; 561f2db2e6cSHeiko Carstens /* Get the token (= pid of the affected task). */ 562f2db2e6cSHeiko Carstens pid = sizeof(void *) == 4 ? param32 : param64; 563f2db2e6cSHeiko Carstens rcu_read_lock(); 564f2db2e6cSHeiko Carstens tsk = find_task_by_pid_ns(pid, &init_pid_ns); 565f2db2e6cSHeiko Carstens if (tsk) 566f2db2e6cSHeiko Carstens get_task_struct(tsk); 567f2db2e6cSHeiko Carstens rcu_read_unlock(); 568f2db2e6cSHeiko Carstens if (!tsk) 569f2db2e6cSHeiko Carstens return; 570f2db2e6cSHeiko Carstens spin_lock(&pfault_lock); 5711da177e4SLinus Torvalds if (subcode & 0x0080) { 5721da177e4SLinus Torvalds /* signal bit is set -> a page has been swapped in by VM */ 573f2db2e6cSHeiko Carstens if (tsk->thread.pfault_wait == 1) { 5741da177e4SLinus Torvalds /* Initial interrupt was faster than the completion 5751da177e4SLinus Torvalds * interrupt. pfault_wait is valid. Set pfault_wait 5761da177e4SLinus Torvalds * back to zero and wake up the process. This can 5771da177e4SLinus Torvalds * safely be done because the task is still sleeping 578b6d09449SMartin Schwidefsky * and can't produce new pfaults. */ 5791da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 580f2db2e6cSHeiko Carstens list_del(&tsk->thread.list); 5811da177e4SLinus Torvalds wake_up_process(tsk); 582d5e50a51SHeiko Carstens put_task_struct(tsk); 583f2db2e6cSHeiko Carstens } else { 584f2db2e6cSHeiko Carstens /* Completion interrupt was faster than initial 585f2db2e6cSHeiko Carstens * interrupt. Set pfault_wait to -1 so the initial 586fa2fb2f4SHeiko Carstens * interrupt doesn't put the task to sleep. 587fa2fb2f4SHeiko Carstens * If the task is not running, ignore the completion 588fa2fb2f4SHeiko Carstens * interrupt since it must be a leftover of a PFAULT 589fa2fb2f4SHeiko Carstens * CANCEL operation which didn't remove all pending 590fa2fb2f4SHeiko Carstens * completion interrupts. */ 591fa2fb2f4SHeiko Carstens if (tsk->state == TASK_RUNNING) 592f2db2e6cSHeiko Carstens tsk->thread.pfault_wait = -1; 5931da177e4SLinus Torvalds } 5941da177e4SLinus Torvalds } else { 5951da177e4SLinus Torvalds /* signal bit not set -> a real page is missing. */ 596d49f47f8SHeiko Carstens if (WARN_ON_ONCE(tsk != current)) 597d49f47f8SHeiko Carstens goto out; 598d5e50a51SHeiko Carstens if (tsk->thread.pfault_wait == 1) { 599d5e50a51SHeiko Carstens /* Already on the list with a reference: put to sleep */ 6000a16ba78SHeiko Carstens __set_task_state(tsk, TASK_UNINTERRUPTIBLE); 601d5e50a51SHeiko Carstens set_tsk_need_resched(tsk); 602d5e50a51SHeiko Carstens } else if (tsk->thread.pfault_wait == -1) { 6031da177e4SLinus Torvalds /* Completion interrupt was faster than the initial 604f2db2e6cSHeiko Carstens * interrupt (pfault_wait == -1). Set pfault_wait 605f2db2e6cSHeiko Carstens * back to zero and exit. */ 6061da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 607f2db2e6cSHeiko Carstens } else { 608f2db2e6cSHeiko Carstens /* Initial interrupt arrived before completion 609d5e50a51SHeiko Carstens * interrupt. Let the task sleep. 610d5e50a51SHeiko Carstens * An extra task reference is needed since a different 611d5e50a51SHeiko Carstens * cpu may set the task state to TASK_RUNNING again 612d5e50a51SHeiko Carstens * before the scheduler is reached. */ 613d5e50a51SHeiko Carstens get_task_struct(tsk); 614f2db2e6cSHeiko Carstens tsk->thread.pfault_wait = 1; 615f2db2e6cSHeiko Carstens list_add(&tsk->thread.list, &pfault_list); 6160a16ba78SHeiko Carstens __set_task_state(tsk, TASK_UNINTERRUPTIBLE); 6171da177e4SLinus Torvalds set_tsk_need_resched(tsk); 6181da177e4SLinus Torvalds } 6191da177e4SLinus Torvalds } 620d49f47f8SHeiko Carstens out: 621f2db2e6cSHeiko Carstens spin_unlock(&pfault_lock); 62254c27791SHeiko Carstens put_task_struct(tsk); 623f2db2e6cSHeiko Carstens } 624f2db2e6cSHeiko Carstens 625f2db2e6cSHeiko Carstens static int __cpuinit pfault_cpu_notify(struct notifier_block *self, 626f2db2e6cSHeiko Carstens unsigned long action, void *hcpu) 627f2db2e6cSHeiko Carstens { 628f2db2e6cSHeiko Carstens struct thread_struct *thread, *next; 629f2db2e6cSHeiko Carstens struct task_struct *tsk; 630f2db2e6cSHeiko Carstens 6311c725922SHeiko Carstens switch (action & ~CPU_TASKS_FROZEN) { 632f2db2e6cSHeiko Carstens case CPU_DEAD: 633f2db2e6cSHeiko Carstens spin_lock_irq(&pfault_lock); 634f2db2e6cSHeiko Carstens list_for_each_entry_safe(thread, next, &pfault_list, list) { 635f2db2e6cSHeiko Carstens thread->pfault_wait = 0; 636f2db2e6cSHeiko Carstens list_del(&thread->list); 637f2db2e6cSHeiko Carstens tsk = container_of(thread, struct task_struct, thread); 638f2db2e6cSHeiko Carstens wake_up_process(tsk); 639d5e50a51SHeiko Carstens put_task_struct(tsk); 640f2db2e6cSHeiko Carstens } 641f2db2e6cSHeiko Carstens spin_unlock_irq(&pfault_lock); 642f2db2e6cSHeiko Carstens break; 643f2db2e6cSHeiko Carstens default: 644f2db2e6cSHeiko Carstens break; 645f2db2e6cSHeiko Carstens } 646f2db2e6cSHeiko Carstens return NOTIFY_OK; 647f2db2e6cSHeiko Carstens } 6481da177e4SLinus Torvalds 649fb0a9d7eSHeiko Carstens static int __init pfault_irq_init(void) 65029b08d2bSHeiko Carstens { 651fb0a9d7eSHeiko Carstens int rc; 65229b08d2bSHeiko Carstens 653fb0a9d7eSHeiko Carstens rc = register_external_interrupt(0x2603, pfault_interrupt); 6547dd8fe1fSHeiko Carstens if (rc) 6557dd8fe1fSHeiko Carstens goto out_extint; 6567dd8fe1fSHeiko Carstens rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP; 6577dd8fe1fSHeiko Carstens if (rc) 6587dd8fe1fSHeiko Carstens goto out_pfault; 659df7997abSHeiko Carstens service_subclass_irq_register(); 6607dd8fe1fSHeiko Carstens hotcpu_notifier(pfault_cpu_notify, 0); 6617dd8fe1fSHeiko Carstens return 0; 6627dd8fe1fSHeiko Carstens 6637dd8fe1fSHeiko Carstens out_pfault: 6647dd8fe1fSHeiko Carstens unregister_external_interrupt(0x2603, pfault_interrupt); 6657dd8fe1fSHeiko Carstens out_extint: 666fb0a9d7eSHeiko Carstens pfault_disable = 1; 667fb0a9d7eSHeiko Carstens return rc; 668fb0a9d7eSHeiko Carstens } 669fb0a9d7eSHeiko Carstens early_initcall(pfault_irq_init); 670fb0a9d7eSHeiko Carstens 6717dd8fe1fSHeiko Carstens #endif /* CONFIG_PFAULT */ 672