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> 331ec2772eSMartin Schwidefsky #include <asm/diag.h> 341da177e4SLinus Torvalds #include <asm/pgtable.h> 351e133ab2SMartin Schwidefsky #include <asm/gmap.h> 36d7b250e2SHeiko Carstens #include <asm/irq.h> 376252d702SMartin Schwidefsky #include <asm/mmu_context.h> 38a0616cdeSDavid Howells #include <asm/facility.h> 39a806170eSHeiko Carstens #include "../kernel/entry.h" 401da177e4SLinus Torvalds 411da177e4SLinus Torvalds #define __FAIL_ADDR_MASK -4096L 421da177e4SLinus Torvalds #define __SUBCODE_MASK 0x0600 431da177e4SLinus Torvalds #define __PF_RES_FIELD 0x8000000000000000ULL 441da177e4SLinus Torvalds 4550d7280dSMartin Schwidefsky #define VM_FAULT_BADCONTEXT 0x010000 4650d7280dSMartin Schwidefsky #define VM_FAULT_BADMAP 0x020000 4750d7280dSMartin Schwidefsky #define VM_FAULT_BADACCESS 0x040000 48f2c76e3bSHeiko Carstens #define VM_FAULT_SIGNAL 0x080000 4924eb3a82SDominik Dingel #define VM_FAULT_PFAULT 0x100000 5050d7280dSMartin Schwidefsky 51a4f32bdbSHeiko Carstens static unsigned long store_indication __read_mostly; 5292f842eaSMartin Schwidefsky 53a4f32bdbSHeiko Carstens static int __init fault_init(void) 5492f842eaSMartin Schwidefsky { 55a4f32bdbSHeiko Carstens if (test_facility(75)) 5692f842eaSMartin Schwidefsky store_indication = 0xc00; 57a4f32bdbSHeiko Carstens return 0; 5892f842eaSMartin Schwidefsky } 59a4f32bdbSHeiko Carstens early_initcall(fault_init); 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 */ 103457f2180SHeiko Carstens static inline int user_space_fault(struct pt_regs *regs) 1041da177e4SLinus Torvalds { 105457f2180SHeiko Carstens unsigned long trans_exc_code; 106457f2180SHeiko Carstens 1071da177e4SLinus Torvalds /* 10861365e13SMartin Schwidefsky * The lowest two bits of the translation exception 10961365e13SMartin Schwidefsky * identification indicate which paging table was used. 1101da177e4SLinus Torvalds */ 111457f2180SHeiko Carstens trans_exc_code = regs->int_parm_long & 3; 112457f2180SHeiko Carstens if (trans_exc_code == 3) /* home space -> kernel */ 113457f2180SHeiko Carstens return 0; 114457f2180SHeiko Carstens if (user_mode(regs)) 115457f2180SHeiko Carstens return 1; 116457f2180SHeiko Carstens if (trans_exc_code == 2) /* secondary space -> set_fs */ 11761365e13SMartin Schwidefsky return current->thread.mm_segment.ar4; 118457f2180SHeiko Carstens if (current->flags & PF_VCPU) 119457f2180SHeiko Carstens return 1; 120457f2180SHeiko Carstens return 0; 1211da177e4SLinus Torvalds } 1221da177e4SLinus Torvalds 1233b7df342SHeiko Carstens static int bad_address(void *p) 1243b7df342SHeiko Carstens { 1253b7df342SHeiko Carstens unsigned long dummy; 1263b7df342SHeiko Carstens 1273b7df342SHeiko Carstens return probe_kernel_address((unsigned long *)p, dummy); 1283b7df342SHeiko Carstens } 1293b7df342SHeiko Carstens 1303b7df342SHeiko Carstens static void dump_pagetable(unsigned long asce, unsigned long address) 1313b7df342SHeiko Carstens { 1323b7df342SHeiko Carstens unsigned long *table = __va(asce & PAGE_MASK); 1333b7df342SHeiko Carstens 1343b7df342SHeiko Carstens pr_alert("AS:%016lx ", asce); 1353b7df342SHeiko Carstens switch (asce & _ASCE_TYPE_MASK) { 1363b7df342SHeiko Carstens case _ASCE_TYPE_REGION1: 1373b7df342SHeiko Carstens table = table + ((address >> 53) & 0x7ff); 1383b7df342SHeiko Carstens if (bad_address(table)) 1393b7df342SHeiko Carstens goto bad; 1403b7df342SHeiko Carstens pr_cont("R1:%016lx ", *table); 1413b7df342SHeiko Carstens if (*table & _REGION_ENTRY_INVALID) 1423b7df342SHeiko Carstens goto out; 1433b7df342SHeiko Carstens table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 1443b7df342SHeiko Carstens /* fallthrough */ 1453b7df342SHeiko Carstens case _ASCE_TYPE_REGION2: 1463b7df342SHeiko Carstens table = table + ((address >> 42) & 0x7ff); 1473b7df342SHeiko Carstens if (bad_address(table)) 1483b7df342SHeiko Carstens goto bad; 1493b7df342SHeiko Carstens pr_cont("R2:%016lx ", *table); 1503b7df342SHeiko Carstens if (*table & _REGION_ENTRY_INVALID) 1513b7df342SHeiko Carstens goto out; 1523b7df342SHeiko Carstens table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 1533b7df342SHeiko Carstens /* fallthrough */ 1543b7df342SHeiko Carstens case _ASCE_TYPE_REGION3: 1553b7df342SHeiko Carstens table = table + ((address >> 31) & 0x7ff); 1563b7df342SHeiko Carstens if (bad_address(table)) 1573b7df342SHeiko Carstens goto bad; 1583b7df342SHeiko Carstens pr_cont("R3:%016lx ", *table); 1593b7df342SHeiko Carstens if (*table & (_REGION_ENTRY_INVALID | _REGION3_ENTRY_LARGE)) 1603b7df342SHeiko Carstens goto out; 1613b7df342SHeiko Carstens table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 1623b7df342SHeiko Carstens /* fallthrough */ 1633b7df342SHeiko Carstens case _ASCE_TYPE_SEGMENT: 1643b7df342SHeiko Carstens table = table + ((address >> 20) & 0x7ff); 1653b7df342SHeiko Carstens if (bad_address(table)) 1663b7df342SHeiko Carstens goto bad; 16791c0837eSJoe Perches pr_cont("S:%016lx ", *table); 1683b7df342SHeiko Carstens if (*table & (_SEGMENT_ENTRY_INVALID | _SEGMENT_ENTRY_LARGE)) 1693b7df342SHeiko Carstens goto out; 1703b7df342SHeiko Carstens table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN); 1713b7df342SHeiko Carstens } 1723b7df342SHeiko Carstens table = table + ((address >> 12) & 0xff); 1733b7df342SHeiko Carstens if (bad_address(table)) 1743b7df342SHeiko Carstens goto bad; 1753b7df342SHeiko Carstens pr_cont("P:%016lx ", *table); 1763b7df342SHeiko Carstens out: 1773b7df342SHeiko Carstens pr_cont("\n"); 1783b7df342SHeiko Carstens return; 1793b7df342SHeiko Carstens bad: 1803b7df342SHeiko Carstens pr_cont("BAD\n"); 1813b7df342SHeiko Carstens } 1823b7df342SHeiko Carstens 1833b7df342SHeiko Carstens static void dump_fault_info(struct pt_regs *regs) 1843b7df342SHeiko Carstens { 1853b7df342SHeiko Carstens unsigned long asce; 1863b7df342SHeiko Carstens 1875d7eccecSHeiko Carstens pr_alert("Failing address: %016lx TEID: %016lx\n", 1885d7eccecSHeiko Carstens regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long); 1893b7df342SHeiko Carstens pr_alert("Fault in "); 1903b7df342SHeiko Carstens switch (regs->int_parm_long & 3) { 1913b7df342SHeiko Carstens case 3: 1923b7df342SHeiko Carstens pr_cont("home space "); 1933b7df342SHeiko Carstens break; 1943b7df342SHeiko Carstens case 2: 1953b7df342SHeiko Carstens pr_cont("secondary space "); 1963b7df342SHeiko Carstens break; 1973b7df342SHeiko Carstens case 1: 1983b7df342SHeiko Carstens pr_cont("access register "); 1993b7df342SHeiko Carstens break; 2003b7df342SHeiko Carstens case 0: 2013b7df342SHeiko Carstens pr_cont("primary space "); 2023b7df342SHeiko Carstens break; 2033b7df342SHeiko Carstens } 2043b7df342SHeiko Carstens pr_cont("mode while using "); 2053b7df342SHeiko Carstens if (!user_space_fault(regs)) { 2063b7df342SHeiko Carstens asce = S390_lowcore.kernel_asce; 2073b7df342SHeiko Carstens pr_cont("kernel "); 2083b7df342SHeiko Carstens } 2093b7df342SHeiko Carstens #ifdef CONFIG_PGSTE 2103b7df342SHeiko Carstens else if ((current->flags & PF_VCPU) && S390_lowcore.gmap) { 2113b7df342SHeiko Carstens struct gmap *gmap = (struct gmap *)S390_lowcore.gmap; 2123b7df342SHeiko Carstens asce = gmap->asce; 2133b7df342SHeiko Carstens pr_cont("gmap "); 2143b7df342SHeiko Carstens } 2153b7df342SHeiko Carstens #endif 2163b7df342SHeiko Carstens else { 2173b7df342SHeiko Carstens asce = S390_lowcore.user_asce; 2183b7df342SHeiko Carstens pr_cont("user "); 2193b7df342SHeiko Carstens } 2203b7df342SHeiko Carstens pr_cont("ASCE.\n"); 2213b7df342SHeiko Carstens dump_pagetable(asce, regs->int_parm_long & __FAIL_ADDR_MASK); 2223b7df342SHeiko Carstens } 2233b7df342SHeiko Carstens 2245d7eccecSHeiko Carstens int show_unhandled_signals = 1; 2255d7eccecSHeiko Carstens 2265d7eccecSHeiko Carstens void report_user_fault(struct pt_regs *regs, long signr, int is_mm_fault) 227ab3c68eeSHeiko Carstens { 228ab3c68eeSHeiko Carstens if ((task_pid_nr(current) > 1) && !show_unhandled_signals) 229ab3c68eeSHeiko Carstens return; 230ab3c68eeSHeiko Carstens if (!unhandled_signal(current, signr)) 231ab3c68eeSHeiko Carstens return; 232ab3c68eeSHeiko Carstens if (!printk_ratelimit()) 233ab3c68eeSHeiko Carstens return; 234413d4047SHeiko Carstens printk(KERN_ALERT "User process fault: interruption code %04x ilc:%d ", 235413d4047SHeiko Carstens regs->int_code & 0xffff, regs->int_code >> 17); 2369cb1ccecSHeiko Carstens print_vma_addr(KERN_CONT "in ", regs->psw.addr); 237aa33c8cbSMartin Schwidefsky printk(KERN_CONT "\n"); 2385d7eccecSHeiko Carstens if (is_mm_fault) 2393b7df342SHeiko Carstens dump_fault_info(regs); 240ab3c68eeSHeiko Carstens show_regs(regs); 241ab3c68eeSHeiko Carstens } 242ab3c68eeSHeiko Carstens 2431da177e4SLinus Torvalds /* 2441da177e4SLinus Torvalds * Send SIGSEGV to task. This is an external routine 2451da177e4SLinus Torvalds * to keep the stack usage of do_page_fault small. 2461da177e4SLinus Torvalds */ 247aa33c8cbSMartin Schwidefsky static noinline void do_sigsegv(struct pt_regs *regs, int si_code) 2481da177e4SLinus Torvalds { 2491da177e4SLinus Torvalds struct siginfo si; 2501da177e4SLinus Torvalds 2515d7eccecSHeiko Carstens report_user_fault(regs, SIGSEGV, 1); 2521da177e4SLinus Torvalds si.si_signo = SIGSEGV; 253cf0d44d5SMichal Hocko si.si_errno = 0; 2541da177e4SLinus Torvalds si.si_code = si_code; 255aa33c8cbSMartin Schwidefsky si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); 2561da177e4SLinus Torvalds force_sig_info(SIGSEGV, &si, current); 2571da177e4SLinus Torvalds } 2581da177e4SLinus Torvalds 259aa33c8cbSMartin Schwidefsky static noinline void do_no_context(struct pt_regs *regs) 26010c1031fSMartin Schwidefsky { 26110c1031fSMartin Schwidefsky const struct exception_table_entry *fixup; 26210c1031fSMartin Schwidefsky 26310c1031fSMartin Schwidefsky /* Are we prepared to handle this kernel fault? */ 2649cb1ccecSHeiko Carstens fixup = search_exception_tables(regs->psw.addr); 26510c1031fSMartin Schwidefsky if (fixup) { 266fecc868aSHeiko Carstens regs->psw.addr = extable_fixup(fixup); 26710c1031fSMartin Schwidefsky return; 26810c1031fSMartin Schwidefsky } 26910c1031fSMartin Schwidefsky 27010c1031fSMartin Schwidefsky /* 27110c1031fSMartin Schwidefsky * Oops. The kernel tried to access some bad page. We'll have to 27210c1031fSMartin Schwidefsky * terminate things with extreme prejudice. 27310c1031fSMartin Schwidefsky */ 274457f2180SHeiko Carstens if (!user_space_fault(regs)) 27510c1031fSMartin Schwidefsky printk(KERN_ALERT "Unable to handle kernel pointer dereference" 2763b7df342SHeiko Carstens " in virtual kernel address space\n"); 27710c1031fSMartin Schwidefsky else 27810c1031fSMartin Schwidefsky printk(KERN_ALERT "Unable to handle kernel paging request" 2793b7df342SHeiko Carstens " in virtual user address space\n"); 2803b7df342SHeiko Carstens dump_fault_info(regs); 281aa33c8cbSMartin Schwidefsky die(regs, "Oops"); 28210c1031fSMartin Schwidefsky do_exit(SIGKILL); 28310c1031fSMartin Schwidefsky } 28410c1031fSMartin Schwidefsky 285aa33c8cbSMartin Schwidefsky static noinline void do_low_address(struct pt_regs *regs) 28610c1031fSMartin Schwidefsky { 28710c1031fSMartin Schwidefsky /* Low-address protection hit in kernel mode means 28810c1031fSMartin Schwidefsky NULL pointer write access in kernel mode. */ 28910c1031fSMartin Schwidefsky if (regs->psw.mask & PSW_MASK_PSTATE) { 29010c1031fSMartin Schwidefsky /* Low-address protection hit in user mode 'cannot happen'. */ 291aa33c8cbSMartin Schwidefsky die (regs, "Low-address protection"); 29210c1031fSMartin Schwidefsky do_exit(SIGKILL); 29310c1031fSMartin Schwidefsky } 29410c1031fSMartin Schwidefsky 295aa33c8cbSMartin Schwidefsky do_no_context(regs); 29610c1031fSMartin Schwidefsky } 29710c1031fSMartin Schwidefsky 298aa33c8cbSMartin Schwidefsky static noinline void do_sigbus(struct pt_regs *regs) 29910c1031fSMartin Schwidefsky { 30010c1031fSMartin Schwidefsky struct task_struct *tsk = current; 30136bf9680SMartin Schwidefsky struct siginfo si; 30210c1031fSMartin Schwidefsky 30310c1031fSMartin Schwidefsky /* 30410c1031fSMartin Schwidefsky * Send a sigbus, regardless of whether we were in kernel 30510c1031fSMartin Schwidefsky * or user mode. 30610c1031fSMartin Schwidefsky */ 30736bf9680SMartin Schwidefsky si.si_signo = SIGBUS; 30836bf9680SMartin Schwidefsky si.si_errno = 0; 30936bf9680SMartin Schwidefsky si.si_code = BUS_ADRERR; 310aa33c8cbSMartin Schwidefsky si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); 31136bf9680SMartin Schwidefsky force_sig_info(SIGBUS, &si, tsk); 31210c1031fSMartin Schwidefsky } 31310c1031fSMartin Schwidefsky 314aa33c8cbSMartin Schwidefsky static noinline void do_fault_error(struct pt_regs *regs, int fault) 31550d7280dSMartin Schwidefsky { 31650d7280dSMartin Schwidefsky int si_code; 31750d7280dSMartin Schwidefsky 31850d7280dSMartin Schwidefsky switch (fault) { 31950d7280dSMartin Schwidefsky case VM_FAULT_BADACCESS: 32050d7280dSMartin Schwidefsky case VM_FAULT_BADMAP: 32150d7280dSMartin Schwidefsky /* Bad memory access. Check if it is kernel or user space. */ 3227d256175SHeiko Carstens if (user_mode(regs)) { 32350d7280dSMartin Schwidefsky /* User mode accesses just cause a SIGSEGV */ 32450d7280dSMartin Schwidefsky si_code = (fault == VM_FAULT_BADMAP) ? 32550d7280dSMartin Schwidefsky SEGV_MAPERR : SEGV_ACCERR; 326aa33c8cbSMartin Schwidefsky do_sigsegv(regs, si_code); 32750d7280dSMartin Schwidefsky return; 32850d7280dSMartin Schwidefsky } 32950d7280dSMartin Schwidefsky case VM_FAULT_BADCONTEXT: 33024eb3a82SDominik Dingel case VM_FAULT_PFAULT: 331aa33c8cbSMartin Schwidefsky do_no_context(regs); 33250d7280dSMartin Schwidefsky break; 333f2c76e3bSHeiko Carstens case VM_FAULT_SIGNAL: 334f2c76e3bSHeiko Carstens if (!user_mode(regs)) 335f2c76e3bSHeiko Carstens do_no_context(regs); 336f2c76e3bSHeiko Carstens break; 33750d7280dSMartin Schwidefsky default: /* fault & VM_FAULT_ERROR */ 33899583181SHeiko Carstens if (fault & VM_FAULT_OOM) { 3397d256175SHeiko Carstens if (!user_mode(regs)) 340aa33c8cbSMartin Schwidefsky do_no_context(regs); 34199583181SHeiko Carstens else 34250d7280dSMartin Schwidefsky pagefault_out_of_memory(); 34333692f27SLinus Torvalds } else if (fault & VM_FAULT_SIGSEGV) { 34433692f27SLinus Torvalds /* Kernel mode? Handle exceptions or die */ 34533692f27SLinus Torvalds if (!user_mode(regs)) 34633692f27SLinus Torvalds do_no_context(regs); 34733692f27SLinus Torvalds else 34833692f27SLinus Torvalds do_sigsegv(regs, SEGV_MAPERR); 34999583181SHeiko Carstens } else if (fault & VM_FAULT_SIGBUS) { 35050d7280dSMartin Schwidefsky /* Kernel mode? Handle exceptions or die */ 3517d256175SHeiko Carstens if (!user_mode(regs)) 352aa33c8cbSMartin Schwidefsky do_no_context(regs); 35336bf9680SMartin Schwidefsky else 354aa33c8cbSMartin Schwidefsky do_sigbus(regs); 35550d7280dSMartin Schwidefsky } else 35650d7280dSMartin Schwidefsky BUG(); 35750d7280dSMartin Schwidefsky break; 35850d7280dSMartin Schwidefsky } 35950d7280dSMartin Schwidefsky } 36050d7280dSMartin Schwidefsky 3611da177e4SLinus Torvalds /* 3621da177e4SLinus Torvalds * This routine handles page faults. It determines the address, 3631da177e4SLinus Torvalds * and the problem, and then passes it off to one of the appropriate 3641da177e4SLinus Torvalds * routines. 3651da177e4SLinus Torvalds * 36650d7280dSMartin Schwidefsky * interruption code (int_code): 3671da177e4SLinus Torvalds * 04 Protection -> Write-Protection (suprression) 3681da177e4SLinus Torvalds * 10 Segment translation -> Not present (nullification) 3691da177e4SLinus Torvalds * 11 Page translation -> Not present (nullification) 3701da177e4SLinus Torvalds * 3b Region third trans. -> Not present (nullification) 3711da177e4SLinus Torvalds */ 372aa33c8cbSMartin Schwidefsky static inline int do_exception(struct pt_regs *regs, int access) 3731da177e4SLinus Torvalds { 37424eb3a82SDominik Dingel #ifdef CONFIG_PGSTE 37524eb3a82SDominik Dingel struct gmap *gmap; 37624eb3a82SDominik Dingel #endif 3771da177e4SLinus Torvalds struct task_struct *tsk; 3781da177e4SLinus Torvalds struct mm_struct *mm; 3791da177e4SLinus Torvalds struct vm_area_struct *vma; 380aa33c8cbSMartin Schwidefsky unsigned long trans_exc_code; 3811da177e4SLinus Torvalds unsigned long address; 38233ce6140SHeiko Carstens unsigned int flags; 38333ce6140SHeiko Carstens int fault; 38410c1031fSMartin Schwidefsky 38539efd4ecSMartin Schwidefsky tsk = current; 38639efd4ecSMartin Schwidefsky /* 38739efd4ecSMartin Schwidefsky * The instruction that caused the program check has 38839efd4ecSMartin Schwidefsky * been nullified. Don't signal single step via SIGTRAP. 38939efd4ecSMartin Schwidefsky */ 390d3a73acbSMartin Schwidefsky clear_pt_regs_flag(regs, PIF_PER_TRAP); 39139efd4ecSMartin Schwidefsky 3927ecb344aSMartin Schwidefsky if (notify_page_fault(regs)) 39350d7280dSMartin Schwidefsky return 0; 3941da177e4SLinus Torvalds 3951da177e4SLinus Torvalds mm = tsk->mm; 396aa33c8cbSMartin Schwidefsky trans_exc_code = regs->int_parm_long; 3971da177e4SLinus Torvalds 3981da177e4SLinus Torvalds /* 3991da177e4SLinus Torvalds * Verify that the fault happened in user space, that 4001da177e4SLinus Torvalds * we are not in an interrupt and that there is a 4011da177e4SLinus Torvalds * user context. 4021da177e4SLinus Torvalds */ 40350d7280dSMartin Schwidefsky fault = VM_FAULT_BADCONTEXT; 40470ffdb93SDavid Hildenbrand if (unlikely(!user_space_fault(regs) || faulthandler_disabled() || !mm)) 40550d7280dSMartin Schwidefsky goto out; 4061da177e4SLinus Torvalds 40761365e13SMartin Schwidefsky address = trans_exc_code & __FAIL_ADDR_MASK; 408a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); 409f2c76e3bSHeiko Carstens flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; 410759496baSJohannes Weiner if (user_mode(regs)) 411759496baSJohannes Weiner flags |= FAULT_FLAG_USER; 41233ce6140SHeiko Carstens if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400) 41333ce6140SHeiko Carstens flags |= FAULT_FLAG_WRITE; 4141da177e4SLinus Torvalds down_read(&mm->mmap_sem); 4151da177e4SLinus Torvalds 416e5992f2eSMartin Schwidefsky #ifdef CONFIG_PGSTE 417527e30b4SMartin Schwidefsky gmap = (current->flags & PF_VCPU) ? 418527e30b4SMartin Schwidefsky (struct gmap *) S390_lowcore.gmap : NULL; 41924eb3a82SDominik Dingel if (gmap) { 420527e30b4SMartin Schwidefsky current->thread.gmap_addr = address; 4214be130a0SMartin Schwidefsky current->thread.gmap_write_flag = !!(flags & FAULT_FLAG_WRITE); 422527e30b4SMartin Schwidefsky address = __gmap_translate(gmap, address); 423e5992f2eSMartin Schwidefsky if (address == -EFAULT) { 424e5992f2eSMartin Schwidefsky fault = VM_FAULT_BADMAP; 425e5992f2eSMartin Schwidefsky goto out_up; 426e5992f2eSMartin Schwidefsky } 42724eb3a82SDominik Dingel if (gmap->pfault_enabled) 42824eb3a82SDominik Dingel flags |= FAULT_FLAG_RETRY_NOWAIT; 429e5992f2eSMartin Schwidefsky } 430e5992f2eSMartin Schwidefsky #endif 431e5992f2eSMartin Schwidefsky 432e5992f2eSMartin Schwidefsky retry: 43350d7280dSMartin Schwidefsky fault = VM_FAULT_BADMAP; 4341da177e4SLinus Torvalds vma = find_vma(mm, address); 4351da177e4SLinus Torvalds if (!vma) 43650d7280dSMartin Schwidefsky goto out_up; 437c1821c2eSGerald Schaefer 43850d7280dSMartin Schwidefsky if (unlikely(vma->vm_start > address)) { 4391da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 44050d7280dSMartin Schwidefsky goto out_up; 4411da177e4SLinus Torvalds if (expand_stack(vma, address)) 44250d7280dSMartin Schwidefsky goto out_up; 44350d7280dSMartin Schwidefsky } 44450d7280dSMartin Schwidefsky 4451da177e4SLinus Torvalds /* 4461da177e4SLinus Torvalds * Ok, we have a good vm_area for this memory access, so 4471da177e4SLinus Torvalds * we can handle it.. 4481da177e4SLinus Torvalds */ 44950d7280dSMartin Schwidefsky fault = VM_FAULT_BADACCESS; 4501ab947deSMartin Schwidefsky if (unlikely(!(vma->vm_flags & access))) 45150d7280dSMartin Schwidefsky goto out_up; 4521da177e4SLinus Torvalds 45353492b1dSGerald Schaefer if (is_vm_hugetlb_page(vma)) 45453492b1dSGerald Schaefer address &= HPAGE_MASK; 4551da177e4SLinus Torvalds /* 4561da177e4SLinus Torvalds * If for any reason at all we couldn't handle the fault, 4571da177e4SLinus Torvalds * make sure we exit gracefully rather than endlessly redo 4581da177e4SLinus Torvalds * the fault. 4591da177e4SLinus Torvalds */ 46033ce6140SHeiko Carstens fault = handle_mm_fault(mm, vma, address, flags); 461f2c76e3bSHeiko Carstens /* No reason to continue if interrupted by SIGKILL. */ 462f2c76e3bSHeiko Carstens if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { 463f2c76e3bSHeiko Carstens fault = VM_FAULT_SIGNAL; 464f2c76e3bSHeiko Carstens goto out; 465f2c76e3bSHeiko Carstens } 46650d7280dSMartin Schwidefsky if (unlikely(fault & VM_FAULT_ERROR)) 46750d7280dSMartin Schwidefsky goto out_up; 46850d7280dSMartin Schwidefsky 46933ce6140SHeiko Carstens /* 47033ce6140SHeiko Carstens * Major/minor page fault accounting is only done on the 47133ce6140SHeiko Carstens * initial attempt. If we go through a retry, it is extremely 47233ce6140SHeiko Carstens * likely that the page will be found in page cache at that point. 47333ce6140SHeiko Carstens */ 47433ce6140SHeiko Carstens if (flags & FAULT_FLAG_ALLOW_RETRY) { 475bde69af2SHeiko Carstens if (fault & VM_FAULT_MAJOR) { 47683c54070SNick Piggin tsk->maj_flt++; 477a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 478bde69af2SHeiko Carstens regs, address); 479bde69af2SHeiko Carstens } else { 48083c54070SNick Piggin tsk->min_flt++; 481a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 482bde69af2SHeiko Carstens regs, address); 483bde69af2SHeiko Carstens } 48433ce6140SHeiko Carstens if (fault & VM_FAULT_RETRY) { 48524eb3a82SDominik Dingel #ifdef CONFIG_PGSTE 48624eb3a82SDominik Dingel if (gmap && (flags & FAULT_FLAG_RETRY_NOWAIT)) { 48724eb3a82SDominik Dingel /* FAULT_FLAG_RETRY_NOWAIT has been set, 48824eb3a82SDominik Dingel * mmap_sem has not been released */ 48924eb3a82SDominik Dingel current->thread.gmap_pfault = 1; 49024eb3a82SDominik Dingel fault = VM_FAULT_PFAULT; 49124eb3a82SDominik Dingel goto out_up; 49224eb3a82SDominik Dingel } 49324eb3a82SDominik Dingel #endif 49433ce6140SHeiko Carstens /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk 49533ce6140SHeiko Carstens * of starvation. */ 49624eb3a82SDominik Dingel flags &= ~(FAULT_FLAG_ALLOW_RETRY | 49724eb3a82SDominik Dingel FAULT_FLAG_RETRY_NOWAIT); 49845cac65bSShaohua Li flags |= FAULT_FLAG_TRIED; 499e5992f2eSMartin Schwidefsky down_read(&mm->mmap_sem); 50033ce6140SHeiko Carstens goto retry; 50133ce6140SHeiko Carstens } 50233ce6140SHeiko Carstens } 503527e30b4SMartin Schwidefsky #ifdef CONFIG_PGSTE 504527e30b4SMartin Schwidefsky if (gmap) { 505527e30b4SMartin Schwidefsky address = __gmap_link(gmap, current->thread.gmap_addr, 506527e30b4SMartin Schwidefsky address); 507527e30b4SMartin Schwidefsky if (address == -EFAULT) { 508527e30b4SMartin Schwidefsky fault = VM_FAULT_BADMAP; 509527e30b4SMartin Schwidefsky goto out_up; 510527e30b4SMartin Schwidefsky } 511527e30b4SMartin Schwidefsky if (address == -ENOMEM) { 512527e30b4SMartin Schwidefsky fault = VM_FAULT_OOM; 513527e30b4SMartin Schwidefsky goto out_up; 514527e30b4SMartin Schwidefsky } 515527e30b4SMartin Schwidefsky } 516527e30b4SMartin Schwidefsky #endif 51750d7280dSMartin Schwidefsky fault = 0; 51850d7280dSMartin Schwidefsky out_up: 5191da177e4SLinus Torvalds up_read(&mm->mmap_sem); 52050d7280dSMartin Schwidefsky out: 52150d7280dSMartin Schwidefsky return fault; 5221da177e4SLinus Torvalds } 5231da177e4SLinus Torvalds 5247a5388deSHeiko Carstens void do_protection_exception(struct pt_regs *regs) 5251da177e4SLinus Torvalds { 526aa33c8cbSMartin Schwidefsky unsigned long trans_exc_code; 52750d7280dSMartin Schwidefsky int fault; 52861365e13SMartin Schwidefsky 529aa33c8cbSMartin Schwidefsky trans_exc_code = regs->int_parm_long; 530f752ac4dSMartin Schwidefsky /* 531f752ac4dSMartin Schwidefsky * Protection exceptions are suppressing, decrement psw address. 532f752ac4dSMartin Schwidefsky * The exception to this rule are aborted transactions, for these 533f752ac4dSMartin Schwidefsky * the PSW already points to the correct location. 534f752ac4dSMartin Schwidefsky */ 535f752ac4dSMartin Schwidefsky if (!(regs->int_code & 0x200)) 536aa33c8cbSMartin Schwidefsky regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16); 53710c1031fSMartin Schwidefsky /* 53810c1031fSMartin Schwidefsky * Check for low-address protection. This needs to be treated 53910c1031fSMartin Schwidefsky * as a special case because the translation exception code 54010c1031fSMartin Schwidefsky * field is not guaranteed to contain valid data in this case. 54110c1031fSMartin Schwidefsky */ 54261365e13SMartin Schwidefsky if (unlikely(!(trans_exc_code & 4))) { 543aa33c8cbSMartin Schwidefsky do_low_address(regs); 54410c1031fSMartin Schwidefsky return; 54510c1031fSMartin Schwidefsky } 546aa33c8cbSMartin Schwidefsky fault = do_exception(regs, VM_WRITE); 54750d7280dSMartin Schwidefsky if (unlikely(fault)) 548aa33c8cbSMartin Schwidefsky do_fault_error(regs, fault); 5491da177e4SLinus Torvalds } 5507a5388deSHeiko Carstens NOKPROBE_SYMBOL(do_protection_exception); 5511da177e4SLinus Torvalds 5527a5388deSHeiko Carstens void do_dat_exception(struct pt_regs *regs) 5531da177e4SLinus Torvalds { 5541ab947deSMartin Schwidefsky int access, fault; 55550d7280dSMartin Schwidefsky 5561ab947deSMartin Schwidefsky access = VM_READ | VM_EXEC | VM_WRITE; 557aa33c8cbSMartin Schwidefsky fault = do_exception(regs, access); 55850d7280dSMartin Schwidefsky if (unlikely(fault)) 559aa33c8cbSMartin Schwidefsky do_fault_error(regs, fault); 5601da177e4SLinus Torvalds } 5617a5388deSHeiko Carstens NOKPROBE_SYMBOL(do_dat_exception); 5621da177e4SLinus Torvalds 5631da177e4SLinus Torvalds #ifdef CONFIG_PFAULT 5641da177e4SLinus Torvalds /* 5651da177e4SLinus Torvalds * 'pfault' pseudo page faults routines. 5661da177e4SLinus Torvalds */ 567fb0a9d7eSHeiko Carstens static int pfault_disable; 5681da177e4SLinus Torvalds 5691da177e4SLinus Torvalds static int __init nopfault(char *str) 5701da177e4SLinus Torvalds { 5711da177e4SLinus Torvalds pfault_disable = 1; 5721da177e4SLinus Torvalds return 1; 5731da177e4SLinus Torvalds } 5741da177e4SLinus Torvalds 5751da177e4SLinus Torvalds __setup("nopfault", nopfault); 5761da177e4SLinus Torvalds 5777dd8fe1fSHeiko Carstens struct pfault_refbk { 5787dd8fe1fSHeiko Carstens u16 refdiagc; 5797dd8fe1fSHeiko Carstens u16 reffcode; 5807dd8fe1fSHeiko Carstens u16 refdwlen; 5817dd8fe1fSHeiko Carstens u16 refversn; 5827dd8fe1fSHeiko Carstens u64 refgaddr; 5837dd8fe1fSHeiko Carstens u64 refselmk; 5847dd8fe1fSHeiko Carstens u64 refcmpmk; 5857dd8fe1fSHeiko Carstens u64 reserved; 5867dd8fe1fSHeiko Carstens } __attribute__ ((packed, aligned(8))); 5871da177e4SLinus Torvalds 5881da177e4SLinus Torvalds int pfault_init(void) 5891da177e4SLinus Torvalds { 5907dd8fe1fSHeiko Carstens struct pfault_refbk refbk = { 5917dd8fe1fSHeiko Carstens .refdiagc = 0x258, 5927dd8fe1fSHeiko Carstens .reffcode = 0, 5937dd8fe1fSHeiko Carstens .refdwlen = 5, 5947dd8fe1fSHeiko Carstens .refversn = 2, 595e22cf8caSChristian Borntraeger .refgaddr = __LC_LPP, 5967dd8fe1fSHeiko Carstens .refselmk = 1ULL << 48, 5977dd8fe1fSHeiko Carstens .refcmpmk = 1ULL << 48, 5987dd8fe1fSHeiko Carstens .reserved = __PF_RES_FIELD }; 5991da177e4SLinus Torvalds int rc; 6001da177e4SLinus Torvalds 601f32269a0SCarsten Otte if (pfault_disable) 6021da177e4SLinus Torvalds return -1; 6031ec2772eSMartin Schwidefsky diag_stat_inc(DIAG_STAT_X258); 60494c12cc7SMartin Schwidefsky asm volatile( 6051da177e4SLinus Torvalds " diag %1,%0,0x258\n" 6061da177e4SLinus Torvalds "0: j 2f\n" 6071da177e4SLinus Torvalds "1: la %0,8\n" 6081da177e4SLinus Torvalds "2:\n" 60994c12cc7SMartin Schwidefsky EX_TABLE(0b,1b) 610d4b68996SMartin Schwidefsky : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); 6111da177e4SLinus Torvalds return rc; 6121da177e4SLinus Torvalds } 6131da177e4SLinus Torvalds 6141da177e4SLinus Torvalds void pfault_fini(void) 6151da177e4SLinus Torvalds { 6167dd8fe1fSHeiko Carstens struct pfault_refbk refbk = { 6177dd8fe1fSHeiko Carstens .refdiagc = 0x258, 6187dd8fe1fSHeiko Carstens .reffcode = 1, 6197dd8fe1fSHeiko Carstens .refdwlen = 5, 6207dd8fe1fSHeiko Carstens .refversn = 2, 6217dd8fe1fSHeiko Carstens }; 6221da177e4SLinus Torvalds 623f32269a0SCarsten Otte if (pfault_disable) 6241da177e4SLinus Torvalds return; 6251ec2772eSMartin Schwidefsky diag_stat_inc(DIAG_STAT_X258); 62694c12cc7SMartin Schwidefsky asm volatile( 6271da177e4SLinus Torvalds " diag %0,0,0x258\n" 6281da177e4SLinus Torvalds "0:\n" 62994c12cc7SMartin Schwidefsky EX_TABLE(0b,0b) 630d4b68996SMartin Schwidefsky : : "a" (&refbk), "m" (refbk) : "cc"); 6311da177e4SLinus Torvalds } 6321da177e4SLinus Torvalds 633f2db2e6cSHeiko Carstens static DEFINE_SPINLOCK(pfault_lock); 634f2db2e6cSHeiko Carstens static LIST_HEAD(pfault_list); 635f2db2e6cSHeiko Carstens 6360227f7c4SPeter Zijlstra #define PF_COMPLETE 0x0080 6370227f7c4SPeter Zijlstra 6380227f7c4SPeter Zijlstra /* 6390227f7c4SPeter Zijlstra * The mechanism of our pfault code: if Linux is running as guest, runs a user 6400227f7c4SPeter Zijlstra * space process and the user space process accesses a page that the host has 6410227f7c4SPeter Zijlstra * paged out we get a pfault interrupt. 6420227f7c4SPeter Zijlstra * 6430227f7c4SPeter Zijlstra * This allows us, within the guest, to schedule a different process. Without 6440227f7c4SPeter Zijlstra * this mechanism the host would have to suspend the whole virtual cpu until 6450227f7c4SPeter Zijlstra * the page has been paged in. 6460227f7c4SPeter Zijlstra * 6470227f7c4SPeter Zijlstra * So when we get such an interrupt then we set the state of the current task 6480227f7c4SPeter Zijlstra * to uninterruptible and also set the need_resched flag. Both happens within 6490227f7c4SPeter Zijlstra * interrupt context(!). If we later on want to return to user space we 6500227f7c4SPeter Zijlstra * recognize the need_resched flag and then call schedule(). It's not very 6510227f7c4SPeter Zijlstra * obvious how this works... 6520227f7c4SPeter Zijlstra * 6530227f7c4SPeter Zijlstra * Of course we have a lot of additional fun with the completion interrupt (-> 6540227f7c4SPeter Zijlstra * host signals that a page of a process has been paged in and the process can 6550227f7c4SPeter Zijlstra * continue to run). This interrupt can arrive on any cpu and, since we have 6560227f7c4SPeter Zijlstra * virtual cpus, actually appear before the interrupt that signals that a page 6570227f7c4SPeter Zijlstra * is missing. 6580227f7c4SPeter Zijlstra */ 659fde15c3aSHeiko Carstens static void pfault_interrupt(struct ext_code ext_code, 660f6649a7eSMartin Schwidefsky unsigned int param32, unsigned long param64) 6611da177e4SLinus Torvalds { 6621da177e4SLinus Torvalds struct task_struct *tsk; 6631da177e4SLinus Torvalds __u16 subcode; 664f2db2e6cSHeiko Carstens pid_t pid; 6651da177e4SLinus Torvalds 6661da177e4SLinus Torvalds /* 6670227f7c4SPeter Zijlstra * Get the external interruption subcode & pfault initial/completion 6680227f7c4SPeter Zijlstra * signal bit. VM stores this in the 'cpu address' field associated 6690227f7c4SPeter Zijlstra * with the external interrupt. 6701da177e4SLinus Torvalds */ 671fde15c3aSHeiko Carstens subcode = ext_code.subcode; 6721da177e4SLinus Torvalds if ((subcode & 0xff00) != __SUBCODE_MASK) 6731da177e4SLinus Torvalds return; 674420f42ecSHeiko Carstens inc_irq_stat(IRQEXT_PFL); 675f2db2e6cSHeiko Carstens /* Get the token (= pid of the affected task). */ 676e22cf8caSChristian Borntraeger pid = param64 & LPP_PFAULT_PID_MASK; 677f2db2e6cSHeiko Carstens rcu_read_lock(); 678f2db2e6cSHeiko Carstens tsk = find_task_by_pid_ns(pid, &init_pid_ns); 679f2db2e6cSHeiko Carstens if (tsk) 680f2db2e6cSHeiko Carstens get_task_struct(tsk); 681f2db2e6cSHeiko Carstens rcu_read_unlock(); 682f2db2e6cSHeiko Carstens if (!tsk) 683f2db2e6cSHeiko Carstens return; 684f2db2e6cSHeiko Carstens spin_lock(&pfault_lock); 6850227f7c4SPeter Zijlstra if (subcode & PF_COMPLETE) { 6861da177e4SLinus Torvalds /* signal bit is set -> a page has been swapped in by VM */ 687f2db2e6cSHeiko Carstens if (tsk->thread.pfault_wait == 1) { 6881da177e4SLinus Torvalds /* Initial interrupt was faster than the completion 6891da177e4SLinus Torvalds * interrupt. pfault_wait is valid. Set pfault_wait 6901da177e4SLinus Torvalds * back to zero and wake up the process. This can 6911da177e4SLinus Torvalds * safely be done because the task is still sleeping 692b6d09449SMartin Schwidefsky * and can't produce new pfaults. */ 6931da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 694f2db2e6cSHeiko Carstens list_del(&tsk->thread.list); 6951da177e4SLinus Torvalds wake_up_process(tsk); 696d5e50a51SHeiko Carstens put_task_struct(tsk); 697f2db2e6cSHeiko Carstens } else { 698f2db2e6cSHeiko Carstens /* Completion interrupt was faster than initial 699f2db2e6cSHeiko Carstens * interrupt. Set pfault_wait to -1 so the initial 700fa2fb2f4SHeiko Carstens * interrupt doesn't put the task to sleep. 701fa2fb2f4SHeiko Carstens * If the task is not running, ignore the completion 702fa2fb2f4SHeiko Carstens * interrupt since it must be a leftover of a PFAULT 703fa2fb2f4SHeiko Carstens * CANCEL operation which didn't remove all pending 704fa2fb2f4SHeiko Carstens * completion interrupts. */ 705fa2fb2f4SHeiko Carstens if (tsk->state == TASK_RUNNING) 706f2db2e6cSHeiko Carstens tsk->thread.pfault_wait = -1; 7071da177e4SLinus Torvalds } 7081da177e4SLinus Torvalds } else { 7091da177e4SLinus Torvalds /* signal bit not set -> a real page is missing. */ 710d49f47f8SHeiko Carstens if (WARN_ON_ONCE(tsk != current)) 711d49f47f8SHeiko Carstens goto out; 712d5e50a51SHeiko Carstens if (tsk->thread.pfault_wait == 1) { 713d5e50a51SHeiko Carstens /* Already on the list with a reference: put to sleep */ 7140227f7c4SPeter Zijlstra goto block; 715d5e50a51SHeiko Carstens } else if (tsk->thread.pfault_wait == -1) { 7161da177e4SLinus Torvalds /* Completion interrupt was faster than the initial 717f2db2e6cSHeiko Carstens * interrupt (pfault_wait == -1). Set pfault_wait 718f2db2e6cSHeiko Carstens * back to zero and exit. */ 7191da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 720f2db2e6cSHeiko Carstens } else { 721f2db2e6cSHeiko Carstens /* Initial interrupt arrived before completion 722d5e50a51SHeiko Carstens * interrupt. Let the task sleep. 723d5e50a51SHeiko Carstens * An extra task reference is needed since a different 724d5e50a51SHeiko Carstens * cpu may set the task state to TASK_RUNNING again 725d5e50a51SHeiko Carstens * before the scheduler is reached. */ 726d5e50a51SHeiko Carstens get_task_struct(tsk); 727f2db2e6cSHeiko Carstens tsk->thread.pfault_wait = 1; 728f2db2e6cSHeiko Carstens list_add(&tsk->thread.list, &pfault_list); 7290227f7c4SPeter Zijlstra block: 7300227f7c4SPeter Zijlstra /* Since this must be a userspace fault, there 7310227f7c4SPeter Zijlstra * is no kernel task state to trample. Rely on the 7320227f7c4SPeter Zijlstra * return to userspace schedule() to block. */ 7330227f7c4SPeter Zijlstra __set_current_state(TASK_UNINTERRUPTIBLE); 7341da177e4SLinus Torvalds set_tsk_need_resched(tsk); 7351da177e4SLinus Torvalds } 7361da177e4SLinus Torvalds } 737d49f47f8SHeiko Carstens out: 738f2db2e6cSHeiko Carstens spin_unlock(&pfault_lock); 73954c27791SHeiko Carstens put_task_struct(tsk); 740f2db2e6cSHeiko Carstens } 741f2db2e6cSHeiko Carstens 742e2741f17SPaul Gortmaker static int pfault_cpu_notify(struct notifier_block *self, unsigned long action, 743e2741f17SPaul Gortmaker void *hcpu) 744f2db2e6cSHeiko Carstens { 745f2db2e6cSHeiko Carstens struct thread_struct *thread, *next; 746f2db2e6cSHeiko Carstens struct task_struct *tsk; 747f2db2e6cSHeiko Carstens 7481c725922SHeiko Carstens switch (action & ~CPU_TASKS_FROZEN) { 749f2db2e6cSHeiko Carstens case CPU_DEAD: 750f2db2e6cSHeiko Carstens spin_lock_irq(&pfault_lock); 751f2db2e6cSHeiko Carstens list_for_each_entry_safe(thread, next, &pfault_list, list) { 752f2db2e6cSHeiko Carstens thread->pfault_wait = 0; 753f2db2e6cSHeiko Carstens list_del(&thread->list); 754f2db2e6cSHeiko Carstens tsk = container_of(thread, struct task_struct, thread); 755f2db2e6cSHeiko Carstens wake_up_process(tsk); 756d5e50a51SHeiko Carstens put_task_struct(tsk); 757f2db2e6cSHeiko Carstens } 758f2db2e6cSHeiko Carstens spin_unlock_irq(&pfault_lock); 759f2db2e6cSHeiko Carstens break; 760f2db2e6cSHeiko Carstens default: 761f2db2e6cSHeiko Carstens break; 762f2db2e6cSHeiko Carstens } 763f2db2e6cSHeiko Carstens return NOTIFY_OK; 764f2db2e6cSHeiko Carstens } 7651da177e4SLinus Torvalds 766fb0a9d7eSHeiko Carstens static int __init pfault_irq_init(void) 76729b08d2bSHeiko Carstens { 768fb0a9d7eSHeiko Carstens int rc; 76929b08d2bSHeiko Carstens 7701dad093bSThomas Huth rc = register_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt); 7717dd8fe1fSHeiko Carstens if (rc) 7727dd8fe1fSHeiko Carstens goto out_extint; 7737dd8fe1fSHeiko Carstens rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP; 7747dd8fe1fSHeiko Carstens if (rc) 7757dd8fe1fSHeiko Carstens goto out_pfault; 77682003c3eSHeiko Carstens irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL); 7777dd8fe1fSHeiko Carstens hotcpu_notifier(pfault_cpu_notify, 0); 7787dd8fe1fSHeiko Carstens return 0; 7797dd8fe1fSHeiko Carstens 7807dd8fe1fSHeiko Carstens out_pfault: 7811dad093bSThomas Huth unregister_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt); 7827dd8fe1fSHeiko Carstens out_extint: 783fb0a9d7eSHeiko Carstens pfault_disable = 1; 784fb0a9d7eSHeiko Carstens return rc; 785fb0a9d7eSHeiko Carstens } 786fb0a9d7eSHeiko Carstens early_initcall(pfault_irq_init); 787fb0a9d7eSHeiko Carstens 7887dd8fe1fSHeiko Carstens #endif /* CONFIG_PFAULT */ 789