11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * arch/s390/mm/fault.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * S390 version 51da177e4SLinus Torvalds * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation 61da177e4SLinus Torvalds * Author(s): Hartmut Penner (hp@de.ibm.com) 71da177e4SLinus Torvalds * Ulrich Weigand (uweigand@de.ibm.com) 81da177e4SLinus Torvalds * 91da177e4SLinus Torvalds * Derived from "arch/i386/mm/fault.c" 101da177e4SLinus Torvalds * Copyright (C) 1995 Linus Torvalds 111da177e4SLinus Torvalds */ 121da177e4SLinus Torvalds 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> 221da177e4SLinus Torvalds #include <linux/smp.h> 231da177e4SLinus Torvalds #include <linux/smp_lock.h> 241da177e4SLinus Torvalds #include <linux/init.h> 251da177e4SLinus Torvalds #include <linux/console.h> 261da177e4SLinus Torvalds #include <linux/module.h> 271da177e4SLinus Torvalds #include <linux/hardirq.h> 284ba069b8SMichael Grundy #include <linux/kprobes.h> 29be5ec363SMartin Schwidefsky #include <linux/uaccess.h> 301da177e4SLinus Torvalds 311da177e4SLinus Torvalds #include <asm/system.h> 321da177e4SLinus Torvalds #include <asm/pgtable.h> 334ba069b8SMichael Grundy #include <asm/kdebug.h> 3429b08d2bSHeiko Carstens #include <asm/s390_ext.h> 351da177e4SLinus Torvalds 36347a8dc3SMartin Schwidefsky #ifndef CONFIG_64BIT 371da177e4SLinus Torvalds #define __FAIL_ADDR_MASK 0x7ffff000 381da177e4SLinus Torvalds #define __FIXUP_MASK 0x7fffffff 391da177e4SLinus Torvalds #define __SUBCODE_MASK 0x0200 401da177e4SLinus Torvalds #define __PF_RES_FIELD 0ULL 41347a8dc3SMartin Schwidefsky #else /* CONFIG_64BIT */ 421da177e4SLinus Torvalds #define __FAIL_ADDR_MASK -4096L 431da177e4SLinus Torvalds #define __FIXUP_MASK ~0L 441da177e4SLinus Torvalds #define __SUBCODE_MASK 0x0600 451da177e4SLinus Torvalds #define __PF_RES_FIELD 0x8000000000000000ULL 46347a8dc3SMartin Schwidefsky #endif /* CONFIG_64BIT */ 471da177e4SLinus Torvalds 481da177e4SLinus Torvalds #ifdef CONFIG_SYSCTL 491da177e4SLinus Torvalds extern int sysctl_userprocess_debug; 501da177e4SLinus Torvalds #endif 511da177e4SLinus Torvalds 521da177e4SLinus Torvalds extern void die(const char *,struct pt_regs *,long); 531da177e4SLinus Torvalds 544ba069b8SMichael Grundy #ifdef CONFIG_KPROBES 552b67fc46SHeiko Carstens static ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain); 564ba069b8SMichael Grundy int register_page_fault_notifier(struct notifier_block *nb) 574ba069b8SMichael Grundy { 584ba069b8SMichael Grundy return atomic_notifier_chain_register(¬ify_page_fault_chain, nb); 594ba069b8SMichael Grundy } 604ba069b8SMichael Grundy 614ba069b8SMichael Grundy int unregister_page_fault_notifier(struct notifier_block *nb) 624ba069b8SMichael Grundy { 634ba069b8SMichael Grundy return atomic_notifier_chain_unregister(¬ify_page_fault_chain, nb); 644ba069b8SMichael Grundy } 654ba069b8SMichael Grundy 6610c1031fSMartin Schwidefsky static int __kprobes __notify_page_fault(struct pt_regs *regs, long err) 674ba069b8SMichael Grundy { 6810c1031fSMartin Schwidefsky struct die_args args = { .str = "page fault", 6910c1031fSMartin Schwidefsky .trapnr = 14, 7010c1031fSMartin Schwidefsky .signr = SIGSEGV }; 7110c1031fSMartin Schwidefsky args.regs = regs; 7210c1031fSMartin Schwidefsky args.err = err; 7310c1031fSMartin Schwidefsky return atomic_notifier_call_chain(¬ify_page_fault_chain, 7410c1031fSMartin Schwidefsky DIE_PAGE_FAULT, &args); 7510c1031fSMartin Schwidefsky } 7610c1031fSMartin Schwidefsky 7710c1031fSMartin Schwidefsky static inline int notify_page_fault(struct pt_regs *regs, long err) 7810c1031fSMartin Schwidefsky { 7910c1031fSMartin Schwidefsky if (unlikely(kprobe_running())) 8010c1031fSMartin Schwidefsky return __notify_page_fault(regs, err); 8110c1031fSMartin Schwidefsky return NOTIFY_DONE; 824ba069b8SMichael Grundy } 834ba069b8SMichael Grundy #else 8410c1031fSMartin Schwidefsky static inline int notify_page_fault(struct pt_regs *regs, long err) 854ba069b8SMichael Grundy { 864ba069b8SMichael Grundy return NOTIFY_DONE; 874ba069b8SMichael Grundy } 884ba069b8SMichael Grundy #endif 894ba069b8SMichael Grundy 901da177e4SLinus Torvalds 911da177e4SLinus Torvalds /* 921da177e4SLinus Torvalds * Unlock any spinlocks which will prevent us from getting the 93cefc8be8SKirill Korotaev * message out. 941da177e4SLinus Torvalds */ 951da177e4SLinus Torvalds void bust_spinlocks(int yes) 961da177e4SLinus Torvalds { 971da177e4SLinus Torvalds if (yes) { 981da177e4SLinus Torvalds oops_in_progress = 1; 991da177e4SLinus Torvalds } else { 1001da177e4SLinus Torvalds int loglevel_save = console_loglevel; 1011da177e4SLinus Torvalds console_unblank(); 1021da177e4SLinus Torvalds oops_in_progress = 0; 1031da177e4SLinus Torvalds /* 1041da177e4SLinus Torvalds * OK, the message is on the console. Now we call printk() 1051da177e4SLinus Torvalds * without oops_in_progress set so that printk will give klogd 1061da177e4SLinus Torvalds * a poke. Hold onto your hats... 1071da177e4SLinus Torvalds */ 1081da177e4SLinus Torvalds console_loglevel = 15; 1091da177e4SLinus Torvalds printk(" "); 1101da177e4SLinus Torvalds console_loglevel = loglevel_save; 1111da177e4SLinus Torvalds } 1121da177e4SLinus Torvalds } 1131da177e4SLinus Torvalds 1141da177e4SLinus Torvalds /* 115482b05ddSGerald Schaefer * Returns the address space associated with the fault. 116482b05ddSGerald Schaefer * Returns 0 for kernel space, 1 for user space and 117482b05ddSGerald Schaefer * 2 for code execution in user space with noexec=on. 1181da177e4SLinus Torvalds */ 119482b05ddSGerald Schaefer static inline int check_space(struct task_struct *tsk) 1201da177e4SLinus Torvalds { 1211da177e4SLinus Torvalds /* 122482b05ddSGerald Schaefer * The lowest two bits of S390_lowcore.trans_exc_code 123482b05ddSGerald Schaefer * indicate which paging table was used. 1241da177e4SLinus Torvalds */ 125482b05ddSGerald Schaefer int desc = S390_lowcore.trans_exc_code & 3; 1261da177e4SLinus Torvalds 127482b05ddSGerald Schaefer if (desc == 3) /* Home Segment Table Descriptor */ 128482b05ddSGerald Schaefer return switch_amode == 0; 129482b05ddSGerald Schaefer if (desc == 2) /* Secondary Segment Table Descriptor */ 130482b05ddSGerald Schaefer return tsk->thread.mm_segment.ar4; 131482b05ddSGerald Schaefer #ifdef CONFIG_S390_SWITCH_AMODE 132482b05ddSGerald Schaefer if (unlikely(desc == 1)) { /* STD determined via access register */ 133482b05ddSGerald Schaefer /* %a0 always indicates primary space. */ 134482b05ddSGerald Schaefer if (S390_lowcore.exc_access_id != 0) { 135482b05ddSGerald Schaefer save_access_regs(tsk->thread.acrs); 136482b05ddSGerald Schaefer /* 137482b05ddSGerald Schaefer * An alet of 0 indicates primary space. 138482b05ddSGerald Schaefer * An alet of 1 indicates secondary space. 139482b05ddSGerald Schaefer * Any other alet values generate an 140482b05ddSGerald Schaefer * alen-translation exception. 141482b05ddSGerald Schaefer */ 142482b05ddSGerald Schaefer if (tsk->thread.acrs[S390_lowcore.exc_access_id]) 143482b05ddSGerald Schaefer return tsk->thread.mm_segment.ar4; 1441da177e4SLinus Torvalds } 145482b05ddSGerald Schaefer } 146482b05ddSGerald Schaefer #endif 147482b05ddSGerald Schaefer /* Primary Segment Table Descriptor */ 148482b05ddSGerald Schaefer return switch_amode << s390_noexec; 1491da177e4SLinus Torvalds } 1501da177e4SLinus Torvalds 1511da177e4SLinus Torvalds /* 1521da177e4SLinus Torvalds * Send SIGSEGV to task. This is an external routine 1531da177e4SLinus Torvalds * to keep the stack usage of do_page_fault small. 1541da177e4SLinus Torvalds */ 1551da177e4SLinus Torvalds static void do_sigsegv(struct pt_regs *regs, unsigned long error_code, 1561da177e4SLinus Torvalds int si_code, unsigned long address) 1571da177e4SLinus Torvalds { 1581da177e4SLinus Torvalds struct siginfo si; 1591da177e4SLinus Torvalds 1601da177e4SLinus Torvalds #if defined(CONFIG_SYSCTL) || defined(CONFIG_PROCESS_DEBUG) 1611da177e4SLinus Torvalds #if defined(CONFIG_SYSCTL) 1621da177e4SLinus Torvalds if (sysctl_userprocess_debug) 1631da177e4SLinus Torvalds #endif 1641da177e4SLinus Torvalds { 1651da177e4SLinus Torvalds printk("User process fault: interruption code 0x%lX\n", 1661da177e4SLinus Torvalds error_code); 1671da177e4SLinus Torvalds printk("failing address: %lX\n", address); 1681da177e4SLinus Torvalds show_regs(regs); 1691da177e4SLinus Torvalds } 1701da177e4SLinus Torvalds #endif 1711da177e4SLinus Torvalds si.si_signo = SIGSEGV; 1721da177e4SLinus Torvalds si.si_code = si_code; 173d2c993d8SHeiko Carstens si.si_addr = (void __user *) address; 1741da177e4SLinus Torvalds force_sig_info(SIGSEGV, &si, current); 1751da177e4SLinus Torvalds } 1761da177e4SLinus Torvalds 17710c1031fSMartin Schwidefsky static void do_no_context(struct pt_regs *regs, unsigned long error_code, 17810c1031fSMartin Schwidefsky unsigned long address) 17910c1031fSMartin Schwidefsky { 18010c1031fSMartin Schwidefsky const struct exception_table_entry *fixup; 18110c1031fSMartin Schwidefsky 18210c1031fSMartin Schwidefsky /* Are we prepared to handle this kernel fault? */ 18310c1031fSMartin Schwidefsky fixup = search_exception_tables(regs->psw.addr & __FIXUP_MASK); 18410c1031fSMartin Schwidefsky if (fixup) { 18510c1031fSMartin Schwidefsky regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE; 18610c1031fSMartin Schwidefsky return; 18710c1031fSMartin Schwidefsky } 18810c1031fSMartin Schwidefsky 18910c1031fSMartin Schwidefsky /* 19010c1031fSMartin Schwidefsky * Oops. The kernel tried to access some bad page. We'll have to 19110c1031fSMartin Schwidefsky * terminate things with extreme prejudice. 19210c1031fSMartin Schwidefsky */ 19310c1031fSMartin Schwidefsky if (check_space(current) == 0) 19410c1031fSMartin Schwidefsky printk(KERN_ALERT "Unable to handle kernel pointer dereference" 19510c1031fSMartin Schwidefsky " at virtual kernel address %p\n", (void *)address); 19610c1031fSMartin Schwidefsky else 19710c1031fSMartin Schwidefsky printk(KERN_ALERT "Unable to handle kernel paging request" 19810c1031fSMartin Schwidefsky " at virtual user address %p\n", (void *)address); 19910c1031fSMartin Schwidefsky 20010c1031fSMartin Schwidefsky die("Oops", regs, error_code); 20110c1031fSMartin Schwidefsky do_exit(SIGKILL); 20210c1031fSMartin Schwidefsky } 20310c1031fSMartin Schwidefsky 20410c1031fSMartin Schwidefsky static void do_low_address(struct pt_regs *regs, unsigned long error_code) 20510c1031fSMartin Schwidefsky { 20610c1031fSMartin Schwidefsky /* Low-address protection hit in kernel mode means 20710c1031fSMartin Schwidefsky NULL pointer write access in kernel mode. */ 20810c1031fSMartin Schwidefsky if (regs->psw.mask & PSW_MASK_PSTATE) { 20910c1031fSMartin Schwidefsky /* Low-address protection hit in user mode 'cannot happen'. */ 21010c1031fSMartin Schwidefsky die ("Low-address protection", regs, error_code); 21110c1031fSMartin Schwidefsky do_exit(SIGKILL); 21210c1031fSMartin Schwidefsky } 21310c1031fSMartin Schwidefsky 21410c1031fSMartin Schwidefsky do_no_context(regs, error_code, 0); 21510c1031fSMartin Schwidefsky } 21610c1031fSMartin Schwidefsky 21710c1031fSMartin Schwidefsky /* 21810c1031fSMartin Schwidefsky * We ran out of memory, or some other thing happened to us that made 21910c1031fSMartin Schwidefsky * us unable to handle the page fault gracefully. 22010c1031fSMartin Schwidefsky */ 22110c1031fSMartin Schwidefsky static int do_out_of_memory(struct pt_regs *regs, unsigned long error_code, 22210c1031fSMartin Schwidefsky unsigned long address) 22310c1031fSMartin Schwidefsky { 22410c1031fSMartin Schwidefsky struct task_struct *tsk = current; 22510c1031fSMartin Schwidefsky struct mm_struct *mm = tsk->mm; 22610c1031fSMartin Schwidefsky 22710c1031fSMartin Schwidefsky up_read(&mm->mmap_sem); 22810c1031fSMartin Schwidefsky if (is_init(tsk)) { 22910c1031fSMartin Schwidefsky yield(); 23010c1031fSMartin Schwidefsky down_read(&mm->mmap_sem); 23110c1031fSMartin Schwidefsky return 1; 23210c1031fSMartin Schwidefsky } 23310c1031fSMartin Schwidefsky printk("VM: killing process %s\n", tsk->comm); 23410c1031fSMartin Schwidefsky if (regs->psw.mask & PSW_MASK_PSTATE) 23510c1031fSMartin Schwidefsky do_exit(SIGKILL); 23610c1031fSMartin Schwidefsky do_no_context(regs, error_code, address); 23710c1031fSMartin Schwidefsky return 0; 23810c1031fSMartin Schwidefsky } 23910c1031fSMartin Schwidefsky 24010c1031fSMartin Schwidefsky static void do_sigbus(struct pt_regs *regs, unsigned long error_code, 24110c1031fSMartin Schwidefsky unsigned long address) 24210c1031fSMartin Schwidefsky { 24310c1031fSMartin Schwidefsky struct task_struct *tsk = current; 24410c1031fSMartin Schwidefsky struct mm_struct *mm = tsk->mm; 24510c1031fSMartin Schwidefsky 24610c1031fSMartin Schwidefsky up_read(&mm->mmap_sem); 24710c1031fSMartin Schwidefsky /* 24810c1031fSMartin Schwidefsky * Send a sigbus, regardless of whether we were in kernel 24910c1031fSMartin Schwidefsky * or user mode. 25010c1031fSMartin Schwidefsky */ 25110c1031fSMartin Schwidefsky tsk->thread.prot_addr = address; 25210c1031fSMartin Schwidefsky tsk->thread.trap_no = error_code; 25310c1031fSMartin Schwidefsky force_sig(SIGBUS, tsk); 25410c1031fSMartin Schwidefsky 25510c1031fSMartin Schwidefsky /* Kernel mode? Handle exceptions or die */ 25610c1031fSMartin Schwidefsky if (!(regs->psw.mask & PSW_MASK_PSTATE)) 25710c1031fSMartin Schwidefsky do_no_context(regs, error_code, address); 25810c1031fSMartin Schwidefsky } 25910c1031fSMartin Schwidefsky 260c1821c2eSGerald Schaefer #ifdef CONFIG_S390_EXEC_PROTECT 261c1821c2eSGerald Schaefer extern long sys_sigreturn(struct pt_regs *regs); 262c1821c2eSGerald Schaefer extern long sys_rt_sigreturn(struct pt_regs *regs); 263c1821c2eSGerald Schaefer extern long sys32_sigreturn(struct pt_regs *regs); 264c1821c2eSGerald Schaefer extern long sys32_rt_sigreturn(struct pt_regs *regs); 265c1821c2eSGerald Schaefer 266c1821c2eSGerald Schaefer static int signal_return(struct mm_struct *mm, struct pt_regs *regs, 267c1821c2eSGerald Schaefer unsigned long address, unsigned long error_code) 268c1821c2eSGerald Schaefer { 269be5ec363SMartin Schwidefsky u16 instruction; 270be5ec363SMartin Schwidefsky int rc, compat; 271c1821c2eSGerald Schaefer 272be5ec363SMartin Schwidefsky pagefault_disable(); 273be5ec363SMartin Schwidefsky rc = __get_user(instruction, (u16 __user *) regs->psw.addr); 274be5ec363SMartin Schwidefsky pagefault_enable(); 275be5ec363SMartin Schwidefsky if (rc) 276be5ec363SMartin Schwidefsky return -EFAULT; 277c1821c2eSGerald Schaefer 278c1821c2eSGerald Schaefer up_read(&mm->mmap_sem); 279be5ec363SMartin Schwidefsky clear_tsk_thread_flag(current, TIF_SINGLE_STEP); 280be5ec363SMartin Schwidefsky #ifdef CONFIG_COMPAT 281be5ec363SMartin Schwidefsky compat = test_tsk_thread_flag(current, TIF_31BIT); 282be5ec363SMartin Schwidefsky if (compat && instruction == 0x0a77) 283be5ec363SMartin Schwidefsky sys32_sigreturn(regs); 284be5ec363SMartin Schwidefsky else if (compat && instruction == 0x0aad) 285be5ec363SMartin Schwidefsky sys32_rt_sigreturn(regs); 286be5ec363SMartin Schwidefsky else 287be5ec363SMartin Schwidefsky #endif 288be5ec363SMartin Schwidefsky if (instruction == 0x0a77) 289be5ec363SMartin Schwidefsky sys_sigreturn(regs); 290be5ec363SMartin Schwidefsky else if (instruction == 0x0aad) 291be5ec363SMartin Schwidefsky sys_rt_sigreturn(regs); 292be5ec363SMartin Schwidefsky else { 293c1821c2eSGerald Schaefer current->thread.prot_addr = address; 294c1821c2eSGerald Schaefer current->thread.trap_no = error_code; 295c1821c2eSGerald Schaefer do_sigsegv(regs, error_code, SEGV_MAPERR, address); 296c1821c2eSGerald Schaefer } 297c1821c2eSGerald Schaefer return 0; 298c1821c2eSGerald Schaefer } 299c1821c2eSGerald Schaefer #endif /* CONFIG_S390_EXEC_PROTECT */ 300c1821c2eSGerald Schaefer 3011da177e4SLinus Torvalds /* 3021da177e4SLinus Torvalds * This routine handles page faults. It determines the address, 3031da177e4SLinus Torvalds * and the problem, and then passes it off to one of the appropriate 3041da177e4SLinus Torvalds * routines. 3051da177e4SLinus Torvalds * 3061da177e4SLinus Torvalds * error_code: 3071da177e4SLinus Torvalds * 04 Protection -> Write-Protection (suprression) 3081da177e4SLinus Torvalds * 10 Segment translation -> Not present (nullification) 3091da177e4SLinus Torvalds * 11 Page translation -> Not present (nullification) 3101da177e4SLinus Torvalds * 3b Region third trans. -> Not present (nullification) 3111da177e4SLinus Torvalds */ 312482b05ddSGerald Schaefer static inline void 31310c1031fSMartin Schwidefsky do_exception(struct pt_regs *regs, unsigned long error_code, int write) 3141da177e4SLinus Torvalds { 3151da177e4SLinus Torvalds struct task_struct *tsk; 3161da177e4SLinus Torvalds struct mm_struct *mm; 3171da177e4SLinus Torvalds struct vm_area_struct *vma; 3181da177e4SLinus Torvalds unsigned long address; 319482b05ddSGerald Schaefer int space; 32010c1031fSMartin Schwidefsky int si_code; 32110c1031fSMartin Schwidefsky 32210c1031fSMartin Schwidefsky if (notify_page_fault(regs, error_code) == NOTIFY_STOP) 32310c1031fSMartin Schwidefsky return; 3241da177e4SLinus Torvalds 3251da177e4SLinus Torvalds tsk = current; 3261da177e4SLinus Torvalds mm = tsk->mm; 3271da177e4SLinus Torvalds 32810c1031fSMartin Schwidefsky /* get the failing address and the affected space */ 3291da177e4SLinus Torvalds address = S390_lowcore.trans_exc_code & __FAIL_ADDR_MASK; 330482b05ddSGerald Schaefer space = check_space(tsk); 3311da177e4SLinus Torvalds 3321da177e4SLinus Torvalds /* 3331da177e4SLinus Torvalds * Verify that the fault happened in user space, that 3341da177e4SLinus Torvalds * we are not in an interrupt and that there is a 3351da177e4SLinus Torvalds * user context. 3361da177e4SLinus Torvalds */ 337482b05ddSGerald Schaefer if (unlikely(space == 0 || in_atomic() || !mm)) 3381da177e4SLinus Torvalds goto no_context; 3391da177e4SLinus Torvalds 3401da177e4SLinus Torvalds /* 3411da177e4SLinus Torvalds * When we get here, the fault happened in the current 3421da177e4SLinus Torvalds * task's user address space, so we can switch on the 3431da177e4SLinus Torvalds * interrupts again and then search the VMAs 3441da177e4SLinus Torvalds */ 3451da177e4SLinus Torvalds local_irq_enable(); 3461da177e4SLinus Torvalds 3471da177e4SLinus Torvalds down_read(&mm->mmap_sem); 3481da177e4SLinus Torvalds 349482b05ddSGerald Schaefer si_code = SEGV_MAPERR; 3501da177e4SLinus Torvalds vma = find_vma(mm, address); 3511da177e4SLinus Torvalds if (!vma) 3521da177e4SLinus Torvalds goto bad_area; 353c1821c2eSGerald Schaefer 354c1821c2eSGerald Schaefer #ifdef CONFIG_S390_EXEC_PROTECT 355482b05ddSGerald Schaefer if (unlikely((space == 2) && !(vma->vm_flags & VM_EXEC))) 356c1821c2eSGerald Schaefer if (!signal_return(mm, regs, address, error_code)) 357c1821c2eSGerald Schaefer /* 358c1821c2eSGerald Schaefer * signal_return() has done an up_read(&mm->mmap_sem) 359c1821c2eSGerald Schaefer * if it returns 0. 360c1821c2eSGerald Schaefer */ 361c1821c2eSGerald Schaefer return; 362c1821c2eSGerald Schaefer #endif 363c1821c2eSGerald Schaefer 3641da177e4SLinus Torvalds if (vma->vm_start <= address) 3651da177e4SLinus Torvalds goto good_area; 3661da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 3671da177e4SLinus Torvalds goto bad_area; 3681da177e4SLinus Torvalds if (expand_stack(vma, address)) 3691da177e4SLinus Torvalds goto bad_area; 3701da177e4SLinus Torvalds /* 3711da177e4SLinus Torvalds * Ok, we have a good vm_area for this memory access, so 3721da177e4SLinus Torvalds * we can handle it.. 3731da177e4SLinus Torvalds */ 3741da177e4SLinus Torvalds good_area: 3751da177e4SLinus Torvalds si_code = SEGV_ACCERR; 37610c1031fSMartin Schwidefsky if (!write) { 3771da177e4SLinus Torvalds /* page not present, check vm flags */ 3781da177e4SLinus Torvalds if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) 3791da177e4SLinus Torvalds goto bad_area; 3801da177e4SLinus Torvalds } else { 3811da177e4SLinus Torvalds if (!(vma->vm_flags & VM_WRITE)) 3821da177e4SLinus Torvalds goto bad_area; 3831da177e4SLinus Torvalds } 3841da177e4SLinus Torvalds 3851da177e4SLinus Torvalds survive: 3861da177e4SLinus Torvalds /* 3871da177e4SLinus Torvalds * If for any reason at all we couldn't handle the fault, 3881da177e4SLinus Torvalds * make sure we exit gracefully rather than endlessly redo 3891da177e4SLinus Torvalds * the fault. 3901da177e4SLinus Torvalds */ 39110c1031fSMartin Schwidefsky switch (handle_mm_fault(mm, vma, address, write)) { 3921da177e4SLinus Torvalds case VM_FAULT_MINOR: 3931da177e4SLinus Torvalds tsk->min_flt++; 3941da177e4SLinus Torvalds break; 3951da177e4SLinus Torvalds case VM_FAULT_MAJOR: 3961da177e4SLinus Torvalds tsk->maj_flt++; 3971da177e4SLinus Torvalds break; 3981da177e4SLinus Torvalds case VM_FAULT_SIGBUS: 39910c1031fSMartin Schwidefsky do_sigbus(regs, error_code, address); 40010c1031fSMartin Schwidefsky return; 4011da177e4SLinus Torvalds case VM_FAULT_OOM: 40210c1031fSMartin Schwidefsky if (do_out_of_memory(regs, error_code, address)) 40310c1031fSMartin Schwidefsky goto survive; 40410c1031fSMartin Schwidefsky return; 4051da177e4SLinus Torvalds default: 4061da177e4SLinus Torvalds BUG(); 4071da177e4SLinus Torvalds } 4081da177e4SLinus Torvalds 4091da177e4SLinus Torvalds up_read(&mm->mmap_sem); 4101da177e4SLinus Torvalds /* 4111da177e4SLinus Torvalds * The instruction that caused the program check will 4121da177e4SLinus Torvalds * be repeated. Don't signal single step via SIGTRAP. 4131da177e4SLinus Torvalds */ 414482b05ddSGerald Schaefer clear_tsk_thread_flag(tsk, TIF_SINGLE_STEP); 4151da177e4SLinus Torvalds return; 4161da177e4SLinus Torvalds 4171da177e4SLinus Torvalds /* 4181da177e4SLinus Torvalds * Something tried to access memory that isn't in our memory map.. 4191da177e4SLinus Torvalds * Fix it, but check if it's kernel or user first.. 4201da177e4SLinus Torvalds */ 4211da177e4SLinus Torvalds bad_area: 4221da177e4SLinus Torvalds up_read(&mm->mmap_sem); 4231da177e4SLinus Torvalds 4241da177e4SLinus Torvalds /* User mode accesses just cause a SIGSEGV */ 4251da177e4SLinus Torvalds if (regs->psw.mask & PSW_MASK_PSTATE) { 4261da177e4SLinus Torvalds tsk->thread.prot_addr = address; 4271da177e4SLinus Torvalds tsk->thread.trap_no = error_code; 4281da177e4SLinus Torvalds do_sigsegv(regs, error_code, si_code, address); 4291da177e4SLinus Torvalds return; 4301da177e4SLinus Torvalds } 4311da177e4SLinus Torvalds 4321da177e4SLinus Torvalds no_context: 43310c1031fSMartin Schwidefsky do_no_context(regs, error_code, address); 4341da177e4SLinus Torvalds } 4351da177e4SLinus Torvalds 436482b05ddSGerald Schaefer void __kprobes do_protection_exception(struct pt_regs *regs, 437482b05ddSGerald Schaefer unsigned long error_code) 4381da177e4SLinus Torvalds { 43910c1031fSMartin Schwidefsky /* Protection exception is supressing, decrement psw address. */ 4401da177e4SLinus Torvalds regs->psw.addr -= (error_code >> 16); 44110c1031fSMartin Schwidefsky /* 44210c1031fSMartin Schwidefsky * Check for low-address protection. This needs to be treated 44310c1031fSMartin Schwidefsky * as a special case because the translation exception code 44410c1031fSMartin Schwidefsky * field is not guaranteed to contain valid data in this case. 44510c1031fSMartin Schwidefsky */ 44610c1031fSMartin Schwidefsky if (unlikely(!(S390_lowcore.trans_exc_code & 4))) { 44710c1031fSMartin Schwidefsky do_low_address(regs, error_code); 44810c1031fSMartin Schwidefsky return; 44910c1031fSMartin Schwidefsky } 4501da177e4SLinus Torvalds do_exception(regs, 4, 1); 4511da177e4SLinus Torvalds } 4521da177e4SLinus Torvalds 453482b05ddSGerald Schaefer void __kprobes do_dat_exception(struct pt_regs *regs, unsigned long error_code) 4541da177e4SLinus Torvalds { 4551da177e4SLinus Torvalds do_exception(regs, error_code & 0xff, 0); 4561da177e4SLinus Torvalds } 4571da177e4SLinus Torvalds 4581da177e4SLinus Torvalds #ifdef CONFIG_PFAULT 4591da177e4SLinus Torvalds /* 4601da177e4SLinus Torvalds * 'pfault' pseudo page faults routines. 4611da177e4SLinus Torvalds */ 46229b08d2bSHeiko Carstens static ext_int_info_t ext_int_pfault; 4631da177e4SLinus Torvalds static int pfault_disable = 0; 4641da177e4SLinus Torvalds 4651da177e4SLinus Torvalds static int __init nopfault(char *str) 4661da177e4SLinus Torvalds { 4671da177e4SLinus Torvalds pfault_disable = 1; 4681da177e4SLinus Torvalds return 1; 4691da177e4SLinus Torvalds } 4701da177e4SLinus Torvalds 4711da177e4SLinus Torvalds __setup("nopfault", nopfault); 4721da177e4SLinus Torvalds 4731da177e4SLinus Torvalds typedef struct { 4741da177e4SLinus Torvalds __u16 refdiagc; 4751da177e4SLinus Torvalds __u16 reffcode; 4761da177e4SLinus Torvalds __u16 refdwlen; 4771da177e4SLinus Torvalds __u16 refversn; 4781da177e4SLinus Torvalds __u64 refgaddr; 4791da177e4SLinus Torvalds __u64 refselmk; 4801da177e4SLinus Torvalds __u64 refcmpmk; 4811da177e4SLinus Torvalds __u64 reserved; 4821da177e4SLinus Torvalds } __attribute__ ((packed)) pfault_refbk_t; 4831da177e4SLinus Torvalds 4841da177e4SLinus Torvalds int pfault_init(void) 4851da177e4SLinus Torvalds { 4861da177e4SLinus Torvalds pfault_refbk_t refbk = 4871da177e4SLinus Torvalds { 0x258, 0, 5, 2, __LC_CURRENT, 1ULL << 48, 1ULL << 48, 4881da177e4SLinus Torvalds __PF_RES_FIELD }; 4891da177e4SLinus Torvalds int rc; 4901da177e4SLinus Torvalds 49129b08d2bSHeiko Carstens if (!MACHINE_IS_VM || pfault_disable) 4921da177e4SLinus Torvalds return -1; 49394c12cc7SMartin Schwidefsky asm volatile( 4941da177e4SLinus Torvalds " diag %1,%0,0x258\n" 4951da177e4SLinus Torvalds "0: j 2f\n" 4961da177e4SLinus Torvalds "1: la %0,8\n" 4971da177e4SLinus Torvalds "2:\n" 49894c12cc7SMartin Schwidefsky EX_TABLE(0b,1b) 499d4b68996SMartin Schwidefsky : "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc"); 5001da177e4SLinus Torvalds __ctl_set_bit(0, 9); 5011da177e4SLinus Torvalds return rc; 5021da177e4SLinus Torvalds } 5031da177e4SLinus Torvalds 5041da177e4SLinus Torvalds void pfault_fini(void) 5051da177e4SLinus Torvalds { 5061da177e4SLinus Torvalds pfault_refbk_t refbk = 5071da177e4SLinus Torvalds { 0x258, 1, 5, 2, 0ULL, 0ULL, 0ULL, 0ULL }; 5081da177e4SLinus Torvalds 50929b08d2bSHeiko Carstens if (!MACHINE_IS_VM || pfault_disable) 5101da177e4SLinus Torvalds return; 5111da177e4SLinus Torvalds __ctl_clear_bit(0,9); 51294c12cc7SMartin Schwidefsky asm volatile( 5131da177e4SLinus Torvalds " diag %0,0,0x258\n" 5141da177e4SLinus Torvalds "0:\n" 51594c12cc7SMartin Schwidefsky EX_TABLE(0b,0b) 516d4b68996SMartin Schwidefsky : : "a" (&refbk), "m" (refbk) : "cc"); 5171da177e4SLinus Torvalds } 5181da177e4SLinus Torvalds 5192b67fc46SHeiko Carstens static void pfault_interrupt(__u16 error_code) 5201da177e4SLinus Torvalds { 5211da177e4SLinus Torvalds struct task_struct *tsk; 5221da177e4SLinus Torvalds __u16 subcode; 5231da177e4SLinus Torvalds 5241da177e4SLinus Torvalds /* 5251da177e4SLinus Torvalds * Get the external interruption subcode & pfault 5261da177e4SLinus Torvalds * initial/completion signal bit. VM stores this 5271da177e4SLinus Torvalds * in the 'cpu address' field associated with the 5281da177e4SLinus Torvalds * external interrupt. 5291da177e4SLinus Torvalds */ 5301da177e4SLinus Torvalds subcode = S390_lowcore.cpu_addr; 5311da177e4SLinus Torvalds if ((subcode & 0xff00) != __SUBCODE_MASK) 5321da177e4SLinus Torvalds return; 5331da177e4SLinus Torvalds 5341da177e4SLinus Torvalds /* 5351da177e4SLinus Torvalds * Get the token (= address of the task structure of the affected task). 5361da177e4SLinus Torvalds */ 5371da177e4SLinus Torvalds tsk = *(struct task_struct **) __LC_PFAULT_INTPARM; 5381da177e4SLinus Torvalds 5391da177e4SLinus Torvalds if (subcode & 0x0080) { 5401da177e4SLinus Torvalds /* signal bit is set -> a page has been swapped in by VM */ 5411da177e4SLinus Torvalds if (xchg(&tsk->thread.pfault_wait, -1) != 0) { 5421da177e4SLinus Torvalds /* Initial interrupt was faster than the completion 5431da177e4SLinus Torvalds * interrupt. pfault_wait is valid. Set pfault_wait 5441da177e4SLinus Torvalds * back to zero and wake up the process. This can 5451da177e4SLinus Torvalds * safely be done because the task is still sleeping 546b6d09449SMartin Schwidefsky * and can't produce new pfaults. */ 5471da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 5481da177e4SLinus Torvalds wake_up_process(tsk); 549b6d09449SMartin Schwidefsky put_task_struct(tsk); 5501da177e4SLinus Torvalds } 5511da177e4SLinus Torvalds } else { 5521da177e4SLinus Torvalds /* signal bit not set -> a real page is missing. */ 553b6d09449SMartin Schwidefsky get_task_struct(tsk); 5541da177e4SLinus Torvalds set_task_state(tsk, TASK_UNINTERRUPTIBLE); 5551da177e4SLinus Torvalds if (xchg(&tsk->thread.pfault_wait, 1) != 0) { 5561da177e4SLinus Torvalds /* Completion interrupt was faster than the initial 5571da177e4SLinus Torvalds * interrupt (swapped in a -1 for pfault_wait). Set 5581da177e4SLinus Torvalds * pfault_wait back to zero and exit. This can be 5591da177e4SLinus Torvalds * done safely because tsk is running in kernel 5601da177e4SLinus Torvalds * mode and can't produce new pfaults. */ 5611da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 5621da177e4SLinus Torvalds set_task_state(tsk, TASK_RUNNING); 563b6d09449SMartin Schwidefsky put_task_struct(tsk); 5641da177e4SLinus Torvalds } else 5651da177e4SLinus Torvalds set_tsk_need_resched(tsk); 5661da177e4SLinus Torvalds } 5671da177e4SLinus Torvalds } 5681da177e4SLinus Torvalds 56929b08d2bSHeiko Carstens void __init pfault_irq_init(void) 57029b08d2bSHeiko Carstens { 57129b08d2bSHeiko Carstens if (!MACHINE_IS_VM) 57229b08d2bSHeiko Carstens return; 57329b08d2bSHeiko Carstens 57429b08d2bSHeiko Carstens /* 57529b08d2bSHeiko Carstens * Try to get pfault pseudo page faults going. 57629b08d2bSHeiko Carstens */ 57729b08d2bSHeiko Carstens if (register_early_external_interrupt(0x2603, pfault_interrupt, 57829b08d2bSHeiko Carstens &ext_int_pfault) != 0) 57929b08d2bSHeiko Carstens panic("Couldn't request external interrupt 0x2603"); 58029b08d2bSHeiko Carstens 58129b08d2bSHeiko Carstens if (pfault_init() == 0) 58229b08d2bSHeiko Carstens return; 58329b08d2bSHeiko Carstens 58429b08d2bSHeiko Carstens /* Tough luck, no pfault. */ 58529b08d2bSHeiko Carstens pfault_disable = 1; 58629b08d2bSHeiko Carstens unregister_early_external_interrupt(0x2603, pfault_interrupt, 58729b08d2bSHeiko Carstens &ext_int_pfault); 58829b08d2bSHeiko Carstens } 58929b08d2bSHeiko Carstens #endif 590