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/config.h> 141da177e4SLinus Torvalds #include <linux/signal.h> 151da177e4SLinus Torvalds #include <linux/sched.h> 161da177e4SLinus Torvalds #include <linux/kernel.h> 171da177e4SLinus Torvalds #include <linux/errno.h> 181da177e4SLinus Torvalds #include <linux/string.h> 191da177e4SLinus Torvalds #include <linux/types.h> 201da177e4SLinus Torvalds #include <linux/ptrace.h> 211da177e4SLinus Torvalds #include <linux/mman.h> 221da177e4SLinus Torvalds #include <linux/mm.h> 231da177e4SLinus Torvalds #include <linux/smp.h> 241da177e4SLinus Torvalds #include <linux/smp_lock.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> 291da177e4SLinus Torvalds 301da177e4SLinus Torvalds #include <asm/system.h> 311da177e4SLinus Torvalds #include <asm/uaccess.h> 321da177e4SLinus Torvalds #include <asm/pgtable.h> 331da177e4SLinus Torvalds 341da177e4SLinus Torvalds #ifndef CONFIG_ARCH_S390X 351da177e4SLinus Torvalds #define __FAIL_ADDR_MASK 0x7ffff000 361da177e4SLinus Torvalds #define __FIXUP_MASK 0x7fffffff 371da177e4SLinus Torvalds #define __SUBCODE_MASK 0x0200 381da177e4SLinus Torvalds #define __PF_RES_FIELD 0ULL 391da177e4SLinus Torvalds #else /* CONFIG_ARCH_S390X */ 401da177e4SLinus Torvalds #define __FAIL_ADDR_MASK -4096L 411da177e4SLinus Torvalds #define __FIXUP_MASK ~0L 421da177e4SLinus Torvalds #define __SUBCODE_MASK 0x0600 431da177e4SLinus Torvalds #define __PF_RES_FIELD 0x8000000000000000ULL 441da177e4SLinus Torvalds #endif /* CONFIG_ARCH_S390X */ 451da177e4SLinus Torvalds 461da177e4SLinus Torvalds #ifdef CONFIG_SYSCTL 471da177e4SLinus Torvalds extern int sysctl_userprocess_debug; 481da177e4SLinus Torvalds #endif 491da177e4SLinus Torvalds 501da177e4SLinus Torvalds extern void die(const char *,struct pt_regs *,long); 511da177e4SLinus Torvalds 521da177e4SLinus Torvalds extern spinlock_t timerlist_lock; 531da177e4SLinus Torvalds 541da177e4SLinus Torvalds /* 551da177e4SLinus Torvalds * Unlock any spinlocks which will prevent us from getting the 561da177e4SLinus Torvalds * message out (timerlist_lock is acquired through the 571da177e4SLinus Torvalds * console unblank code) 581da177e4SLinus Torvalds */ 591da177e4SLinus Torvalds void bust_spinlocks(int yes) 601da177e4SLinus Torvalds { 611da177e4SLinus Torvalds if (yes) { 621da177e4SLinus Torvalds oops_in_progress = 1; 631da177e4SLinus Torvalds } else { 641da177e4SLinus Torvalds int loglevel_save = console_loglevel; 651da177e4SLinus Torvalds console_unblank(); 661da177e4SLinus Torvalds oops_in_progress = 0; 671da177e4SLinus Torvalds /* 681da177e4SLinus Torvalds * OK, the message is on the console. Now we call printk() 691da177e4SLinus Torvalds * without oops_in_progress set so that printk will give klogd 701da177e4SLinus Torvalds * a poke. Hold onto your hats... 711da177e4SLinus Torvalds */ 721da177e4SLinus Torvalds console_loglevel = 15; 731da177e4SLinus Torvalds printk(" "); 741da177e4SLinus Torvalds console_loglevel = loglevel_save; 751da177e4SLinus Torvalds } 761da177e4SLinus Torvalds } 771da177e4SLinus Torvalds 781da177e4SLinus Torvalds /* 791da177e4SLinus Torvalds * Check which address space is addressed by the access 801da177e4SLinus Torvalds * register in S390_lowcore.exc_access_id. 811da177e4SLinus Torvalds * Returns 1 for user space and 0 for kernel space. 821da177e4SLinus Torvalds */ 831da177e4SLinus Torvalds static int __check_access_register(struct pt_regs *regs, int error_code) 841da177e4SLinus Torvalds { 851da177e4SLinus Torvalds int areg = S390_lowcore.exc_access_id; 861da177e4SLinus Torvalds 871da177e4SLinus Torvalds if (areg == 0) 881da177e4SLinus Torvalds /* Access via access register 0 -> kernel address */ 891da177e4SLinus Torvalds return 0; 901da177e4SLinus Torvalds save_access_regs(current->thread.acrs); 911da177e4SLinus Torvalds if (regs && areg < NUM_ACRS && current->thread.acrs[areg] <= 1) 921da177e4SLinus Torvalds /* 931da177e4SLinus Torvalds * access register contains 0 -> kernel address, 941da177e4SLinus Torvalds * access register contains 1 -> user space address 951da177e4SLinus Torvalds */ 961da177e4SLinus Torvalds return current->thread.acrs[areg]; 971da177e4SLinus Torvalds 981da177e4SLinus Torvalds /* Something unhealthy was done with the access registers... */ 991da177e4SLinus Torvalds die("page fault via unknown access register", regs, error_code); 1001da177e4SLinus Torvalds do_exit(SIGKILL); 1011da177e4SLinus Torvalds return 0; 1021da177e4SLinus Torvalds } 1031da177e4SLinus Torvalds 1041da177e4SLinus Torvalds /* 1051da177e4SLinus Torvalds * Check which address space the address belongs to. 1061da177e4SLinus Torvalds * Returns 1 for user space and 0 for kernel space. 1071da177e4SLinus Torvalds */ 1081da177e4SLinus Torvalds static inline int check_user_space(struct pt_regs *regs, int error_code) 1091da177e4SLinus Torvalds { 1101da177e4SLinus Torvalds /* 1111da177e4SLinus Torvalds * The lowest two bits of S390_lowcore.trans_exc_code indicate 1121da177e4SLinus Torvalds * which paging table was used: 1131da177e4SLinus Torvalds * 0: Primary Segment Table Descriptor 1141da177e4SLinus Torvalds * 1: STD determined via access register 1151da177e4SLinus Torvalds * 2: Secondary Segment Table Descriptor 1161da177e4SLinus Torvalds * 3: Home Segment Table Descriptor 1171da177e4SLinus Torvalds */ 1181da177e4SLinus Torvalds int descriptor = S390_lowcore.trans_exc_code & 3; 1191da177e4SLinus Torvalds if (unlikely(descriptor == 1)) 1201da177e4SLinus Torvalds return __check_access_register(regs, error_code); 1211da177e4SLinus Torvalds if (descriptor == 2) 1221da177e4SLinus Torvalds return current->thread.mm_segment.ar4; 1231da177e4SLinus Torvalds return descriptor != 0; 1241da177e4SLinus Torvalds } 1251da177e4SLinus Torvalds 1261da177e4SLinus Torvalds /* 1271da177e4SLinus Torvalds * Send SIGSEGV to task. This is an external routine 1281da177e4SLinus Torvalds * to keep the stack usage of do_page_fault small. 1291da177e4SLinus Torvalds */ 1301da177e4SLinus Torvalds static void do_sigsegv(struct pt_regs *regs, unsigned long error_code, 1311da177e4SLinus Torvalds int si_code, unsigned long address) 1321da177e4SLinus Torvalds { 1331da177e4SLinus Torvalds struct siginfo si; 1341da177e4SLinus Torvalds 1351da177e4SLinus Torvalds #if defined(CONFIG_SYSCTL) || defined(CONFIG_PROCESS_DEBUG) 1361da177e4SLinus Torvalds #if defined(CONFIG_SYSCTL) 1371da177e4SLinus Torvalds if (sysctl_userprocess_debug) 1381da177e4SLinus Torvalds #endif 1391da177e4SLinus Torvalds { 1401da177e4SLinus Torvalds printk("User process fault: interruption code 0x%lX\n", 1411da177e4SLinus Torvalds error_code); 1421da177e4SLinus Torvalds printk("failing address: %lX\n", address); 1431da177e4SLinus Torvalds show_regs(regs); 1441da177e4SLinus Torvalds } 1451da177e4SLinus Torvalds #endif 1461da177e4SLinus Torvalds si.si_signo = SIGSEGV; 1471da177e4SLinus Torvalds si.si_code = si_code; 1481da177e4SLinus Torvalds si.si_addr = (void *) address; 1491da177e4SLinus Torvalds force_sig_info(SIGSEGV, &si, current); 1501da177e4SLinus Torvalds } 1511da177e4SLinus Torvalds 1521da177e4SLinus Torvalds /* 1531da177e4SLinus Torvalds * This routine handles page faults. It determines the address, 1541da177e4SLinus Torvalds * and the problem, and then passes it off to one of the appropriate 1551da177e4SLinus Torvalds * routines. 1561da177e4SLinus Torvalds * 1571da177e4SLinus Torvalds * error_code: 1581da177e4SLinus Torvalds * 04 Protection -> Write-Protection (suprression) 1591da177e4SLinus Torvalds * 10 Segment translation -> Not present (nullification) 1601da177e4SLinus Torvalds * 11 Page translation -> Not present (nullification) 1611da177e4SLinus Torvalds * 3b Region third trans. -> Not present (nullification) 1621da177e4SLinus Torvalds */ 1631da177e4SLinus Torvalds extern inline void 1641da177e4SLinus Torvalds do_exception(struct pt_regs *regs, unsigned long error_code, int is_protection) 1651da177e4SLinus Torvalds { 1661da177e4SLinus Torvalds struct task_struct *tsk; 1671da177e4SLinus Torvalds struct mm_struct *mm; 1681da177e4SLinus Torvalds struct vm_area_struct * vma; 1691da177e4SLinus Torvalds unsigned long address; 1701da177e4SLinus Torvalds int user_address; 1711da177e4SLinus Torvalds const struct exception_table_entry *fixup; 1721da177e4SLinus Torvalds int si_code = SEGV_MAPERR; 1731da177e4SLinus Torvalds 1741da177e4SLinus Torvalds tsk = current; 1751da177e4SLinus Torvalds mm = tsk->mm; 1761da177e4SLinus Torvalds 1771da177e4SLinus Torvalds /* 1781da177e4SLinus Torvalds * Check for low-address protection. This needs to be treated 1791da177e4SLinus Torvalds * as a special case because the translation exception code 1801da177e4SLinus Torvalds * field is not guaranteed to contain valid data in this case. 1811da177e4SLinus Torvalds */ 1821da177e4SLinus Torvalds if (is_protection && !(S390_lowcore.trans_exc_code & 4)) { 1831da177e4SLinus Torvalds 1841da177e4SLinus Torvalds /* Low-address protection hit in kernel mode means 1851da177e4SLinus Torvalds NULL pointer write access in kernel mode. */ 1861da177e4SLinus Torvalds if (!(regs->psw.mask & PSW_MASK_PSTATE)) { 1871da177e4SLinus Torvalds address = 0; 1881da177e4SLinus Torvalds user_address = 0; 1891da177e4SLinus Torvalds goto no_context; 1901da177e4SLinus Torvalds } 1911da177e4SLinus Torvalds 1921da177e4SLinus Torvalds /* Low-address protection hit in user mode 'cannot happen'. */ 1931da177e4SLinus Torvalds die ("Low-address protection", regs, error_code); 1941da177e4SLinus Torvalds do_exit(SIGKILL); 1951da177e4SLinus Torvalds } 1961da177e4SLinus Torvalds 1971da177e4SLinus Torvalds /* 1981da177e4SLinus Torvalds * get the failing address 1991da177e4SLinus Torvalds * more specific the segment and page table portion of 2001da177e4SLinus Torvalds * the address 2011da177e4SLinus Torvalds */ 2021da177e4SLinus Torvalds address = S390_lowcore.trans_exc_code & __FAIL_ADDR_MASK; 2031da177e4SLinus Torvalds user_address = check_user_space(regs, error_code); 2041da177e4SLinus Torvalds 2051da177e4SLinus Torvalds /* 2061da177e4SLinus Torvalds * Verify that the fault happened in user space, that 2071da177e4SLinus Torvalds * we are not in an interrupt and that there is a 2081da177e4SLinus Torvalds * user context. 2091da177e4SLinus Torvalds */ 210595bf2aaSMartin Schwidefsky if (user_address == 0 || in_atomic() || !mm) 2111da177e4SLinus Torvalds goto no_context; 2121da177e4SLinus Torvalds 2131da177e4SLinus Torvalds /* 2141da177e4SLinus Torvalds * When we get here, the fault happened in the current 2151da177e4SLinus Torvalds * task's user address space, so we can switch on the 2161da177e4SLinus Torvalds * interrupts again and then search the VMAs 2171da177e4SLinus Torvalds */ 2181da177e4SLinus Torvalds local_irq_enable(); 2191da177e4SLinus Torvalds 2201da177e4SLinus Torvalds down_read(&mm->mmap_sem); 2211da177e4SLinus Torvalds 2221da177e4SLinus Torvalds vma = find_vma(mm, address); 2231da177e4SLinus Torvalds if (!vma) 2241da177e4SLinus Torvalds goto bad_area; 2251da177e4SLinus Torvalds if (vma->vm_start <= address) 2261da177e4SLinus Torvalds goto good_area; 2271da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 2281da177e4SLinus Torvalds goto bad_area; 2291da177e4SLinus Torvalds if (expand_stack(vma, address)) 2301da177e4SLinus Torvalds goto bad_area; 2311da177e4SLinus Torvalds /* 2321da177e4SLinus Torvalds * Ok, we have a good vm_area for this memory access, so 2331da177e4SLinus Torvalds * we can handle it.. 2341da177e4SLinus Torvalds */ 2351da177e4SLinus Torvalds good_area: 2361da177e4SLinus Torvalds si_code = SEGV_ACCERR; 2371da177e4SLinus Torvalds if (!is_protection) { 2381da177e4SLinus Torvalds /* page not present, check vm flags */ 2391da177e4SLinus Torvalds if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) 2401da177e4SLinus Torvalds goto bad_area; 2411da177e4SLinus Torvalds } else { 2421da177e4SLinus Torvalds if (!(vma->vm_flags & VM_WRITE)) 2431da177e4SLinus Torvalds goto bad_area; 2441da177e4SLinus Torvalds } 2451da177e4SLinus Torvalds 2461da177e4SLinus Torvalds survive: 2471da177e4SLinus Torvalds /* 2481da177e4SLinus Torvalds * If for any reason at all we couldn't handle the fault, 2491da177e4SLinus Torvalds * make sure we exit gracefully rather than endlessly redo 2501da177e4SLinus Torvalds * the fault. 2511da177e4SLinus Torvalds */ 2521da177e4SLinus Torvalds switch (handle_mm_fault(mm, vma, address, is_protection)) { 2531da177e4SLinus Torvalds case VM_FAULT_MINOR: 2541da177e4SLinus Torvalds tsk->min_flt++; 2551da177e4SLinus Torvalds break; 2561da177e4SLinus Torvalds case VM_FAULT_MAJOR: 2571da177e4SLinus Torvalds tsk->maj_flt++; 2581da177e4SLinus Torvalds break; 2591da177e4SLinus Torvalds case VM_FAULT_SIGBUS: 2601da177e4SLinus Torvalds goto do_sigbus; 2611da177e4SLinus Torvalds case VM_FAULT_OOM: 2621da177e4SLinus Torvalds goto out_of_memory; 2631da177e4SLinus Torvalds default: 2641da177e4SLinus Torvalds BUG(); 2651da177e4SLinus Torvalds } 2661da177e4SLinus Torvalds 2671da177e4SLinus Torvalds up_read(&mm->mmap_sem); 2681da177e4SLinus Torvalds /* 2691da177e4SLinus Torvalds * The instruction that caused the program check will 2701da177e4SLinus Torvalds * be repeated. Don't signal single step via SIGTRAP. 2711da177e4SLinus Torvalds */ 2721da177e4SLinus Torvalds clear_tsk_thread_flag(current, TIF_SINGLE_STEP); 2731da177e4SLinus Torvalds return; 2741da177e4SLinus Torvalds 2751da177e4SLinus Torvalds /* 2761da177e4SLinus Torvalds * Something tried to access memory that isn't in our memory map.. 2771da177e4SLinus Torvalds * Fix it, but check if it's kernel or user first.. 2781da177e4SLinus Torvalds */ 2791da177e4SLinus Torvalds bad_area: 2801da177e4SLinus Torvalds up_read(&mm->mmap_sem); 2811da177e4SLinus Torvalds 2821da177e4SLinus Torvalds /* User mode accesses just cause a SIGSEGV */ 2831da177e4SLinus Torvalds if (regs->psw.mask & PSW_MASK_PSTATE) { 2841da177e4SLinus Torvalds tsk->thread.prot_addr = address; 2851da177e4SLinus Torvalds tsk->thread.trap_no = error_code; 2861da177e4SLinus Torvalds do_sigsegv(regs, error_code, si_code, address); 2871da177e4SLinus Torvalds return; 2881da177e4SLinus Torvalds } 2891da177e4SLinus Torvalds 2901da177e4SLinus Torvalds no_context: 2911da177e4SLinus Torvalds /* Are we prepared to handle this kernel fault? */ 2921da177e4SLinus Torvalds fixup = search_exception_tables(regs->psw.addr & __FIXUP_MASK); 2931da177e4SLinus Torvalds if (fixup) { 2941da177e4SLinus Torvalds regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE; 2951da177e4SLinus Torvalds return; 2961da177e4SLinus Torvalds } 2971da177e4SLinus Torvalds 2981da177e4SLinus Torvalds /* 2991da177e4SLinus Torvalds * Oops. The kernel tried to access some bad page. We'll have to 3001da177e4SLinus Torvalds * terminate things with extreme prejudice. 3011da177e4SLinus Torvalds */ 3021da177e4SLinus Torvalds if (user_address == 0) 3031da177e4SLinus Torvalds printk(KERN_ALERT "Unable to handle kernel pointer dereference" 3041da177e4SLinus Torvalds " at virtual kernel address %p\n", (void *)address); 3051da177e4SLinus Torvalds else 3061da177e4SLinus Torvalds printk(KERN_ALERT "Unable to handle kernel paging request" 3071da177e4SLinus Torvalds " at virtual user address %p\n", (void *)address); 3081da177e4SLinus Torvalds 3091da177e4SLinus Torvalds die("Oops", regs, error_code); 3101da177e4SLinus Torvalds do_exit(SIGKILL); 3111da177e4SLinus Torvalds 3121da177e4SLinus Torvalds 3131da177e4SLinus Torvalds /* 3141da177e4SLinus Torvalds * We ran out of memory, or some other thing happened to us that made 3151da177e4SLinus Torvalds * us unable to handle the page fault gracefully. 3161da177e4SLinus Torvalds */ 3171da177e4SLinus Torvalds out_of_memory: 3181da177e4SLinus Torvalds up_read(&mm->mmap_sem); 3191da177e4SLinus Torvalds if (tsk->pid == 1) { 3201da177e4SLinus Torvalds yield(); 3211da177e4SLinus Torvalds goto survive; 3221da177e4SLinus Torvalds } 3231da177e4SLinus Torvalds printk("VM: killing process %s\n", tsk->comm); 3241da177e4SLinus Torvalds if (regs->psw.mask & PSW_MASK_PSTATE) 3251da177e4SLinus Torvalds do_exit(SIGKILL); 3261da177e4SLinus Torvalds goto no_context; 3271da177e4SLinus Torvalds 3281da177e4SLinus Torvalds do_sigbus: 3291da177e4SLinus Torvalds up_read(&mm->mmap_sem); 3301da177e4SLinus Torvalds 3311da177e4SLinus Torvalds /* 3321da177e4SLinus Torvalds * Send a sigbus, regardless of whether we were in kernel 3331da177e4SLinus Torvalds * or user mode. 3341da177e4SLinus Torvalds */ 3351da177e4SLinus Torvalds tsk->thread.prot_addr = address; 3361da177e4SLinus Torvalds tsk->thread.trap_no = error_code; 3371da177e4SLinus Torvalds force_sig(SIGBUS, tsk); 3381da177e4SLinus Torvalds 3391da177e4SLinus Torvalds /* Kernel mode? Handle exceptions or die */ 3401da177e4SLinus Torvalds if (!(regs->psw.mask & PSW_MASK_PSTATE)) 3411da177e4SLinus Torvalds goto no_context; 3421da177e4SLinus Torvalds } 3431da177e4SLinus Torvalds 3441da177e4SLinus Torvalds void do_protection_exception(struct pt_regs *regs, unsigned long error_code) 3451da177e4SLinus Torvalds { 3461da177e4SLinus Torvalds regs->psw.addr -= (error_code >> 16); 3471da177e4SLinus Torvalds do_exception(regs, 4, 1); 3481da177e4SLinus Torvalds } 3491da177e4SLinus Torvalds 3501da177e4SLinus Torvalds void do_dat_exception(struct pt_regs *regs, unsigned long error_code) 3511da177e4SLinus Torvalds { 3521da177e4SLinus Torvalds do_exception(regs, error_code & 0xff, 0); 3531da177e4SLinus Torvalds } 3541da177e4SLinus Torvalds 3551da177e4SLinus Torvalds #ifndef CONFIG_ARCH_S390X 3561da177e4SLinus Torvalds 3571da177e4SLinus Torvalds typedef struct _pseudo_wait_t { 3581da177e4SLinus Torvalds struct _pseudo_wait_t *next; 3591da177e4SLinus Torvalds wait_queue_head_t queue; 3601da177e4SLinus Torvalds unsigned long address; 3611da177e4SLinus Torvalds int resolved; 3621da177e4SLinus Torvalds } pseudo_wait_t; 3631da177e4SLinus Torvalds 3641da177e4SLinus Torvalds static pseudo_wait_t *pseudo_lock_queue = NULL; 3651da177e4SLinus Torvalds static spinlock_t pseudo_wait_spinlock; /* spinlock to protect lock queue */ 3661da177e4SLinus Torvalds 3671da177e4SLinus Torvalds /* 3681da177e4SLinus Torvalds * This routine handles 'pagex' pseudo page faults. 3691da177e4SLinus Torvalds */ 3701da177e4SLinus Torvalds asmlinkage void 3711da177e4SLinus Torvalds do_pseudo_page_fault(struct pt_regs *regs, unsigned long error_code) 3721da177e4SLinus Torvalds { 3731da177e4SLinus Torvalds pseudo_wait_t wait_struct; 3741da177e4SLinus Torvalds pseudo_wait_t *ptr, *last, *next; 3751da177e4SLinus Torvalds unsigned long address; 3761da177e4SLinus Torvalds 3771da177e4SLinus Torvalds /* 3781da177e4SLinus Torvalds * get the failing address 3791da177e4SLinus Torvalds * more specific the segment and page table portion of 3801da177e4SLinus Torvalds * the address 3811da177e4SLinus Torvalds */ 3821da177e4SLinus Torvalds address = S390_lowcore.trans_exc_code & 0xfffff000; 3831da177e4SLinus Torvalds 3841da177e4SLinus Torvalds if (address & 0x80000000) { 3851da177e4SLinus Torvalds /* high bit set -> a page has been swapped in by VM */ 3861da177e4SLinus Torvalds address &= 0x7fffffff; 3871da177e4SLinus Torvalds spin_lock(&pseudo_wait_spinlock); 3881da177e4SLinus Torvalds last = NULL; 3891da177e4SLinus Torvalds ptr = pseudo_lock_queue; 3901da177e4SLinus Torvalds while (ptr != NULL) { 3911da177e4SLinus Torvalds next = ptr->next; 3921da177e4SLinus Torvalds if (address == ptr->address) { 3931da177e4SLinus Torvalds /* 3941da177e4SLinus Torvalds * This is one of the processes waiting 3951da177e4SLinus Torvalds * for the page. Unchain from the queue. 3961da177e4SLinus Torvalds * There can be more than one process 3971da177e4SLinus Torvalds * waiting for the same page. VM presents 3981da177e4SLinus Torvalds * an initial and a completion interrupt for 3991da177e4SLinus Torvalds * every process that tries to access a 4001da177e4SLinus Torvalds * page swapped out by VM. 4011da177e4SLinus Torvalds */ 4021da177e4SLinus Torvalds if (last == NULL) 4031da177e4SLinus Torvalds pseudo_lock_queue = next; 4041da177e4SLinus Torvalds else 4051da177e4SLinus Torvalds last->next = next; 4061da177e4SLinus Torvalds /* now wake up the process */ 4071da177e4SLinus Torvalds ptr->resolved = 1; 4081da177e4SLinus Torvalds wake_up(&ptr->queue); 4091da177e4SLinus Torvalds } else 4101da177e4SLinus Torvalds last = ptr; 4111da177e4SLinus Torvalds ptr = next; 4121da177e4SLinus Torvalds } 4131da177e4SLinus Torvalds spin_unlock(&pseudo_wait_spinlock); 4141da177e4SLinus Torvalds } else { 4151da177e4SLinus Torvalds /* Pseudo page faults in kernel mode is a bad idea */ 4161da177e4SLinus Torvalds if (!(regs->psw.mask & PSW_MASK_PSTATE)) { 4171da177e4SLinus Torvalds /* 4181da177e4SLinus Torvalds * VM presents pseudo page faults if the interrupted 4191da177e4SLinus Torvalds * state was not disabled for interrupts. So we can 4201da177e4SLinus Torvalds * get pseudo page fault interrupts while running 4211da177e4SLinus Torvalds * in kernel mode. We simply access the page here 4221da177e4SLinus Torvalds * while we are running disabled. VM will then swap 4231da177e4SLinus Torvalds * in the page synchronously. 4241da177e4SLinus Torvalds */ 4251da177e4SLinus Torvalds if (check_user_space(regs, error_code) == 0) 4261da177e4SLinus Torvalds /* dereference a virtual kernel address */ 4271da177e4SLinus Torvalds __asm__ __volatile__ ( 4281da177e4SLinus Torvalds " ic 0,0(%0)" 4291da177e4SLinus Torvalds : : "a" (address) : "0"); 4301da177e4SLinus Torvalds else 4311da177e4SLinus Torvalds /* dereference a virtual user address */ 4321da177e4SLinus Torvalds __asm__ __volatile__ ( 4331da177e4SLinus Torvalds " la 2,0(%0)\n" 4341da177e4SLinus Torvalds " sacf 512\n" 4351da177e4SLinus Torvalds " ic 2,0(2)\n" 4361da177e4SLinus Torvalds "0:sacf 0\n" 4371da177e4SLinus Torvalds ".section __ex_table,\"a\"\n" 4381da177e4SLinus Torvalds " .align 4\n" 4391da177e4SLinus Torvalds " .long 0b,0b\n" 4401da177e4SLinus Torvalds ".previous" 4411da177e4SLinus Torvalds : : "a" (address) : "2" ); 4421da177e4SLinus Torvalds 4431da177e4SLinus Torvalds return; 4441da177e4SLinus Torvalds } 4451da177e4SLinus Torvalds /* initialize and add element to pseudo_lock_queue */ 4461da177e4SLinus Torvalds init_waitqueue_head (&wait_struct.queue); 4471da177e4SLinus Torvalds wait_struct.address = address; 4481da177e4SLinus Torvalds wait_struct.resolved = 0; 4491da177e4SLinus Torvalds spin_lock(&pseudo_wait_spinlock); 4501da177e4SLinus Torvalds wait_struct.next = pseudo_lock_queue; 4511da177e4SLinus Torvalds pseudo_lock_queue = &wait_struct; 4521da177e4SLinus Torvalds spin_unlock(&pseudo_wait_spinlock); 4531da177e4SLinus Torvalds /* 4541da177e4SLinus Torvalds * The instruction that caused the program check will 4551da177e4SLinus Torvalds * be repeated. Don't signal single step via SIGTRAP. 4561da177e4SLinus Torvalds */ 4571da177e4SLinus Torvalds clear_tsk_thread_flag(current, TIF_SINGLE_STEP); 4581da177e4SLinus Torvalds /* go to sleep */ 4591da177e4SLinus Torvalds wait_event(wait_struct.queue, wait_struct.resolved); 4601da177e4SLinus Torvalds } 4611da177e4SLinus Torvalds } 4621da177e4SLinus Torvalds #endif /* CONFIG_ARCH_S390X */ 4631da177e4SLinus Torvalds 4641da177e4SLinus Torvalds #ifdef CONFIG_PFAULT 4651da177e4SLinus Torvalds /* 4661da177e4SLinus Torvalds * 'pfault' pseudo page faults routines. 4671da177e4SLinus Torvalds */ 4681da177e4SLinus Torvalds static int pfault_disable = 0; 4691da177e4SLinus Torvalds 4701da177e4SLinus Torvalds static int __init nopfault(char *str) 4711da177e4SLinus Torvalds { 4721da177e4SLinus Torvalds pfault_disable = 1; 4731da177e4SLinus Torvalds return 1; 4741da177e4SLinus Torvalds } 4751da177e4SLinus Torvalds 4761da177e4SLinus Torvalds __setup("nopfault", nopfault); 4771da177e4SLinus Torvalds 4781da177e4SLinus Torvalds typedef struct { 4791da177e4SLinus Torvalds __u16 refdiagc; 4801da177e4SLinus Torvalds __u16 reffcode; 4811da177e4SLinus Torvalds __u16 refdwlen; 4821da177e4SLinus Torvalds __u16 refversn; 4831da177e4SLinus Torvalds __u64 refgaddr; 4841da177e4SLinus Torvalds __u64 refselmk; 4851da177e4SLinus Torvalds __u64 refcmpmk; 4861da177e4SLinus Torvalds __u64 reserved; 4871da177e4SLinus Torvalds } __attribute__ ((packed)) pfault_refbk_t; 4881da177e4SLinus Torvalds 4891da177e4SLinus Torvalds int pfault_init(void) 4901da177e4SLinus Torvalds { 4911da177e4SLinus Torvalds pfault_refbk_t refbk = 4921da177e4SLinus Torvalds { 0x258, 0, 5, 2, __LC_CURRENT, 1ULL << 48, 1ULL << 48, 4931da177e4SLinus Torvalds __PF_RES_FIELD }; 4941da177e4SLinus Torvalds int rc; 4951da177e4SLinus Torvalds 4961da177e4SLinus Torvalds if (pfault_disable) 4971da177e4SLinus Torvalds return -1; 4981da177e4SLinus Torvalds __asm__ __volatile__( 4991da177e4SLinus Torvalds " diag %1,%0,0x258\n" 5001da177e4SLinus Torvalds "0: j 2f\n" 5011da177e4SLinus Torvalds "1: la %0,8\n" 5021da177e4SLinus Torvalds "2:\n" 5031da177e4SLinus Torvalds ".section __ex_table,\"a\"\n" 5041da177e4SLinus Torvalds " .align 4\n" 5051da177e4SLinus Torvalds #ifndef CONFIG_ARCH_S390X 5061da177e4SLinus Torvalds " .long 0b,1b\n" 5071da177e4SLinus Torvalds #else /* CONFIG_ARCH_S390X */ 5081da177e4SLinus Torvalds " .quad 0b,1b\n" 5091da177e4SLinus Torvalds #endif /* CONFIG_ARCH_S390X */ 5101da177e4SLinus Torvalds ".previous" 5111da177e4SLinus Torvalds : "=d" (rc) : "a" (&refbk) : "cc" ); 5121da177e4SLinus Torvalds __ctl_set_bit(0, 9); 5131da177e4SLinus Torvalds return rc; 5141da177e4SLinus Torvalds } 5151da177e4SLinus Torvalds 5161da177e4SLinus Torvalds void pfault_fini(void) 5171da177e4SLinus Torvalds { 5181da177e4SLinus Torvalds pfault_refbk_t refbk = 5191da177e4SLinus Torvalds { 0x258, 1, 5, 2, 0ULL, 0ULL, 0ULL, 0ULL }; 5201da177e4SLinus Torvalds 5211da177e4SLinus Torvalds if (pfault_disable) 5221da177e4SLinus Torvalds return; 5231da177e4SLinus Torvalds __ctl_clear_bit(0,9); 5241da177e4SLinus Torvalds __asm__ __volatile__( 5251da177e4SLinus Torvalds " diag %0,0,0x258\n" 5261da177e4SLinus Torvalds "0:\n" 5271da177e4SLinus Torvalds ".section __ex_table,\"a\"\n" 5281da177e4SLinus Torvalds " .align 4\n" 5291da177e4SLinus Torvalds #ifndef CONFIG_ARCH_S390X 5301da177e4SLinus Torvalds " .long 0b,0b\n" 5311da177e4SLinus Torvalds #else /* CONFIG_ARCH_S390X */ 5321da177e4SLinus Torvalds " .quad 0b,0b\n" 5331da177e4SLinus Torvalds #endif /* CONFIG_ARCH_S390X */ 5341da177e4SLinus Torvalds ".previous" 5351da177e4SLinus Torvalds : : "a" (&refbk) : "cc" ); 5361da177e4SLinus Torvalds } 5371da177e4SLinus Torvalds 5381da177e4SLinus Torvalds asmlinkage void 5391da177e4SLinus Torvalds pfault_interrupt(struct pt_regs *regs, __u16 error_code) 5401da177e4SLinus Torvalds { 5411da177e4SLinus Torvalds struct task_struct *tsk; 5421da177e4SLinus Torvalds __u16 subcode; 5431da177e4SLinus Torvalds 5441da177e4SLinus Torvalds /* 5451da177e4SLinus Torvalds * Get the external interruption subcode & pfault 5461da177e4SLinus Torvalds * initial/completion signal bit. VM stores this 5471da177e4SLinus Torvalds * in the 'cpu address' field associated with the 5481da177e4SLinus Torvalds * external interrupt. 5491da177e4SLinus Torvalds */ 5501da177e4SLinus Torvalds subcode = S390_lowcore.cpu_addr; 5511da177e4SLinus Torvalds if ((subcode & 0xff00) != __SUBCODE_MASK) 5521da177e4SLinus Torvalds return; 5531da177e4SLinus Torvalds 5541da177e4SLinus Torvalds /* 5551da177e4SLinus Torvalds * Get the token (= address of the task structure of the affected task). 5561da177e4SLinus Torvalds */ 5571da177e4SLinus Torvalds tsk = *(struct task_struct **) __LC_PFAULT_INTPARM; 5581da177e4SLinus Torvalds 5591da177e4SLinus Torvalds if (subcode & 0x0080) { 5601da177e4SLinus Torvalds /* signal bit is set -> a page has been swapped in by VM */ 5611da177e4SLinus Torvalds if (xchg(&tsk->thread.pfault_wait, -1) != 0) { 5621da177e4SLinus Torvalds /* Initial interrupt was faster than the completion 5631da177e4SLinus Torvalds * interrupt. pfault_wait is valid. Set pfault_wait 5641da177e4SLinus Torvalds * back to zero and wake up the process. This can 5651da177e4SLinus Torvalds * safely be done because the task is still sleeping 566b6d09449SMartin Schwidefsky * and can't produce new pfaults. */ 5671da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 5681da177e4SLinus Torvalds wake_up_process(tsk); 569b6d09449SMartin Schwidefsky put_task_struct(tsk); 5701da177e4SLinus Torvalds } 5711da177e4SLinus Torvalds } else { 5721da177e4SLinus Torvalds /* signal bit not set -> a real page is missing. */ 573b6d09449SMartin Schwidefsky get_task_struct(tsk); 5741da177e4SLinus Torvalds set_task_state(tsk, TASK_UNINTERRUPTIBLE); 5751da177e4SLinus Torvalds if (xchg(&tsk->thread.pfault_wait, 1) != 0) { 5761da177e4SLinus Torvalds /* Completion interrupt was faster than the initial 5771da177e4SLinus Torvalds * interrupt (swapped in a -1 for pfault_wait). Set 5781da177e4SLinus Torvalds * pfault_wait back to zero and exit. This can be 5791da177e4SLinus Torvalds * done safely because tsk is running in kernel 5801da177e4SLinus Torvalds * mode and can't produce new pfaults. */ 5811da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 5821da177e4SLinus Torvalds set_task_state(tsk, TASK_RUNNING); 583b6d09449SMartin Schwidefsky put_task_struct(tsk); 5841da177e4SLinus Torvalds } else 5851da177e4SLinus Torvalds set_tsk_need_resched(tsk); 5861da177e4SLinus Torvalds } 5871da177e4SLinus Torvalds } 5881da177e4SLinus Torvalds #endif 5891da177e4SLinus Torvalds 590