| 1 |
1275 |
phoenix |
/*
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| 2 |
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* arch/s390/mm/fault.c
|
| 3 |
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*
|
| 4 |
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* S390 version
|
| 5 |
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* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
|
| 6 |
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* Author(s): Hartmut Penner (hp@de.ibm.com)
|
| 7 |
|
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* Ulrich Weigand (uweigand@de.ibm.com)
|
| 8 |
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*
|
| 9 |
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* Derived from "arch/i386/mm/fault.c"
|
| 10 |
|
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* Copyright (C) 1995 Linus Torvalds
|
| 11 |
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*/
|
| 12 |
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| 13 |
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#include <linux/config.h>
|
| 14 |
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#include <linux/signal.h>
|
| 15 |
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#include <linux/sched.h>
|
| 16 |
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#include <linux/kernel.h>
|
| 17 |
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#include <linux/errno.h>
|
| 18 |
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#include <linux/string.h>
|
| 19 |
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#include <linux/types.h>
|
| 20 |
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#include <linux/ptrace.h>
|
| 21 |
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#include <linux/mman.h>
|
| 22 |
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#include <linux/mm.h>
|
| 23 |
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#include <linux/smp.h>
|
| 24 |
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#include <linux/smp_lock.h>
|
| 25 |
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#include <linux/compatmac.h>
|
| 26 |
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#include <linux/init.h>
|
| 27 |
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#include <linux/console.h>
|
| 28 |
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| 29 |
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#include <asm/system.h>
|
| 30 |
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#include <asm/uaccess.h>
|
| 31 |
|
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#include <asm/pgtable.h>
|
| 32 |
|
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#include <asm/hardirq.h>
|
| 33 |
|
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|
| 34 |
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#ifdef CONFIG_SYSCTL
|
| 35 |
|
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extern int sysctl_userprocess_debug;
|
| 36 |
|
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#endif
|
| 37 |
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|
| 38 |
|
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extern void die(const char *,struct pt_regs *,long);
|
| 39 |
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|
| 40 |
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extern spinlock_t timerlist_lock;
|
| 41 |
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|
| 42 |
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/*
|
| 43 |
|
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* Unlock any spinlocks which will prevent us from getting the
|
| 44 |
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* message out (timerlist_lock is acquired through the
|
| 45 |
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* console unblank code)
|
| 46 |
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*/
|
| 47 |
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void bust_spinlocks(int yes)
|
| 48 |
|
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{
|
| 49 |
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spin_lock_init(&timerlist_lock);
|
| 50 |
|
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if (yes) {
|
| 51 |
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oops_in_progress = 1;
|
| 52 |
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} else {
|
| 53 |
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int loglevel_save = console_loglevel;
|
| 54 |
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oops_in_progress = 0;
|
| 55 |
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console_unblank();
|
| 56 |
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/*
|
| 57 |
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* OK, the message is on the console. Now we call printk()
|
| 58 |
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* without oops_in_progress set so that printk will give klogd
|
| 59 |
|
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* a poke. Hold onto your hats...
|
| 60 |
|
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*/
|
| 61 |
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console_loglevel = 15;
|
| 62 |
|
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printk(" ");
|
| 63 |
|
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console_loglevel = loglevel_save;
|
| 64 |
|
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}
|
| 65 |
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}
|
| 66 |
|
|
|
| 67 |
|
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/*
|
| 68 |
|
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* Check which address space is addressed by the access
|
| 69 |
|
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* register in S390_lowcore.exc_access_id.
|
| 70 |
|
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* Returns 1 for user space and 0 for kernel space.
|
| 71 |
|
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*/
|
| 72 |
|
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static int __check_access_register(struct pt_regs *regs, int error_code)
|
| 73 |
|
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{
|
| 74 |
|
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int areg = S390_lowcore.exc_access_id;
|
| 75 |
|
|
|
| 76 |
|
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if (areg == 0)
|
| 77 |
|
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/* Access via access register 0 -> kernel address */
|
| 78 |
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return 0;
|
| 79 |
|
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if (regs && areg < NUM_ACRS && regs->acrs[areg] <= 1)
|
| 80 |
|
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/*
|
| 81 |
|
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* access register contains 0 -> kernel address,
|
| 82 |
|
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* access register contains 1 -> user space address
|
| 83 |
|
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*/
|
| 84 |
|
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return regs->acrs[areg];
|
| 85 |
|
|
|
| 86 |
|
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/* Something unhealthy was done with the access registers... */
|
| 87 |
|
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die("page fault via unknown access register", regs, error_code);
|
| 88 |
|
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do_exit(SIGKILL);
|
| 89 |
|
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return 0;
|
| 90 |
|
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}
|
| 91 |
|
|
|
| 92 |
|
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/*
|
| 93 |
|
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* Check which address space the address belongs to.
|
| 94 |
|
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* Returns 1 for user space and 0 for kernel space.
|
| 95 |
|
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*/
|
| 96 |
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static inline int check_user_space(struct pt_regs *regs, int error_code)
|
| 97 |
|
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{
|
| 98 |
|
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/*
|
| 99 |
|
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* The lowest two bits of S390_lowcore.trans_exc_code indicate
|
| 100 |
|
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* which paging table was used:
|
| 101 |
|
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* 0: Primary Segment Table Descriptor
|
| 102 |
|
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* 1: STD determined via access register
|
| 103 |
|
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* 2: Secondary Segment Table Descriptor
|
| 104 |
|
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* 3: Home Segment Table Descriptor
|
| 105 |
|
|
*/
|
| 106 |
|
|
int descriptor = S390_lowcore.trans_exc_code & 3;
|
| 107 |
|
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if (descriptor == 1)
|
| 108 |
|
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return __check_access_register(regs, error_code);
|
| 109 |
|
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return descriptor >> 1;
|
| 110 |
|
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}
|
| 111 |
|
|
|
| 112 |
|
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/*
|
| 113 |
|
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* Send SIGSEGV to task. This is an external routine
|
| 114 |
|
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* to keep the stack usage of do_page_fault small.
|
| 115 |
|
|
*/
|
| 116 |
|
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static void force_sigsegv(struct pt_regs *regs, unsigned long error_code,
|
| 117 |
|
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int si_code, unsigned long address)
|
| 118 |
|
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{
|
| 119 |
|
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struct siginfo si;
|
| 120 |
|
|
|
| 121 |
|
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#if defined(CONFIG_SYSCTL) || defined(CONFIG_PROCESS_DEBUG)
|
| 122 |
|
|
#if defined(CONFIG_SYSCTL)
|
| 123 |
|
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if (sysctl_userprocess_debug)
|
| 124 |
|
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#endif
|
| 125 |
|
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{
|
| 126 |
|
|
printk("User process fault: interruption code 0x%lX\n",
|
| 127 |
|
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error_code);
|
| 128 |
|
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printk("failing address: %lX\n", address);
|
| 129 |
|
|
show_regs(regs);
|
| 130 |
|
|
}
|
| 131 |
|
|
#endif
|
| 132 |
|
|
si.si_signo = SIGSEGV;
|
| 133 |
|
|
si.si_code = si_code;
|
| 134 |
|
|
si.si_addr = (void *) address;
|
| 135 |
|
|
force_sig_info(SIGSEGV, &si, current);
|
| 136 |
|
|
}
|
| 137 |
|
|
|
| 138 |
|
|
/*
|
| 139 |
|
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* This routine handles page faults. It determines the address,
|
| 140 |
|
|
* and the problem, and then passes it off to one of the appropriate
|
| 141 |
|
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* routines.
|
| 142 |
|
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*
|
| 143 |
|
|
* error_code:
|
| 144 |
|
|
* 04 Protection -> Write-Protection (suprression)
|
| 145 |
|
|
* 10 Segment translation -> Not present (nullification)
|
| 146 |
|
|
* 11 Page translation -> Not present (nullification)
|
| 147 |
|
|
*/
|
| 148 |
|
|
extern inline void do_exception(struct pt_regs *regs, unsigned long error_code)
|
| 149 |
|
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{
|
| 150 |
|
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struct task_struct *tsk;
|
| 151 |
|
|
struct mm_struct *mm;
|
| 152 |
|
|
struct vm_area_struct * vma;
|
| 153 |
|
|
unsigned long address;
|
| 154 |
|
|
int user_address;
|
| 155 |
|
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unsigned long fixup;
|
| 156 |
|
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int si_code = SEGV_MAPERR;
|
| 157 |
|
|
|
| 158 |
|
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tsk = current;
|
| 159 |
|
|
mm = tsk->mm;
|
| 160 |
|
|
|
| 161 |
|
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/*
|
| 162 |
|
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* Check for low-address protection. This needs to be treated
|
| 163 |
|
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* as a special case because the translation exception code
|
| 164 |
|
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* field is not guaranteed to contain valid data in this case.
|
| 165 |
|
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*/
|
| 166 |
|
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if (error_code == 4 && !(S390_lowcore.trans_exc_code & 4)) {
|
| 167 |
|
|
|
| 168 |
|
|
/* Low-address protection hit in kernel mode means
|
| 169 |
|
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NULL pointer write access in kernel mode. */
|
| 170 |
|
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if (!(regs->psw.mask & PSW_PROBLEM_STATE)) {
|
| 171 |
|
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address = 0;
|
| 172 |
|
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user_address = 0;
|
| 173 |
|
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goto no_context;
|
| 174 |
|
|
}
|
| 175 |
|
|
|
| 176 |
|
|
/* Low-address protection hit in user mode 'cannot happen'. */
|
| 177 |
|
|
die ("Low-address protection", regs, error_code);
|
| 178 |
|
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do_exit(SIGKILL);
|
| 179 |
|
|
}
|
| 180 |
|
|
|
| 181 |
|
|
/*
|
| 182 |
|
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* get the failing address
|
| 183 |
|
|
* more specific the segment and page table portion of
|
| 184 |
|
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* the address
|
| 185 |
|
|
*/
|
| 186 |
|
|
address = S390_lowcore.trans_exc_code&0x7ffff000;
|
| 187 |
|
|
user_address = check_user_space(regs, error_code);
|
| 188 |
|
|
|
| 189 |
|
|
/*
|
| 190 |
|
|
* Verify that the fault happened in user space, that
|
| 191 |
|
|
* we are not in an interrupt and that there is a
|
| 192 |
|
|
* user context.
|
| 193 |
|
|
*/
|
| 194 |
|
|
if (user_address == 0 || in_interrupt() || !mm)
|
| 195 |
|
|
goto no_context;
|
| 196 |
|
|
|
| 197 |
|
|
/*
|
| 198 |
|
|
* When we get here, the fault happened in the current
|
| 199 |
|
|
* task's user address space, so we can switch on the
|
| 200 |
|
|
* interrupts again and then search the VMAs
|
| 201 |
|
|
*/
|
| 202 |
|
|
__sti();
|
| 203 |
|
|
|
| 204 |
|
|
down_read(&mm->mmap_sem);
|
| 205 |
|
|
|
| 206 |
|
|
vma = find_vma(mm, address);
|
| 207 |
|
|
if (!vma)
|
| 208 |
|
|
goto bad_area;
|
| 209 |
|
|
if (vma->vm_start <= address)
|
| 210 |
|
|
goto good_area;
|
| 211 |
|
|
if (!(vma->vm_flags & VM_GROWSDOWN))
|
| 212 |
|
|
goto bad_area;
|
| 213 |
|
|
if (expand_stack(vma, address))
|
| 214 |
|
|
goto bad_area;
|
| 215 |
|
|
/*
|
| 216 |
|
|
* Ok, we have a good vm_area for this memory access, so
|
| 217 |
|
|
* we can handle it..
|
| 218 |
|
|
*/
|
| 219 |
|
|
good_area:
|
| 220 |
|
|
si_code = SEGV_ACCERR;
|
| 221 |
|
|
if (error_code != 4) {
|
| 222 |
|
|
/* page not present, check vm flags */
|
| 223 |
|
|
if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
|
| 224 |
|
|
goto bad_area;
|
| 225 |
|
|
} else {
|
| 226 |
|
|
if (!(vma->vm_flags & VM_WRITE))
|
| 227 |
|
|
goto bad_area;
|
| 228 |
|
|
}
|
| 229 |
|
|
|
| 230 |
|
|
survive:
|
| 231 |
|
|
/*
|
| 232 |
|
|
* If for any reason at all we couldn't handle the fault,
|
| 233 |
|
|
* make sure we exit gracefully rather than endlessly redo
|
| 234 |
|
|
* the fault.
|
| 235 |
|
|
*/
|
| 236 |
|
|
switch (handle_mm_fault(mm, vma, address, error_code == 4)) {
|
| 237 |
|
|
case 1:
|
| 238 |
|
|
tsk->min_flt++;
|
| 239 |
|
|
break;
|
| 240 |
|
|
case 2:
|
| 241 |
|
|
tsk->maj_flt++;
|
| 242 |
|
|
break;
|
| 243 |
|
|
case 0:
|
| 244 |
|
|
goto do_sigbus;
|
| 245 |
|
|
default:
|
| 246 |
|
|
goto out_of_memory;
|
| 247 |
|
|
}
|
| 248 |
|
|
|
| 249 |
|
|
up_read(&mm->mmap_sem);
|
| 250 |
|
|
return;
|
| 251 |
|
|
|
| 252 |
|
|
/*
|
| 253 |
|
|
* Something tried to access memory that isn't in our memory map..
|
| 254 |
|
|
* Fix it, but check if it's kernel or user first..
|
| 255 |
|
|
*/
|
| 256 |
|
|
bad_area:
|
| 257 |
|
|
up_read(&mm->mmap_sem);
|
| 258 |
|
|
|
| 259 |
|
|
/* User mode accesses just cause a SIGSEGV */
|
| 260 |
|
|
if (regs->psw.mask & PSW_PROBLEM_STATE) {
|
| 261 |
|
|
tsk->thread.prot_addr = address;
|
| 262 |
|
|
tsk->thread.trap_no = error_code;
|
| 263 |
|
|
force_sigsegv(regs, error_code, si_code, address);
|
| 264 |
|
|
return;
|
| 265 |
|
|
}
|
| 266 |
|
|
|
| 267 |
|
|
no_context:
|
| 268 |
|
|
/* Are we prepared to handle this kernel fault? */
|
| 269 |
|
|
if ((fixup = search_exception_table(regs->psw.addr)) != 0) {
|
| 270 |
|
|
regs->psw.addr = fixup;
|
| 271 |
|
|
return;
|
| 272 |
|
|
}
|
| 273 |
|
|
|
| 274 |
|
|
/*
|
| 275 |
|
|
* Oops. The kernel tried to access some bad page. We'll have to
|
| 276 |
|
|
* terminate things with extreme prejudice.
|
| 277 |
|
|
*/
|
| 278 |
|
|
if (user_address == 0)
|
| 279 |
|
|
printk(KERN_ALERT "Unable to handle kernel pointer dereference"
|
| 280 |
|
|
" at virtual kernel address %08lx\n", address);
|
| 281 |
|
|
else
|
| 282 |
|
|
printk(KERN_ALERT "Unable to handle kernel paging request"
|
| 283 |
|
|
" at virtual user address %08lx\n", address);
|
| 284 |
|
|
|
| 285 |
|
|
die("Oops", regs, error_code);
|
| 286 |
|
|
do_exit(SIGKILL);
|
| 287 |
|
|
|
| 288 |
|
|
|
| 289 |
|
|
/*
|
| 290 |
|
|
* We ran out of memory, or some other thing happened to us that made
|
| 291 |
|
|
* us unable to handle the page fault gracefully.
|
| 292 |
|
|
*/
|
| 293 |
|
|
out_of_memory:
|
| 294 |
|
|
if (tsk->pid == 1) {
|
| 295 |
|
|
yield();
|
| 296 |
|
|
goto survive;
|
| 297 |
|
|
}
|
| 298 |
|
|
up_read(&mm->mmap_sem);
|
| 299 |
|
|
printk("VM: killing process %s\n", tsk->comm);
|
| 300 |
|
|
if (regs->psw.mask & PSW_PROBLEM_STATE)
|
| 301 |
|
|
do_exit(SIGKILL);
|
| 302 |
|
|
goto no_context;
|
| 303 |
|
|
|
| 304 |
|
|
do_sigbus:
|
| 305 |
|
|
up_read(&mm->mmap_sem);
|
| 306 |
|
|
|
| 307 |
|
|
/*
|
| 308 |
|
|
* Send a sigbus, regardless of whether we were in kernel
|
| 309 |
|
|
* or user mode.
|
| 310 |
|
|
*/
|
| 311 |
|
|
tsk->thread.prot_addr = address;
|
| 312 |
|
|
tsk->thread.trap_no = error_code;
|
| 313 |
|
|
force_sig(SIGBUS, tsk);
|
| 314 |
|
|
|
| 315 |
|
|
/* Kernel mode? Handle exceptions or die */
|
| 316 |
|
|
if (!(regs->psw.mask & PSW_PROBLEM_STATE))
|
| 317 |
|
|
goto no_context;
|
| 318 |
|
|
}
|
| 319 |
|
|
|
| 320 |
|
|
void do_protection_exception(struct pt_regs *regs, unsigned long error_code)
|
| 321 |
|
|
{
|
| 322 |
|
|
regs->psw.addr -= (error_code >> 16);
|
| 323 |
|
|
do_exception(regs, 4);
|
| 324 |
|
|
}
|
| 325 |
|
|
|
| 326 |
|
|
void do_segment_exception(struct pt_regs *regs, unsigned long error_code)
|
| 327 |
|
|
{
|
| 328 |
|
|
do_exception(regs, 0x10);
|
| 329 |
|
|
}
|
| 330 |
|
|
|
| 331 |
|
|
void do_page_exception(struct pt_regs *regs, unsigned long error_code)
|
| 332 |
|
|
{
|
| 333 |
|
|
do_exception(regs, 0x11);
|
| 334 |
|
|
}
|
| 335 |
|
|
|
| 336 |
|
|
typedef struct _pseudo_wait_t {
|
| 337 |
|
|
struct _pseudo_wait_t *next;
|
| 338 |
|
|
wait_queue_head_t queue;
|
| 339 |
|
|
unsigned long address;
|
| 340 |
|
|
int resolved;
|
| 341 |
|
|
} pseudo_wait_t;
|
| 342 |
|
|
|
| 343 |
|
|
static pseudo_wait_t *pseudo_lock_queue = NULL;
|
| 344 |
|
|
static spinlock_t pseudo_wait_spinlock; /* spinlock to protect lock queue */
|
| 345 |
|
|
|
| 346 |
|
|
/*
|
| 347 |
|
|
* This routine handles 'pagex' pseudo page faults.
|
| 348 |
|
|
*/
|
| 349 |
|
|
asmlinkage void
|
| 350 |
|
|
do_pseudo_page_fault(struct pt_regs *regs, unsigned long error_code)
|
| 351 |
|
|
{
|
| 352 |
|
|
pseudo_wait_t wait_struct;
|
| 353 |
|
|
pseudo_wait_t *ptr, *last, *next;
|
| 354 |
|
|
unsigned long address;
|
| 355 |
|
|
|
| 356 |
|
|
/*
|
| 357 |
|
|
* get the failing address
|
| 358 |
|
|
* more specific the segment and page table portion of
|
| 359 |
|
|
* the address
|
| 360 |
|
|
*/
|
| 361 |
|
|
address = S390_lowcore.trans_exc_code & 0xfffff000;
|
| 362 |
|
|
|
| 363 |
|
|
if (address & 0x80000000) {
|
| 364 |
|
|
/* high bit set -> a page has been swapped in by VM */
|
| 365 |
|
|
address &= 0x7fffffff;
|
| 366 |
|
|
spin_lock(&pseudo_wait_spinlock);
|
| 367 |
|
|
last = NULL;
|
| 368 |
|
|
ptr = pseudo_lock_queue;
|
| 369 |
|
|
while (ptr != NULL) {
|
| 370 |
|
|
next = ptr->next;
|
| 371 |
|
|
if (address == ptr->address) {
|
| 372 |
|
|
/*
|
| 373 |
|
|
* This is one of the processes waiting
|
| 374 |
|
|
* for the page. Unchain from the queue.
|
| 375 |
|
|
* There can be more than one process
|
| 376 |
|
|
* waiting for the same page. VM presents
|
| 377 |
|
|
* an initial and a completion interrupt for
|
| 378 |
|
|
* every process that tries to access a
|
| 379 |
|
|
* page swapped out by VM.
|
| 380 |
|
|
*/
|
| 381 |
|
|
if (last == NULL)
|
| 382 |
|
|
pseudo_lock_queue = next;
|
| 383 |
|
|
else
|
| 384 |
|
|
last->next = next;
|
| 385 |
|
|
/* now wake up the process */
|
| 386 |
|
|
ptr->resolved = 1;
|
| 387 |
|
|
wake_up(&ptr->queue);
|
| 388 |
|
|
} else
|
| 389 |
|
|
last = ptr;
|
| 390 |
|
|
ptr = next;
|
| 391 |
|
|
}
|
| 392 |
|
|
spin_unlock(&pseudo_wait_spinlock);
|
| 393 |
|
|
} else {
|
| 394 |
|
|
/* Pseudo page faults in kernel mode is a bad idea */
|
| 395 |
|
|
if (!(regs->psw.mask & PSW_PROBLEM_STATE)) {
|
| 396 |
|
|
/*
|
| 397 |
|
|
* VM presents pseudo page faults if the interrupted
|
| 398 |
|
|
* state was not disabled for interrupts. So we can
|
| 399 |
|
|
* get pseudo page fault interrupts while running
|
| 400 |
|
|
* in kernel mode. We simply access the page here
|
| 401 |
|
|
* while we are running disabled. VM will then swap
|
| 402 |
|
|
* in the page synchronously.
|
| 403 |
|
|
*/
|
| 404 |
|
|
if (check_user_space(regs, error_code) == 0)
|
| 405 |
|
|
/* dereference a virtual kernel address */
|
| 406 |
|
|
__asm__ __volatile__ (
|
| 407 |
|
|
" ic 0,0(%0)"
|
| 408 |
|
|
: : "a" (address) : "0");
|
| 409 |
|
|
else
|
| 410 |
|
|
/* dereference a virtual user address */
|
| 411 |
|
|
__asm__ __volatile__ (
|
| 412 |
|
|
" la 2,0(%0)\n"
|
| 413 |
|
|
" sacf 512\n"
|
| 414 |
|
|
" ic 2,0(2)\n"
|
| 415 |
|
|
"0:sacf 0\n"
|
| 416 |
|
|
".section __ex_table,\"a\"\n"
|
| 417 |
|
|
" .align 4\n"
|
| 418 |
|
|
" .long 0b,0b\n"
|
| 419 |
|
|
".previous"
|
| 420 |
|
|
: : "a" (address) : "2" );
|
| 421 |
|
|
|
| 422 |
|
|
return;
|
| 423 |
|
|
}
|
| 424 |
|
|
/* initialize and add element to pseudo_lock_queue */
|
| 425 |
|
|
init_waitqueue_head (&wait_struct.queue);
|
| 426 |
|
|
wait_struct.address = address;
|
| 427 |
|
|
wait_struct.resolved = 0;
|
| 428 |
|
|
spin_lock(&pseudo_wait_spinlock);
|
| 429 |
|
|
wait_struct.next = pseudo_lock_queue;
|
| 430 |
|
|
pseudo_lock_queue = &wait_struct;
|
| 431 |
|
|
spin_unlock(&pseudo_wait_spinlock);
|
| 432 |
|
|
/* go to sleep */
|
| 433 |
|
|
wait_event(wait_struct.queue, wait_struct.resolved);
|
| 434 |
|
|
}
|
| 435 |
|
|
}
|
| 436 |
|
|
|
| 437 |
|
|
#ifdef CONFIG_PFAULT
|
| 438 |
|
|
/*
|
| 439 |
|
|
* 'pfault' pseudo page faults routines.
|
| 440 |
|
|
*/
|
| 441 |
|
|
static int pfault_disable = 0;
|
| 442 |
|
|
|
| 443 |
|
|
static int __init nopfault(char *str)
|
| 444 |
|
|
{
|
| 445 |
|
|
pfault_disable = 1;
|
| 446 |
|
|
return 1;
|
| 447 |
|
|
}
|
| 448 |
|
|
|
| 449 |
|
|
__setup("nopfault", nopfault);
|
| 450 |
|
|
|
| 451 |
|
|
typedef struct {
|
| 452 |
|
|
__u16 refdiagc;
|
| 453 |
|
|
__u16 reffcode;
|
| 454 |
|
|
__u16 refdwlen;
|
| 455 |
|
|
__u16 refversn;
|
| 456 |
|
|
__u64 refgaddr;
|
| 457 |
|
|
__u64 refselmk;
|
| 458 |
|
|
__u64 refcmpmk;
|
| 459 |
|
|
__u64 reserved;
|
| 460 |
|
|
} __attribute__ ((packed)) pfault_refbk_t;
|
| 461 |
|
|
|
| 462 |
|
|
int pfault_init(void)
|
| 463 |
|
|
{
|
| 464 |
|
|
pfault_refbk_t refbk =
|
| 465 |
|
|
{ 0x258, 0, 5, 2, __LC_KERNEL_STACK, 1ULL << 48, 1ULL << 48, 0ULL };
|
| 466 |
|
|
int rc;
|
| 467 |
|
|
|
| 468 |
|
|
if (pfault_disable)
|
| 469 |
|
|
return -1;
|
| 470 |
|
|
__asm__ __volatile__(
|
| 471 |
|
|
" diag %1,%0,0x258\n"
|
| 472 |
|
|
"0: j 2f\n"
|
| 473 |
|
|
"1: la %0,8\n"
|
| 474 |
|
|
"2:\n"
|
| 475 |
|
|
".section __ex_table,\"a\"\n"
|
| 476 |
|
|
" .align 4\n"
|
| 477 |
|
|
" .long 0b,1b\n"
|
| 478 |
|
|
".previous"
|
| 479 |
|
|
: "=d" (rc) : "a" (&refbk) : "cc" );
|
| 480 |
|
|
__ctl_set_bit(0, 9);
|
| 481 |
|
|
return rc;
|
| 482 |
|
|
}
|
| 483 |
|
|
|
| 484 |
|
|
void pfault_fini(void)
|
| 485 |
|
|
{
|
| 486 |
|
|
pfault_refbk_t refbk =
|
| 487 |
|
|
{ 0x258, 1, 5, 2, 0ULL, 0ULL, 0ULL, 0ULL };
|
| 488 |
|
|
|
| 489 |
|
|
if (pfault_disable)
|
| 490 |
|
|
return;
|
| 491 |
|
|
__ctl_clear_bit(0,9);
|
| 492 |
|
|
__asm__ __volatile__(
|
| 493 |
|
|
" diag %0,0,0x258\n"
|
| 494 |
|
|
"0:\n"
|
| 495 |
|
|
".section __ex_table,\"a\"\n"
|
| 496 |
|
|
" .align 4\n"
|
| 497 |
|
|
" .long 0b,0b\n"
|
| 498 |
|
|
".previous"
|
| 499 |
|
|
: : "a" (&refbk) : "cc" );
|
| 500 |
|
|
}
|
| 501 |
|
|
|
| 502 |
|
|
asmlinkage void
|
| 503 |
|
|
pfault_interrupt(struct pt_regs *regs, __u16 error_code)
|
| 504 |
|
|
{
|
| 505 |
|
|
struct task_struct *tsk;
|
| 506 |
|
|
wait_queue_head_t queue;
|
| 507 |
|
|
wait_queue_head_t *qp;
|
| 508 |
|
|
__u16 subcode;
|
| 509 |
|
|
|
| 510 |
|
|
/*
|
| 511 |
|
|
* Get the external interruption subcode & pfault
|
| 512 |
|
|
* initial/completion signal bit. VM stores this
|
| 513 |
|
|
* in the 'cpu address' field associated with the
|
| 514 |
|
|
* external interrupt.
|
| 515 |
|
|
*/
|
| 516 |
|
|
subcode = S390_lowcore.cpu_addr;
|
| 517 |
|
|
if ((subcode & 0xff00) != 0x0200)
|
| 518 |
|
|
return;
|
| 519 |
|
|
|
| 520 |
|
|
/*
|
| 521 |
|
|
* Get the token (= address of kernel stack of affected task).
|
| 522 |
|
|
*/
|
| 523 |
|
|
tsk = (struct task_struct *)
|
| 524 |
|
|
(*((unsigned long *) __LC_PFAULT_INTPARM) - THREAD_SIZE);
|
| 525 |
|
|
|
| 526 |
|
|
/*
|
| 527 |
|
|
* We got all needed information from the lowcore and can
|
| 528 |
|
|
* now safely switch on interrupts.
|
| 529 |
|
|
*/
|
| 530 |
|
|
if (regs->psw.mask & PSW_PROBLEM_STATE)
|
| 531 |
|
|
__sti();
|
| 532 |
|
|
|
| 533 |
|
|
if (subcode & 0x0080) {
|
| 534 |
|
|
/* signal bit is set -> a page has been swapped in by VM */
|
| 535 |
|
|
qp = (wait_queue_head_t *)
|
| 536 |
|
|
xchg(&tsk->thread.pfault_wait, -1);
|
| 537 |
|
|
if (qp != NULL) {
|
| 538 |
|
|
/* Initial interrupt was faster than the completion
|
| 539 |
|
|
* interrupt. pfault_wait is valid. Set pfault_wait
|
| 540 |
|
|
* back to zero and wake up the process. This can
|
| 541 |
|
|
* safely be done because the task is still sleeping
|
| 542 |
|
|
* and can't procude new pfaults. */
|
| 543 |
|
|
tsk->thread.pfault_wait = 0ULL;
|
| 544 |
|
|
wake_up(qp);
|
| 545 |
|
|
}
|
| 546 |
|
|
} else {
|
| 547 |
|
|
/* signal bit not set -> a real page is missing. */
|
| 548 |
|
|
init_waitqueue_head (&queue);
|
| 549 |
|
|
qp = (wait_queue_head_t *)
|
| 550 |
|
|
xchg(&tsk->thread.pfault_wait, (addr_t) &queue);
|
| 551 |
|
|
if (qp != NULL) {
|
| 552 |
|
|
/* Completion interrupt was faster than the initial
|
| 553 |
|
|
* interrupt (swapped in a -1 for pfault_wait). Set
|
| 554 |
|
|
* pfault_wait back to zero and exit. This can be
|
| 555 |
|
|
* done safely because tsk is running in kernel
|
| 556 |
|
|
* mode and can't produce new pfaults. */
|
| 557 |
|
|
tsk->thread.pfault_wait = 0ULL;
|
| 558 |
|
|
}
|
| 559 |
|
|
|
| 560 |
|
|
/* go to sleep */
|
| 561 |
|
|
wait_event(queue, tsk->thread.pfault_wait == 0ULL);
|
| 562 |
|
|
}
|
| 563 |
|
|
}
|
| 564 |
|
|
#endif
|
| 565 |
|
|
|
