816 строки
21 KiB
C
816 строки
21 KiB
C
/*
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* S390 version
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* Copyright IBM Corp. 1999
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* Author(s): Hartmut Penner (hp@de.ibm.com)
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* Ulrich Weigand (uweigand@de.ibm.com)
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*
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* Derived from "arch/i386/mm/fault.c"
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* Copyright (C) 1995 Linus Torvalds
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*/
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#include <linux/kernel_stat.h>
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#include <linux/perf_event.h>
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#include <linux/signal.h>
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#include <linux/sched.h>
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#include <linux/sched/debug.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/ptrace.h>
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#include <linux/mman.h>
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#include <linux/mm.h>
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#include <linux/compat.h>
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#include <linux/smp.h>
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#include <linux/kdebug.h>
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#include <linux/init.h>
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#include <linux/console.h>
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#include <linux/extable.h>
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#include <linux/hardirq.h>
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#include <linux/kprobes.h>
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#include <linux/uaccess.h>
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#include <linux/hugetlb.h>
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#include <asm/asm-offsets.h>
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#include <asm/diag.h>
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#include <asm/pgtable.h>
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#include <asm/gmap.h>
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#include <asm/irq.h>
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#include <asm/mmu_context.h>
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#include <asm/facility.h>
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#include "../kernel/entry.h"
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#define __FAIL_ADDR_MASK -4096L
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#define __SUBCODE_MASK 0x0600
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#define __PF_RES_FIELD 0x8000000000000000ULL
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#define VM_FAULT_BADCONTEXT 0x010000
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#define VM_FAULT_BADMAP 0x020000
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#define VM_FAULT_BADACCESS 0x040000
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#define VM_FAULT_SIGNAL 0x080000
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#define VM_FAULT_PFAULT 0x100000
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static unsigned long store_indication __read_mostly;
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static int __init fault_init(void)
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{
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if (test_facility(75))
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store_indication = 0xc00;
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return 0;
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}
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early_initcall(fault_init);
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static inline int notify_page_fault(struct pt_regs *regs)
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{
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int ret = 0;
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/* kprobe_running() needs smp_processor_id() */
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if (kprobes_built_in() && !user_mode(regs)) {
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preempt_disable();
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if (kprobe_running() && kprobe_fault_handler(regs, 14))
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ret = 1;
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preempt_enable();
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}
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return ret;
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}
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/*
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* Unlock any spinlocks which will prevent us from getting the
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* message out.
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*/
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void bust_spinlocks(int yes)
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{
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if (yes) {
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oops_in_progress = 1;
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} else {
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int loglevel_save = console_loglevel;
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console_unblank();
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oops_in_progress = 0;
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/*
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* OK, the message is on the console. Now we call printk()
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* without oops_in_progress set so that printk will give klogd
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* a poke. Hold onto your hats...
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*/
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console_loglevel = 15;
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printk(" ");
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console_loglevel = loglevel_save;
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}
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}
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/*
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* Returns the address space associated with the fault.
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* Returns 0 for kernel space and 1 for user space.
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*/
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static inline int user_space_fault(struct pt_regs *regs)
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{
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unsigned long trans_exc_code;
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/*
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* The lowest two bits of the translation exception
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* identification indicate which paging table was used.
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*/
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trans_exc_code = regs->int_parm_long & 3;
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if (trans_exc_code == 3) /* home space -> kernel */
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return 0;
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if (user_mode(regs))
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return 1;
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if (trans_exc_code == 2) /* secondary space -> set_fs */
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return current->thread.mm_segment.ar4;
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if (current->flags & PF_VCPU)
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return 1;
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return 0;
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}
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static int bad_address(void *p)
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{
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unsigned long dummy;
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return probe_kernel_address((unsigned long *)p, dummy);
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}
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static void dump_pagetable(unsigned long asce, unsigned long address)
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{
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unsigned long *table = __va(asce & _ASCE_ORIGIN);
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pr_alert("AS:%016lx ", asce);
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switch (asce & _ASCE_TYPE_MASK) {
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case _ASCE_TYPE_REGION1:
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table = table + ((address >> 53) & 0x7ff);
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if (bad_address(table))
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goto bad;
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pr_cont("R1:%016lx ", *table);
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if (*table & _REGION_ENTRY_INVALID)
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goto out;
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table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
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/* fallthrough */
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case _ASCE_TYPE_REGION2:
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table = table + ((address >> 42) & 0x7ff);
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if (bad_address(table))
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goto bad;
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pr_cont("R2:%016lx ", *table);
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if (*table & _REGION_ENTRY_INVALID)
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goto out;
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table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
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/* fallthrough */
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case _ASCE_TYPE_REGION3:
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table = table + ((address >> 31) & 0x7ff);
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if (bad_address(table))
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goto bad;
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pr_cont("R3:%016lx ", *table);
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if (*table & (_REGION_ENTRY_INVALID | _REGION3_ENTRY_LARGE))
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goto out;
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table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
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/* fallthrough */
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case _ASCE_TYPE_SEGMENT:
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table = table + ((address >> 20) & 0x7ff);
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if (bad_address(table))
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goto bad;
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pr_cont("S:%016lx ", *table);
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if (*table & (_SEGMENT_ENTRY_INVALID | _SEGMENT_ENTRY_LARGE))
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goto out;
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table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN);
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}
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table = table + ((address >> 12) & 0xff);
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if (bad_address(table))
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goto bad;
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pr_cont("P:%016lx ", *table);
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out:
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pr_cont("\n");
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return;
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bad:
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pr_cont("BAD\n");
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}
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static void dump_fault_info(struct pt_regs *regs)
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{
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unsigned long asce;
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pr_alert("Failing address: %016lx TEID: %016lx\n",
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regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long);
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pr_alert("Fault in ");
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switch (regs->int_parm_long & 3) {
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case 3:
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pr_cont("home space ");
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break;
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case 2:
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pr_cont("secondary space ");
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break;
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case 1:
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pr_cont("access register ");
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break;
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case 0:
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pr_cont("primary space ");
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break;
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}
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pr_cont("mode while using ");
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if (!user_space_fault(regs)) {
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asce = S390_lowcore.kernel_asce;
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pr_cont("kernel ");
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}
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#ifdef CONFIG_PGSTE
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else if ((current->flags & PF_VCPU) && S390_lowcore.gmap) {
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struct gmap *gmap = (struct gmap *)S390_lowcore.gmap;
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asce = gmap->asce;
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pr_cont("gmap ");
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}
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#endif
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else {
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asce = S390_lowcore.user_asce;
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pr_cont("user ");
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}
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pr_cont("ASCE.\n");
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dump_pagetable(asce, regs->int_parm_long & __FAIL_ADDR_MASK);
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}
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int show_unhandled_signals = 1;
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void report_user_fault(struct pt_regs *regs, long signr, int is_mm_fault)
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{
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if ((task_pid_nr(current) > 1) && !show_unhandled_signals)
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return;
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if (!unhandled_signal(current, signr))
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return;
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if (!printk_ratelimit())
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return;
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printk(KERN_ALERT "User process fault: interruption code %04x ilc:%d ",
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regs->int_code & 0xffff, regs->int_code >> 17);
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print_vma_addr(KERN_CONT "in ", regs->psw.addr);
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printk(KERN_CONT "\n");
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if (is_mm_fault)
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dump_fault_info(regs);
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show_regs(regs);
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}
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/*
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* Send SIGSEGV to task. This is an external routine
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* to keep the stack usage of do_page_fault small.
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*/
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static noinline void do_sigsegv(struct pt_regs *regs, int si_code)
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{
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struct siginfo si;
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report_user_fault(regs, SIGSEGV, 1);
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si.si_signo = SIGSEGV;
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si.si_errno = 0;
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si.si_code = si_code;
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si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK);
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force_sig_info(SIGSEGV, &si, current);
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}
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static noinline void do_no_context(struct pt_regs *regs)
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{
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const struct exception_table_entry *fixup;
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/* Are we prepared to handle this kernel fault? */
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fixup = search_exception_tables(regs->psw.addr);
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if (fixup) {
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regs->psw.addr = extable_fixup(fixup);
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return;
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}
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/*
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* Oops. The kernel tried to access some bad page. We'll have to
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* terminate things with extreme prejudice.
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*/
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if (!user_space_fault(regs))
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printk(KERN_ALERT "Unable to handle kernel pointer dereference"
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" in virtual kernel address space\n");
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else
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printk(KERN_ALERT "Unable to handle kernel paging request"
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" in virtual user address space\n");
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dump_fault_info(regs);
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die(regs, "Oops");
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do_exit(SIGKILL);
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}
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static noinline void do_low_address(struct pt_regs *regs)
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{
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/* Low-address protection hit in kernel mode means
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NULL pointer write access in kernel mode. */
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if (regs->psw.mask & PSW_MASK_PSTATE) {
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/* Low-address protection hit in user mode 'cannot happen'. */
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die (regs, "Low-address protection");
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do_exit(SIGKILL);
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}
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do_no_context(regs);
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}
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static noinline void do_sigbus(struct pt_regs *regs)
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{
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struct task_struct *tsk = current;
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struct siginfo si;
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/*
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* Send a sigbus, regardless of whether we were in kernel
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* or user mode.
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*/
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si.si_signo = SIGBUS;
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si.si_errno = 0;
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si.si_code = BUS_ADRERR;
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si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK);
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force_sig_info(SIGBUS, &si, tsk);
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}
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static noinline int signal_return(struct pt_regs *regs)
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{
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u16 instruction;
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int rc;
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rc = __get_user(instruction, (u16 __user *) regs->psw.addr);
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if (rc)
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return rc;
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if (instruction == 0x0a77) {
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set_pt_regs_flag(regs, PIF_SYSCALL);
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regs->int_code = 0x00040077;
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return 0;
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} else if (instruction == 0x0aad) {
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set_pt_regs_flag(regs, PIF_SYSCALL);
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regs->int_code = 0x000400ad;
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return 0;
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}
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return -EACCES;
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}
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static noinline void do_fault_error(struct pt_regs *regs, int access, int fault)
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{
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int si_code;
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switch (fault) {
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case VM_FAULT_BADACCESS:
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if (access == VM_EXEC && signal_return(regs) == 0)
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break;
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case VM_FAULT_BADMAP:
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/* Bad memory access. Check if it is kernel or user space. */
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if (user_mode(regs)) {
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/* User mode accesses just cause a SIGSEGV */
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si_code = (fault == VM_FAULT_BADMAP) ?
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SEGV_MAPERR : SEGV_ACCERR;
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do_sigsegv(regs, si_code);
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break;
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}
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case VM_FAULT_BADCONTEXT:
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case VM_FAULT_PFAULT:
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do_no_context(regs);
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break;
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case VM_FAULT_SIGNAL:
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if (!user_mode(regs))
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do_no_context(regs);
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break;
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default: /* fault & VM_FAULT_ERROR */
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if (fault & VM_FAULT_OOM) {
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if (!user_mode(regs))
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do_no_context(regs);
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else
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pagefault_out_of_memory();
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} else if (fault & VM_FAULT_SIGSEGV) {
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/* Kernel mode? Handle exceptions or die */
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if (!user_mode(regs))
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do_no_context(regs);
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else
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do_sigsegv(regs, SEGV_MAPERR);
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} else if (fault & VM_FAULT_SIGBUS) {
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/* Kernel mode? Handle exceptions or die */
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if (!user_mode(regs))
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do_no_context(regs);
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else
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do_sigbus(regs);
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} else
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BUG();
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break;
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}
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}
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/*
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* This routine handles page faults. It determines the address,
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* and the problem, and then passes it off to one of the appropriate
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* routines.
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*
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* interruption code (int_code):
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* 04 Protection -> Write-Protection (suprression)
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* 10 Segment translation -> Not present (nullification)
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* 11 Page translation -> Not present (nullification)
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* 3b Region third trans. -> Not present (nullification)
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*/
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static inline int do_exception(struct pt_regs *regs, int access)
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{
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#ifdef CONFIG_PGSTE
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struct gmap *gmap;
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#endif
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struct task_struct *tsk;
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struct mm_struct *mm;
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struct vm_area_struct *vma;
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unsigned long trans_exc_code;
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unsigned long address;
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unsigned int flags;
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int fault;
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tsk = current;
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/*
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* The instruction that caused the program check has
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* been nullified. Don't signal single step via SIGTRAP.
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*/
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clear_pt_regs_flag(regs, PIF_PER_TRAP);
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if (notify_page_fault(regs))
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return 0;
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mm = tsk->mm;
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trans_exc_code = regs->int_parm_long;
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/*
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* Verify that the fault happened in user space, that
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* we are not in an interrupt and that there is a
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* user context.
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*/
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fault = VM_FAULT_BADCONTEXT;
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if (unlikely(!user_space_fault(regs) || faulthandler_disabled() || !mm))
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goto out;
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address = trans_exc_code & __FAIL_ADDR_MASK;
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perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
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flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
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if (user_mode(regs))
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flags |= FAULT_FLAG_USER;
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if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400)
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flags |= FAULT_FLAG_WRITE;
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down_read(&mm->mmap_sem);
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#ifdef CONFIG_PGSTE
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gmap = (current->flags & PF_VCPU) ?
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(struct gmap *) S390_lowcore.gmap : NULL;
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if (gmap) {
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current->thread.gmap_addr = address;
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current->thread.gmap_write_flag = !!(flags & FAULT_FLAG_WRITE);
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current->thread.gmap_int_code = regs->int_code & 0xffff;
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address = __gmap_translate(gmap, address);
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if (address == -EFAULT) {
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fault = VM_FAULT_BADMAP;
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goto out_up;
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}
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if (gmap->pfault_enabled)
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flags |= FAULT_FLAG_RETRY_NOWAIT;
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}
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#endif
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retry:
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fault = VM_FAULT_BADMAP;
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vma = find_vma(mm, address);
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if (!vma)
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goto out_up;
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if (unlikely(vma->vm_start > address)) {
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if (!(vma->vm_flags & VM_GROWSDOWN))
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goto out_up;
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if (expand_stack(vma, address))
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goto out_up;
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}
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/*
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* Ok, we have a good vm_area for this memory access, so
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* we can handle it..
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*/
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fault = VM_FAULT_BADACCESS;
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if (unlikely(!(vma->vm_flags & access)))
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goto out_up;
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if (is_vm_hugetlb_page(vma))
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address &= HPAGE_MASK;
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/*
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* If for any reason at all we couldn't handle the fault,
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* make sure we exit gracefully rather than endlessly redo
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* the fault.
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*/
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fault = handle_mm_fault(vma, address, flags);
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/* No reason to continue if interrupted by SIGKILL. */
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if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) {
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fault = VM_FAULT_SIGNAL;
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goto out;
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}
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if (unlikely(fault & VM_FAULT_ERROR))
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goto out_up;
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/*
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* Major/minor page fault accounting is only done on the
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* initial attempt. If we go through a retry, it is extremely
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* likely that the page will be found in page cache at that point.
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*/
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if (flags & FAULT_FLAG_ALLOW_RETRY) {
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if (fault & VM_FAULT_MAJOR) {
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tsk->maj_flt++;
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perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
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regs, address);
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} else {
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tsk->min_flt++;
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perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
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regs, address);
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}
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if (fault & VM_FAULT_RETRY) {
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#ifdef CONFIG_PGSTE
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if (gmap && (flags & FAULT_FLAG_RETRY_NOWAIT)) {
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/* FAULT_FLAG_RETRY_NOWAIT has been set,
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* mmap_sem has not been released */
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current->thread.gmap_pfault = 1;
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fault = VM_FAULT_PFAULT;
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goto out_up;
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}
|
|
#endif
|
|
/* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk
|
|
* of starvation. */
|
|
flags &= ~(FAULT_FLAG_ALLOW_RETRY |
|
|
FAULT_FLAG_RETRY_NOWAIT);
|
|
flags |= FAULT_FLAG_TRIED;
|
|
down_read(&mm->mmap_sem);
|
|
goto retry;
|
|
}
|
|
}
|
|
#ifdef CONFIG_PGSTE
|
|
if (gmap) {
|
|
address = __gmap_link(gmap, current->thread.gmap_addr,
|
|
address);
|
|
if (address == -EFAULT) {
|
|
fault = VM_FAULT_BADMAP;
|
|
goto out_up;
|
|
}
|
|
if (address == -ENOMEM) {
|
|
fault = VM_FAULT_OOM;
|
|
goto out_up;
|
|
}
|
|
}
|
|
#endif
|
|
fault = 0;
|
|
out_up:
|
|
up_read(&mm->mmap_sem);
|
|
out:
|
|
return fault;
|
|
}
|
|
|
|
void do_protection_exception(struct pt_regs *regs)
|
|
{
|
|
unsigned long trans_exc_code;
|
|
int access, fault;
|
|
|
|
trans_exc_code = regs->int_parm_long;
|
|
/*
|
|
* Protection exceptions are suppressing, decrement psw address.
|
|
* The exception to this rule are aborted transactions, for these
|
|
* the PSW already points to the correct location.
|
|
*/
|
|
if (!(regs->int_code & 0x200))
|
|
regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16);
|
|
/*
|
|
* Check for low-address protection. This needs to be treated
|
|
* as a special case because the translation exception code
|
|
* field is not guaranteed to contain valid data in this case.
|
|
*/
|
|
if (unlikely(!(trans_exc_code & 4))) {
|
|
do_low_address(regs);
|
|
return;
|
|
}
|
|
if (unlikely(MACHINE_HAS_NX && (trans_exc_code & 0x80))) {
|
|
regs->int_parm_long = (trans_exc_code & ~PAGE_MASK) |
|
|
(regs->psw.addr & PAGE_MASK);
|
|
access = VM_EXEC;
|
|
fault = VM_FAULT_BADACCESS;
|
|
} else {
|
|
access = VM_WRITE;
|
|
fault = do_exception(regs, access);
|
|
}
|
|
if (unlikely(fault))
|
|
do_fault_error(regs, access, fault);
|
|
}
|
|
NOKPROBE_SYMBOL(do_protection_exception);
|
|
|
|
void do_dat_exception(struct pt_regs *regs)
|
|
{
|
|
int access, fault;
|
|
|
|
access = VM_READ | VM_EXEC | VM_WRITE;
|
|
fault = do_exception(regs, access);
|
|
if (unlikely(fault))
|
|
do_fault_error(regs, access, fault);
|
|
}
|
|
NOKPROBE_SYMBOL(do_dat_exception);
|
|
|
|
#ifdef CONFIG_PFAULT
|
|
/*
|
|
* 'pfault' pseudo page faults routines.
|
|
*/
|
|
static int pfault_disable;
|
|
|
|
static int __init nopfault(char *str)
|
|
{
|
|
pfault_disable = 1;
|
|
return 1;
|
|
}
|
|
|
|
__setup("nopfault", nopfault);
|
|
|
|
struct pfault_refbk {
|
|
u16 refdiagc;
|
|
u16 reffcode;
|
|
u16 refdwlen;
|
|
u16 refversn;
|
|
u64 refgaddr;
|
|
u64 refselmk;
|
|
u64 refcmpmk;
|
|
u64 reserved;
|
|
} __attribute__ ((packed, aligned(8)));
|
|
|
|
int pfault_init(void)
|
|
{
|
|
struct pfault_refbk refbk = {
|
|
.refdiagc = 0x258,
|
|
.reffcode = 0,
|
|
.refdwlen = 5,
|
|
.refversn = 2,
|
|
.refgaddr = __LC_LPP,
|
|
.refselmk = 1ULL << 48,
|
|
.refcmpmk = 1ULL << 48,
|
|
.reserved = __PF_RES_FIELD };
|
|
int rc;
|
|
|
|
if (pfault_disable)
|
|
return -1;
|
|
diag_stat_inc(DIAG_STAT_X258);
|
|
asm volatile(
|
|
" diag %1,%0,0x258\n"
|
|
"0: j 2f\n"
|
|
"1: la %0,8\n"
|
|
"2:\n"
|
|
EX_TABLE(0b,1b)
|
|
: "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc");
|
|
return rc;
|
|
}
|
|
|
|
void pfault_fini(void)
|
|
{
|
|
struct pfault_refbk refbk = {
|
|
.refdiagc = 0x258,
|
|
.reffcode = 1,
|
|
.refdwlen = 5,
|
|
.refversn = 2,
|
|
};
|
|
|
|
if (pfault_disable)
|
|
return;
|
|
diag_stat_inc(DIAG_STAT_X258);
|
|
asm volatile(
|
|
" diag %0,0,0x258\n"
|
|
"0: nopr %%r7\n"
|
|
EX_TABLE(0b,0b)
|
|
: : "a" (&refbk), "m" (refbk) : "cc");
|
|
}
|
|
|
|
static DEFINE_SPINLOCK(pfault_lock);
|
|
static LIST_HEAD(pfault_list);
|
|
|
|
#define PF_COMPLETE 0x0080
|
|
|
|
/*
|
|
* The mechanism of our pfault code: if Linux is running as guest, runs a user
|
|
* space process and the user space process accesses a page that the host has
|
|
* paged out we get a pfault interrupt.
|
|
*
|
|
* This allows us, within the guest, to schedule a different process. Without
|
|
* this mechanism the host would have to suspend the whole virtual cpu until
|
|
* the page has been paged in.
|
|
*
|
|
* So when we get such an interrupt then we set the state of the current task
|
|
* to uninterruptible and also set the need_resched flag. Both happens within
|
|
* interrupt context(!). If we later on want to return to user space we
|
|
* recognize the need_resched flag and then call schedule(). It's not very
|
|
* obvious how this works...
|
|
*
|
|
* Of course we have a lot of additional fun with the completion interrupt (->
|
|
* host signals that a page of a process has been paged in and the process can
|
|
* continue to run). This interrupt can arrive on any cpu and, since we have
|
|
* virtual cpus, actually appear before the interrupt that signals that a page
|
|
* is missing.
|
|
*/
|
|
static void pfault_interrupt(struct ext_code ext_code,
|
|
unsigned int param32, unsigned long param64)
|
|
{
|
|
struct task_struct *tsk;
|
|
__u16 subcode;
|
|
pid_t pid;
|
|
|
|
/*
|
|
* Get the external interruption subcode & pfault initial/completion
|
|
* signal bit. VM stores this in the 'cpu address' field associated
|
|
* with the external interrupt.
|
|
*/
|
|
subcode = ext_code.subcode;
|
|
if ((subcode & 0xff00) != __SUBCODE_MASK)
|
|
return;
|
|
inc_irq_stat(IRQEXT_PFL);
|
|
/* Get the token (= pid of the affected task). */
|
|
pid = param64 & LPP_PFAULT_PID_MASK;
|
|
rcu_read_lock();
|
|
tsk = find_task_by_pid_ns(pid, &init_pid_ns);
|
|
if (tsk)
|
|
get_task_struct(tsk);
|
|
rcu_read_unlock();
|
|
if (!tsk)
|
|
return;
|
|
spin_lock(&pfault_lock);
|
|
if (subcode & PF_COMPLETE) {
|
|
/* signal bit is set -> a page has been swapped in by VM */
|
|
if (tsk->thread.pfault_wait == 1) {
|
|
/* Initial interrupt was faster than the completion
|
|
* interrupt. pfault_wait is valid. Set pfault_wait
|
|
* back to zero and wake up the process. This can
|
|
* safely be done because the task is still sleeping
|
|
* and can't produce new pfaults. */
|
|
tsk->thread.pfault_wait = 0;
|
|
list_del(&tsk->thread.list);
|
|
wake_up_process(tsk);
|
|
put_task_struct(tsk);
|
|
} else {
|
|
/* Completion interrupt was faster than initial
|
|
* interrupt. Set pfault_wait to -1 so the initial
|
|
* interrupt doesn't put the task to sleep.
|
|
* If the task is not running, ignore the completion
|
|
* interrupt since it must be a leftover of a PFAULT
|
|
* CANCEL operation which didn't remove all pending
|
|
* completion interrupts. */
|
|
if (tsk->state == TASK_RUNNING)
|
|
tsk->thread.pfault_wait = -1;
|
|
}
|
|
} else {
|
|
/* signal bit not set -> a real page is missing. */
|
|
if (WARN_ON_ONCE(tsk != current))
|
|
goto out;
|
|
if (tsk->thread.pfault_wait == 1) {
|
|
/* Already on the list with a reference: put to sleep */
|
|
goto block;
|
|
} else if (tsk->thread.pfault_wait == -1) {
|
|
/* Completion interrupt was faster than the initial
|
|
* interrupt (pfault_wait == -1). Set pfault_wait
|
|
* back to zero and exit. */
|
|
tsk->thread.pfault_wait = 0;
|
|
} else {
|
|
/* Initial interrupt arrived before completion
|
|
* interrupt. Let the task sleep.
|
|
* An extra task reference is needed since a different
|
|
* cpu may set the task state to TASK_RUNNING again
|
|
* before the scheduler is reached. */
|
|
get_task_struct(tsk);
|
|
tsk->thread.pfault_wait = 1;
|
|
list_add(&tsk->thread.list, &pfault_list);
|
|
block:
|
|
/* Since this must be a userspace fault, there
|
|
* is no kernel task state to trample. Rely on the
|
|
* return to userspace schedule() to block. */
|
|
__set_current_state(TASK_UNINTERRUPTIBLE);
|
|
set_tsk_need_resched(tsk);
|
|
set_preempt_need_resched();
|
|
}
|
|
}
|
|
out:
|
|
spin_unlock(&pfault_lock);
|
|
put_task_struct(tsk);
|
|
}
|
|
|
|
static int pfault_cpu_dead(unsigned int cpu)
|
|
{
|
|
struct thread_struct *thread, *next;
|
|
struct task_struct *tsk;
|
|
|
|
spin_lock_irq(&pfault_lock);
|
|
list_for_each_entry_safe(thread, next, &pfault_list, list) {
|
|
thread->pfault_wait = 0;
|
|
list_del(&thread->list);
|
|
tsk = container_of(thread, struct task_struct, thread);
|
|
wake_up_process(tsk);
|
|
put_task_struct(tsk);
|
|
}
|
|
spin_unlock_irq(&pfault_lock);
|
|
return 0;
|
|
}
|
|
|
|
static int __init pfault_irq_init(void)
|
|
{
|
|
int rc;
|
|
|
|
rc = register_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt);
|
|
if (rc)
|
|
goto out_extint;
|
|
rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP;
|
|
if (rc)
|
|
goto out_pfault;
|
|
irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
|
|
cpuhp_setup_state_nocalls(CPUHP_S390_PFAULT_DEAD, "s390/pfault:dead",
|
|
NULL, pfault_cpu_dead);
|
|
return 0;
|
|
|
|
out_pfault:
|
|
unregister_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt);
|
|
out_extint:
|
|
pfault_disable = 1;
|
|
return rc;
|
|
}
|
|
early_initcall(pfault_irq_init);
|
|
|
|
#endif /* CONFIG_PFAULT */
|