1b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0 21da177e4SLinus Torvalds /* 31da177e4SLinus Torvalds * S390 version 4a53c8fabSHeiko Carstens * Copyright IBM Corp. 1999 51da177e4SLinus Torvalds * Author(s): Hartmut Penner (hp@de.ibm.com) 61da177e4SLinus Torvalds * Ulrich Weigand (uweigand@de.ibm.com) 71da177e4SLinus Torvalds * 81da177e4SLinus Torvalds * Derived from "arch/i386/mm/fault.c" 91da177e4SLinus Torvalds * Copyright (C) 1995 Linus Torvalds 101da177e4SLinus Torvalds */ 111da177e4SLinus Torvalds 12052ff461SHeiko Carstens #include <linux/kernel_stat.h> 13cdd6c482SIngo Molnar #include <linux/perf_event.h> 141da177e4SLinus Torvalds #include <linux/signal.h> 151da177e4SLinus Torvalds #include <linux/sched.h> 16b17b0153SIngo Molnar #include <linux/sched/debug.h> 171da177e4SLinus Torvalds #include <linux/kernel.h> 181da177e4SLinus Torvalds #include <linux/errno.h> 191da177e4SLinus Torvalds #include <linux/string.h> 201da177e4SLinus Torvalds #include <linux/types.h> 211da177e4SLinus Torvalds #include <linux/ptrace.h> 221da177e4SLinus Torvalds #include <linux/mman.h> 231da177e4SLinus Torvalds #include <linux/mm.h> 247757591aSHeiko Carstens #include <linux/compat.h> 251da177e4SLinus Torvalds #include <linux/smp.h> 261eeb66a1SChristoph Hellwig #include <linux/kdebug.h> 271da177e4SLinus Torvalds #include <linux/init.h> 281da177e4SLinus Torvalds #include <linux/console.h> 29dcc096c5SPaul Gortmaker #include <linux/extable.h> 301da177e4SLinus Torvalds #include <linux/hardirq.h> 314ba069b8SMichael Grundy #include <linux/kprobes.h> 32be5ec363SMartin Schwidefsky #include <linux/uaccess.h> 3353492b1dSGerald Schaefer #include <linux/hugetlb.h> 34e41ba111SSven Schnelle #include <linux/kfence.h> 35d09a307fSHeiko Carstens #include <asm/asm-extable.h> 36cbb870c8SHeiko Carstens #include <asm/asm-offsets.h> 371ec2772eSMartin Schwidefsky #include <asm/diag.h> 381e133ab2SMartin Schwidefsky #include <asm/gmap.h> 39d7b250e2SHeiko Carstens #include <asm/irq.h> 406252d702SMartin Schwidefsky #include <asm/mmu_context.h> 41a0616cdeSDavid Howells #include <asm/facility.h> 42084ea4d6SVasily Gorbik #include <asm/uv.h> 43a806170eSHeiko Carstens #include "../kernel/entry.h" 441da177e4SLinus Torvalds 451da177e4SLinus Torvalds #define __FAIL_ADDR_MASK -4096L 461da177e4SLinus Torvalds #define __SUBCODE_MASK 0x0600 471da177e4SLinus Torvalds #define __PF_RES_FIELD 0x8000000000000000ULL 481da177e4SLinus Torvalds 4912437759SChristian Borntraeger #define VM_FAULT_BADCONTEXT ((__force vm_fault_t) 0x010000) 5012437759SChristian Borntraeger #define VM_FAULT_BADMAP ((__force vm_fault_t) 0x020000) 5112437759SChristian Borntraeger #define VM_FAULT_BADACCESS ((__force vm_fault_t) 0x040000) 5212437759SChristian Borntraeger #define VM_FAULT_SIGNAL ((__force vm_fault_t) 0x080000) 5312437759SChristian Borntraeger #define VM_FAULT_PFAULT ((__force vm_fault_t) 0x100000) 5450d7280dSMartin Schwidefsky 550aaba41bSMartin Schwidefsky enum fault_type { 560aaba41bSMartin Schwidefsky KERNEL_FAULT, 570aaba41bSMartin Schwidefsky USER_FAULT, 580aaba41bSMartin Schwidefsky GMAP_FAULT, 590aaba41bSMartin Schwidefsky }; 600aaba41bSMartin Schwidefsky 61a4f32bdbSHeiko Carstens static unsigned long store_indication __read_mostly; 6292f842eaSMartin Schwidefsky 63a4f32bdbSHeiko Carstens static int __init fault_init(void) 6492f842eaSMartin Schwidefsky { 65a4f32bdbSHeiko Carstens if (test_facility(75)) 6692f842eaSMartin Schwidefsky store_indication = 0xc00; 67a4f32bdbSHeiko Carstens return 0; 6892f842eaSMartin Schwidefsky } 69a4f32bdbSHeiko Carstens early_initcall(fault_init); 7092f842eaSMartin Schwidefsky 711da177e4SLinus Torvalds /* 720aaba41bSMartin Schwidefsky * Find out which address space caused the exception. 731da177e4SLinus Torvalds */ 74bf2f1eeeSMasahiro Yamada static enum fault_type get_fault_type(struct pt_regs *regs) 751da177e4SLinus Torvalds { 76457f2180SHeiko Carstens unsigned long trans_exc_code; 77457f2180SHeiko Carstens 78457f2180SHeiko Carstens trans_exc_code = regs->int_parm_long & 3; 790aaba41bSMartin Schwidefsky if (likely(trans_exc_code == 0)) { 800aaba41bSMartin Schwidefsky /* primary space exception */ 8187d59863SHeiko Carstens if (user_mode(regs)) 8287d59863SHeiko Carstens return USER_FAULT; 8387d59863SHeiko Carstens if (!IS_ENABLED(CONFIG_PGSTE)) 8487d59863SHeiko Carstens return KERNEL_FAULT; 8587d59863SHeiko Carstens if (test_pt_regs_flag(regs, PIF_GUEST_FAULT)) 860aaba41bSMartin Schwidefsky return GMAP_FAULT; 870aaba41bSMartin Schwidefsky return KERNEL_FAULT; 880aaba41bSMartin Schwidefsky } 8987d59863SHeiko Carstens if (trans_exc_code == 2) 900aaba41bSMartin Schwidefsky return USER_FAULT; 91962f0af8SGerald Schaefer if (trans_exc_code == 1) { 92962f0af8SGerald Schaefer /* access register mode, not used in the kernel */ 93962f0af8SGerald Schaefer return USER_FAULT; 94962f0af8SGerald Schaefer } 950aaba41bSMartin Schwidefsky /* home space exception -> access via kernel ASCE */ 960aaba41bSMartin Schwidefsky return KERNEL_FAULT; 971da177e4SLinus Torvalds } 981da177e4SLinus Torvalds 993b7df342SHeiko Carstens static int bad_address(void *p) 1003b7df342SHeiko Carstens { 1013b7df342SHeiko Carstens unsigned long dummy; 1023b7df342SHeiko Carstens 10325f12ae4SChristoph Hellwig return get_kernel_nofault(dummy, (unsigned long *)p); 1043b7df342SHeiko Carstens } 1053b7df342SHeiko Carstens 1063b7df342SHeiko Carstens static void dump_pagetable(unsigned long asce, unsigned long address) 1073b7df342SHeiko Carstens { 108fe7b2747SHeiko Carstens unsigned long *table = __va(asce & _ASCE_ORIGIN); 1093b7df342SHeiko Carstens 1103b7df342SHeiko Carstens pr_alert("AS:%016lx ", asce); 1113b7df342SHeiko Carstens switch (asce & _ASCE_TYPE_MASK) { 1123b7df342SHeiko Carstens case _ASCE_TYPE_REGION1: 113f1c1174fSHeiko Carstens table += (address & _REGION1_INDEX) >> _REGION1_SHIFT; 1143b7df342SHeiko Carstens if (bad_address(table)) 1153b7df342SHeiko Carstens goto bad; 1163b7df342SHeiko Carstens pr_cont("R1:%016lx ", *table); 1173b7df342SHeiko Carstens if (*table & _REGION_ENTRY_INVALID) 1183b7df342SHeiko Carstens goto out; 119d2f2949aSHeiko Carstens table = __va(*table & _REGION_ENTRY_ORIGIN); 1202c7749b9SJoe Perches fallthrough; 1213b7df342SHeiko Carstens case _ASCE_TYPE_REGION2: 122f1c1174fSHeiko Carstens table += (address & _REGION2_INDEX) >> _REGION2_SHIFT; 1233b7df342SHeiko Carstens if (bad_address(table)) 1243b7df342SHeiko Carstens goto bad; 1253b7df342SHeiko Carstens pr_cont("R2:%016lx ", *table); 1263b7df342SHeiko Carstens if (*table & _REGION_ENTRY_INVALID) 1273b7df342SHeiko Carstens goto out; 128d2f2949aSHeiko Carstens table = __va(*table & _REGION_ENTRY_ORIGIN); 1292c7749b9SJoe Perches fallthrough; 1303b7df342SHeiko Carstens case _ASCE_TYPE_REGION3: 131f1c1174fSHeiko Carstens table += (address & _REGION3_INDEX) >> _REGION3_SHIFT; 1323b7df342SHeiko Carstens if (bad_address(table)) 1333b7df342SHeiko Carstens goto bad; 1343b7df342SHeiko Carstens pr_cont("R3:%016lx ", *table); 1353b7df342SHeiko Carstens if (*table & (_REGION_ENTRY_INVALID | _REGION3_ENTRY_LARGE)) 1363b7df342SHeiko Carstens goto out; 137d2f2949aSHeiko Carstens table = __va(*table & _REGION_ENTRY_ORIGIN); 1382c7749b9SJoe Perches fallthrough; 1393b7df342SHeiko Carstens case _ASCE_TYPE_SEGMENT: 140f1c1174fSHeiko Carstens table += (address & _SEGMENT_INDEX) >> _SEGMENT_SHIFT; 1413b7df342SHeiko Carstens if (bad_address(table)) 1423b7df342SHeiko Carstens goto bad; 14391c0837eSJoe Perches pr_cont("S:%016lx ", *table); 1443b7df342SHeiko Carstens if (*table & (_SEGMENT_ENTRY_INVALID | _SEGMENT_ENTRY_LARGE)) 1453b7df342SHeiko Carstens goto out; 146d2f2949aSHeiko Carstens table = __va(*table & _SEGMENT_ENTRY_ORIGIN); 1473b7df342SHeiko Carstens } 148f1c1174fSHeiko Carstens table += (address & _PAGE_INDEX) >> _PAGE_SHIFT; 1493b7df342SHeiko Carstens if (bad_address(table)) 1503b7df342SHeiko Carstens goto bad; 1513b7df342SHeiko Carstens pr_cont("P:%016lx ", *table); 1523b7df342SHeiko Carstens out: 1533b7df342SHeiko Carstens pr_cont("\n"); 1543b7df342SHeiko Carstens return; 1553b7df342SHeiko Carstens bad: 1563b7df342SHeiko Carstens pr_cont("BAD\n"); 1573b7df342SHeiko Carstens } 1583b7df342SHeiko Carstens 1593b7df342SHeiko Carstens static void dump_fault_info(struct pt_regs *regs) 1603b7df342SHeiko Carstens { 1613b7df342SHeiko Carstens unsigned long asce; 1623b7df342SHeiko Carstens 1635d7eccecSHeiko Carstens pr_alert("Failing address: %016lx TEID: %016lx\n", 1645d7eccecSHeiko Carstens regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long); 1653b7df342SHeiko Carstens pr_alert("Fault in "); 1663b7df342SHeiko Carstens switch (regs->int_parm_long & 3) { 1673b7df342SHeiko Carstens case 3: 1683b7df342SHeiko Carstens pr_cont("home space "); 1693b7df342SHeiko Carstens break; 1703b7df342SHeiko Carstens case 2: 1713b7df342SHeiko Carstens pr_cont("secondary space "); 1723b7df342SHeiko Carstens break; 1733b7df342SHeiko Carstens case 1: 1743b7df342SHeiko Carstens pr_cont("access register "); 1753b7df342SHeiko Carstens break; 1763b7df342SHeiko Carstens case 0: 1773b7df342SHeiko Carstens pr_cont("primary space "); 1783b7df342SHeiko Carstens break; 1793b7df342SHeiko Carstens } 1803b7df342SHeiko Carstens pr_cont("mode while using "); 1810aaba41bSMartin Schwidefsky switch (get_fault_type(regs)) { 1820aaba41bSMartin Schwidefsky case USER_FAULT: 1833b7df342SHeiko Carstens asce = S390_lowcore.user_asce; 1843b7df342SHeiko Carstens pr_cont("user "); 1850aaba41bSMartin Schwidefsky break; 1860aaba41bSMartin Schwidefsky case GMAP_FAULT: 1870aaba41bSMartin Schwidefsky asce = ((struct gmap *) S390_lowcore.gmap)->asce; 1880aaba41bSMartin Schwidefsky pr_cont("gmap "); 1890aaba41bSMartin Schwidefsky break; 1900aaba41bSMartin Schwidefsky case KERNEL_FAULT: 1910aaba41bSMartin Schwidefsky asce = S390_lowcore.kernel_asce; 1920aaba41bSMartin Schwidefsky pr_cont("kernel "); 1930aaba41bSMartin Schwidefsky break; 194bf2f1eeeSMasahiro Yamada default: 195bf2f1eeeSMasahiro Yamada unreachable(); 1963b7df342SHeiko Carstens } 1973b7df342SHeiko Carstens pr_cont("ASCE.\n"); 1983b7df342SHeiko Carstens dump_pagetable(asce, regs->int_parm_long & __FAIL_ADDR_MASK); 1993b7df342SHeiko Carstens } 2003b7df342SHeiko Carstens 2015d7eccecSHeiko Carstens int show_unhandled_signals = 1; 2025d7eccecSHeiko Carstens 2035d7eccecSHeiko Carstens void report_user_fault(struct pt_regs *regs, long signr, int is_mm_fault) 204ab3c68eeSHeiko Carstens { 205ab3c68eeSHeiko Carstens if ((task_pid_nr(current) > 1) && !show_unhandled_signals) 206ab3c68eeSHeiko Carstens return; 207ab3c68eeSHeiko Carstens if (!unhandled_signal(current, signr)) 208ab3c68eeSHeiko Carstens return; 209ab3c68eeSHeiko Carstens if (!printk_ratelimit()) 210ab3c68eeSHeiko Carstens return; 211413d4047SHeiko Carstens printk(KERN_ALERT "User process fault: interruption code %04x ilc:%d ", 212413d4047SHeiko Carstens regs->int_code & 0xffff, regs->int_code >> 17); 2139cb1ccecSHeiko Carstens print_vma_addr(KERN_CONT "in ", regs->psw.addr); 214aa33c8cbSMartin Schwidefsky printk(KERN_CONT "\n"); 2155d7eccecSHeiko Carstens if (is_mm_fault) 2163b7df342SHeiko Carstens dump_fault_info(regs); 217ab3c68eeSHeiko Carstens show_regs(regs); 218ab3c68eeSHeiko Carstens } 219ab3c68eeSHeiko Carstens 2201da177e4SLinus Torvalds /* 2211da177e4SLinus Torvalds * Send SIGSEGV to task. This is an external routine 2221da177e4SLinus Torvalds * to keep the stack usage of do_page_fault small. 2231da177e4SLinus Torvalds */ 224aa33c8cbSMartin Schwidefsky static noinline void do_sigsegv(struct pt_regs *regs, int si_code) 2251da177e4SLinus Torvalds { 2265d7eccecSHeiko Carstens report_user_fault(regs, SIGSEGV, 1); 2279507a5d0SEric W. Biederman force_sig_fault(SIGSEGV, si_code, 2282e1661d2SEric W. Biederman (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK)); 2291da177e4SLinus Torvalds } 2301da177e4SLinus Torvalds 231aa33c8cbSMartin Schwidefsky static noinline void do_no_context(struct pt_regs *regs) 23210c1031fSMartin Schwidefsky { 23346fee16fSHeiko Carstens if (fixup_exception(regs)) 23410c1031fSMartin Schwidefsky return; 23510c1031fSMartin Schwidefsky /* 23610c1031fSMartin Schwidefsky * Oops. The kernel tried to access some bad page. We'll have to 23710c1031fSMartin Schwidefsky * terminate things with extreme prejudice. 23810c1031fSMartin Schwidefsky */ 2390aaba41bSMartin Schwidefsky if (get_fault_type(regs) == KERNEL_FAULT) 24010c1031fSMartin Schwidefsky printk(KERN_ALERT "Unable to handle kernel pointer dereference" 2413b7df342SHeiko Carstens " in virtual kernel address space\n"); 24210c1031fSMartin Schwidefsky else 24310c1031fSMartin Schwidefsky printk(KERN_ALERT "Unable to handle kernel paging request" 2443b7df342SHeiko Carstens " in virtual user address space\n"); 2453b7df342SHeiko Carstens dump_fault_info(regs); 246aa33c8cbSMartin Schwidefsky die(regs, "Oops"); 24710c1031fSMartin Schwidefsky } 24810c1031fSMartin Schwidefsky 249aa33c8cbSMartin Schwidefsky static noinline void do_low_address(struct pt_regs *regs) 25010c1031fSMartin Schwidefsky { 25110c1031fSMartin Schwidefsky /* Low-address protection hit in kernel mode means 25210c1031fSMartin Schwidefsky NULL pointer write access in kernel mode. */ 25310c1031fSMartin Schwidefsky if (regs->psw.mask & PSW_MASK_PSTATE) { 25410c1031fSMartin Schwidefsky /* Low-address protection hit in user mode 'cannot happen'. */ 255aa33c8cbSMartin Schwidefsky die (regs, "Low-address protection"); 25610c1031fSMartin Schwidefsky } 25710c1031fSMartin Schwidefsky 258aa33c8cbSMartin Schwidefsky do_no_context(regs); 25910c1031fSMartin Schwidefsky } 26010c1031fSMartin Schwidefsky 261aa33c8cbSMartin Schwidefsky static noinline void do_sigbus(struct pt_regs *regs) 26210c1031fSMartin Schwidefsky { 26310c1031fSMartin Schwidefsky /* 26410c1031fSMartin Schwidefsky * Send a sigbus, regardless of whether we were in kernel 26510c1031fSMartin Schwidefsky * or user mode. 26610c1031fSMartin Schwidefsky */ 2679507a5d0SEric W. Biederman force_sig_fault(SIGBUS, BUS_ADRERR, 2682e1661d2SEric W. Biederman (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK)); 26910c1031fSMartin Schwidefsky } 27010c1031fSMartin Schwidefsky 27150a7ca3cSSouptick Joarder static noinline void do_fault_error(struct pt_regs *regs, int access, 27250a7ca3cSSouptick Joarder vm_fault_t fault) 27350d7280dSMartin Schwidefsky { 27450d7280dSMartin Schwidefsky int si_code; 27550d7280dSMartin Schwidefsky 27650d7280dSMartin Schwidefsky switch (fault) { 27750d7280dSMartin Schwidefsky case VM_FAULT_BADACCESS: 27850d7280dSMartin Schwidefsky case VM_FAULT_BADMAP: 27950d7280dSMartin Schwidefsky /* Bad memory access. Check if it is kernel or user space. */ 2807d256175SHeiko Carstens if (user_mode(regs)) { 28150d7280dSMartin Schwidefsky /* User mode accesses just cause a SIGSEGV */ 28250d7280dSMartin Schwidefsky si_code = (fault == VM_FAULT_BADMAP) ? 28350d7280dSMartin Schwidefsky SEGV_MAPERR : SEGV_ACCERR; 284aa33c8cbSMartin Schwidefsky do_sigsegv(regs, si_code); 28557d7f939SMartin Schwidefsky break; 28650d7280dSMartin Schwidefsky } 2872c7749b9SJoe Perches fallthrough; 28850d7280dSMartin Schwidefsky case VM_FAULT_BADCONTEXT: 28924eb3a82SDominik Dingel case VM_FAULT_PFAULT: 290aa33c8cbSMartin Schwidefsky do_no_context(regs); 29150d7280dSMartin Schwidefsky break; 292f2c76e3bSHeiko Carstens case VM_FAULT_SIGNAL: 293f2c76e3bSHeiko Carstens if (!user_mode(regs)) 294f2c76e3bSHeiko Carstens do_no_context(regs); 295f2c76e3bSHeiko Carstens break; 29650d7280dSMartin Schwidefsky default: /* fault & VM_FAULT_ERROR */ 29799583181SHeiko Carstens if (fault & VM_FAULT_OOM) { 2987d256175SHeiko Carstens if (!user_mode(regs)) 299aa33c8cbSMartin Schwidefsky do_no_context(regs); 30099583181SHeiko Carstens else 30150d7280dSMartin Schwidefsky pagefault_out_of_memory(); 30233692f27SLinus Torvalds } else if (fault & VM_FAULT_SIGSEGV) { 30333692f27SLinus Torvalds /* Kernel mode? Handle exceptions or die */ 30433692f27SLinus Torvalds if (!user_mode(regs)) 30533692f27SLinus Torvalds do_no_context(regs); 30633692f27SLinus Torvalds else 30733692f27SLinus Torvalds do_sigsegv(regs, SEGV_MAPERR); 30899583181SHeiko Carstens } else if (fault & VM_FAULT_SIGBUS) { 30950d7280dSMartin Schwidefsky /* Kernel mode? Handle exceptions or die */ 3107d256175SHeiko Carstens if (!user_mode(regs)) 311aa33c8cbSMartin Schwidefsky do_no_context(regs); 31236bf9680SMartin Schwidefsky else 313aa33c8cbSMartin Schwidefsky do_sigbus(regs); 31450d7280dSMartin Schwidefsky } else 31550d7280dSMartin Schwidefsky BUG(); 31650d7280dSMartin Schwidefsky break; 31750d7280dSMartin Schwidefsky } 31850d7280dSMartin Schwidefsky } 31950d7280dSMartin Schwidefsky 3201da177e4SLinus Torvalds /* 3211da177e4SLinus Torvalds * This routine handles page faults. It determines the address, 3221da177e4SLinus Torvalds * and the problem, and then passes it off to one of the appropriate 3231da177e4SLinus Torvalds * routines. 3241da177e4SLinus Torvalds * 32550d7280dSMartin Schwidefsky * interruption code (int_code): 3267904aaa8SHeiko Carstens * 04 Protection -> Write-Protection (suppression) 3271da177e4SLinus Torvalds * 10 Segment translation -> Not present (nullification) 3281da177e4SLinus Torvalds * 11 Page translation -> Not present (nullification) 3291da177e4SLinus Torvalds * 3b Region third trans. -> Not present (nullification) 3301da177e4SLinus Torvalds */ 33150a7ca3cSSouptick Joarder static inline vm_fault_t do_exception(struct pt_regs *regs, int access) 3321da177e4SLinus Torvalds { 33324eb3a82SDominik Dingel struct gmap *gmap; 3341da177e4SLinus Torvalds struct task_struct *tsk; 3351da177e4SLinus Torvalds struct mm_struct *mm; 3361da177e4SLinus Torvalds struct vm_area_struct *vma; 3370aaba41bSMartin Schwidefsky enum fault_type type; 338aa33c8cbSMartin Schwidefsky unsigned long trans_exc_code; 3391da177e4SLinus Torvalds unsigned long address; 34033ce6140SHeiko Carstens unsigned int flags; 34150a7ca3cSSouptick Joarder vm_fault_t fault; 342e41ba111SSven Schnelle bool is_write; 34310c1031fSMartin Schwidefsky 34439efd4ecSMartin Schwidefsky tsk = current; 34539efd4ecSMartin Schwidefsky /* 34639efd4ecSMartin Schwidefsky * The instruction that caused the program check has 34739efd4ecSMartin Schwidefsky * been nullified. Don't signal single step via SIGTRAP. 34839efd4ecSMartin Schwidefsky */ 34956e62a73SSven Schnelle clear_thread_flag(TIF_PER_TRAP); 35039efd4ecSMartin Schwidefsky 351b98cca44SAnshuman Khandual if (kprobe_page_fault(regs, 14)) 35250d7280dSMartin Schwidefsky return 0; 3531da177e4SLinus Torvalds 3541da177e4SLinus Torvalds mm = tsk->mm; 355aa33c8cbSMartin Schwidefsky trans_exc_code = regs->int_parm_long; 356e41ba111SSven Schnelle address = trans_exc_code & __FAIL_ADDR_MASK; 357e41ba111SSven Schnelle is_write = (trans_exc_code & store_indication) == 0x400; 3581da177e4SLinus Torvalds 3591da177e4SLinus Torvalds /* 3601da177e4SLinus Torvalds * Verify that the fault happened in user space, that 3611da177e4SLinus Torvalds * we are not in an interrupt and that there is a 3621da177e4SLinus Torvalds * user context. 3631da177e4SLinus Torvalds */ 36450d7280dSMartin Schwidefsky fault = VM_FAULT_BADCONTEXT; 3650aaba41bSMartin Schwidefsky type = get_fault_type(regs); 3660aaba41bSMartin Schwidefsky switch (type) { 3670aaba41bSMartin Schwidefsky case KERNEL_FAULT: 368e41ba111SSven Schnelle if (kfence_handle_page_fault(address, is_write, regs)) 369e41ba111SSven Schnelle return 0; 37050d7280dSMartin Schwidefsky goto out; 3710aaba41bSMartin Schwidefsky case USER_FAULT: 3720aaba41bSMartin Schwidefsky case GMAP_FAULT: 3730aaba41bSMartin Schwidefsky if (faulthandler_disabled() || !mm) 3740aaba41bSMartin Schwidefsky goto out; 3750aaba41bSMartin Schwidefsky break; 3760aaba41bSMartin Schwidefsky } 3771da177e4SLinus Torvalds 378a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); 379dde16072SPeter Xu flags = FAULT_FLAG_DEFAULT; 380759496baSJohannes Weiner if (user_mode(regs)) 381759496baSJohannes Weiner flags |= FAULT_FLAG_USER; 382*41ac42f1SGerald Schaefer if (is_write) 383*41ac42f1SGerald Schaefer access = VM_WRITE; 384*41ac42f1SGerald Schaefer if (access == VM_WRITE) 38533ce6140SHeiko Carstens flags |= FAULT_FLAG_WRITE; 386d8ed45c5SMichel Lespinasse mmap_read_lock(mm); 3871da177e4SLinus Torvalds 3880aaba41bSMartin Schwidefsky gmap = NULL; 3890aaba41bSMartin Schwidefsky if (IS_ENABLED(CONFIG_PGSTE) && type == GMAP_FAULT) { 3900aaba41bSMartin Schwidefsky gmap = (struct gmap *) S390_lowcore.gmap; 391527e30b4SMartin Schwidefsky current->thread.gmap_addr = address; 3924be130a0SMartin Schwidefsky current->thread.gmap_write_flag = !!(flags & FAULT_FLAG_WRITE); 3934a494439SDavid Hildenbrand current->thread.gmap_int_code = regs->int_code & 0xffff; 394527e30b4SMartin Schwidefsky address = __gmap_translate(gmap, address); 395e5992f2eSMartin Schwidefsky if (address == -EFAULT) { 396e5992f2eSMartin Schwidefsky fault = VM_FAULT_BADMAP; 397e5992f2eSMartin Schwidefsky goto out_up; 398e5992f2eSMartin Schwidefsky } 39924eb3a82SDominik Dingel if (gmap->pfault_enabled) 40024eb3a82SDominik Dingel flags |= FAULT_FLAG_RETRY_NOWAIT; 401e5992f2eSMartin Schwidefsky } 402e5992f2eSMartin Schwidefsky 403e5992f2eSMartin Schwidefsky retry: 40450d7280dSMartin Schwidefsky fault = VM_FAULT_BADMAP; 4051da177e4SLinus Torvalds vma = find_vma(mm, address); 4061da177e4SLinus Torvalds if (!vma) 40750d7280dSMartin Schwidefsky goto out_up; 408c1821c2eSGerald Schaefer 40950d7280dSMartin Schwidefsky if (unlikely(vma->vm_start > address)) { 4101da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 41150d7280dSMartin Schwidefsky goto out_up; 4121da177e4SLinus Torvalds if (expand_stack(vma, address)) 41350d7280dSMartin Schwidefsky goto out_up; 41450d7280dSMartin Schwidefsky } 41550d7280dSMartin Schwidefsky 4161da177e4SLinus Torvalds /* 4171da177e4SLinus Torvalds * Ok, we have a good vm_area for this memory access, so 4181da177e4SLinus Torvalds * we can handle it.. 4191da177e4SLinus Torvalds */ 42050d7280dSMartin Schwidefsky fault = VM_FAULT_BADACCESS; 4211ab947deSMartin Schwidefsky if (unlikely(!(vma->vm_flags & access))) 42250d7280dSMartin Schwidefsky goto out_up; 4231da177e4SLinus Torvalds 42453492b1dSGerald Schaefer if (is_vm_hugetlb_page(vma)) 42553492b1dSGerald Schaefer address &= HPAGE_MASK; 4261da177e4SLinus Torvalds /* 4271da177e4SLinus Torvalds * If for any reason at all we couldn't handle the fault, 4281da177e4SLinus Torvalds * make sure we exit gracefully rather than endlessly redo 4291da177e4SLinus Torvalds * the fault. 4301da177e4SLinus Torvalds */ 43135e45f3eSPeter Xu fault = handle_mm_fault(vma, address, flags, regs); 4324ef87322SPeter Xu if (fault_signal_pending(fault, regs)) { 433f2c76e3bSHeiko Carstens fault = VM_FAULT_SIGNAL; 434306d6c49SClaudio Imbrenda if (flags & FAULT_FLAG_RETRY_NOWAIT) 435306d6c49SClaudio Imbrenda goto out_up; 436f2c76e3bSHeiko Carstens goto out; 437f2c76e3bSHeiko Carstens } 438d9272525SPeter Xu 439d9272525SPeter Xu /* The fault is fully completed (including releasing mmap lock) */ 440d9272525SPeter Xu if (fault & VM_FAULT_COMPLETED) { 441d9272525SPeter Xu if (gmap) { 442d9272525SPeter Xu mmap_read_lock(mm); 443d9272525SPeter Xu goto out_gmap; 444d9272525SPeter Xu } 445d9272525SPeter Xu fault = 0; 446d9272525SPeter Xu goto out; 447d9272525SPeter Xu } 448d9272525SPeter Xu 44950d7280dSMartin Schwidefsky if (unlikely(fault & VM_FAULT_ERROR)) 45050d7280dSMartin Schwidefsky goto out_up; 45150d7280dSMartin Schwidefsky 45233ce6140SHeiko Carstens if (fault & VM_FAULT_RETRY) { 4530aaba41bSMartin Schwidefsky if (IS_ENABLED(CONFIG_PGSTE) && gmap && 4540aaba41bSMartin Schwidefsky (flags & FAULT_FLAG_RETRY_NOWAIT)) { 45536ef159fSQi Zheng /* 45636ef159fSQi Zheng * FAULT_FLAG_RETRY_NOWAIT has been set, mmap_lock has 45736ef159fSQi Zheng * not been released 45836ef159fSQi Zheng */ 45924eb3a82SDominik Dingel current->thread.gmap_pfault = 1; 46024eb3a82SDominik Dingel fault = VM_FAULT_PFAULT; 46124eb3a82SDominik Dingel goto out_up; 46224eb3a82SDominik Dingel } 4634064b982SPeter Xu flags &= ~FAULT_FLAG_RETRY_NOWAIT; 46445cac65bSShaohua Li flags |= FAULT_FLAG_TRIED; 465d8ed45c5SMichel Lespinasse mmap_read_lock(mm); 46633ce6140SHeiko Carstens goto retry; 46733ce6140SHeiko Carstens } 468d9272525SPeter Xu out_gmap: 4690aaba41bSMartin Schwidefsky if (IS_ENABLED(CONFIG_PGSTE) && gmap) { 470527e30b4SMartin Schwidefsky address = __gmap_link(gmap, current->thread.gmap_addr, 471527e30b4SMartin Schwidefsky address); 472527e30b4SMartin Schwidefsky if (address == -EFAULT) { 473527e30b4SMartin Schwidefsky fault = VM_FAULT_BADMAP; 474527e30b4SMartin Schwidefsky goto out_up; 475527e30b4SMartin Schwidefsky } 476527e30b4SMartin Schwidefsky if (address == -ENOMEM) { 477527e30b4SMartin Schwidefsky fault = VM_FAULT_OOM; 478527e30b4SMartin Schwidefsky goto out_up; 479527e30b4SMartin Schwidefsky } 480527e30b4SMartin Schwidefsky } 48150d7280dSMartin Schwidefsky fault = 0; 48250d7280dSMartin Schwidefsky out_up: 483d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 48450d7280dSMartin Schwidefsky out: 48550d7280dSMartin Schwidefsky return fault; 4861da177e4SLinus Torvalds } 4871da177e4SLinus Torvalds 4887a5388deSHeiko Carstens void do_protection_exception(struct pt_regs *regs) 4891da177e4SLinus Torvalds { 490aa33c8cbSMartin Schwidefsky unsigned long trans_exc_code; 49150a7ca3cSSouptick Joarder int access; 49250a7ca3cSSouptick Joarder vm_fault_t fault; 49361365e13SMartin Schwidefsky 494aa33c8cbSMartin Schwidefsky trans_exc_code = regs->int_parm_long; 495f752ac4dSMartin Schwidefsky /* 496f752ac4dSMartin Schwidefsky * Protection exceptions are suppressing, decrement psw address. 497f752ac4dSMartin Schwidefsky * The exception to this rule are aborted transactions, for these 498f752ac4dSMartin Schwidefsky * the PSW already points to the correct location. 499f752ac4dSMartin Schwidefsky */ 500f752ac4dSMartin Schwidefsky if (!(regs->int_code & 0x200)) 501aa33c8cbSMartin Schwidefsky regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16); 50210c1031fSMartin Schwidefsky /* 50310c1031fSMartin Schwidefsky * Check for low-address protection. This needs to be treated 50410c1031fSMartin Schwidefsky * as a special case because the translation exception code 50510c1031fSMartin Schwidefsky * field is not guaranteed to contain valid data in this case. 50610c1031fSMartin Schwidefsky */ 50761365e13SMartin Schwidefsky if (unlikely(!(trans_exc_code & 4))) { 508aa33c8cbSMartin Schwidefsky do_low_address(regs); 50910c1031fSMartin Schwidefsky return; 51010c1031fSMartin Schwidefsky } 51157d7f939SMartin Schwidefsky if (unlikely(MACHINE_HAS_NX && (trans_exc_code & 0x80))) { 51257d7f939SMartin Schwidefsky regs->int_parm_long = (trans_exc_code & ~PAGE_MASK) | 51357d7f939SMartin Schwidefsky (regs->psw.addr & PAGE_MASK); 51457d7f939SMartin Schwidefsky access = VM_EXEC; 51557d7f939SMartin Schwidefsky fault = VM_FAULT_BADACCESS; 51657d7f939SMartin Schwidefsky } else { 51757d7f939SMartin Schwidefsky access = VM_WRITE; 51857d7f939SMartin Schwidefsky fault = do_exception(regs, access); 51957d7f939SMartin Schwidefsky } 52050d7280dSMartin Schwidefsky if (unlikely(fault)) 52157d7f939SMartin Schwidefsky do_fault_error(regs, access, fault); 5221da177e4SLinus Torvalds } 5237a5388deSHeiko Carstens NOKPROBE_SYMBOL(do_protection_exception); 5241da177e4SLinus Torvalds 5257a5388deSHeiko Carstens void do_dat_exception(struct pt_regs *regs) 5261da177e4SLinus Torvalds { 52750a7ca3cSSouptick Joarder int access; 52850a7ca3cSSouptick Joarder vm_fault_t fault; 52950d7280dSMartin Schwidefsky 5306cb4d9a2SAnshuman Khandual access = VM_ACCESS_FLAGS; 531aa33c8cbSMartin Schwidefsky fault = do_exception(regs, access); 53250d7280dSMartin Schwidefsky if (unlikely(fault)) 53357d7f939SMartin Schwidefsky do_fault_error(regs, access, fault); 5341da177e4SLinus Torvalds } 5357a5388deSHeiko Carstens NOKPROBE_SYMBOL(do_dat_exception); 5361da177e4SLinus Torvalds 5371da177e4SLinus Torvalds #ifdef CONFIG_PFAULT 5381da177e4SLinus Torvalds /* 5391da177e4SLinus Torvalds * 'pfault' pseudo page faults routines. 5401da177e4SLinus Torvalds */ 541fb0a9d7eSHeiko Carstens static int pfault_disable; 5421da177e4SLinus Torvalds 5431da177e4SLinus Torvalds static int __init nopfault(char *str) 5441da177e4SLinus Torvalds { 5451da177e4SLinus Torvalds pfault_disable = 1; 5461da177e4SLinus Torvalds return 1; 5471da177e4SLinus Torvalds } 5481da177e4SLinus Torvalds 5491da177e4SLinus Torvalds __setup("nopfault", nopfault); 5501da177e4SLinus Torvalds 5517dd8fe1fSHeiko Carstens struct pfault_refbk { 5527dd8fe1fSHeiko Carstens u16 refdiagc; 5537dd8fe1fSHeiko Carstens u16 reffcode; 5547dd8fe1fSHeiko Carstens u16 refdwlen; 5557dd8fe1fSHeiko Carstens u16 refversn; 5567dd8fe1fSHeiko Carstens u64 refgaddr; 5577dd8fe1fSHeiko Carstens u64 refselmk; 5587dd8fe1fSHeiko Carstens u64 refcmpmk; 5597dd8fe1fSHeiko Carstens u64 reserved; 5607dd8fe1fSHeiko Carstens } __attribute__ ((packed, aligned(8))); 5611da177e4SLinus Torvalds 56200e9e664SMartin Schwidefsky static struct pfault_refbk pfault_init_refbk = { 5637dd8fe1fSHeiko Carstens .refdiagc = 0x258, 5647dd8fe1fSHeiko Carstens .reffcode = 0, 5657dd8fe1fSHeiko Carstens .refdwlen = 5, 5667dd8fe1fSHeiko Carstens .refversn = 2, 567e22cf8caSChristian Borntraeger .refgaddr = __LC_LPP, 5687dd8fe1fSHeiko Carstens .refselmk = 1ULL << 48, 5697dd8fe1fSHeiko Carstens .refcmpmk = 1ULL << 48, 57000e9e664SMartin Schwidefsky .reserved = __PF_RES_FIELD 57100e9e664SMartin Schwidefsky }; 57200e9e664SMartin Schwidefsky 57300e9e664SMartin Schwidefsky int pfault_init(void) 57400e9e664SMartin Schwidefsky { 5751da177e4SLinus Torvalds int rc; 5761da177e4SLinus Torvalds 577f32269a0SCarsten Otte if (pfault_disable) 5781da177e4SLinus Torvalds return -1; 5791ec2772eSMartin Schwidefsky diag_stat_inc(DIAG_STAT_X258); 58094c12cc7SMartin Schwidefsky asm volatile( 5811da177e4SLinus Torvalds " diag %1,%0,0x258\n" 5821da177e4SLinus Torvalds "0: j 2f\n" 5831da177e4SLinus Torvalds "1: la %0,8\n" 5841da177e4SLinus Torvalds "2:\n" 58594c12cc7SMartin Schwidefsky EX_TABLE(0b,1b) 58600e9e664SMartin Schwidefsky : "=d" (rc) 58700e9e664SMartin Schwidefsky : "a" (&pfault_init_refbk), "m" (pfault_init_refbk) : "cc"); 5881da177e4SLinus Torvalds return rc; 5891da177e4SLinus Torvalds } 5901da177e4SLinus Torvalds 59100e9e664SMartin Schwidefsky static struct pfault_refbk pfault_fini_refbk = { 5927dd8fe1fSHeiko Carstens .refdiagc = 0x258, 5937dd8fe1fSHeiko Carstens .reffcode = 1, 5947dd8fe1fSHeiko Carstens .refdwlen = 5, 5957dd8fe1fSHeiko Carstens .refversn = 2, 5967dd8fe1fSHeiko Carstens }; 5971da177e4SLinus Torvalds 59800e9e664SMartin Schwidefsky void pfault_fini(void) 59900e9e664SMartin Schwidefsky { 60000e9e664SMartin Schwidefsky 601f32269a0SCarsten Otte if (pfault_disable) 6021da177e4SLinus Torvalds return; 6031ec2772eSMartin Schwidefsky diag_stat_inc(DIAG_STAT_X258); 60494c12cc7SMartin Schwidefsky asm volatile( 6051da177e4SLinus Torvalds " diag %0,0,0x258\n" 6066c22c986SHeiko Carstens "0: nopr %%r7\n" 60794c12cc7SMartin Schwidefsky EX_TABLE(0b,0b) 60800e9e664SMartin Schwidefsky : : "a" (&pfault_fini_refbk), "m" (pfault_fini_refbk) : "cc"); 6091da177e4SLinus Torvalds } 6101da177e4SLinus Torvalds 611f2db2e6cSHeiko Carstens static DEFINE_SPINLOCK(pfault_lock); 612f2db2e6cSHeiko Carstens static LIST_HEAD(pfault_list); 613f2db2e6cSHeiko Carstens 6140227f7c4SPeter Zijlstra #define PF_COMPLETE 0x0080 6150227f7c4SPeter Zijlstra 6160227f7c4SPeter Zijlstra /* 6170227f7c4SPeter Zijlstra * The mechanism of our pfault code: if Linux is running as guest, runs a user 6180227f7c4SPeter Zijlstra * space process and the user space process accesses a page that the host has 6190227f7c4SPeter Zijlstra * paged out we get a pfault interrupt. 6200227f7c4SPeter Zijlstra * 6210227f7c4SPeter Zijlstra * This allows us, within the guest, to schedule a different process. Without 6220227f7c4SPeter Zijlstra * this mechanism the host would have to suspend the whole virtual cpu until 6230227f7c4SPeter Zijlstra * the page has been paged in. 6240227f7c4SPeter Zijlstra * 6250227f7c4SPeter Zijlstra * So when we get such an interrupt then we set the state of the current task 6260227f7c4SPeter Zijlstra * to uninterruptible and also set the need_resched flag. Both happens within 6270227f7c4SPeter Zijlstra * interrupt context(!). If we later on want to return to user space we 6280227f7c4SPeter Zijlstra * recognize the need_resched flag and then call schedule(). It's not very 6290227f7c4SPeter Zijlstra * obvious how this works... 6300227f7c4SPeter Zijlstra * 6310227f7c4SPeter Zijlstra * Of course we have a lot of additional fun with the completion interrupt (-> 6320227f7c4SPeter Zijlstra * host signals that a page of a process has been paged in and the process can 6330227f7c4SPeter Zijlstra * continue to run). This interrupt can arrive on any cpu and, since we have 6340227f7c4SPeter Zijlstra * virtual cpus, actually appear before the interrupt that signals that a page 6350227f7c4SPeter Zijlstra * is missing. 6360227f7c4SPeter Zijlstra */ 637fde15c3aSHeiko Carstens static void pfault_interrupt(struct ext_code ext_code, 638f6649a7eSMartin Schwidefsky unsigned int param32, unsigned long param64) 6391da177e4SLinus Torvalds { 6401da177e4SLinus Torvalds struct task_struct *tsk; 6411da177e4SLinus Torvalds __u16 subcode; 642f2db2e6cSHeiko Carstens pid_t pid; 6431da177e4SLinus Torvalds 6441da177e4SLinus Torvalds /* 6450227f7c4SPeter Zijlstra * Get the external interruption subcode & pfault initial/completion 6460227f7c4SPeter Zijlstra * signal bit. VM stores this in the 'cpu address' field associated 6470227f7c4SPeter Zijlstra * with the external interrupt. 6481da177e4SLinus Torvalds */ 649fde15c3aSHeiko Carstens subcode = ext_code.subcode; 6501da177e4SLinus Torvalds if ((subcode & 0xff00) != __SUBCODE_MASK) 6511da177e4SLinus Torvalds return; 652420f42ecSHeiko Carstens inc_irq_stat(IRQEXT_PFL); 653f2db2e6cSHeiko Carstens /* Get the token (= pid of the affected task). */ 654544e8dd7SHendrik Brueckner pid = param64 & LPP_PID_MASK; 655f2db2e6cSHeiko Carstens rcu_read_lock(); 656f2db2e6cSHeiko Carstens tsk = find_task_by_pid_ns(pid, &init_pid_ns); 657f2db2e6cSHeiko Carstens if (tsk) 658f2db2e6cSHeiko Carstens get_task_struct(tsk); 659f2db2e6cSHeiko Carstens rcu_read_unlock(); 660f2db2e6cSHeiko Carstens if (!tsk) 661f2db2e6cSHeiko Carstens return; 662f2db2e6cSHeiko Carstens spin_lock(&pfault_lock); 6630227f7c4SPeter Zijlstra if (subcode & PF_COMPLETE) { 6641da177e4SLinus Torvalds /* signal bit is set -> a page has been swapped in by VM */ 665f2db2e6cSHeiko Carstens if (tsk->thread.pfault_wait == 1) { 6661da177e4SLinus Torvalds /* Initial interrupt was faster than the completion 6671da177e4SLinus Torvalds * interrupt. pfault_wait is valid. Set pfault_wait 6681da177e4SLinus Torvalds * back to zero and wake up the process. This can 6691da177e4SLinus Torvalds * safely be done because the task is still sleeping 670b6d09449SMartin Schwidefsky * and can't produce new pfaults. */ 6711da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 672f2db2e6cSHeiko Carstens list_del(&tsk->thread.list); 6731da177e4SLinus Torvalds wake_up_process(tsk); 674d5e50a51SHeiko Carstens put_task_struct(tsk); 675f2db2e6cSHeiko Carstens } else { 676f2db2e6cSHeiko Carstens /* Completion interrupt was faster than initial 677f2db2e6cSHeiko Carstens * interrupt. Set pfault_wait to -1 so the initial 678fa2fb2f4SHeiko Carstens * interrupt doesn't put the task to sleep. 679fa2fb2f4SHeiko Carstens * If the task is not running, ignore the completion 680fa2fb2f4SHeiko Carstens * interrupt since it must be a leftover of a PFAULT 681fa2fb2f4SHeiko Carstens * CANCEL operation which didn't remove all pending 682fa2fb2f4SHeiko Carstens * completion interrupts. */ 683b03fbd4fSPeter Zijlstra if (task_is_running(tsk)) 684f2db2e6cSHeiko Carstens tsk->thread.pfault_wait = -1; 6851da177e4SLinus Torvalds } 6861da177e4SLinus Torvalds } else { 6871da177e4SLinus Torvalds /* signal bit not set -> a real page is missing. */ 688d49f47f8SHeiko Carstens if (WARN_ON_ONCE(tsk != current)) 689d49f47f8SHeiko Carstens goto out; 690d5e50a51SHeiko Carstens if (tsk->thread.pfault_wait == 1) { 691d5e50a51SHeiko Carstens /* Already on the list with a reference: put to sleep */ 6920227f7c4SPeter Zijlstra goto block; 693d5e50a51SHeiko Carstens } else if (tsk->thread.pfault_wait == -1) { 6941da177e4SLinus Torvalds /* Completion interrupt was faster than the initial 695f2db2e6cSHeiko Carstens * interrupt (pfault_wait == -1). Set pfault_wait 696f2db2e6cSHeiko Carstens * back to zero and exit. */ 6971da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 698f2db2e6cSHeiko Carstens } else { 699f2db2e6cSHeiko Carstens /* Initial interrupt arrived before completion 700d5e50a51SHeiko Carstens * interrupt. Let the task sleep. 701d5e50a51SHeiko Carstens * An extra task reference is needed since a different 702d5e50a51SHeiko Carstens * cpu may set the task state to TASK_RUNNING again 703d5e50a51SHeiko Carstens * before the scheduler is reached. */ 704d5e50a51SHeiko Carstens get_task_struct(tsk); 705f2db2e6cSHeiko Carstens tsk->thread.pfault_wait = 1; 706f2db2e6cSHeiko Carstens list_add(&tsk->thread.list, &pfault_list); 7070227f7c4SPeter Zijlstra block: 7080227f7c4SPeter Zijlstra /* Since this must be a userspace fault, there 7090227f7c4SPeter Zijlstra * is no kernel task state to trample. Rely on the 7100227f7c4SPeter Zijlstra * return to userspace schedule() to block. */ 7110227f7c4SPeter Zijlstra __set_current_state(TASK_UNINTERRUPTIBLE); 7121da177e4SLinus Torvalds set_tsk_need_resched(tsk); 713c360192bSMartin Schwidefsky set_preempt_need_resched(); 7141da177e4SLinus Torvalds } 7151da177e4SLinus Torvalds } 716d49f47f8SHeiko Carstens out: 717f2db2e6cSHeiko Carstens spin_unlock(&pfault_lock); 71854c27791SHeiko Carstens put_task_struct(tsk); 719f2db2e6cSHeiko Carstens } 720f2db2e6cSHeiko Carstens 72184c9ceefSSebastian Andrzej Siewior static int pfault_cpu_dead(unsigned int cpu) 722f2db2e6cSHeiko Carstens { 723f2db2e6cSHeiko Carstens struct thread_struct *thread, *next; 724f2db2e6cSHeiko Carstens struct task_struct *tsk; 725f2db2e6cSHeiko Carstens 726f2db2e6cSHeiko Carstens spin_lock_irq(&pfault_lock); 727f2db2e6cSHeiko Carstens list_for_each_entry_safe(thread, next, &pfault_list, list) { 728f2db2e6cSHeiko Carstens thread->pfault_wait = 0; 729f2db2e6cSHeiko Carstens list_del(&thread->list); 730f2db2e6cSHeiko Carstens tsk = container_of(thread, struct task_struct, thread); 731f2db2e6cSHeiko Carstens wake_up_process(tsk); 732d5e50a51SHeiko Carstens put_task_struct(tsk); 733f2db2e6cSHeiko Carstens } 734f2db2e6cSHeiko Carstens spin_unlock_irq(&pfault_lock); 73584c9ceefSSebastian Andrzej Siewior return 0; 736f2db2e6cSHeiko Carstens } 7371da177e4SLinus Torvalds 738fb0a9d7eSHeiko Carstens static int __init pfault_irq_init(void) 73929b08d2bSHeiko Carstens { 740fb0a9d7eSHeiko Carstens int rc; 74129b08d2bSHeiko Carstens 7421dad093bSThomas Huth rc = register_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt); 7437dd8fe1fSHeiko Carstens if (rc) 7447dd8fe1fSHeiko Carstens goto out_extint; 7457dd8fe1fSHeiko Carstens rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP; 7467dd8fe1fSHeiko Carstens if (rc) 7477dd8fe1fSHeiko Carstens goto out_pfault; 74882003c3eSHeiko Carstens irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL); 74984c9ceefSSebastian Andrzej Siewior cpuhp_setup_state_nocalls(CPUHP_S390_PFAULT_DEAD, "s390/pfault:dead", 75084c9ceefSSebastian Andrzej Siewior NULL, pfault_cpu_dead); 7517dd8fe1fSHeiko Carstens return 0; 7527dd8fe1fSHeiko Carstens 7537dd8fe1fSHeiko Carstens out_pfault: 7541dad093bSThomas Huth unregister_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt); 7557dd8fe1fSHeiko Carstens out_extint: 756fb0a9d7eSHeiko Carstens pfault_disable = 1; 757fb0a9d7eSHeiko Carstens return rc; 758fb0a9d7eSHeiko Carstens } 759fb0a9d7eSHeiko Carstens early_initcall(pfault_irq_init); 760fb0a9d7eSHeiko Carstens 7617dd8fe1fSHeiko Carstens #endif /* CONFIG_PFAULT */ 762084ea4d6SVasily Gorbik 763084ea4d6SVasily Gorbik #if IS_ENABLED(CONFIG_PGSTE) 76417a363dcSHeiko Carstens 765084ea4d6SVasily Gorbik void do_secure_storage_access(struct pt_regs *regs) 766084ea4d6SVasily Gorbik { 767084ea4d6SVasily Gorbik unsigned long addr = regs->int_parm_long & __FAIL_ADDR_MASK; 768084ea4d6SVasily Gorbik struct vm_area_struct *vma; 769084ea4d6SVasily Gorbik struct mm_struct *mm; 770084ea4d6SVasily Gorbik struct page *page; 771b108f7f0SClaudio Imbrenda struct gmap *gmap; 772084ea4d6SVasily Gorbik int rc; 773084ea4d6SVasily Gorbik 77485b18d7bSJanosch Frank /* 77585b18d7bSJanosch Frank * bit 61 tells us if the address is valid, if it's not we 77685b18d7bSJanosch Frank * have a major problem and should stop the kernel or send a 77785b18d7bSJanosch Frank * SIGSEGV to the process. Unfortunately bit 61 is not 77885b18d7bSJanosch Frank * reliable without the misc UV feature so we need to check 77985b18d7bSJanosch Frank * for that as well. 78085b18d7bSJanosch Frank */ 78185b18d7bSJanosch Frank if (test_bit_inv(BIT_UV_FEAT_MISC, &uv_info.uv_feature_indications) && 78285b18d7bSJanosch Frank !test_bit_inv(61, ®s->int_parm_long)) { 78385b18d7bSJanosch Frank /* 78485b18d7bSJanosch Frank * When this happens, userspace did something that it 78585b18d7bSJanosch Frank * was not supposed to do, e.g. branching into secure 78685b18d7bSJanosch Frank * memory. Trigger a segmentation fault. 78785b18d7bSJanosch Frank */ 78885b18d7bSJanosch Frank if (user_mode(regs)) { 78985b18d7bSJanosch Frank send_sig(SIGSEGV, current, 0); 79085b18d7bSJanosch Frank return; 79185b18d7bSJanosch Frank } 79285b18d7bSJanosch Frank 79385b18d7bSJanosch Frank /* 79485b18d7bSJanosch Frank * The kernel should never run into this case and we 79585b18d7bSJanosch Frank * have no way out of this situation. 79685b18d7bSJanosch Frank */ 79785b18d7bSJanosch Frank panic("Unexpected PGM 0x3d with TEID bit 61=0"); 79885b18d7bSJanosch Frank } 79985b18d7bSJanosch Frank 800084ea4d6SVasily Gorbik switch (get_fault_type(regs)) { 801b108f7f0SClaudio Imbrenda case GMAP_FAULT: 802b108f7f0SClaudio Imbrenda mm = current->mm; 803b108f7f0SClaudio Imbrenda gmap = (struct gmap *)S390_lowcore.gmap; 804b108f7f0SClaudio Imbrenda mmap_read_lock(mm); 805b108f7f0SClaudio Imbrenda addr = __gmap_translate(gmap, addr); 806b108f7f0SClaudio Imbrenda mmap_read_unlock(mm); 807b108f7f0SClaudio Imbrenda if (IS_ERR_VALUE(addr)) { 808b108f7f0SClaudio Imbrenda do_fault_error(regs, VM_ACCESS_FLAGS, VM_FAULT_BADMAP); 809b108f7f0SClaudio Imbrenda break; 810b108f7f0SClaudio Imbrenda } 811b108f7f0SClaudio Imbrenda fallthrough; 812084ea4d6SVasily Gorbik case USER_FAULT: 813084ea4d6SVasily Gorbik mm = current->mm; 814d8ed45c5SMichel Lespinasse mmap_read_lock(mm); 815084ea4d6SVasily Gorbik vma = find_vma(mm, addr); 816084ea4d6SVasily Gorbik if (!vma) { 817d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 818084ea4d6SVasily Gorbik do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP); 819084ea4d6SVasily Gorbik break; 820084ea4d6SVasily Gorbik } 821084ea4d6SVasily Gorbik page = follow_page(vma, addr, FOLL_WRITE | FOLL_GET); 822084ea4d6SVasily Gorbik if (IS_ERR_OR_NULL(page)) { 823d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 824084ea4d6SVasily Gorbik break; 825084ea4d6SVasily Gorbik } 826084ea4d6SVasily Gorbik if (arch_make_page_accessible(page)) 827084ea4d6SVasily Gorbik send_sig(SIGSEGV, current, 0); 828084ea4d6SVasily Gorbik put_page(page); 829d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 830084ea4d6SVasily Gorbik break; 831084ea4d6SVasily Gorbik case KERNEL_FAULT: 832084ea4d6SVasily Gorbik page = phys_to_page(addr); 833cd1adf1bSLinus Torvalds if (unlikely(!try_get_page(page))) 834084ea4d6SVasily Gorbik break; 835084ea4d6SVasily Gorbik rc = arch_make_page_accessible(page); 836084ea4d6SVasily Gorbik put_page(page); 837084ea4d6SVasily Gorbik if (rc) 838084ea4d6SVasily Gorbik BUG(); 839084ea4d6SVasily Gorbik break; 840084ea4d6SVasily Gorbik default: 841084ea4d6SVasily Gorbik do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP); 842084ea4d6SVasily Gorbik WARN_ON_ONCE(1); 843084ea4d6SVasily Gorbik } 844084ea4d6SVasily Gorbik } 845084ea4d6SVasily Gorbik NOKPROBE_SYMBOL(do_secure_storage_access); 846084ea4d6SVasily Gorbik 847084ea4d6SVasily Gorbik void do_non_secure_storage_access(struct pt_regs *regs) 848084ea4d6SVasily Gorbik { 849084ea4d6SVasily Gorbik unsigned long gaddr = regs->int_parm_long & __FAIL_ADDR_MASK; 850084ea4d6SVasily Gorbik struct gmap *gmap = (struct gmap *)S390_lowcore.gmap; 851084ea4d6SVasily Gorbik 852084ea4d6SVasily Gorbik if (get_fault_type(regs) != GMAP_FAULT) { 853084ea4d6SVasily Gorbik do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP); 854084ea4d6SVasily Gorbik WARN_ON_ONCE(1); 855084ea4d6SVasily Gorbik return; 856084ea4d6SVasily Gorbik } 857084ea4d6SVasily Gorbik 858084ea4d6SVasily Gorbik if (gmap_convert_to_secure(gmap, gaddr) == -EINVAL) 859084ea4d6SVasily Gorbik send_sig(SIGSEGV, current, 0); 860084ea4d6SVasily Gorbik } 861084ea4d6SVasily Gorbik NOKPROBE_SYMBOL(do_non_secure_storage_access); 862084ea4d6SVasily Gorbik 863cd4d3d5fSJanosch Frank void do_secure_storage_violation(struct pt_regs *regs) 864cd4d3d5fSJanosch Frank { 865a52c2584SClaudio Imbrenda unsigned long gaddr = regs->int_parm_long & __FAIL_ADDR_MASK; 866a52c2584SClaudio Imbrenda struct gmap *gmap = (struct gmap *)S390_lowcore.gmap; 867a52c2584SClaudio Imbrenda 868a52c2584SClaudio Imbrenda /* 869a52c2584SClaudio Imbrenda * If the VM has been rebooted, its address space might still contain 870a52c2584SClaudio Imbrenda * secure pages from the previous boot. 871a52c2584SClaudio Imbrenda * Clear the page so it can be reused. 872a52c2584SClaudio Imbrenda */ 873a52c2584SClaudio Imbrenda if (!gmap_destroy_page(gmap, gaddr)) 874a52c2584SClaudio Imbrenda return; 875cd4d3d5fSJanosch Frank /* 876cd4d3d5fSJanosch Frank * Either KVM messed up the secure guest mapping or the same 877cd4d3d5fSJanosch Frank * page is mapped into multiple secure guests. 878cd4d3d5fSJanosch Frank * 879cd4d3d5fSJanosch Frank * This exception is only triggered when a guest 2 is running 880cd4d3d5fSJanosch Frank * and can therefore never occur in kernel context. 881cd4d3d5fSJanosch Frank */ 882cd4d3d5fSJanosch Frank printk_ratelimited(KERN_WARNING 883cd4d3d5fSJanosch Frank "Secure storage violation in task: %s, pid %d\n", 884cd4d3d5fSJanosch Frank current->comm, current->pid); 885cd4d3d5fSJanosch Frank send_sig(SIGSEGV, current, 0); 886cd4d3d5fSJanosch Frank } 887cd4d3d5fSJanosch Frank 88817a363dcSHeiko Carstens #endif /* CONFIG_PGSTE */ 889