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> 35cbb870c8SHeiko Carstens #include <asm/asm-offsets.h> 361ec2772eSMartin Schwidefsky #include <asm/diag.h> 371e133ab2SMartin Schwidefsky #include <asm/gmap.h> 38d7b250e2SHeiko Carstens #include <asm/irq.h> 396252d702SMartin Schwidefsky #include <asm/mmu_context.h> 40a0616cdeSDavid Howells #include <asm/facility.h> 41084ea4d6SVasily Gorbik #include <asm/uv.h> 42a806170eSHeiko Carstens #include "../kernel/entry.h" 431da177e4SLinus Torvalds 441da177e4SLinus Torvalds #define __FAIL_ADDR_MASK -4096L 451da177e4SLinus Torvalds #define __SUBCODE_MASK 0x0600 461da177e4SLinus Torvalds #define __PF_RES_FIELD 0x8000000000000000ULL 471da177e4SLinus Torvalds 4812437759SChristian Borntraeger #define VM_FAULT_BADCONTEXT ((__force vm_fault_t) 0x010000) 4912437759SChristian Borntraeger #define VM_FAULT_BADMAP ((__force vm_fault_t) 0x020000) 5012437759SChristian Borntraeger #define VM_FAULT_BADACCESS ((__force vm_fault_t) 0x040000) 5112437759SChristian Borntraeger #define VM_FAULT_SIGNAL ((__force vm_fault_t) 0x080000) 5212437759SChristian Borntraeger #define VM_FAULT_PFAULT ((__force vm_fault_t) 0x100000) 5350d7280dSMartin Schwidefsky 540aaba41bSMartin Schwidefsky enum fault_type { 550aaba41bSMartin Schwidefsky KERNEL_FAULT, 560aaba41bSMartin Schwidefsky USER_FAULT, 570aaba41bSMartin Schwidefsky GMAP_FAULT, 580aaba41bSMartin Schwidefsky }; 590aaba41bSMartin Schwidefsky 60a4f32bdbSHeiko Carstens static unsigned long store_indication __read_mostly; 6192f842eaSMartin Schwidefsky 62a4f32bdbSHeiko Carstens static int __init fault_init(void) 6392f842eaSMartin Schwidefsky { 64a4f32bdbSHeiko Carstens if (test_facility(75)) 6592f842eaSMartin Schwidefsky store_indication = 0xc00; 66a4f32bdbSHeiko Carstens return 0; 6792f842eaSMartin Schwidefsky } 68a4f32bdbSHeiko Carstens early_initcall(fault_init); 6992f842eaSMartin Schwidefsky 701da177e4SLinus Torvalds /* 710aaba41bSMartin Schwidefsky * Find out which address space caused the exception. 721da177e4SLinus Torvalds */ 73bf2f1eeeSMasahiro Yamada static enum fault_type get_fault_type(struct pt_regs *regs) 741da177e4SLinus Torvalds { 75457f2180SHeiko Carstens unsigned long trans_exc_code; 76457f2180SHeiko Carstens 77457f2180SHeiko Carstens trans_exc_code = regs->int_parm_long & 3; 780aaba41bSMartin Schwidefsky if (likely(trans_exc_code == 0)) { 790aaba41bSMartin Schwidefsky /* primary space exception */ 8087d59863SHeiko Carstens if (user_mode(regs)) 8187d59863SHeiko Carstens return USER_FAULT; 8287d59863SHeiko Carstens if (!IS_ENABLED(CONFIG_PGSTE)) 8387d59863SHeiko Carstens return KERNEL_FAULT; 8487d59863SHeiko Carstens if (test_pt_regs_flag(regs, PIF_GUEST_FAULT)) 850aaba41bSMartin Schwidefsky return GMAP_FAULT; 860aaba41bSMartin Schwidefsky return KERNEL_FAULT; 870aaba41bSMartin Schwidefsky } 8887d59863SHeiko Carstens if (trans_exc_code == 2) 890aaba41bSMartin Schwidefsky return USER_FAULT; 90962f0af8SGerald Schaefer if (trans_exc_code == 1) { 91962f0af8SGerald Schaefer /* access register mode, not used in the kernel */ 92962f0af8SGerald Schaefer return USER_FAULT; 93962f0af8SGerald Schaefer } 940aaba41bSMartin Schwidefsky /* home space exception -> access via kernel ASCE */ 950aaba41bSMartin Schwidefsky return KERNEL_FAULT; 961da177e4SLinus Torvalds } 971da177e4SLinus Torvalds 983b7df342SHeiko Carstens static int bad_address(void *p) 993b7df342SHeiko Carstens { 1003b7df342SHeiko Carstens unsigned long dummy; 1013b7df342SHeiko Carstens 10225f12ae4SChristoph Hellwig return get_kernel_nofault(dummy, (unsigned long *)p); 1033b7df342SHeiko Carstens } 1043b7df342SHeiko Carstens 1053b7df342SHeiko Carstens static void dump_pagetable(unsigned long asce, unsigned long address) 1063b7df342SHeiko Carstens { 107fe7b2747SHeiko Carstens unsigned long *table = __va(asce & _ASCE_ORIGIN); 1083b7df342SHeiko Carstens 1093b7df342SHeiko Carstens pr_alert("AS:%016lx ", asce); 1103b7df342SHeiko Carstens switch (asce & _ASCE_TYPE_MASK) { 1113b7df342SHeiko Carstens case _ASCE_TYPE_REGION1: 112f1c1174fSHeiko Carstens table += (address & _REGION1_INDEX) >> _REGION1_SHIFT; 1133b7df342SHeiko Carstens if (bad_address(table)) 1143b7df342SHeiko Carstens goto bad; 1153b7df342SHeiko Carstens pr_cont("R1:%016lx ", *table); 1163b7df342SHeiko Carstens if (*table & _REGION_ENTRY_INVALID) 1173b7df342SHeiko Carstens goto out; 1183b7df342SHeiko Carstens table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 1192c7749b9SJoe Perches fallthrough; 1203b7df342SHeiko Carstens case _ASCE_TYPE_REGION2: 121f1c1174fSHeiko Carstens table += (address & _REGION2_INDEX) >> _REGION2_SHIFT; 1223b7df342SHeiko Carstens if (bad_address(table)) 1233b7df342SHeiko Carstens goto bad; 1243b7df342SHeiko Carstens pr_cont("R2:%016lx ", *table); 1253b7df342SHeiko Carstens if (*table & _REGION_ENTRY_INVALID) 1263b7df342SHeiko Carstens goto out; 1273b7df342SHeiko Carstens table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 1282c7749b9SJoe Perches fallthrough; 1293b7df342SHeiko Carstens case _ASCE_TYPE_REGION3: 130f1c1174fSHeiko Carstens table += (address & _REGION3_INDEX) >> _REGION3_SHIFT; 1313b7df342SHeiko Carstens if (bad_address(table)) 1323b7df342SHeiko Carstens goto bad; 1333b7df342SHeiko Carstens pr_cont("R3:%016lx ", *table); 1343b7df342SHeiko Carstens if (*table & (_REGION_ENTRY_INVALID | _REGION3_ENTRY_LARGE)) 1353b7df342SHeiko Carstens goto out; 1363b7df342SHeiko Carstens table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); 1372c7749b9SJoe Perches fallthrough; 1383b7df342SHeiko Carstens case _ASCE_TYPE_SEGMENT: 139f1c1174fSHeiko Carstens table += (address & _SEGMENT_INDEX) >> _SEGMENT_SHIFT; 1403b7df342SHeiko Carstens if (bad_address(table)) 1413b7df342SHeiko Carstens goto bad; 14291c0837eSJoe Perches pr_cont("S:%016lx ", *table); 1433b7df342SHeiko Carstens if (*table & (_SEGMENT_ENTRY_INVALID | _SEGMENT_ENTRY_LARGE)) 1443b7df342SHeiko Carstens goto out; 1453b7df342SHeiko Carstens table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN); 1463b7df342SHeiko Carstens } 147f1c1174fSHeiko Carstens table += (address & _PAGE_INDEX) >> _PAGE_SHIFT; 1483b7df342SHeiko Carstens if (bad_address(table)) 1493b7df342SHeiko Carstens goto bad; 1503b7df342SHeiko Carstens pr_cont("P:%016lx ", *table); 1513b7df342SHeiko Carstens out: 1523b7df342SHeiko Carstens pr_cont("\n"); 1533b7df342SHeiko Carstens return; 1543b7df342SHeiko Carstens bad: 1553b7df342SHeiko Carstens pr_cont("BAD\n"); 1563b7df342SHeiko Carstens } 1573b7df342SHeiko Carstens 1583b7df342SHeiko Carstens static void dump_fault_info(struct pt_regs *regs) 1593b7df342SHeiko Carstens { 1603b7df342SHeiko Carstens unsigned long asce; 1613b7df342SHeiko Carstens 1625d7eccecSHeiko Carstens pr_alert("Failing address: %016lx TEID: %016lx\n", 1635d7eccecSHeiko Carstens regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long); 1643b7df342SHeiko Carstens pr_alert("Fault in "); 1653b7df342SHeiko Carstens switch (regs->int_parm_long & 3) { 1663b7df342SHeiko Carstens case 3: 1673b7df342SHeiko Carstens pr_cont("home space "); 1683b7df342SHeiko Carstens break; 1693b7df342SHeiko Carstens case 2: 1703b7df342SHeiko Carstens pr_cont("secondary space "); 1713b7df342SHeiko Carstens break; 1723b7df342SHeiko Carstens case 1: 1733b7df342SHeiko Carstens pr_cont("access register "); 1743b7df342SHeiko Carstens break; 1753b7df342SHeiko Carstens case 0: 1763b7df342SHeiko Carstens pr_cont("primary space "); 1773b7df342SHeiko Carstens break; 1783b7df342SHeiko Carstens } 1793b7df342SHeiko Carstens pr_cont("mode while using "); 1800aaba41bSMartin Schwidefsky switch (get_fault_type(regs)) { 1810aaba41bSMartin Schwidefsky case USER_FAULT: 1823b7df342SHeiko Carstens asce = S390_lowcore.user_asce; 1833b7df342SHeiko Carstens pr_cont("user "); 1840aaba41bSMartin Schwidefsky break; 1850aaba41bSMartin Schwidefsky case GMAP_FAULT: 1860aaba41bSMartin Schwidefsky asce = ((struct gmap *) S390_lowcore.gmap)->asce; 1870aaba41bSMartin Schwidefsky pr_cont("gmap "); 1880aaba41bSMartin Schwidefsky break; 1890aaba41bSMartin Schwidefsky case KERNEL_FAULT: 1900aaba41bSMartin Schwidefsky asce = S390_lowcore.kernel_asce; 1910aaba41bSMartin Schwidefsky pr_cont("kernel "); 1920aaba41bSMartin Schwidefsky break; 193bf2f1eeeSMasahiro Yamada default: 194bf2f1eeeSMasahiro Yamada unreachable(); 1953b7df342SHeiko Carstens } 1963b7df342SHeiko Carstens pr_cont("ASCE.\n"); 1973b7df342SHeiko Carstens dump_pagetable(asce, regs->int_parm_long & __FAIL_ADDR_MASK); 1983b7df342SHeiko Carstens } 1993b7df342SHeiko Carstens 2005d7eccecSHeiko Carstens int show_unhandled_signals = 1; 2015d7eccecSHeiko Carstens 2025d7eccecSHeiko Carstens void report_user_fault(struct pt_regs *regs, long signr, int is_mm_fault) 203ab3c68eeSHeiko Carstens { 204ab3c68eeSHeiko Carstens if ((task_pid_nr(current) > 1) && !show_unhandled_signals) 205ab3c68eeSHeiko Carstens return; 206ab3c68eeSHeiko Carstens if (!unhandled_signal(current, signr)) 207ab3c68eeSHeiko Carstens return; 208ab3c68eeSHeiko Carstens if (!printk_ratelimit()) 209ab3c68eeSHeiko Carstens return; 210413d4047SHeiko Carstens printk(KERN_ALERT "User process fault: interruption code %04x ilc:%d ", 211413d4047SHeiko Carstens regs->int_code & 0xffff, regs->int_code >> 17); 2129cb1ccecSHeiko Carstens print_vma_addr(KERN_CONT "in ", regs->psw.addr); 213aa33c8cbSMartin Schwidefsky printk(KERN_CONT "\n"); 2145d7eccecSHeiko Carstens if (is_mm_fault) 2153b7df342SHeiko Carstens dump_fault_info(regs); 216ab3c68eeSHeiko Carstens show_regs(regs); 217ab3c68eeSHeiko Carstens } 218ab3c68eeSHeiko Carstens 2191da177e4SLinus Torvalds /* 2201da177e4SLinus Torvalds * Send SIGSEGV to task. This is an external routine 2211da177e4SLinus Torvalds * to keep the stack usage of do_page_fault small. 2221da177e4SLinus Torvalds */ 223aa33c8cbSMartin Schwidefsky static noinline void do_sigsegv(struct pt_regs *regs, int si_code) 2241da177e4SLinus Torvalds { 2255d7eccecSHeiko Carstens report_user_fault(regs, SIGSEGV, 1); 2269507a5d0SEric W. Biederman force_sig_fault(SIGSEGV, si_code, 2272e1661d2SEric W. Biederman (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK)); 2281da177e4SLinus Torvalds } 2291da177e4SLinus Torvalds 230a80313ffSGerald Schaefer const struct exception_table_entry *s390_search_extables(unsigned long addr) 231a80313ffSGerald Schaefer { 232a80313ffSGerald Schaefer const struct exception_table_entry *fixup; 233a80313ffSGerald Schaefer 234c78d0c74SHeiko Carstens fixup = search_extable(__start_amode31_ex_table, 235c78d0c74SHeiko Carstens __stop_amode31_ex_table - __start_amode31_ex_table, 236a80313ffSGerald Schaefer addr); 237a80313ffSGerald Schaefer if (!fixup) 238a80313ffSGerald Schaefer fixup = search_exception_tables(addr); 239a80313ffSGerald Schaefer return fixup; 240a80313ffSGerald Schaefer } 241a80313ffSGerald Schaefer 242aa33c8cbSMartin Schwidefsky static noinline void do_no_context(struct pt_regs *regs) 24310c1031fSMartin Schwidefsky { 24410c1031fSMartin Schwidefsky const struct exception_table_entry *fixup; 24510c1031fSMartin Schwidefsky 24610c1031fSMartin Schwidefsky /* Are we prepared to handle this kernel fault? */ 247a80313ffSGerald Schaefer fixup = s390_search_extables(regs->psw.addr); 24805a68e89SIlya Leoshkevich if (fixup && ex_handle(fixup, regs)) 24910c1031fSMartin Schwidefsky return; 25010c1031fSMartin Schwidefsky 25110c1031fSMartin Schwidefsky /* 25210c1031fSMartin Schwidefsky * Oops. The kernel tried to access some bad page. We'll have to 25310c1031fSMartin Schwidefsky * terminate things with extreme prejudice. 25410c1031fSMartin Schwidefsky */ 2550aaba41bSMartin Schwidefsky if (get_fault_type(regs) == KERNEL_FAULT) 25610c1031fSMartin Schwidefsky printk(KERN_ALERT "Unable to handle kernel pointer dereference" 2573b7df342SHeiko Carstens " in virtual kernel address space\n"); 25810c1031fSMartin Schwidefsky else 25910c1031fSMartin Schwidefsky printk(KERN_ALERT "Unable to handle kernel paging request" 2603b7df342SHeiko Carstens " in virtual user address space\n"); 2613b7df342SHeiko Carstens dump_fault_info(regs); 262aa33c8cbSMartin Schwidefsky die(regs, "Oops"); 26310c1031fSMartin Schwidefsky do_exit(SIGKILL); 26410c1031fSMartin Schwidefsky } 26510c1031fSMartin Schwidefsky 266aa33c8cbSMartin Schwidefsky static noinline void do_low_address(struct pt_regs *regs) 26710c1031fSMartin Schwidefsky { 26810c1031fSMartin Schwidefsky /* Low-address protection hit in kernel mode means 26910c1031fSMartin Schwidefsky NULL pointer write access in kernel mode. */ 27010c1031fSMartin Schwidefsky if (regs->psw.mask & PSW_MASK_PSTATE) { 27110c1031fSMartin Schwidefsky /* Low-address protection hit in user mode 'cannot happen'. */ 272aa33c8cbSMartin Schwidefsky die (regs, "Low-address protection"); 27310c1031fSMartin Schwidefsky do_exit(SIGKILL); 27410c1031fSMartin Schwidefsky } 27510c1031fSMartin Schwidefsky 276aa33c8cbSMartin Schwidefsky do_no_context(regs); 27710c1031fSMartin Schwidefsky } 27810c1031fSMartin Schwidefsky 279aa33c8cbSMartin Schwidefsky static noinline void do_sigbus(struct pt_regs *regs) 28010c1031fSMartin Schwidefsky { 28110c1031fSMartin Schwidefsky /* 28210c1031fSMartin Schwidefsky * Send a sigbus, regardless of whether we were in kernel 28310c1031fSMartin Schwidefsky * or user mode. 28410c1031fSMartin Schwidefsky */ 2859507a5d0SEric W. Biederman force_sig_fault(SIGBUS, BUS_ADRERR, 2862e1661d2SEric W. Biederman (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK)); 28710c1031fSMartin Schwidefsky } 28810c1031fSMartin Schwidefsky 28950a7ca3cSSouptick Joarder static noinline void do_fault_error(struct pt_regs *regs, int access, 29050a7ca3cSSouptick Joarder vm_fault_t fault) 29150d7280dSMartin Schwidefsky { 29250d7280dSMartin Schwidefsky int si_code; 29350d7280dSMartin Schwidefsky 29450d7280dSMartin Schwidefsky switch (fault) { 29550d7280dSMartin Schwidefsky case VM_FAULT_BADACCESS: 29650d7280dSMartin Schwidefsky case VM_FAULT_BADMAP: 29750d7280dSMartin Schwidefsky /* Bad memory access. Check if it is kernel or user space. */ 2987d256175SHeiko Carstens if (user_mode(regs)) { 29950d7280dSMartin Schwidefsky /* User mode accesses just cause a SIGSEGV */ 30050d7280dSMartin Schwidefsky si_code = (fault == VM_FAULT_BADMAP) ? 30150d7280dSMartin Schwidefsky SEGV_MAPERR : SEGV_ACCERR; 302aa33c8cbSMartin Schwidefsky do_sigsegv(regs, si_code); 30357d7f939SMartin Schwidefsky break; 30450d7280dSMartin Schwidefsky } 3052c7749b9SJoe Perches fallthrough; 30650d7280dSMartin Schwidefsky case VM_FAULT_BADCONTEXT: 30724eb3a82SDominik Dingel case VM_FAULT_PFAULT: 308aa33c8cbSMartin Schwidefsky do_no_context(regs); 30950d7280dSMartin Schwidefsky break; 310f2c76e3bSHeiko Carstens case VM_FAULT_SIGNAL: 311f2c76e3bSHeiko Carstens if (!user_mode(regs)) 312f2c76e3bSHeiko Carstens do_no_context(regs); 313f2c76e3bSHeiko Carstens break; 31450d7280dSMartin Schwidefsky default: /* fault & VM_FAULT_ERROR */ 31599583181SHeiko Carstens if (fault & VM_FAULT_OOM) { 3167d256175SHeiko Carstens if (!user_mode(regs)) 317aa33c8cbSMartin Schwidefsky do_no_context(regs); 31899583181SHeiko Carstens else 31950d7280dSMartin Schwidefsky pagefault_out_of_memory(); 32033692f27SLinus Torvalds } else if (fault & VM_FAULT_SIGSEGV) { 32133692f27SLinus Torvalds /* Kernel mode? Handle exceptions or die */ 32233692f27SLinus Torvalds if (!user_mode(regs)) 32333692f27SLinus Torvalds do_no_context(regs); 32433692f27SLinus Torvalds else 32533692f27SLinus Torvalds do_sigsegv(regs, SEGV_MAPERR); 32699583181SHeiko Carstens } else if (fault & VM_FAULT_SIGBUS) { 32750d7280dSMartin Schwidefsky /* Kernel mode? Handle exceptions or die */ 3287d256175SHeiko Carstens if (!user_mode(regs)) 329aa33c8cbSMartin Schwidefsky do_no_context(regs); 33036bf9680SMartin Schwidefsky else 331aa33c8cbSMartin Schwidefsky do_sigbus(regs); 33250d7280dSMartin Schwidefsky } else 33350d7280dSMartin Schwidefsky BUG(); 33450d7280dSMartin Schwidefsky break; 33550d7280dSMartin Schwidefsky } 33650d7280dSMartin Schwidefsky } 33750d7280dSMartin Schwidefsky 3381da177e4SLinus Torvalds /* 3391da177e4SLinus Torvalds * This routine handles page faults. It determines the address, 3401da177e4SLinus Torvalds * and the problem, and then passes it off to one of the appropriate 3411da177e4SLinus Torvalds * routines. 3421da177e4SLinus Torvalds * 34350d7280dSMartin Schwidefsky * interruption code (int_code): 3447904aaa8SHeiko Carstens * 04 Protection -> Write-Protection (suppression) 3451da177e4SLinus Torvalds * 10 Segment translation -> Not present (nullification) 3461da177e4SLinus Torvalds * 11 Page translation -> Not present (nullification) 3471da177e4SLinus Torvalds * 3b Region third trans. -> Not present (nullification) 3481da177e4SLinus Torvalds */ 34950a7ca3cSSouptick Joarder static inline vm_fault_t do_exception(struct pt_regs *regs, int access) 3501da177e4SLinus Torvalds { 35124eb3a82SDominik Dingel struct gmap *gmap; 3521da177e4SLinus Torvalds struct task_struct *tsk; 3531da177e4SLinus Torvalds struct mm_struct *mm; 3541da177e4SLinus Torvalds struct vm_area_struct *vma; 3550aaba41bSMartin Schwidefsky enum fault_type type; 356aa33c8cbSMartin Schwidefsky unsigned long trans_exc_code; 3571da177e4SLinus Torvalds unsigned long address; 35833ce6140SHeiko Carstens unsigned int flags; 35950a7ca3cSSouptick Joarder vm_fault_t fault; 360e41ba111SSven Schnelle bool is_write; 36110c1031fSMartin Schwidefsky 36239efd4ecSMartin Schwidefsky tsk = current; 36339efd4ecSMartin Schwidefsky /* 36439efd4ecSMartin Schwidefsky * The instruction that caused the program check has 36539efd4ecSMartin Schwidefsky * been nullified. Don't signal single step via SIGTRAP. 36639efd4ecSMartin Schwidefsky */ 36756e62a73SSven Schnelle clear_thread_flag(TIF_PER_TRAP); 36839efd4ecSMartin Schwidefsky 369b98cca44SAnshuman Khandual if (kprobe_page_fault(regs, 14)) 37050d7280dSMartin Schwidefsky return 0; 3711da177e4SLinus Torvalds 3721da177e4SLinus Torvalds mm = tsk->mm; 373aa33c8cbSMartin Schwidefsky trans_exc_code = regs->int_parm_long; 374e41ba111SSven Schnelle address = trans_exc_code & __FAIL_ADDR_MASK; 375e41ba111SSven Schnelle is_write = (trans_exc_code & store_indication) == 0x400; 3761da177e4SLinus Torvalds 3771da177e4SLinus Torvalds /* 3781da177e4SLinus Torvalds * Verify that the fault happened in user space, that 3791da177e4SLinus Torvalds * we are not in an interrupt and that there is a 3801da177e4SLinus Torvalds * user context. 3811da177e4SLinus Torvalds */ 38250d7280dSMartin Schwidefsky fault = VM_FAULT_BADCONTEXT; 3830aaba41bSMartin Schwidefsky type = get_fault_type(regs); 3840aaba41bSMartin Schwidefsky switch (type) { 3850aaba41bSMartin Schwidefsky case KERNEL_FAULT: 386e41ba111SSven Schnelle if (kfence_handle_page_fault(address, is_write, regs)) 387e41ba111SSven Schnelle return 0; 38850d7280dSMartin Schwidefsky goto out; 3890aaba41bSMartin Schwidefsky case USER_FAULT: 3900aaba41bSMartin Schwidefsky case GMAP_FAULT: 3910aaba41bSMartin Schwidefsky if (faulthandler_disabled() || !mm) 3920aaba41bSMartin Schwidefsky goto out; 3930aaba41bSMartin Schwidefsky break; 3940aaba41bSMartin Schwidefsky } 3951da177e4SLinus Torvalds 396a8b0ca17SPeter Zijlstra perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); 397dde16072SPeter Xu flags = FAULT_FLAG_DEFAULT; 398759496baSJohannes Weiner if (user_mode(regs)) 399759496baSJohannes Weiner flags |= FAULT_FLAG_USER; 400e41ba111SSven Schnelle if (access == VM_WRITE || is_write) 40133ce6140SHeiko Carstens flags |= FAULT_FLAG_WRITE; 402d8ed45c5SMichel Lespinasse mmap_read_lock(mm); 4031da177e4SLinus Torvalds 4040aaba41bSMartin Schwidefsky gmap = NULL; 4050aaba41bSMartin Schwidefsky if (IS_ENABLED(CONFIG_PGSTE) && type == GMAP_FAULT) { 4060aaba41bSMartin Schwidefsky gmap = (struct gmap *) S390_lowcore.gmap; 407527e30b4SMartin Schwidefsky current->thread.gmap_addr = address; 4084be130a0SMartin Schwidefsky current->thread.gmap_write_flag = !!(flags & FAULT_FLAG_WRITE); 4094a494439SDavid Hildenbrand current->thread.gmap_int_code = regs->int_code & 0xffff; 410527e30b4SMartin Schwidefsky address = __gmap_translate(gmap, address); 411e5992f2eSMartin Schwidefsky if (address == -EFAULT) { 412e5992f2eSMartin Schwidefsky fault = VM_FAULT_BADMAP; 413e5992f2eSMartin Schwidefsky goto out_up; 414e5992f2eSMartin Schwidefsky } 41524eb3a82SDominik Dingel if (gmap->pfault_enabled) 41624eb3a82SDominik Dingel flags |= FAULT_FLAG_RETRY_NOWAIT; 417e5992f2eSMartin Schwidefsky } 418e5992f2eSMartin Schwidefsky 419e5992f2eSMartin Schwidefsky retry: 42050d7280dSMartin Schwidefsky fault = VM_FAULT_BADMAP; 4211da177e4SLinus Torvalds vma = find_vma(mm, address); 4221da177e4SLinus Torvalds if (!vma) 42350d7280dSMartin Schwidefsky goto out_up; 424c1821c2eSGerald Schaefer 42550d7280dSMartin Schwidefsky if (unlikely(vma->vm_start > address)) { 4261da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 42750d7280dSMartin Schwidefsky goto out_up; 4281da177e4SLinus Torvalds if (expand_stack(vma, address)) 42950d7280dSMartin Schwidefsky goto out_up; 43050d7280dSMartin Schwidefsky } 43150d7280dSMartin Schwidefsky 4321da177e4SLinus Torvalds /* 4331da177e4SLinus Torvalds * Ok, we have a good vm_area for this memory access, so 4341da177e4SLinus Torvalds * we can handle it.. 4351da177e4SLinus Torvalds */ 43650d7280dSMartin Schwidefsky fault = VM_FAULT_BADACCESS; 4371ab947deSMartin Schwidefsky if (unlikely(!(vma->vm_flags & access))) 43850d7280dSMartin Schwidefsky goto out_up; 4391da177e4SLinus Torvalds 44053492b1dSGerald Schaefer if (is_vm_hugetlb_page(vma)) 44153492b1dSGerald Schaefer address &= HPAGE_MASK; 4421da177e4SLinus Torvalds /* 4431da177e4SLinus Torvalds * If for any reason at all we couldn't handle the fault, 4441da177e4SLinus Torvalds * make sure we exit gracefully rather than endlessly redo 4451da177e4SLinus Torvalds * the fault. 4461da177e4SLinus Torvalds */ 44735e45f3eSPeter Xu fault = handle_mm_fault(vma, address, flags, regs); 4484ef87322SPeter Xu if (fault_signal_pending(fault, regs)) { 449f2c76e3bSHeiko Carstens fault = VM_FAULT_SIGNAL; 450306d6c49SClaudio Imbrenda if (flags & FAULT_FLAG_RETRY_NOWAIT) 451306d6c49SClaudio Imbrenda goto out_up; 452f2c76e3bSHeiko Carstens goto out; 453f2c76e3bSHeiko Carstens } 45450d7280dSMartin Schwidefsky if (unlikely(fault & VM_FAULT_ERROR)) 45550d7280dSMartin Schwidefsky goto out_up; 45650d7280dSMartin Schwidefsky 45733ce6140SHeiko Carstens if (flags & FAULT_FLAG_ALLOW_RETRY) { 45833ce6140SHeiko Carstens if (fault & VM_FAULT_RETRY) { 4590aaba41bSMartin Schwidefsky if (IS_ENABLED(CONFIG_PGSTE) && gmap && 4600aaba41bSMartin Schwidefsky (flags & FAULT_FLAG_RETRY_NOWAIT)) { 46124eb3a82SDominik Dingel /* FAULT_FLAG_RETRY_NOWAIT has been set, 462c1e8d7c6SMichel Lespinasse * mmap_lock has not been released */ 46324eb3a82SDominik Dingel current->thread.gmap_pfault = 1; 46424eb3a82SDominik Dingel fault = VM_FAULT_PFAULT; 46524eb3a82SDominik Dingel goto out_up; 46624eb3a82SDominik Dingel } 4674064b982SPeter Xu flags &= ~FAULT_FLAG_RETRY_NOWAIT; 46845cac65bSShaohua Li flags |= FAULT_FLAG_TRIED; 469d8ed45c5SMichel Lespinasse mmap_read_lock(mm); 47033ce6140SHeiko Carstens goto retry; 47133ce6140SHeiko Carstens } 47233ce6140SHeiko Carstens } 4730aaba41bSMartin Schwidefsky if (IS_ENABLED(CONFIG_PGSTE) && gmap) { 474527e30b4SMartin Schwidefsky address = __gmap_link(gmap, current->thread.gmap_addr, 475527e30b4SMartin Schwidefsky address); 476527e30b4SMartin Schwidefsky if (address == -EFAULT) { 477527e30b4SMartin Schwidefsky fault = VM_FAULT_BADMAP; 478527e30b4SMartin Schwidefsky goto out_up; 479527e30b4SMartin Schwidefsky } 480527e30b4SMartin Schwidefsky if (address == -ENOMEM) { 481527e30b4SMartin Schwidefsky fault = VM_FAULT_OOM; 482527e30b4SMartin Schwidefsky goto out_up; 483527e30b4SMartin Schwidefsky } 484527e30b4SMartin Schwidefsky } 48550d7280dSMartin Schwidefsky fault = 0; 48650d7280dSMartin Schwidefsky out_up: 487d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 48850d7280dSMartin Schwidefsky out: 48950d7280dSMartin Schwidefsky return fault; 4901da177e4SLinus Torvalds } 4911da177e4SLinus Torvalds 4927a5388deSHeiko Carstens void do_protection_exception(struct pt_regs *regs) 4931da177e4SLinus Torvalds { 494aa33c8cbSMartin Schwidefsky unsigned long trans_exc_code; 49550a7ca3cSSouptick Joarder int access; 49650a7ca3cSSouptick Joarder vm_fault_t fault; 49761365e13SMartin Schwidefsky 498aa33c8cbSMartin Schwidefsky trans_exc_code = regs->int_parm_long; 499f752ac4dSMartin Schwidefsky /* 500f752ac4dSMartin Schwidefsky * Protection exceptions are suppressing, decrement psw address. 501f752ac4dSMartin Schwidefsky * The exception to this rule are aborted transactions, for these 502f752ac4dSMartin Schwidefsky * the PSW already points to the correct location. 503f752ac4dSMartin Schwidefsky */ 504f752ac4dSMartin Schwidefsky if (!(regs->int_code & 0x200)) 505aa33c8cbSMartin Schwidefsky regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16); 50610c1031fSMartin Schwidefsky /* 50710c1031fSMartin Schwidefsky * Check for low-address protection. This needs to be treated 50810c1031fSMartin Schwidefsky * as a special case because the translation exception code 50910c1031fSMartin Schwidefsky * field is not guaranteed to contain valid data in this case. 51010c1031fSMartin Schwidefsky */ 51161365e13SMartin Schwidefsky if (unlikely(!(trans_exc_code & 4))) { 512aa33c8cbSMartin Schwidefsky do_low_address(regs); 51310c1031fSMartin Schwidefsky return; 51410c1031fSMartin Schwidefsky } 51557d7f939SMartin Schwidefsky if (unlikely(MACHINE_HAS_NX && (trans_exc_code & 0x80))) { 51657d7f939SMartin Schwidefsky regs->int_parm_long = (trans_exc_code & ~PAGE_MASK) | 51757d7f939SMartin Schwidefsky (regs->psw.addr & PAGE_MASK); 51857d7f939SMartin Schwidefsky access = VM_EXEC; 51957d7f939SMartin Schwidefsky fault = VM_FAULT_BADACCESS; 52057d7f939SMartin Schwidefsky } else { 52157d7f939SMartin Schwidefsky access = VM_WRITE; 52257d7f939SMartin Schwidefsky fault = do_exception(regs, access); 52357d7f939SMartin Schwidefsky } 52450d7280dSMartin Schwidefsky if (unlikely(fault)) 52557d7f939SMartin Schwidefsky do_fault_error(regs, access, fault); 5261da177e4SLinus Torvalds } 5277a5388deSHeiko Carstens NOKPROBE_SYMBOL(do_protection_exception); 5281da177e4SLinus Torvalds 5297a5388deSHeiko Carstens void do_dat_exception(struct pt_regs *regs) 5301da177e4SLinus Torvalds { 53150a7ca3cSSouptick Joarder int access; 53250a7ca3cSSouptick Joarder vm_fault_t fault; 53350d7280dSMartin Schwidefsky 5346cb4d9a2SAnshuman Khandual access = VM_ACCESS_FLAGS; 535aa33c8cbSMartin Schwidefsky fault = do_exception(regs, access); 53650d7280dSMartin Schwidefsky if (unlikely(fault)) 53757d7f939SMartin Schwidefsky do_fault_error(regs, access, fault); 5381da177e4SLinus Torvalds } 5397a5388deSHeiko Carstens NOKPROBE_SYMBOL(do_dat_exception); 5401da177e4SLinus Torvalds 5411da177e4SLinus Torvalds #ifdef CONFIG_PFAULT 5421da177e4SLinus Torvalds /* 5431da177e4SLinus Torvalds * 'pfault' pseudo page faults routines. 5441da177e4SLinus Torvalds */ 545fb0a9d7eSHeiko Carstens static int pfault_disable; 5461da177e4SLinus Torvalds 5471da177e4SLinus Torvalds static int __init nopfault(char *str) 5481da177e4SLinus Torvalds { 5491da177e4SLinus Torvalds pfault_disable = 1; 5501da177e4SLinus Torvalds return 1; 5511da177e4SLinus Torvalds } 5521da177e4SLinus Torvalds 5531da177e4SLinus Torvalds __setup("nopfault", nopfault); 5541da177e4SLinus Torvalds 5557dd8fe1fSHeiko Carstens struct pfault_refbk { 5567dd8fe1fSHeiko Carstens u16 refdiagc; 5577dd8fe1fSHeiko Carstens u16 reffcode; 5587dd8fe1fSHeiko Carstens u16 refdwlen; 5597dd8fe1fSHeiko Carstens u16 refversn; 5607dd8fe1fSHeiko Carstens u64 refgaddr; 5617dd8fe1fSHeiko Carstens u64 refselmk; 5627dd8fe1fSHeiko Carstens u64 refcmpmk; 5637dd8fe1fSHeiko Carstens u64 reserved; 5647dd8fe1fSHeiko Carstens } __attribute__ ((packed, aligned(8))); 5651da177e4SLinus Torvalds 56600e9e664SMartin Schwidefsky static struct pfault_refbk pfault_init_refbk = { 5677dd8fe1fSHeiko Carstens .refdiagc = 0x258, 5687dd8fe1fSHeiko Carstens .reffcode = 0, 5697dd8fe1fSHeiko Carstens .refdwlen = 5, 5707dd8fe1fSHeiko Carstens .refversn = 2, 571e22cf8caSChristian Borntraeger .refgaddr = __LC_LPP, 5727dd8fe1fSHeiko Carstens .refselmk = 1ULL << 48, 5737dd8fe1fSHeiko Carstens .refcmpmk = 1ULL << 48, 57400e9e664SMartin Schwidefsky .reserved = __PF_RES_FIELD 57500e9e664SMartin Schwidefsky }; 57600e9e664SMartin Schwidefsky 57700e9e664SMartin Schwidefsky int pfault_init(void) 57800e9e664SMartin Schwidefsky { 5791da177e4SLinus Torvalds int rc; 5801da177e4SLinus Torvalds 581f32269a0SCarsten Otte if (pfault_disable) 5821da177e4SLinus Torvalds return -1; 5831ec2772eSMartin Schwidefsky diag_stat_inc(DIAG_STAT_X258); 58494c12cc7SMartin Schwidefsky asm volatile( 5851da177e4SLinus Torvalds " diag %1,%0,0x258\n" 5861da177e4SLinus Torvalds "0: j 2f\n" 5871da177e4SLinus Torvalds "1: la %0,8\n" 5881da177e4SLinus Torvalds "2:\n" 58994c12cc7SMartin Schwidefsky EX_TABLE(0b,1b) 59000e9e664SMartin Schwidefsky : "=d" (rc) 59100e9e664SMartin Schwidefsky : "a" (&pfault_init_refbk), "m" (pfault_init_refbk) : "cc"); 5921da177e4SLinus Torvalds return rc; 5931da177e4SLinus Torvalds } 5941da177e4SLinus Torvalds 59500e9e664SMartin Schwidefsky static struct pfault_refbk pfault_fini_refbk = { 5967dd8fe1fSHeiko Carstens .refdiagc = 0x258, 5977dd8fe1fSHeiko Carstens .reffcode = 1, 5987dd8fe1fSHeiko Carstens .refdwlen = 5, 5997dd8fe1fSHeiko Carstens .refversn = 2, 6007dd8fe1fSHeiko Carstens }; 6011da177e4SLinus Torvalds 60200e9e664SMartin Schwidefsky void pfault_fini(void) 60300e9e664SMartin Schwidefsky { 60400e9e664SMartin Schwidefsky 605f32269a0SCarsten Otte if (pfault_disable) 6061da177e4SLinus Torvalds return; 6071ec2772eSMartin Schwidefsky diag_stat_inc(DIAG_STAT_X258); 60894c12cc7SMartin Schwidefsky asm volatile( 6091da177e4SLinus Torvalds " diag %0,0,0x258\n" 6106c22c986SHeiko Carstens "0: nopr %%r7\n" 61194c12cc7SMartin Schwidefsky EX_TABLE(0b,0b) 61200e9e664SMartin Schwidefsky : : "a" (&pfault_fini_refbk), "m" (pfault_fini_refbk) : "cc"); 6131da177e4SLinus Torvalds } 6141da177e4SLinus Torvalds 615f2db2e6cSHeiko Carstens static DEFINE_SPINLOCK(pfault_lock); 616f2db2e6cSHeiko Carstens static LIST_HEAD(pfault_list); 617f2db2e6cSHeiko Carstens 6180227f7c4SPeter Zijlstra #define PF_COMPLETE 0x0080 6190227f7c4SPeter Zijlstra 6200227f7c4SPeter Zijlstra /* 6210227f7c4SPeter Zijlstra * The mechanism of our pfault code: if Linux is running as guest, runs a user 6220227f7c4SPeter Zijlstra * space process and the user space process accesses a page that the host has 6230227f7c4SPeter Zijlstra * paged out we get a pfault interrupt. 6240227f7c4SPeter Zijlstra * 6250227f7c4SPeter Zijlstra * This allows us, within the guest, to schedule a different process. Without 6260227f7c4SPeter Zijlstra * this mechanism the host would have to suspend the whole virtual cpu until 6270227f7c4SPeter Zijlstra * the page has been paged in. 6280227f7c4SPeter Zijlstra * 6290227f7c4SPeter Zijlstra * So when we get such an interrupt then we set the state of the current task 6300227f7c4SPeter Zijlstra * to uninterruptible and also set the need_resched flag. Both happens within 6310227f7c4SPeter Zijlstra * interrupt context(!). If we later on want to return to user space we 6320227f7c4SPeter Zijlstra * recognize the need_resched flag and then call schedule(). It's not very 6330227f7c4SPeter Zijlstra * obvious how this works... 6340227f7c4SPeter Zijlstra * 6350227f7c4SPeter Zijlstra * Of course we have a lot of additional fun with the completion interrupt (-> 6360227f7c4SPeter Zijlstra * host signals that a page of a process has been paged in and the process can 6370227f7c4SPeter Zijlstra * continue to run). This interrupt can arrive on any cpu and, since we have 6380227f7c4SPeter Zijlstra * virtual cpus, actually appear before the interrupt that signals that a page 6390227f7c4SPeter Zijlstra * is missing. 6400227f7c4SPeter Zijlstra */ 641fde15c3aSHeiko Carstens static void pfault_interrupt(struct ext_code ext_code, 642f6649a7eSMartin Schwidefsky unsigned int param32, unsigned long param64) 6431da177e4SLinus Torvalds { 6441da177e4SLinus Torvalds struct task_struct *tsk; 6451da177e4SLinus Torvalds __u16 subcode; 646f2db2e6cSHeiko Carstens pid_t pid; 6471da177e4SLinus Torvalds 6481da177e4SLinus Torvalds /* 6490227f7c4SPeter Zijlstra * Get the external interruption subcode & pfault initial/completion 6500227f7c4SPeter Zijlstra * signal bit. VM stores this in the 'cpu address' field associated 6510227f7c4SPeter Zijlstra * with the external interrupt. 6521da177e4SLinus Torvalds */ 653fde15c3aSHeiko Carstens subcode = ext_code.subcode; 6541da177e4SLinus Torvalds if ((subcode & 0xff00) != __SUBCODE_MASK) 6551da177e4SLinus Torvalds return; 656420f42ecSHeiko Carstens inc_irq_stat(IRQEXT_PFL); 657f2db2e6cSHeiko Carstens /* Get the token (= pid of the affected task). */ 658544e8dd7SHendrik Brueckner pid = param64 & LPP_PID_MASK; 659f2db2e6cSHeiko Carstens rcu_read_lock(); 660f2db2e6cSHeiko Carstens tsk = find_task_by_pid_ns(pid, &init_pid_ns); 661f2db2e6cSHeiko Carstens if (tsk) 662f2db2e6cSHeiko Carstens get_task_struct(tsk); 663f2db2e6cSHeiko Carstens rcu_read_unlock(); 664f2db2e6cSHeiko Carstens if (!tsk) 665f2db2e6cSHeiko Carstens return; 666f2db2e6cSHeiko Carstens spin_lock(&pfault_lock); 6670227f7c4SPeter Zijlstra if (subcode & PF_COMPLETE) { 6681da177e4SLinus Torvalds /* signal bit is set -> a page has been swapped in by VM */ 669f2db2e6cSHeiko Carstens if (tsk->thread.pfault_wait == 1) { 6701da177e4SLinus Torvalds /* Initial interrupt was faster than the completion 6711da177e4SLinus Torvalds * interrupt. pfault_wait is valid. Set pfault_wait 6721da177e4SLinus Torvalds * back to zero and wake up the process. This can 6731da177e4SLinus Torvalds * safely be done because the task is still sleeping 674b6d09449SMartin Schwidefsky * and can't produce new pfaults. */ 6751da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 676f2db2e6cSHeiko Carstens list_del(&tsk->thread.list); 6771da177e4SLinus Torvalds wake_up_process(tsk); 678d5e50a51SHeiko Carstens put_task_struct(tsk); 679f2db2e6cSHeiko Carstens } else { 680f2db2e6cSHeiko Carstens /* Completion interrupt was faster than initial 681f2db2e6cSHeiko Carstens * interrupt. Set pfault_wait to -1 so the initial 682fa2fb2f4SHeiko Carstens * interrupt doesn't put the task to sleep. 683fa2fb2f4SHeiko Carstens * If the task is not running, ignore the completion 684fa2fb2f4SHeiko Carstens * interrupt since it must be a leftover of a PFAULT 685fa2fb2f4SHeiko Carstens * CANCEL operation which didn't remove all pending 686fa2fb2f4SHeiko Carstens * completion interrupts. */ 687b03fbd4fSPeter Zijlstra if (task_is_running(tsk)) 688f2db2e6cSHeiko Carstens tsk->thread.pfault_wait = -1; 6891da177e4SLinus Torvalds } 6901da177e4SLinus Torvalds } else { 6911da177e4SLinus Torvalds /* signal bit not set -> a real page is missing. */ 692d49f47f8SHeiko Carstens if (WARN_ON_ONCE(tsk != current)) 693d49f47f8SHeiko Carstens goto out; 694d5e50a51SHeiko Carstens if (tsk->thread.pfault_wait == 1) { 695d5e50a51SHeiko Carstens /* Already on the list with a reference: put to sleep */ 6960227f7c4SPeter Zijlstra goto block; 697d5e50a51SHeiko Carstens } else if (tsk->thread.pfault_wait == -1) { 6981da177e4SLinus Torvalds /* Completion interrupt was faster than the initial 699f2db2e6cSHeiko Carstens * interrupt (pfault_wait == -1). Set pfault_wait 700f2db2e6cSHeiko Carstens * back to zero and exit. */ 7011da177e4SLinus Torvalds tsk->thread.pfault_wait = 0; 702f2db2e6cSHeiko Carstens } else { 703f2db2e6cSHeiko Carstens /* Initial interrupt arrived before completion 704d5e50a51SHeiko Carstens * interrupt. Let the task sleep. 705d5e50a51SHeiko Carstens * An extra task reference is needed since a different 706d5e50a51SHeiko Carstens * cpu may set the task state to TASK_RUNNING again 707d5e50a51SHeiko Carstens * before the scheduler is reached. */ 708d5e50a51SHeiko Carstens get_task_struct(tsk); 709f2db2e6cSHeiko Carstens tsk->thread.pfault_wait = 1; 710f2db2e6cSHeiko Carstens list_add(&tsk->thread.list, &pfault_list); 7110227f7c4SPeter Zijlstra block: 7120227f7c4SPeter Zijlstra /* Since this must be a userspace fault, there 7130227f7c4SPeter Zijlstra * is no kernel task state to trample. Rely on the 7140227f7c4SPeter Zijlstra * return to userspace schedule() to block. */ 7150227f7c4SPeter Zijlstra __set_current_state(TASK_UNINTERRUPTIBLE); 7161da177e4SLinus Torvalds set_tsk_need_resched(tsk); 717c360192bSMartin Schwidefsky set_preempt_need_resched(); 7181da177e4SLinus Torvalds } 7191da177e4SLinus Torvalds } 720d49f47f8SHeiko Carstens out: 721f2db2e6cSHeiko Carstens spin_unlock(&pfault_lock); 72254c27791SHeiko Carstens put_task_struct(tsk); 723f2db2e6cSHeiko Carstens } 724f2db2e6cSHeiko Carstens 72584c9ceefSSebastian Andrzej Siewior static int pfault_cpu_dead(unsigned int cpu) 726f2db2e6cSHeiko Carstens { 727f2db2e6cSHeiko Carstens struct thread_struct *thread, *next; 728f2db2e6cSHeiko Carstens struct task_struct *tsk; 729f2db2e6cSHeiko Carstens 730f2db2e6cSHeiko Carstens spin_lock_irq(&pfault_lock); 731f2db2e6cSHeiko Carstens list_for_each_entry_safe(thread, next, &pfault_list, list) { 732f2db2e6cSHeiko Carstens thread->pfault_wait = 0; 733f2db2e6cSHeiko Carstens list_del(&thread->list); 734f2db2e6cSHeiko Carstens tsk = container_of(thread, struct task_struct, thread); 735f2db2e6cSHeiko Carstens wake_up_process(tsk); 736d5e50a51SHeiko Carstens put_task_struct(tsk); 737f2db2e6cSHeiko Carstens } 738f2db2e6cSHeiko Carstens spin_unlock_irq(&pfault_lock); 73984c9ceefSSebastian Andrzej Siewior return 0; 740f2db2e6cSHeiko Carstens } 7411da177e4SLinus Torvalds 742fb0a9d7eSHeiko Carstens static int __init pfault_irq_init(void) 74329b08d2bSHeiko Carstens { 744fb0a9d7eSHeiko Carstens int rc; 74529b08d2bSHeiko Carstens 7461dad093bSThomas Huth rc = register_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt); 7477dd8fe1fSHeiko Carstens if (rc) 7487dd8fe1fSHeiko Carstens goto out_extint; 7497dd8fe1fSHeiko Carstens rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP; 7507dd8fe1fSHeiko Carstens if (rc) 7517dd8fe1fSHeiko Carstens goto out_pfault; 75282003c3eSHeiko Carstens irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL); 75384c9ceefSSebastian Andrzej Siewior cpuhp_setup_state_nocalls(CPUHP_S390_PFAULT_DEAD, "s390/pfault:dead", 75484c9ceefSSebastian Andrzej Siewior NULL, pfault_cpu_dead); 7557dd8fe1fSHeiko Carstens return 0; 7567dd8fe1fSHeiko Carstens 7577dd8fe1fSHeiko Carstens out_pfault: 7581dad093bSThomas Huth unregister_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt); 7597dd8fe1fSHeiko Carstens out_extint: 760fb0a9d7eSHeiko Carstens pfault_disable = 1; 761fb0a9d7eSHeiko Carstens return rc; 762fb0a9d7eSHeiko Carstens } 763fb0a9d7eSHeiko Carstens early_initcall(pfault_irq_init); 764fb0a9d7eSHeiko Carstens 7657dd8fe1fSHeiko Carstens #endif /* CONFIG_PFAULT */ 766084ea4d6SVasily Gorbik 767084ea4d6SVasily Gorbik #if IS_ENABLED(CONFIG_PGSTE) 76817a363dcSHeiko Carstens 769084ea4d6SVasily Gorbik void do_secure_storage_access(struct pt_regs *regs) 770084ea4d6SVasily Gorbik { 771084ea4d6SVasily Gorbik unsigned long addr = regs->int_parm_long & __FAIL_ADDR_MASK; 772084ea4d6SVasily Gorbik struct vm_area_struct *vma; 773084ea4d6SVasily Gorbik struct mm_struct *mm; 774084ea4d6SVasily Gorbik struct page *page; 775084ea4d6SVasily Gorbik int rc; 776084ea4d6SVasily Gorbik 77785b18d7bSJanosch Frank /* 77885b18d7bSJanosch Frank * bit 61 tells us if the address is valid, if it's not we 77985b18d7bSJanosch Frank * have a major problem and should stop the kernel or send a 78085b18d7bSJanosch Frank * SIGSEGV to the process. Unfortunately bit 61 is not 78185b18d7bSJanosch Frank * reliable without the misc UV feature so we need to check 78285b18d7bSJanosch Frank * for that as well. 78385b18d7bSJanosch Frank */ 78485b18d7bSJanosch Frank if (test_bit_inv(BIT_UV_FEAT_MISC, &uv_info.uv_feature_indications) && 78585b18d7bSJanosch Frank !test_bit_inv(61, ®s->int_parm_long)) { 78685b18d7bSJanosch Frank /* 78785b18d7bSJanosch Frank * When this happens, userspace did something that it 78885b18d7bSJanosch Frank * was not supposed to do, e.g. branching into secure 78985b18d7bSJanosch Frank * memory. Trigger a segmentation fault. 79085b18d7bSJanosch Frank */ 79185b18d7bSJanosch Frank if (user_mode(regs)) { 79285b18d7bSJanosch Frank send_sig(SIGSEGV, current, 0); 79385b18d7bSJanosch Frank return; 79485b18d7bSJanosch Frank } 79585b18d7bSJanosch Frank 79685b18d7bSJanosch Frank /* 79785b18d7bSJanosch Frank * The kernel should never run into this case and we 79885b18d7bSJanosch Frank * have no way out of this situation. 79985b18d7bSJanosch Frank */ 80085b18d7bSJanosch Frank panic("Unexpected PGM 0x3d with TEID bit 61=0"); 80185b18d7bSJanosch Frank } 80285b18d7bSJanosch Frank 803084ea4d6SVasily Gorbik switch (get_fault_type(regs)) { 804084ea4d6SVasily Gorbik case USER_FAULT: 805084ea4d6SVasily Gorbik mm = current->mm; 806d8ed45c5SMichel Lespinasse mmap_read_lock(mm); 807084ea4d6SVasily Gorbik vma = find_vma(mm, addr); 808084ea4d6SVasily Gorbik if (!vma) { 809d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 810084ea4d6SVasily Gorbik do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP); 811084ea4d6SVasily Gorbik break; 812084ea4d6SVasily Gorbik } 813084ea4d6SVasily Gorbik page = follow_page(vma, addr, FOLL_WRITE | FOLL_GET); 814084ea4d6SVasily Gorbik if (IS_ERR_OR_NULL(page)) { 815d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 816084ea4d6SVasily Gorbik break; 817084ea4d6SVasily Gorbik } 818084ea4d6SVasily Gorbik if (arch_make_page_accessible(page)) 819084ea4d6SVasily Gorbik send_sig(SIGSEGV, current, 0); 820084ea4d6SVasily Gorbik put_page(page); 821d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 822084ea4d6SVasily Gorbik break; 823084ea4d6SVasily Gorbik case KERNEL_FAULT: 824084ea4d6SVasily Gorbik page = phys_to_page(addr); 825*cd1adf1bSLinus Torvalds if (unlikely(!try_get_page(page))) 826084ea4d6SVasily Gorbik break; 827084ea4d6SVasily Gorbik rc = arch_make_page_accessible(page); 828084ea4d6SVasily Gorbik put_page(page); 829084ea4d6SVasily Gorbik if (rc) 830084ea4d6SVasily Gorbik BUG(); 831084ea4d6SVasily Gorbik break; 832084ea4d6SVasily Gorbik case GMAP_FAULT: 833084ea4d6SVasily Gorbik default: 834084ea4d6SVasily Gorbik do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP); 835084ea4d6SVasily Gorbik WARN_ON_ONCE(1); 836084ea4d6SVasily Gorbik } 837084ea4d6SVasily Gorbik } 838084ea4d6SVasily Gorbik NOKPROBE_SYMBOL(do_secure_storage_access); 839084ea4d6SVasily Gorbik 840084ea4d6SVasily Gorbik void do_non_secure_storage_access(struct pt_regs *regs) 841084ea4d6SVasily Gorbik { 842084ea4d6SVasily Gorbik unsigned long gaddr = regs->int_parm_long & __FAIL_ADDR_MASK; 843084ea4d6SVasily Gorbik struct gmap *gmap = (struct gmap *)S390_lowcore.gmap; 844084ea4d6SVasily Gorbik 845084ea4d6SVasily Gorbik if (get_fault_type(regs) != GMAP_FAULT) { 846084ea4d6SVasily Gorbik do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP); 847084ea4d6SVasily Gorbik WARN_ON_ONCE(1); 848084ea4d6SVasily Gorbik return; 849084ea4d6SVasily Gorbik } 850084ea4d6SVasily Gorbik 851084ea4d6SVasily Gorbik if (gmap_convert_to_secure(gmap, gaddr) == -EINVAL) 852084ea4d6SVasily Gorbik send_sig(SIGSEGV, current, 0); 853084ea4d6SVasily Gorbik } 854084ea4d6SVasily Gorbik NOKPROBE_SYMBOL(do_non_secure_storage_access); 855084ea4d6SVasily Gorbik 856cd4d3d5fSJanosch Frank void do_secure_storage_violation(struct pt_regs *regs) 857cd4d3d5fSJanosch Frank { 858cd4d3d5fSJanosch Frank /* 859cd4d3d5fSJanosch Frank * Either KVM messed up the secure guest mapping or the same 860cd4d3d5fSJanosch Frank * page is mapped into multiple secure guests. 861cd4d3d5fSJanosch Frank * 862cd4d3d5fSJanosch Frank * This exception is only triggered when a guest 2 is running 863cd4d3d5fSJanosch Frank * and can therefore never occur in kernel context. 864cd4d3d5fSJanosch Frank */ 865cd4d3d5fSJanosch Frank printk_ratelimited(KERN_WARNING 866cd4d3d5fSJanosch Frank "Secure storage violation in task: %s, pid %d\n", 867cd4d3d5fSJanosch Frank current->comm, current->pid); 868cd4d3d5fSJanosch Frank send_sig(SIGSEGV, current, 0); 869cd4d3d5fSJanosch Frank } 870cd4d3d5fSJanosch Frank 87117a363dcSHeiko Carstens #endif /* CONFIG_PGSTE */ 872