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linux-zen-server/arch/s390/mm/fault.c

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// SPDX-License-Identifier: GPL-2.0
/*
* S390 version
* Copyright IBM Corp. 1999
* Author(s): Hartmut Penner (hp@de.ibm.com)
* Ulrich Weigand (uweigand@de.ibm.com)
*
* Derived from "arch/i386/mm/fault.c"
* Copyright (C) 1995 Linus Torvalds
*/
#include <linux/kernel_stat.h>
#include <linux/perf_event.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/compat.h>
#include <linux/smp.h>
#include <linux/kdebug.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/extable.h>
#include <linux/hardirq.h>
#include <linux/kprobes.h>
#include <linux/uaccess.h>
#include <linux/hugetlb.h>
#include <linux/kfence.h>
#include <asm/asm-extable.h>
#include <asm/asm-offsets.h>
#include <asm/diag.h>
#include <asm/gmap.h>
#include <asm/irq.h>
#include <asm/mmu_context.h>
#include <asm/facility.h>
#include <asm/uv.h>
#include "../kernel/entry.h"
#define __FAIL_ADDR_MASK -4096L
#define __SUBCODE_MASK 0x0600
#define __PF_RES_FIELD 0x8000000000000000ULL
/*
* Allocate private vm_fault_reason from top. Please make sure it won't
* collide with vm_fault_reason.
*/
#define VM_FAULT_BADCONTEXT ((__force vm_fault_t)0x80000000)
#define VM_FAULT_BADMAP ((__force vm_fault_t)0x40000000)
#define VM_FAULT_BADACCESS ((__force vm_fault_t)0x20000000)
#define VM_FAULT_SIGNAL ((__force vm_fault_t)0x10000000)
#define VM_FAULT_PFAULT ((__force vm_fault_t)0x8000000)
enum fault_type {
KERNEL_FAULT,
USER_FAULT,
GMAP_FAULT,
};
static unsigned long store_indication __read_mostly;
static int __init fault_init(void)
{
if (test_facility(75))
store_indication = 0xc00;
return 0;
}
early_initcall(fault_init);
/*
* Find out which address space caused the exception.
*/
static enum fault_type get_fault_type(struct pt_regs *regs)
{
unsigned long trans_exc_code;
trans_exc_code = regs->int_parm_long & 3;
if (likely(trans_exc_code == 0)) {
/* primary space exception */
if (user_mode(regs))
return USER_FAULT;
if (!IS_ENABLED(CONFIG_PGSTE))
return KERNEL_FAULT;
if (test_pt_regs_flag(regs, PIF_GUEST_FAULT))
return GMAP_FAULT;
return KERNEL_FAULT;
}
if (trans_exc_code == 2)
return USER_FAULT;
if (trans_exc_code == 1) {
/* access register mode, not used in the kernel */
return USER_FAULT;
}
/* home space exception -> access via kernel ASCE */
return KERNEL_FAULT;
}
static unsigned long get_fault_address(struct pt_regs *regs)
{
unsigned long trans_exc_code = regs->int_parm_long;
return trans_exc_code & __FAIL_ADDR_MASK;
}
static bool fault_is_write(struct pt_regs *regs)
{
unsigned long trans_exc_code = regs->int_parm_long;
return (trans_exc_code & store_indication) == 0x400;
}
static int bad_address(void *p)
{
unsigned long dummy;
return get_kernel_nofault(dummy, (unsigned long *)p);
}
static void dump_pagetable(unsigned long asce, unsigned long address)
{
unsigned long *table = __va(asce & _ASCE_ORIGIN);
pr_alert("AS:%016lx ", asce);
switch (asce & _ASCE_TYPE_MASK) {
case _ASCE_TYPE_REGION1:
table += (address & _REGION1_INDEX) >> _REGION1_SHIFT;
if (bad_address(table))
goto bad;
pr_cont("R1:%016lx ", *table);
if (*table & _REGION_ENTRY_INVALID)
goto out;
table = __va(*table & _REGION_ENTRY_ORIGIN);
fallthrough;
case _ASCE_TYPE_REGION2:
table += (address & _REGION2_INDEX) >> _REGION2_SHIFT;
if (bad_address(table))
goto bad;
pr_cont("R2:%016lx ", *table);
if (*table & _REGION_ENTRY_INVALID)
goto out;
table = __va(*table & _REGION_ENTRY_ORIGIN);
fallthrough;
case _ASCE_TYPE_REGION3:
table += (address & _REGION3_INDEX) >> _REGION3_SHIFT;
if (bad_address(table))
goto bad;
pr_cont("R3:%016lx ", *table);
if (*table & (_REGION_ENTRY_INVALID | _REGION3_ENTRY_LARGE))
goto out;
table = __va(*table & _REGION_ENTRY_ORIGIN);
fallthrough;
case _ASCE_TYPE_SEGMENT:
table += (address & _SEGMENT_INDEX) >> _SEGMENT_SHIFT;
if (bad_address(table))
goto bad;
pr_cont("S:%016lx ", *table);
if (*table & (_SEGMENT_ENTRY_INVALID | _SEGMENT_ENTRY_LARGE))
goto out;
table = __va(*table & _SEGMENT_ENTRY_ORIGIN);
}
table += (address & _PAGE_INDEX) >> _PAGE_SHIFT;
if (bad_address(table))
goto bad;
pr_cont("P:%016lx ", *table);
out:
pr_cont("\n");
return;
bad:
pr_cont("BAD\n");
}
static void dump_fault_info(struct pt_regs *regs)
{
unsigned long asce;
pr_alert("Failing address: %016lx TEID: %016lx\n",
regs->int_parm_long & __FAIL_ADDR_MASK, regs->int_parm_long);
pr_alert("Fault in ");
switch (regs->int_parm_long & 3) {
case 3:
pr_cont("home space ");
break;
case 2:
pr_cont("secondary space ");
break;
case 1:
pr_cont("access register ");
break;
case 0:
pr_cont("primary space ");
break;
}
pr_cont("mode while using ");
switch (get_fault_type(regs)) {
case USER_FAULT:
asce = S390_lowcore.user_asce;
pr_cont("user ");
break;
case GMAP_FAULT:
asce = ((struct gmap *) S390_lowcore.gmap)->asce;
pr_cont("gmap ");
break;
case KERNEL_FAULT:
asce = S390_lowcore.kernel_asce;
pr_cont("kernel ");
break;
default:
unreachable();
}
pr_cont("ASCE.\n");
dump_pagetable(asce, regs->int_parm_long & __FAIL_ADDR_MASK);
}
int show_unhandled_signals = 1;
void report_user_fault(struct pt_regs *regs, long signr, int is_mm_fault)
{
if ((task_pid_nr(current) > 1) && !show_unhandled_signals)
return;
if (!unhandled_signal(current, signr))
return;
if (!printk_ratelimit())
return;
printk(KERN_ALERT "User process fault: interruption code %04x ilc:%d ",
regs->int_code & 0xffff, regs->int_code >> 17);
print_vma_addr(KERN_CONT "in ", regs->psw.addr);
printk(KERN_CONT "\n");
if (is_mm_fault)
dump_fault_info(regs);
show_regs(regs);
}
/*
* Send SIGSEGV to task. This is an external routine
* to keep the stack usage of do_page_fault small.
*/
static noinline void do_sigsegv(struct pt_regs *regs, int si_code)
{
report_user_fault(regs, SIGSEGV, 1);
force_sig_fault(SIGSEGV, si_code,
(void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK));
}
static noinline void do_no_context(struct pt_regs *regs, vm_fault_t fault)
{
enum fault_type fault_type;
unsigned long address;
bool is_write;
if (fixup_exception(regs))
return;
fault_type = get_fault_type(regs);
if ((fault_type == KERNEL_FAULT) && (fault == VM_FAULT_BADCONTEXT)) {
address = get_fault_address(regs);
is_write = fault_is_write(regs);
if (kfence_handle_page_fault(address, is_write, regs))
return;
}
/*
* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.
*/
if (fault_type == KERNEL_FAULT)
printk(KERN_ALERT "Unable to handle kernel pointer dereference"
" in virtual kernel address space\n");
else
printk(KERN_ALERT "Unable to handle kernel paging request"
" in virtual user address space\n");
dump_fault_info(regs);
die(regs, "Oops");
}
static noinline void do_low_address(struct pt_regs *regs)
{
/* Low-address protection hit in kernel mode means
NULL pointer write access in kernel mode. */
if (regs->psw.mask & PSW_MASK_PSTATE) {
/* Low-address protection hit in user mode 'cannot happen'. */
die (regs, "Low-address protection");
}
do_no_context(regs, VM_FAULT_BADACCESS);
}
static noinline void do_sigbus(struct pt_regs *regs)
{
/*
* Send a sigbus, regardless of whether we were in kernel
* or user mode.
*/
force_sig_fault(SIGBUS, BUS_ADRERR,
(void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK));
}
static noinline void do_fault_error(struct pt_regs *regs, vm_fault_t fault)
{
int si_code;
switch (fault) {
case VM_FAULT_BADACCESS:
case VM_FAULT_BADMAP:
/* Bad memory access. Check if it is kernel or user space. */
if (user_mode(regs)) {
/* User mode accesses just cause a SIGSEGV */
si_code = (fault == VM_FAULT_BADMAP) ?
SEGV_MAPERR : SEGV_ACCERR;
do_sigsegv(regs, si_code);
break;
}
fallthrough;
case VM_FAULT_BADCONTEXT:
case VM_FAULT_PFAULT:
do_no_context(regs, fault);
break;
case VM_FAULT_SIGNAL:
if (!user_mode(regs))
do_no_context(regs, fault);
break;
default: /* fault & VM_FAULT_ERROR */
if (fault & VM_FAULT_OOM) {
if (!user_mode(regs))
do_no_context(regs, fault);
else
pagefault_out_of_memory();
} else if (fault & VM_FAULT_SIGSEGV) {
/* Kernel mode? Handle exceptions or die */
if (!user_mode(regs))
do_no_context(regs, fault);
else
do_sigsegv(regs, SEGV_MAPERR);
} else if (fault & VM_FAULT_SIGBUS) {
/* Kernel mode? Handle exceptions or die */
if (!user_mode(regs))
do_no_context(regs, fault);
else
do_sigbus(regs);
} else
BUG();
break;
}
}
/*
* This routine handles page faults. It determines the address,
* and the problem, and then passes it off to one of the appropriate
* routines.
*
* interruption code (int_code):
* 04 Protection -> Write-Protection (suppression)
* 10 Segment translation -> Not present (nullification)
* 11 Page translation -> Not present (nullification)
* 3b Region third trans. -> Not present (nullification)
*/
static inline vm_fault_t do_exception(struct pt_regs *regs, int access)
{
struct gmap *gmap;
struct task_struct *tsk;
struct mm_struct *mm;
struct vm_area_struct *vma;
enum fault_type type;
unsigned long address;
unsigned int flags;
vm_fault_t fault;
bool is_write;
tsk = current;
/*
* The instruction that caused the program check has
* been nullified. Don't signal single step via SIGTRAP.
*/
clear_thread_flag(TIF_PER_TRAP);
if (kprobe_page_fault(regs, 14))
return 0;
mm = tsk->mm;
address = get_fault_address(regs);
is_write = fault_is_write(regs);
/*
* Verify that the fault happened in user space, that
* we are not in an interrupt and that there is a
* user context.
*/
fault = VM_FAULT_BADCONTEXT;
type = get_fault_type(regs);
switch (type) {
case KERNEL_FAULT:
goto out;
case USER_FAULT:
case GMAP_FAULT:
if (faulthandler_disabled() || !mm)
goto out;
break;
}
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
flags = FAULT_FLAG_DEFAULT;
if (user_mode(regs))
flags |= FAULT_FLAG_USER;
if (is_write)
access = VM_WRITE;
if (access == VM_WRITE)
flags |= FAULT_FLAG_WRITE;
mmap_read_lock(mm);
gmap = NULL;
if (IS_ENABLED(CONFIG_PGSTE) && type == GMAP_FAULT) {
gmap = (struct gmap *) S390_lowcore.gmap;
current->thread.gmap_addr = address;
current->thread.gmap_write_flag = !!(flags & FAULT_FLAG_WRITE);
current->thread.gmap_int_code = regs->int_code & 0xffff;
address = __gmap_translate(gmap, address);
if (address == -EFAULT) {
fault = VM_FAULT_BADMAP;
goto out_up;
}
if (gmap->pfault_enabled)
flags |= FAULT_FLAG_RETRY_NOWAIT;
}
retry:
fault = VM_FAULT_BADMAP;
vma = find_vma(mm, address);
if (!vma)
goto out_up;
if (unlikely(vma->vm_start > address)) {
if (!(vma->vm_flags & VM_GROWSDOWN))
goto out_up;
if (expand_stack(vma, address))
goto out_up;
}
/*
* Ok, we have a good vm_area for this memory access, so
* we can handle it..
*/
fault = VM_FAULT_BADACCESS;
if (unlikely(!(vma->vm_flags & access)))
goto out_up;
/*
* If for any reason at all we couldn't handle the fault,
* make sure we exit gracefully rather than endlessly redo
* the fault.
*/
fault = handle_mm_fault(vma, address, flags, regs);
if (fault_signal_pending(fault, regs)) {
fault = VM_FAULT_SIGNAL;
if (flags & FAULT_FLAG_RETRY_NOWAIT)
goto out_up;
goto out;
}
/* The fault is fully completed (including releasing mmap lock) */
if (fault & VM_FAULT_COMPLETED) {
if (gmap) {
mmap_read_lock(mm);
goto out_gmap;
}
fault = 0;
goto out;
}
if (unlikely(fault & VM_FAULT_ERROR))
goto out_up;
if (fault & VM_FAULT_RETRY) {
if (IS_ENABLED(CONFIG_PGSTE) && gmap &&
(flags & FAULT_FLAG_RETRY_NOWAIT)) {
/*
* FAULT_FLAG_RETRY_NOWAIT has been set, mmap_lock has
* not been released
*/
current->thread.gmap_pfault = 1;
fault = VM_FAULT_PFAULT;
goto out_up;
}
flags &= ~FAULT_FLAG_RETRY_NOWAIT;
flags |= FAULT_FLAG_TRIED;
mmap_read_lock(mm);
goto retry;
}
out_gmap:
if (IS_ENABLED(CONFIG_PGSTE) && 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;
}
}
fault = 0;
out_up:
mmap_read_unlock(mm);
out:
return fault;
}
void do_protection_exception(struct pt_regs *regs)
{
unsigned long trans_exc_code;
int access;
vm_fault_t 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, fault);
}
NOKPROBE_SYMBOL(do_protection_exception);
void do_dat_exception(struct pt_regs *regs)
{
int access;
vm_fault_t fault;
access = VM_ACCESS_FLAGS;
fault = do_exception(regs, access);
if (unlikely(fault))
do_fault_error(regs, 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)));
static struct pfault_refbk pfault_init_refbk = {
.refdiagc = 0x258,
.reffcode = 0,
.refdwlen = 5,
.refversn = 2,
.refgaddr = __LC_LPP,
.refselmk = 1ULL << 48,
.refcmpmk = 1ULL << 48,
.reserved = __PF_RES_FIELD
};
int pfault_init(void)
{
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" (&pfault_init_refbk), "m" (pfault_init_refbk) : "cc");
return rc;
}
static struct pfault_refbk pfault_fini_refbk = {
.refdiagc = 0x258,
.reffcode = 1,
.refdwlen = 5,
.refversn = 2,
};
void pfault_fini(void)
{
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" (&pfault_fini_refbk), "m" (pfault_fini_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_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 (task_is_running(tsk))
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 */
#if IS_ENABLED(CONFIG_PGSTE)
void do_secure_storage_access(struct pt_regs *regs)
{
unsigned long addr = regs->int_parm_long & __FAIL_ADDR_MASK;
struct vm_area_struct *vma;
struct mm_struct *mm;
struct page *page;
struct gmap *gmap;
int rc;
/*
* bit 61 tells us if the address is valid, if it's not we
* have a major problem and should stop the kernel or send a
* SIGSEGV to the process. Unfortunately bit 61 is not
* reliable without the misc UV feature so we need to check
* for that as well.
*/
if (test_bit_inv(BIT_UV_FEAT_MISC, &uv_info.uv_feature_indications) &&
!test_bit_inv(61, &regs->int_parm_long)) {
/*
* When this happens, userspace did something that it
* was not supposed to do, e.g. branching into secure
* memory. Trigger a segmentation fault.
*/
if (user_mode(regs)) {
send_sig(SIGSEGV, current, 0);
return;
}
/*
* The kernel should never run into this case and we
* have no way out of this situation.
*/
panic("Unexpected PGM 0x3d with TEID bit 61=0");
}
switch (get_fault_type(regs)) {
case GMAP_FAULT:
mm = current->mm;
gmap = (struct gmap *)S390_lowcore.gmap;
mmap_read_lock(mm);
addr = __gmap_translate(gmap, addr);
mmap_read_unlock(mm);
if (IS_ERR_VALUE(addr)) {
do_fault_error(regs, VM_FAULT_BADMAP);
break;
}
fallthrough;
case USER_FAULT:
mm = current->mm;
mmap_read_lock(mm);
vma = find_vma(mm, addr);
if (!vma) {
mmap_read_unlock(mm);
do_fault_error(regs, VM_FAULT_BADMAP);
break;
}
page = follow_page(vma, addr, FOLL_WRITE | FOLL_GET);
if (IS_ERR_OR_NULL(page)) {
mmap_read_unlock(mm);
break;
}
if (arch_make_page_accessible(page))
send_sig(SIGSEGV, current, 0);
put_page(page);
mmap_read_unlock(mm);
break;
case KERNEL_FAULT:
page = phys_to_page(addr);
if (unlikely(!try_get_page(page)))
break;
rc = arch_make_page_accessible(page);
put_page(page);
if (rc)
BUG();
break;
default:
do_fault_error(regs, VM_FAULT_BADMAP);
WARN_ON_ONCE(1);
}
}
NOKPROBE_SYMBOL(do_secure_storage_access);
void do_non_secure_storage_access(struct pt_regs *regs)
{
unsigned long gaddr = regs->int_parm_long & __FAIL_ADDR_MASK;
struct gmap *gmap = (struct gmap *)S390_lowcore.gmap;
if (get_fault_type(regs) != GMAP_FAULT) {
do_fault_error(regs, VM_FAULT_BADMAP);
WARN_ON_ONCE(1);
return;
}
if (gmap_convert_to_secure(gmap, gaddr) == -EINVAL)
send_sig(SIGSEGV, current, 0);
}
NOKPROBE_SYMBOL(do_non_secure_storage_access);
void do_secure_storage_violation(struct pt_regs *regs)
{
unsigned long gaddr = regs->int_parm_long & __FAIL_ADDR_MASK;
struct gmap *gmap = (struct gmap *)S390_lowcore.gmap;
/*
* If the VM has been rebooted, its address space might still contain
* secure pages from the previous boot.
* Clear the page so it can be reused.
*/
if (!gmap_destroy_page(gmap, gaddr))
return;
/*
* Either KVM messed up the secure guest mapping or the same
* page is mapped into multiple secure guests.
*
* This exception is only triggered when a guest 2 is running
* and can therefore never occur in kernel context.
*/
printk_ratelimited(KERN_WARNING
"Secure storage violation in task: %s, pid %d\n",
current->comm, current->pid);
send_sig(SIGSEGV, current, 0);
}
#endif /* CONFIG_PGSTE */
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