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linux/arch/s390/mm/fault.c
Heiko Carstens 87d5986345 s390/mm: remove set_fs / rework address space handling 
Remove set_fs support from s390. With doing this rework address space
handling and simplify it. As a result address spaces are now setup
like this:

CPU running in              | %cr1 ASCE | %cr7 ASCE | %cr13 ASCE
----------------------------|-----------|-----------|-----------
user space                  |  user     |  user     |  kernel
kernel, normal execution    |  kernel   |  user     |  kernel
kernel, kvm guest execution |  gmap     |  user     |  kernel

To achieve this the getcpu vdso syscall is removed in order to avoid
secondary address mode and a separate vdso address space in for user
space. The getcpu vdso syscall will be implemented differently with a
subsequent patch.

The kernel accesses user space always via secondary address space.
This happens in different ways:
- with mvcos in home space mode and directly read/write to secondary
  address space
- with mvcs/mvcp in primary space mode and copy from primary space to
  secondary space or vice versa
- with e.g. cs in secondary space mode and access secondary space

Switching translation modes happens with sacf before and after
instructions which access user space, like before.

Lazy handling of control register reloading is removed in the hope to
make everything simpler, but at the cost of making kernel entry and
exit a bit slower. That is: on kernel entry the primary asce is always
changed to contain the kernel asce, and on kernel exit the primary
asce is changed again so it contains the user asce.

In kernel mode there is only one exception to the primary asce: when
kvm guests are executed the primary asce contains the gmap asce (which
describes the guest address space). The primary asce is reset to
kernel asce whenever kvm guest execution is interrupted, so that this
doesn't has to be taken into account for any user space accesses.

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2020-11-23 12:01:12 +01:00

878 lines
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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 <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
#define VM_FAULT_BADCONTEXT ((__force vm_fault_t) 0x010000)
#define VM_FAULT_BADMAP ((__force vm_fault_t) 0x020000)
#define VM_FAULT_BADACCESS ((__force vm_fault_t) 0x040000)
#define VM_FAULT_SIGNAL ((__force vm_fault_t) 0x080000)
#define VM_FAULT_PFAULT ((__force vm_fault_t) 0x100000)
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 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 = (unsigned long *)(*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 = (unsigned long *)(*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 = (unsigned long *)(*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 = (unsigned long *)(*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));
}
const struct exception_table_entry *s390_search_extables(unsigned long addr)
{
const struct exception_table_entry *fixup;
fixup = search_extable(__start_dma_ex_table,
__stop_dma_ex_table - __start_dma_ex_table,
addr);
if (!fixup)
fixup = search_exception_tables(addr);
return fixup;
}
static noinline void do_no_context(struct pt_regs *regs)
{
const struct exception_table_entry *fixup;
/* Are we prepared to handle this kernel fault? */
fixup = s390_search_extables(regs->psw.addr);
if (fixup && ex_handle(fixup, regs))
return;
/*
* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.
*/
if (get_fault_type(regs) == 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");
do_exit(SIGKILL);
}
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_exit(SIGKILL);
}
do_no_context(regs);
}
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 int signal_return(struct pt_regs *regs)
{
u16 instruction;
int rc;
rc = __get_user(instruction, (u16 __user *) regs->psw.addr);
if (rc)
return rc;
if (instruction == 0x0a77) {
set_pt_regs_flag(regs, PIF_SYSCALL);
regs->int_code = 0x00040077;
return 0;
} else if (instruction == 0x0aad) {
set_pt_regs_flag(regs, PIF_SYSCALL);
regs->int_code = 0x000400ad;
return 0;
}
return -EACCES;
}
static noinline void do_fault_error(struct pt_regs *regs, int access,
vm_fault_t fault)
{
int si_code;
switch (fault) {
case VM_FAULT_BADACCESS:
if (access == VM_EXEC && signal_return(regs) == 0)
break;
fallthrough;
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);
break;
case VM_FAULT_SIGNAL:
if (!user_mode(regs))
do_no_context(regs);
break;
default: /* fault & VM_FAULT_ERROR */
if (fault & VM_FAULT_OOM) {
if (!user_mode(regs))
do_no_context(regs);
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);
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);
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 trans_exc_code;
unsigned long address;
unsigned int flags;
vm_fault_t fault;
tsk = current;
/*
* The instruction that caused the program check has
* been nullified. Don't signal single step via SIGTRAP.
*/
clear_pt_regs_flag(regs, PIF_PER_TRAP);
if (kprobe_page_fault(regs, 14))
return 0;
mm = tsk->mm;
trans_exc_code = regs->int_parm_long;
/*
* 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;
}
address = trans_exc_code & __FAIL_ADDR_MASK;
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
flags = FAULT_FLAG_DEFAULT;
if (user_mode(regs))
flags |= FAULT_FLAG_USER;
if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400)
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 (is_vm_hugetlb_page(vma))
address &= HPAGE_MASK;
/*
* 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;
}
if (unlikely(fault & VM_FAULT_ERROR))
goto out_up;
if (flags & FAULT_FLAG_ALLOW_RETRY) {
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;
}
}
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, access, 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, access, fault);
}
NOKPROBE_SYMBOL(do_dat_exception);
#ifdef CONFIG_PFAULT
/*
* 'pfault' pseudo page faults routines.
*/
static int pfault_disable;
static int __init nopfault(char *str)
{
pfault_disable = 1;
return 1;
}
__setup("nopfault", nopfault);
struct pfault_refbk {
u16 refdiagc;
u16 reffcode;
u16 refdwlen;
u16 refversn;
u64 refgaddr;
u64 refselmk;
u64 refcmpmk;
u64 reserved;
} __attribute__ ((packed, aligned(8)));
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 (tsk->state == TASK_RUNNING)
tsk->thread.pfault_wait = -1;
}
} else {
/* signal bit not set -> a real page is missing. */
if (WARN_ON_ONCE(tsk != current))
goto out;
if (tsk->thread.pfault_wait == 1) {
/* Already on the list with a reference: put to sleep */
goto block;
} else if (tsk->thread.pfault_wait == -1) {
/* Completion interrupt was faster than the initial
* interrupt (pfault_wait == -1). Set pfault_wait
* back to zero and exit. */
tsk->thread.pfault_wait = 0;
} else {
/* Initial interrupt arrived before completion
* interrupt. Let the task sleep.
* An extra task reference is needed since a different
* cpu may set the task state to TASK_RUNNING again
* before the scheduler is reached. */
get_task_struct(tsk);
tsk->thread.pfault_wait = 1;
list_add(&tsk->thread.list, &pfault_list);
block:
/* Since this must be a userspace fault, there
* is no kernel task state to trample. Rely on the
* return to userspace schedule() to block. */
__set_current_state(TASK_UNINTERRUPTIBLE);
set_tsk_need_resched(tsk);
set_preempt_need_resched();
}
}
out:
spin_unlock(&pfault_lock);
put_task_struct(tsk);
}
static int pfault_cpu_dead(unsigned int cpu)
{
struct thread_struct *thread, *next;
struct task_struct *tsk;
spin_lock_irq(&pfault_lock);
list_for_each_entry_safe(thread, next, &pfault_list, list) {
thread->pfault_wait = 0;
list_del(&thread->list);
tsk = container_of(thread, struct task_struct, thread);
wake_up_process(tsk);
put_task_struct(tsk);
}
spin_unlock_irq(&pfault_lock);
return 0;
}
static int __init pfault_irq_init(void)
{
int rc;
rc = register_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt);
if (rc)
goto out_extint;
rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP;
if (rc)
goto out_pfault;
irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
cpuhp_setup_state_nocalls(CPUHP_S390_PFAULT_DEAD, "s390/pfault:dead",
NULL, pfault_cpu_dead);
return 0;
out_pfault:
unregister_external_irq(EXT_IRQ_CP_SERVICE, pfault_interrupt);
out_extint:
pfault_disable = 1;
return rc;
}
early_initcall(pfault_irq_init);
#endif /* CONFIG_PFAULT */
#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;
int rc;
switch (get_fault_type(regs)) {
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_READ | VM_WRITE, 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;
case GMAP_FAULT:
default:
do_fault_error(regs, VM_READ | VM_WRITE, 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_READ | VM_WRITE, 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)
{
/*
* 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);
}
#else
void do_secure_storage_access(struct pt_regs *regs)
{
default_trap_handler(regs);
}
void do_non_secure_storage_access(struct pt_regs *regs)
{
default_trap_handler(regs);
}
void do_secure_storage_violation(struct pt_regs *regs)
{
default_trap_handler(regs);
}
#endif
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