Contributors: 33
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Heiko Carstens |
1328 |
50.08% |
47 |
30.92% |
| Martin Schwidefsky |
579 |
21.83% |
28 |
18.42% |
| Vasily Gorbik |
248 |
9.35% |
1 |
0.66% |
| Linus Torvalds (pre-git) |
124 |
4.68% |
25 |
16.45% |
| Claudio Imbrenda |
51 |
1.92% |
3 |
1.97% |
| Gerald Schaefer |
49 |
1.85% |
5 |
3.29% |
| Linus Torvalds |
37 |
1.40% |
5 |
3.29% |
| Janosch Frank |
35 |
1.32% |
2 |
1.32% |
| Dominik Dingel |
35 |
1.32% |
1 |
0.66% |
| Peter Xu |
25 |
0.94% |
5 |
3.29% |
| Suren Baghdasaryan |
23 |
0.87% |
2 |
1.32% |
| Sven Schnelle |
22 |
0.83% |
3 |
1.97% |
| Michel Lespinasse |
13 |
0.49% |
1 |
0.66% |
| David Hildenbrand |
13 |
0.49% |
2 |
1.32% |
| Nicholas Piggin |
9 |
0.34% |
1 |
0.66% |
| Eric W. Biedermann |
8 |
0.30% |
2 |
1.32% |
| Joe Perches |
6 |
0.23% |
1 |
0.66% |
| Andrew Morton |
6 |
0.23% |
1 |
0.66% |
| Johannes Weiner |
6 |
0.23% |
1 |
0.66% |
| Ingo Molnar |
5 |
0.19% |
2 |
1.32% |
| Christoph Hellwig |
4 |
0.15% |
2 |
1.32% |
| Shaohua Li |
4 |
0.15% |
1 |
0.66% |
| Masahiro Yamada |
4 |
0.15% |
1 |
0.66% |
| Michael Grundy |
3 |
0.11% |
1 |
0.66% |
| Anshuman Khandual |
3 |
0.11% |
1 |
0.66% |
| Michael Holzheu |
3 |
0.11% |
1 |
0.66% |
| David Howells |
2 |
0.08% |
1 |
0.66% |
| Ilya Leoshkevich |
2 |
0.08% |
1 |
0.66% |
| Souptick Joarder |
1 |
0.04% |
1 |
0.66% |
| Paul Gortmaker |
1 |
0.04% |
1 |
0.66% |
| Steffen Eiden |
1 |
0.04% |
1 |
0.66% |
| Hendrik Brueckner |
1 |
0.04% |
1 |
0.66% |
| Greg Kroah-Hartman |
1 |
0.04% |
1 |
0.66% |
| Total |
2652 |
|
152 |
|
// 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/mmu_context.h>
#include <linux/perf_event.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/jump_label.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/ptrace.h>
#include <asm/fault.h>
#include <asm/diag.h>
#include <asm/gmap.h>
#include <asm/irq.h>
#include <asm/facility.h>
#include <asm/uv.h>
#include "../kernel/entry.h"
enum fault_type {
KERNEL_FAULT,
USER_FAULT,
GMAP_FAULT,
};
static DEFINE_STATIC_KEY_FALSE(have_store_indication);
static int __init fault_init(void)
{
if (test_facility(75))
static_branch_enable(&have_store_indication);
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)
{
union teid teid = { .val = regs->int_parm_long };
if (likely(teid.as == PSW_BITS_AS_PRIMARY)) {
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 (teid.as == PSW_BITS_AS_SECONDARY)
return USER_FAULT;
/* Access register mode, not used in the kernel */
if (teid.as == PSW_BITS_AS_ACCREG)
return USER_FAULT;
/* Home space -> access via kernel ASCE */
return KERNEL_FAULT;
}
static unsigned long get_fault_address(struct pt_regs *regs)
{
union teid teid = { .val = regs->int_parm_long };
return teid.addr * PAGE_SIZE;
}
static __always_inline bool fault_is_write(struct pt_regs *regs)
{
union teid teid = { .val = regs->int_parm_long };
if (static_branch_likely(&have_store_indication))
return teid.fsi == TEID_FSI_STORE;
return false;
}
static void dump_pagetable(unsigned long asce, unsigned long address)
{
unsigned long entry, *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 (get_kernel_nofault(entry, table))
goto bad;
pr_cont("R1:%016lx ", entry);
if (entry & _REGION_ENTRY_INVALID)
goto out;
table = __va(entry & _REGION_ENTRY_ORIGIN);
fallthrough;
case _ASCE_TYPE_REGION2:
table += (address & _REGION2_INDEX) >> _REGION2_SHIFT;
if (get_kernel_nofault(entry, table))
goto bad;
pr_cont("R2:%016lx ", entry);
if (entry & _REGION_ENTRY_INVALID)
goto out;
table = __va(entry & _REGION_ENTRY_ORIGIN);
fallthrough;
case _ASCE_TYPE_REGION3:
table += (address & _REGION3_INDEX) >> _REGION3_SHIFT;
if (get_kernel_nofault(entry, table))
goto bad;
pr_cont("R3:%016lx ", entry);
if (entry & (_REGION_ENTRY_INVALID | _REGION3_ENTRY_LARGE))
goto out;
table = __va(entry & _REGION_ENTRY_ORIGIN);
fallthrough;
case _ASCE_TYPE_SEGMENT:
table += (address & _SEGMENT_INDEX) >> _SEGMENT_SHIFT;
if (get_kernel_nofault(entry, table))
goto bad;
pr_cont("S:%016lx ", entry);
if (entry & (_SEGMENT_ENTRY_INVALID | _SEGMENT_ENTRY_LARGE))
goto out;
table = __va(entry & _SEGMENT_ENTRY_ORIGIN);
}
table += (address & _PAGE_INDEX) >> _PAGE_SHIFT;
if (get_kernel_nofault(entry, table))
goto bad;
pr_cont("P:%016lx ", entry);
out:
pr_cont("\n");
return;
bad:
pr_cont("BAD\n");
}
static void dump_fault_info(struct pt_regs *regs)
{
union teid teid = { .val = regs->int_parm_long };
unsigned long asce;
pr_alert("Failing address: %016lx TEID: %016lx\n",
get_fault_address(regs), teid.val);
pr_alert("Fault in ");
switch (teid.as) {
case PSW_BITS_AS_HOME:
pr_cont("home space ");
break;
case PSW_BITS_AS_SECONDARY:
pr_cont("secondary space ");
break;
case PSW_BITS_AS_ACCREG:
pr_cont("access register ");
break;
case PSW_BITS_AS_PRIMARY:
pr_cont("primary space ");
break;
}
pr_cont("mode while using ");
switch (get_fault_type(regs)) {
case USER_FAULT:
asce = S390_lowcore.user_asce.val;
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.val;
pr_cont("kernel ");
break;
default:
unreachable();
}
pr_cont("ASCE.\n");
dump_pagetable(asce, get_fault_address(regs));
}
int show_unhandled_signals = 1;
void report_user_fault(struct pt_regs *regs, long signr, int is_mm_fault)
{
static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST);
if ((task_pid_nr(current) > 1) && !show_unhandled_signals)
return;
if (!unhandled_signal(current, signr))
return;
if (!__ratelimit(&rs))
return;
pr_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);
pr_cont("\n");
if (is_mm_fault)
dump_fault_info(regs);
show_regs(regs);
}
static void do_sigsegv(struct pt_regs *regs, int si_code)
{
report_user_fault(regs, SIGSEGV, 1);
force_sig_fault(SIGSEGV, si_code, (void __user *)get_fault_address(regs));
}
static void handle_fault_error_nolock(struct pt_regs *regs, int si_code)
{
enum fault_type fault_type;
unsigned long address;
bool is_write;
if (user_mode(regs)) {
if (WARN_ON_ONCE(!si_code))
si_code = SEGV_MAPERR;
return do_sigsegv(regs, si_code);
}
if (fixup_exception(regs))
return;
fault_type = get_fault_type(regs);
if (fault_type == KERNEL_FAULT) {
address = get_fault_address(regs);
is_write = fault_is_write(regs);
if (kfence_handle_page_fault(address, is_write, regs))
return;
}
if (fault_type == KERNEL_FAULT)
pr_alert("Unable to handle kernel pointer dereference in virtual kernel address space\n");
else
pr_alert("Unable to handle kernel paging request in virtual user address space\n");
dump_fault_info(regs);
die(regs, "Oops");
}
static void handle_fault_error(struct pt_regs *regs, int si_code)
{
struct mm_struct *mm = current->mm;
mmap_read_unlock(mm);
handle_fault_error_nolock(regs, si_code);
}
static void do_sigbus(struct pt_regs *regs)
{
force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)get_fault_address(regs));
}
/*
* 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 void do_exception(struct pt_regs *regs, int access)
{
struct vm_area_struct *vma;
struct task_struct *tsk;
unsigned long address;
struct mm_struct *mm;
enum fault_type type;
unsigned int flags;
struct gmap *gmap;
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;
mm = tsk->mm;
address = get_fault_address(regs);
is_write = fault_is_write(regs);
type = get_fault_type(regs);
switch (type) {
case KERNEL_FAULT:
return handle_fault_error_nolock(regs, 0);
case USER_FAULT:
case GMAP_FAULT:
if (faulthandler_disabled() || !mm)
return handle_fault_error_nolock(regs, 0);
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;
if (!(flags & FAULT_FLAG_USER))
goto lock_mmap;
vma = lock_vma_under_rcu(mm, address);
if (!vma)
goto lock_mmap;
if (!(vma->vm_flags & access)) {
vma_end_read(vma);
goto lock_mmap;
}
fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, regs);
if (!(fault & (VM_FAULT_RETRY | VM_FAULT_COMPLETED)))
vma_end_read(vma);
if (!(fault & VM_FAULT_RETRY)) {
count_vm_vma_lock_event(VMA_LOCK_SUCCESS);
if (unlikely(fault & VM_FAULT_ERROR))
goto error;
return;
}
count_vm_vma_lock_event(VMA_LOCK_RETRY);
if (fault & VM_FAULT_MAJOR)
flags |= FAULT_FLAG_TRIED;
/* Quick path to respond to signals */
if (fault_signal_pending(fault, regs)) {
if (!user_mode(regs))
handle_fault_error_nolock(regs, 0);
return;
}
lock_mmap:
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)
return handle_fault_error(regs, SEGV_MAPERR);
if (gmap->pfault_enabled)
flags |= FAULT_FLAG_RETRY_NOWAIT;
}
retry:
vma = find_vma(mm, address);
if (!vma)
return handle_fault_error(regs, SEGV_MAPERR);
if (unlikely(vma->vm_start > address)) {
if (!(vma->vm_flags & VM_GROWSDOWN))
return handle_fault_error(regs, SEGV_MAPERR);
vma = expand_stack(mm, address);
if (!vma)
return handle_fault_error_nolock(regs, SEGV_MAPERR);
}
if (unlikely(!(vma->vm_flags & access)))
return handle_fault_error(regs, SEGV_ACCERR);
fault = handle_mm_fault(vma, address, flags, regs);
if (fault_signal_pending(fault, regs)) {
if (flags & FAULT_FLAG_RETRY_NOWAIT)
mmap_read_unlock(mm);
if (!user_mode(regs))
handle_fault_error_nolock(regs, 0);
return;
}
/* The fault is fully completed (including releasing mmap lock) */
if (fault & VM_FAULT_COMPLETED) {
if (gmap) {
mmap_read_lock(mm);
goto gmap;
}
return;
}
if (unlikely(fault & VM_FAULT_ERROR)) {
mmap_read_unlock(mm);
goto error;
}
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;
return handle_fault_error(regs, 0);
}
flags &= ~FAULT_FLAG_RETRY_NOWAIT;
flags |= FAULT_FLAG_TRIED;
mmap_read_lock(mm);
goto retry;
}
gmap:
if (IS_ENABLED(CONFIG_PGSTE) && gmap) {
address = __gmap_link(gmap, current->thread.gmap_addr,
address);
if (address == -EFAULT)
return handle_fault_error(regs, SEGV_MAPERR);
if (address == -ENOMEM) {
fault = VM_FAULT_OOM;
mmap_read_unlock(mm);
goto error;
}
}
mmap_read_unlock(mm);
return;
error:
if (fault & VM_FAULT_OOM) {
if (!user_mode(regs))
handle_fault_error_nolock(regs, 0);
else
pagefault_out_of_memory();
} else if (fault & VM_FAULT_SIGSEGV) {
if (!user_mode(regs))
handle_fault_error_nolock(regs, 0);
else
do_sigsegv(regs, SEGV_MAPERR);
} else if (fault & VM_FAULT_SIGBUS) {
if (!user_mode(regs))
handle_fault_error_nolock(regs, 0);
else
do_sigbus(regs);
} else {
BUG();
}
}
void do_protection_exception(struct pt_regs *regs)
{
union teid teid = { .val = 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(!teid.b61)) {
if (user_mode(regs)) {
/* Low-address protection in user mode: cannot happen */
die(regs, "Low-address protection");
}
/*
* Low-address protection in kernel mode means
* NULL pointer write access in kernel mode.
*/
return handle_fault_error_nolock(regs, 0);
}
if (unlikely(MACHINE_HAS_NX && teid.b56)) {
regs->int_parm_long = (teid.addr * PAGE_SIZE) | (regs->psw.addr & PAGE_MASK);
return handle_fault_error_nolock(regs, SEGV_ACCERR);
}
do_exception(regs, VM_WRITE);
}
NOKPROBE_SYMBOL(do_protection_exception);
void do_dat_exception(struct pt_regs *regs)
{
do_exception(regs, VM_ACCESS_FLAGS);
}
NOKPROBE_SYMBOL(do_dat_exception);
#if IS_ENABLED(CONFIG_PGSTE)
void do_secure_storage_access(struct pt_regs *regs)
{
union teid teid = { .val = regs->int_parm_long };
unsigned long addr = get_fault_address(regs);
struct vm_area_struct *vma;
struct mm_struct *mm;
struct page *page;
struct gmap *gmap;
int rc;
/*
* Bit 61 indicates if the address is valid, if it is not the
* kernel should be stopped or SIGSEGV should be sent to the
* process. Bit 61 is not reliable without the misc UV feature,
* therefore this needs to be checked too.
*/
if (uv_has_feature(BIT_UV_FEAT_MISC) && !teid.b61) {
/*
* 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
* there is 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))
return handle_fault_error_nolock(regs, SEGV_MAPERR);
fallthrough;
case USER_FAULT:
mm = current->mm;
mmap_read_lock(mm);
vma = find_vma(mm, addr);
if (!vma)
return handle_fault_error(regs, SEGV_MAPERR);
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:
unreachable();
}
}
NOKPROBE_SYMBOL(do_secure_storage_access);
void do_non_secure_storage_access(struct pt_regs *regs)
{
struct gmap *gmap = (struct gmap *)S390_lowcore.gmap;
unsigned long gaddr = get_fault_address(regs);
if (WARN_ON_ONCE(get_fault_type(regs) != GMAP_FAULT))
return handle_fault_error_nolock(regs, SEGV_MAPERR);
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)
{
struct gmap *gmap = (struct gmap *)S390_lowcore.gmap;
unsigned long gaddr = get_fault_address(regs);
/*
* 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.
*/
pr_warn_ratelimited("Secure storage violation in task: %s, pid %d\n",
current->comm, current->pid);
send_sig(SIGSEGV, current, 0);
}
#endif /* CONFIG_PGSTE */