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Diffstat (limited to 'arch/s390/mm/fault.c')
-rw-r--r--arch/s390/mm/fault.c111
1 files changed, 67 insertions, 44 deletions
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index bdabb013537b..93faeca52284 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
/*
* S390 version
* Copyright IBM Corp. 1999
@@ -49,6 +50,13 @@
#define VM_FAULT_SIGNAL 0x080000
#define VM_FAULT_PFAULT 0x100000
+enum fault_type {
+ KERNEL_FAULT,
+ USER_FAULT,
+ VDSO_FAULT,
+ GMAP_FAULT,
+};
+
static unsigned long store_indication __read_mostly;
static int __init fault_init(void)
@@ -98,27 +106,34 @@ void bust_spinlocks(int yes)
}
/*
- * Returns the address space associated with the fault.
- * Returns 0 for kernel space and 1 for user space.
+ * Find out which address space caused the exception.
+ * Access register mode is impossible, ignore space == 3.
*/
-static inline int user_space_fault(struct pt_regs *regs)
+static inline enum fault_type get_fault_type(struct pt_regs *regs)
{
unsigned long trans_exc_code;
- /*
- * The lowest two bits of the translation exception
- * identification indicate which paging table was used.
- */
trans_exc_code = regs->int_parm_long & 3;
- if (trans_exc_code == 3) /* home space -> kernel */
- return 0;
- if (user_mode(regs))
- return 1;
- if (trans_exc_code == 2) /* secondary space -> set_fs */
- return current->thread.mm_segment.ar4;
- if (current->flags & PF_VCPU)
- return 1;
- return 0;
+ if (likely(trans_exc_code == 0)) {
+ /* primary space exception */
+ if (IS_ENABLED(CONFIG_PGSTE) &&
+ test_pt_regs_flag(regs, PIF_GUEST_FAULT))
+ return GMAP_FAULT;
+ if (current->thread.mm_segment == USER_DS)
+ return USER_FAULT;
+ return KERNEL_FAULT;
+ }
+ if (trans_exc_code == 2) {
+ /* secondary space exception */
+ if (current->thread.mm_segment & 1) {
+ if (current->thread.mm_segment == USER_DS_SACF)
+ return USER_FAULT;
+ return KERNEL_FAULT;
+ }
+ return VDSO_FAULT;
+ }
+ /* home space exception -> access via kernel ASCE */
+ return KERNEL_FAULT;
}
static int bad_address(void *p)
@@ -203,20 +218,23 @@ static void dump_fault_info(struct pt_regs *regs)
break;
}
pr_cont("mode while using ");
- if (!user_space_fault(regs)) {
- asce = S390_lowcore.kernel_asce;
- pr_cont("kernel ");
- }
-#ifdef CONFIG_PGSTE
- else if ((current->flags & PF_VCPU) && S390_lowcore.gmap) {
- struct gmap *gmap = (struct gmap *)S390_lowcore.gmap;
- asce = gmap->asce;
- pr_cont("gmap ");
- }
-#endif
- else {
+ switch (get_fault_type(regs)) {
+ case USER_FAULT:
asce = S390_lowcore.user_asce;
pr_cont("user ");
+ break;
+ case VDSO_FAULT:
+ asce = S390_lowcore.vdso_asce;
+ pr_cont("vdso ");
+ 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;
}
pr_cont("ASCE.\n");
dump_pagetable(asce, regs->int_parm_long & __FAIL_ADDR_MASK);
@@ -272,7 +290,7 @@ static noinline void do_no_context(struct pt_regs *regs)
* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.
*/
- if (!user_space_fault(regs))
+ if (get_fault_type(regs) == KERNEL_FAULT)
printk(KERN_ALERT "Unable to handle kernel pointer dereference"
" in virtual kernel address space\n");
else
@@ -394,12 +412,11 @@ static noinline void do_fault_error(struct pt_regs *regs, int access, int fault)
*/
static inline int do_exception(struct pt_regs *regs, int access)
{
-#ifdef CONFIG_PGSTE
struct gmap *gmap;
-#endif
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;
@@ -424,8 +441,19 @@ static inline int do_exception(struct pt_regs *regs, int access)
* user context.
*/
fault = VM_FAULT_BADCONTEXT;
- if (unlikely(!user_space_fault(regs) || faulthandler_disabled() || !mm))
+ type = get_fault_type(regs);
+ switch (type) {
+ case KERNEL_FAULT:
+ goto out;
+ case VDSO_FAULT:
+ fault = VM_FAULT_BADMAP;
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);
@@ -436,10 +464,9 @@ static inline int do_exception(struct pt_regs *regs, int access)
flags |= FAULT_FLAG_WRITE;
down_read(&mm->mmap_sem);
-#ifdef CONFIG_PGSTE
- gmap = (current->flags & PF_VCPU) ?
- (struct gmap *) S390_lowcore.gmap : NULL;
- if (gmap) {
+ 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;
@@ -451,7 +478,6 @@ static inline int do_exception(struct pt_regs *regs, int access)
if (gmap->pfault_enabled)
flags |= FAULT_FLAG_RETRY_NOWAIT;
}
-#endif
retry:
fault = VM_FAULT_BADMAP;
@@ -506,15 +532,14 @@ retry:
regs, address);
}
if (fault & VM_FAULT_RETRY) {
-#ifdef CONFIG_PGSTE
- if (gmap && (flags & FAULT_FLAG_RETRY_NOWAIT)) {
+ if (IS_ENABLED(CONFIG_PGSTE) && gmap &&
+ (flags & FAULT_FLAG_RETRY_NOWAIT)) {
/* FAULT_FLAG_RETRY_NOWAIT has been set,
* mmap_sem has not been released */
current->thread.gmap_pfault = 1;
fault = VM_FAULT_PFAULT;
goto out_up;
}
-#endif
/* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk
* of starvation. */
flags &= ~(FAULT_FLAG_ALLOW_RETRY |
@@ -524,8 +549,7 @@ retry:
goto retry;
}
}
-#ifdef CONFIG_PGSTE
- if (gmap) {
+ if (IS_ENABLED(CONFIG_PGSTE) && gmap) {
address = __gmap_link(gmap, current->thread.gmap_addr,
address);
if (address == -EFAULT) {
@@ -537,7 +561,6 @@ retry:
goto out_up;
}
}
-#endif
fault = 0;
out_up:
up_read(&mm->mmap_sem);
@@ -705,7 +728,7 @@ static void pfault_interrupt(struct ext_code ext_code,
return;
inc_irq_stat(IRQEXT_PFL);
/* Get the token (= pid of the affected task). */
- pid = param64 & LPP_PFAULT_PID_MASK;
+ pid = param64 & LPP_PID_MASK;
rcu_read_lock();
tsk = find_task_by_pid_ns(pid, &init_pid_ns);
if (tsk)
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-01 14:37:06 +0300