diff --git a/arch/s390/include/asm/pfault.h b/arch/s390/include/asm/pfault.h
new file mode 100644
index 0000000000000000000000000000000000000000..beabeebf2859f60e12f70c68c511aac773c3620f
--- /dev/null
+++ b/arch/s390/include/asm/pfault.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright IBM Corp. 1999, 2023
+ */
+#ifndef _ASM_S390_PFAULT_H
+#define _ASM_S390_PFAULT_H
+
+int __pfault_init(void);
+void __pfault_fini(void);
+
+static inline int pfault_init(void)
+{
+ if (IS_ENABLED(CONFIG_PFAULT))
+ return __pfault_init();
+ return -1;
+}
+
+static inline void pfault_fini(void)
+{
+ if (IS_ENABLED(CONFIG_PFAULT))
+ __pfault_fini();
+}
+
+#endif /* _ASM_S390_PFAULT_H */
diff --git a/arch/s390/include/asm/setup.h b/arch/s390/include/asm/setup.h
index e795f425627a9c3ce4b739195727f5867d30525e..b30fe91166e3312c9c8579b12882e55a252b143e 100644
--- a/arch/s390/include/asm/setup.h
+++ b/arch/s390/include/asm/setup.h
@@ -118,14 +118,6 @@ extern unsigned int console_irq;
#define SET_CONSOLE_VT220 do { console_mode = 4; } while (0)
#define SET_CONSOLE_HVC do { console_mode = 5; } while (0)
-#ifdef CONFIG_PFAULT
-extern int pfault_init(void);
-extern void pfault_fini(void);
-#else /* CONFIG_PFAULT */
-#define pfault_init() ({-1;})
-#define pfault_fini() do { } while (0)
-#endif /* CONFIG_PFAULT */
-
#ifdef CONFIG_VMCP
void vmcp_cma_reserve(void);
#else
diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c
index 6d9276c096a61115a93ad8f3116529758b242f9e..12a2bd4fc88cb99f9116176c0948fc04170a2f31 100644
--- a/arch/s390/kernel/machine_kexec.c
+++ b/arch/s390/kernel/machine_kexec.c
@@ -13,6 +13,7 @@
#include <linux/reboot.h>
#include <linux/ftrace.h>
#include <linux/debug_locks.h>
+#include <asm/pfault.h>
#include <asm/cio.h>
#include <asm/setup.h>
#include <asm/smp.h>
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index f9a2b755f510527c84e4d1c3a0ebe2d35bb4f01a..9244130721d6f3214b3e37b06d2b0e08ce4dcbe2 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -37,6 +37,7 @@
#include <linux/crash_dump.h>
#include <linux/kprobes.h>
#include <asm/asm-offsets.h>
+#include <asm/pfault.h>
#include <asm/diag.h>
#include <asm/switch_to.h>
#include <asm/facility.h>
diff --git a/arch/s390/mm/Makefile b/arch/s390/mm/Makefile
index d90db06a8af5776937060c94d17baa9b6392f05d..352ff520fd9430a1acffe262c2d7046ba7083890 100644
--- a/arch/s390/mm/Makefile
+++ b/arch/s390/mm/Makefile
@@ -10,3 +10,4 @@ obj-$(CONFIG_CMM) += cmm.o
obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
obj-$(CONFIG_PTDUMP_CORE) += dump_pagetables.o
obj-$(CONFIG_PGSTE) += gmap.o
+obj-$(CONFIG_PFAULT) += pfault.o
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 2f123429a291b7457561ee8e56eeaf39fbbda49c..b5e1bea9194c28d3db654da449ef2621c165621a 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -43,8 +43,6 @@
#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
@@ -583,232 +581,6 @@ void do_dat_exception(struct pt_regs *regs)
}
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)
diff --git a/arch/s390/mm/pfault.c b/arch/s390/mm/pfault.c
new file mode 100644
index 0000000000000000000000000000000000000000..5c0547f8d5ee7222a8284b17fd0097bc9a40f3a1
--- /dev/null
+++ b/arch/s390/mm/pfault.c
@@ -0,0 +1,239 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright IBM Corp. 1999, 2023
+ */
+
+#include <linux/cpuhotplug.h>
+#include <linux/sched/task.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <asm/asm-extable.h>
+#include <asm/pfault.h>
+#include <asm/diag.h>
+
+#define __SUBCODE_MASK 0x0600
+#define __PF_RES_FIELD 0x8000000000000000ULL
+
+/*
+ * '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);