1 files changed, 32 insertions, 80 deletions

diff --git a/arch/s390/kernel/runtime_instr.c b/arch/s390/kernel/runtime_instr.c
index 077a99389b07..1788a5454b6f 100644
--- a/arch/s390/kernel/runtime_instr.c
+++ b/arch/s390/kernel/runtime_instr.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright IBM Corp. 2012
  * Author(s): Jan Glauber <jang@linux.vnet.ibm.com>
@@ -11,23 +12,35 @@
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/kernel_stat.h>
+#include <linux/sched/task_stack.h>
+
 #include <asm/runtime_instr.h>
 #include <asm/cpu_mf.h>
 #include <asm/irq.h>
 
+#include "entry.h"
+
 /* empty control block to disable RI by loading it */
 struct runtime_instr_cb runtime_instr_empty_cb;
 
-static int runtime_instr_avail(void)
+void runtime_instr_release(struct task_struct *tsk)
 {
-	return test_facility(64);
+	kfree(tsk->thread.ri_cb);
 }
 
 static void disable_runtime_instr(void)
 {
-	struct pt_regs *regs = task_pt_regs(current);
+	struct task_struct *task = current;
+	struct pt_regs *regs;
 
+	if (!task->thread.ri_cb)
+		return;
+	regs = task_pt_regs(task);
+	preempt_disable();
 	load_runtime_instr_cb(&runtime_instr_empty_cb);
+	kfree(task->thread.ri_cb);
+	task->thread.ri_cb = NULL;
+	preempt_enable();
 
 	/*
 	 * Make sure the RI bit is deleted from the PSW. If the user did not
@@ -39,77 +52,34 @@ static void disable_runtime_instr(void)
 
 static void init_runtime_instr_cb(struct runtime_instr_cb *cb)
 {
-	cb->buf_limit = 0xfff;
-	if (s390_user_mode == HOME_SPACE_MODE)
-		cb->home_space = 1;
-	cb->int_requested = 1;
-	cb->pstate = 1;
-	cb->pstate_set_buf = 1;
-	cb->pstate_sample = 1;
-	cb->pstate_collect = 1;
-	cb->key = PAGE_DEFAULT_KEY;
-	cb->valid = 1;
-}
-
-void exit_thread_runtime_instr(void)
-{
-	struct task_struct *task = current;
-
-	if (!task->thread.ri_cb)
-		return;
-	disable_runtime_instr();
-	kfree(task->thread.ri_cb);
-	task->thread.ri_signum = 0;
-	task->thread.ri_cb = NULL;
-}
-
-static void runtime_instr_int_handler(struct ext_code ext_code,
-				unsigned int param32, unsigned long param64)
-{
-	struct siginfo info;
-
-	if (!(param32 & CPU_MF_INT_RI_MASK))
-		return;
-
-	inc_irq_stat(IRQEXT_CMR);
-
-	if (!current->thread.ri_cb)
-		return;
-	if (current->thread.ri_signum < SIGRTMIN ||
-	    current->thread.ri_signum > SIGRTMAX) {
-		WARN_ON_ONCE(1);
-		return;
-	}
-
-	memset(&info, 0, sizeof(info));
-	info.si_signo = current->thread.ri_signum;
-	info.si_code = SI_QUEUE;
-	if (param32 & CPU_MF_INT_RI_BUF_FULL)
-		info.si_int = ENOBUFS;
-	else if (param32 & CPU_MF_INT_RI_HALTED)
-		info.si_int = ECANCELED;
-	else
-		return; /* unknown reason */
-
-	send_sig_info(current->thread.ri_signum, &info, current);
+	cb->rla = 0xfff;
+	cb->s = 1;
+	cb->k = 1;
+	cb->ps = 1;
+	cb->pc = 1;
+	cb->key = PAGE_DEFAULT_KEY >> 4;
+	cb->v = 1;
 }
 
+/*
+ * The signum argument is unused. In older kernels it was used to
+ * specify a real-time signal. For backwards compatibility user space
+ * should pass a valid real-time signal number (the signum argument
+ * was checked in older kernels).
+ */
 SYSCALL_DEFINE2(s390_runtime_instr, int, command, int, signum)
 {
 	struct runtime_instr_cb *cb;
 
-	if (!runtime_instr_avail())
+	if (!test_facility(64))
 		return -EOPNOTSUPP;
 
 	if (command == S390_RUNTIME_INSTR_STOP) {
-		preempt_disable();
-		exit_thread_runtime_instr();
-		preempt_enable();
+		disable_runtime_instr();
 		return 0;
 	}
 
-	if (command != S390_RUNTIME_INSTR_START ||
-	    (signum < SIGRTMIN || signum > SIGRTMAX))
+	if (command != S390_RUNTIME_INSTR_START)
 		return -EINVAL;
 
 	if (!current->thread.ri_cb) {
@@ -122,7 +92,6 @@ SYSCALL_DEFINE2(s390_runtime_instr, int, command, int, signum)
 	}
 
 	init_runtime_instr_cb(cb);
-	current->thread.ri_signum = signum;
 
 	/* now load the control block to make it available */
 	preempt_disable();
@@ -131,20 +100,3 @@ SYSCALL_DEFINE2(s390_runtime_instr, int, command, int, signum)
 	preempt_enable();
 	return 0;
 }
-
-static int __init runtime_instr_init(void)
-{
-	int rc;
-
-	if (!runtime_instr_avail())
-		return 0;
-
-	measurement_alert_subclass_register();
-	rc = register_external_interrupt(0x1407, runtime_instr_int_handler);
-	if (rc)
-		measurement_alert_subclass_unregister();
-	else
-		pr_info("Runtime instrumentation facility initialized\n");
-	return rc;
-}
-device_initcall(runtime_instr_init);