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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/s390/kernel/runtime_instr.c
Initial import
Diffstat (limited to 'arch/s390/kernel/runtime_instr.c')
-rw-r--r--arch/s390/kernel/runtime_instr.c149
1 files changed, 149 insertions, 0 deletions
diff --git a/arch/s390/kernel/runtime_instr.c b/arch/s390/kernel/runtime_instr.c
new file mode 100644
index 000000000..26b4ae96f
--- /dev/null
+++ b/arch/s390/kernel/runtime_instr.c
@@ -0,0 +1,149 @@
+/*
+ * Copyright IBM Corp. 2012
+ * Author(s): Jan Glauber <jang@linux.vnet.ibm.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/syscalls.h>
+#include <linux/signal.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/kernel_stat.h>
+#include <asm/runtime_instr.h>
+#include <asm/cpu_mf.h>
+#include <asm/irq.h>
+
+/* empty control block to disable RI by loading it */
+struct runtime_instr_cb runtime_instr_empty_cb;
+
+static int runtime_instr_avail(void)
+{
+ return test_facility(64);
+}
+
+static void disable_runtime_instr(void)
+{
+ struct pt_regs *regs = task_pt_regs(current);
+
+ load_runtime_instr_cb(&runtime_instr_empty_cb);
+
+ /*
+ * Make sure the RI bit is deleted from the PSW. If the user did not
+ * switch off RI before the system call the process will get a
+ * specification exception otherwise.
+ */
+ regs->psw.mask &= ~PSW_MASK_RI;
+}
+
+static void init_runtime_instr_cb(struct runtime_instr_cb *cb)
+{
+ cb->buf_limit = 0xfff;
+ 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);
+}
+
+SYSCALL_DEFINE2(s390_runtime_instr, int, command, int, signum)
+{
+ struct runtime_instr_cb *cb;
+
+ if (!runtime_instr_avail())
+ return -EOPNOTSUPP;
+
+ if (command == S390_RUNTIME_INSTR_STOP) {
+ preempt_disable();
+ exit_thread_runtime_instr();
+ preempt_enable();
+ return 0;
+ }
+
+ if (command != S390_RUNTIME_INSTR_START ||
+ (signum < SIGRTMIN || signum > SIGRTMAX))
+ return -EINVAL;
+
+ if (!current->thread.ri_cb) {
+ cb = kzalloc(sizeof(*cb), GFP_KERNEL);
+ if (!cb)
+ return -ENOMEM;
+ } else {
+ cb = current->thread.ri_cb;
+ memset(cb, 0, sizeof(*cb));
+ }
+
+ init_runtime_instr_cb(cb);
+ current->thread.ri_signum = signum;
+
+ /* now load the control block to make it available */
+ preempt_disable();
+ current->thread.ri_cb = cb;
+ load_runtime_instr_cb(cb);
+ preempt_enable();
+ return 0;
+}
+
+static int __init runtime_instr_init(void)
+{
+ int rc;
+
+ if (!runtime_instr_avail())
+ return 0;
+
+ irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT);
+ rc = register_external_irq(EXT_IRQ_MEASURE_ALERT,
+ runtime_instr_int_handler);
+ if (rc)
+ irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT);
+ else
+ pr_info("Runtime instrumentation facility initialized\n");
+ return rc;
+}
+device_initcall(runtime_instr_init);