150 lines
3.2 KiB
C
150 lines
3.2 KiB
C
/*
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* Copyright IBM Corp. 2012
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* Author(s): Jan Glauber <jang@linux.vnet.ibm.com>
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*/
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#include <linux/kernel.h>
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#include <linux/syscalls.h>
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#include <linux/signal.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/errno.h>
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#include <linux/kernel_stat.h>
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#include <asm/runtime_instr.h>
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#include <asm/cpu_mf.h>
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#include <asm/irq.h>
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/* empty control block to disable RI by loading it */
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struct runtime_instr_cb runtime_instr_empty_cb;
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static int runtime_instr_avail(void)
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{
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return test_facility(64);
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}
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static void disable_runtime_instr(void)
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{
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struct pt_regs *regs = task_pt_regs(current);
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load_runtime_instr_cb(&runtime_instr_empty_cb);
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/*
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* Make sure the RI bit is deleted from the PSW. If the user did not
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* switch off RI before the system call the process will get a
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* specification exception otherwise.
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*/
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regs->psw.mask &= ~PSW_MASK_RI;
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}
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static void init_runtime_instr_cb(struct runtime_instr_cb *cb)
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{
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cb->buf_limit = 0xfff;
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cb->int_requested = 1;
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cb->pstate = 1;
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cb->pstate_set_buf = 1;
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cb->pstate_sample = 1;
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cb->pstate_collect = 1;
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cb->key = PAGE_DEFAULT_KEY;
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cb->valid = 1;
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}
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void exit_thread_runtime_instr(void)
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{
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struct task_struct *task = current;
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if (!task->thread.ri_cb)
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return;
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disable_runtime_instr();
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kfree(task->thread.ri_cb);
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task->thread.ri_signum = 0;
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task->thread.ri_cb = NULL;
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}
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static void runtime_instr_int_handler(struct ext_code ext_code,
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unsigned int param32, unsigned long param64)
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{
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struct siginfo info;
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if (!(param32 & CPU_MF_INT_RI_MASK))
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return;
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inc_irq_stat(IRQEXT_CMR);
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if (!current->thread.ri_cb)
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return;
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if (current->thread.ri_signum < SIGRTMIN ||
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current->thread.ri_signum > SIGRTMAX) {
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WARN_ON_ONCE(1);
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return;
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}
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memset(&info, 0, sizeof(info));
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info.si_signo = current->thread.ri_signum;
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info.si_code = SI_QUEUE;
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if (param32 & CPU_MF_INT_RI_BUF_FULL)
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info.si_int = ENOBUFS;
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else if (param32 & CPU_MF_INT_RI_HALTED)
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info.si_int = ECANCELED;
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else
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return; /* unknown reason */
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send_sig_info(current->thread.ri_signum, &info, current);
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}
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SYSCALL_DEFINE2(s390_runtime_instr, int, command, int, signum)
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{
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struct runtime_instr_cb *cb;
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if (!runtime_instr_avail())
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return -EOPNOTSUPP;
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if (command == S390_RUNTIME_INSTR_STOP) {
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preempt_disable();
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exit_thread_runtime_instr();
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preempt_enable();
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return 0;
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}
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if (command != S390_RUNTIME_INSTR_START ||
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(signum < SIGRTMIN || signum > SIGRTMAX))
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return -EINVAL;
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if (!current->thread.ri_cb) {
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cb = kzalloc(sizeof(*cb), GFP_KERNEL);
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if (!cb)
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return -ENOMEM;
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} else {
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cb = current->thread.ri_cb;
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memset(cb, 0, sizeof(*cb));
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}
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init_runtime_instr_cb(cb);
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current->thread.ri_signum = signum;
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/* now load the control block to make it available */
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preempt_disable();
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current->thread.ri_cb = cb;
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load_runtime_instr_cb(cb);
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preempt_enable();
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return 0;
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}
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static int __init runtime_instr_init(void)
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{
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int rc;
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if (!runtime_instr_avail())
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return 0;
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irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT);
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rc = register_external_irq(EXT_IRQ_MEASURE_ALERT,
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runtime_instr_int_handler);
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if (rc)
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irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT);
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else
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pr_info("Runtime instrumentation facility initialized\n");
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return rc;
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}
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device_initcall(runtime_instr_init);
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