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/*
* 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 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->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_cb = NULL;
}
SYSCALL_DEFINE1(s390_runtime_instr, int, command)
{
struct runtime_instr_cb *cb;
if (!test_facility(64))
return -EOPNOTSUPP;
if (command == S390_RUNTIME_INSTR_STOP) {
preempt_disable();
exit_thread_runtime_instr();
preempt_enable();
return 0;
}
if (command != S390_RUNTIME_INSTR_START)
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);
/* 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;
}
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