mirror of
https://github.com/torvalds/linux.git
synced 2024-11-17 17:41:44 +00:00
9eaba29c79
The key member of the runtime instrumentation control block contains
only the access key, not the complete storage key. Therefore the value
must be shifted by four bits.
Note: this is only relevant for debugging purposes in case somebody
compiles a kernel with a default storage access key set to a value not
equal to zero.
Fixes: e4b8b3f33f ("s390: add support for runtime instrumentation")
Reported-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
103 lines
2.2 KiB
C
103 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* 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 <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;
|
|
|
|
void runtime_instr_release(struct task_struct *tsk)
|
|
{
|
|
kfree(tsk->thread.ri_cb);
|
|
}
|
|
|
|
static void disable_runtime_instr(void)
|
|
{
|
|
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
|
|
* 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->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 (!test_facility(64))
|
|
return -EOPNOTSUPP;
|
|
|
|
if (command == S390_RUNTIME_INSTR_STOP) {
|
|
disable_runtime_instr();
|
|
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;
|
|
}
|