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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright IBM Corp. 2016
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
*/
#include <linux/kernel.h>
#include <linux/syscalls.h>
#include <linux/signal.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <asm/guarded_storage.h>
#include "entry.h"
void exit_thread_gs(void)
{
kfree(current->thread.gs_cb);
kfree(current->thread.gs_bc_cb);
current->thread.gs_cb = current->thread.gs_bc_cb = NULL;
}
static int gs_enable(void)
{
struct gs_cb *gs_cb;
if (!current->thread.gs_cb) {
gs_cb = kzalloc(sizeof(*gs_cb), GFP_KERNEL);
if (!gs_cb)
return -ENOMEM;
gs_cb->gsd = 25;
preempt_disable();
__ctl_set_bit(2, 4);
load_gs_cb(gs_cb);
current->thread.gs_cb = gs_cb;
preempt_enable();
}
return 0;
}
static int gs_disable(void)
{
if (current->thread.gs_cb) {
preempt_disable();
kfree(current->thread.gs_cb);
current->thread.gs_cb = NULL;
__ctl_clear_bit(2, 4);
preempt_enable();
}
return 0;
}
static int gs_set_bc_cb(struct gs_cb __user *u_gs_cb)
{
struct gs_cb *gs_cb;
gs_cb = current->thread.gs_bc_cb;
if (!gs_cb) {
gs_cb = kzalloc(sizeof(*gs_cb), GFP_KERNEL);
if (!gs_cb)
return -ENOMEM;
current->thread.gs_bc_cb = gs_cb;
}
if (copy_from_user(gs_cb, u_gs_cb, sizeof(*gs_cb)))
return -EFAULT;
return 0;
}
static int gs_clear_bc_cb(void)
{
struct gs_cb *gs_cb;
gs_cb = current->thread.gs_bc_cb;
current->thread.gs_bc_cb = NULL;
kfree(gs_cb);
return 0;
}
void gs_load_bc_cb(struct pt_regs *regs)
{
struct gs_cb *gs_cb;
preempt_disable();
clear_thread_flag(TIF_GUARDED_STORAGE);
gs_cb = current->thread.gs_bc_cb;
if (gs_cb) {
kfree(current->thread.gs_cb);
current->thread.gs_bc_cb = NULL;
__ctl_set_bit(2, 4);
load_gs_cb(gs_cb);
current->thread.gs_cb = gs_cb;
}
preempt_enable();
}
static int gs_broadcast(void)
{
struct task_struct *sibling;
read_lock(&tasklist_lock);
for_each_thread(current, sibling) {
if (!sibling->thread.gs_bc_cb)
continue;
if (test_and_set_tsk_thread_flag(sibling, TIF_GUARDED_STORAGE))
kick_process(sibling);
}
read_unlock(&tasklist_lock);
return 0;
}
SYSCALL_DEFINE2(s390_guarded_storage, int, command,
struct gs_cb __user *, gs_cb)
{
if (!MACHINE_HAS_GS)
return -EOPNOTSUPP;
switch (command) {
case GS_ENABLE:
return gs_enable();
case GS_DISABLE:
return gs_disable();
case GS_SET_BC_CB:
return gs_set_bc_cb(gs_cb);
case GS_CLEAR_BC_CB:
return gs_clear_bc_cb();
case GS_BROADCAST:
return gs_broadcast();
default:
return -EINVAL;
}
}
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