Contributors: 12
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Jeff Dike |
175 |
64.58% |
9 |
34.62% |
| Benjamin Berg |
28 |
10.33% |
3 |
11.54% |
| Johannes Berg |
23 |
8.49% |
3 |
11.54% |
| Bodo Stroesser |
22 |
8.12% |
2 |
7.69% |
| Al Viro |
8 |
2.95% |
2 |
7.69% |
| Anton Ivanov |
4 |
1.48% |
1 |
3.85% |
| Geert Uytterhoeven |
3 |
1.11% |
1 |
3.85% |
| Paolo 'Blaisorblade' Giarrusso |
2 |
0.74% |
1 |
3.85% |
| Alex Dewar |
2 |
0.74% |
1 |
3.85% |
| Tejun Heo |
2 |
0.74% |
1 |
3.85% |
| Richard Weinberger |
1 |
0.37% |
1 |
3.85% |
| Ingo Molnar |
1 |
0.37% |
1 |
3.85% |
| Total |
271 |
|
26 |
|
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
* Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
*/
#include <linux/mm.h>
#include <linux/sched/signal.h>
#include <linux/slab.h>
#include <asm/pgalloc.h>
#include <asm/sections.h>
#include <asm/mmu_context.h>
#include <as-layout.h>
#include <os.h>
#include <skas.h>
#include <stub-data.h>
/* Ensure the stub_data struct covers the allocated area */
static_assert(sizeof(struct stub_data) == STUB_DATA_PAGES * UM_KERN_PAGE_SIZE);
int init_new_context(struct task_struct *task, struct mm_struct *mm)
{
struct mm_id *new_id = &mm->context.id;
unsigned long stack = 0;
int ret = -ENOMEM;
stack = __get_free_pages(GFP_KERNEL | __GFP_ZERO, ilog2(STUB_DATA_PAGES));
if (stack == 0)
goto out;
new_id->stack = stack;
block_signals_trace();
new_id->u.pid = start_userspace(stack);
unblock_signals_trace();
if (new_id->u.pid < 0) {
ret = new_id->u.pid;
goto out_free;
}
/*
* Ensure the new MM is clean and nothing unwanted is mapped.
*
* TODO: We should clear the memory up to STUB_START to ensure there is
* nothing mapped there, i.e. we (currently) have:
*
* |- user memory -|- unused -|- stub -|- unused -|
* ^ TASK_SIZE ^ STUB_START
*
* Meaning we have two unused areas where we may still have valid
* mappings from our internal clone(). That isn't really a problem as
* userspace is not going to access them, but it is definitely not
* correct.
*
* However, we are "lucky" and if rseq is configured, then on 32 bit
* it will fall into the first empty range while on 64 bit it is going
* to use an anonymous mapping in the second range. As such, things
* continue to work for now as long as we don't start unmapping these
* areas.
*
* Change this to STUB_START once we have a clean userspace.
*/
unmap(new_id, 0, TASK_SIZE);
return 0;
out_free:
if (new_id->stack != 0)
free_pages(new_id->stack, ilog2(STUB_DATA_PAGES));
out:
return ret;
}
void destroy_context(struct mm_struct *mm)
{
struct mm_context *mmu = &mm->context;
/*
* If init_new_context wasn't called, this will be
* zero, resulting in a kill(0), which will result in the
* whole UML suddenly dying. Also, cover negative and
* 1 cases, since they shouldn't happen either.
*/
if (mmu->id.u.pid < 2) {
printk(KERN_ERR "corrupt mm_context - pid = %d\n",
mmu->id.u.pid);
return;
}
os_kill_ptraced_process(mmu->id.u.pid, 1);
free_pages(mmu->id.stack, ilog2(STUB_DATA_PAGES));
}