155 lines
3.7 KiB
C
155 lines
3.7 KiB
C
/*
|
|
* Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
|
|
* Licensed under the GPL
|
|
*/
|
|
|
|
#include "linux/config.h"
|
|
#include "linux/sched.h"
|
|
#include "linux/list.h"
|
|
#include "linux/spinlock.h"
|
|
#include "linux/slab.h"
|
|
#include "linux/errno.h"
|
|
#include "linux/mm.h"
|
|
#include "asm/current.h"
|
|
#include "asm/segment.h"
|
|
#include "asm/mmu.h"
|
|
#include "asm/pgalloc.h"
|
|
#include "asm/pgtable.h"
|
|
#include "os.h"
|
|
#include "skas.h"
|
|
|
|
extern int __syscall_stub_start;
|
|
|
|
static int init_stub_pte(struct mm_struct *mm, unsigned long proc,
|
|
unsigned long kernel)
|
|
{
|
|
pgd_t *pgd;
|
|
pud_t *pud;
|
|
pmd_t *pmd;
|
|
pte_t *pte;
|
|
|
|
pgd = pgd_offset(mm, proc);
|
|
pud = pud_alloc(mm, pgd, proc);
|
|
if (!pud)
|
|
goto out;
|
|
|
|
pmd = pmd_alloc(mm, pud, proc);
|
|
if (!pmd)
|
|
goto out_pmd;
|
|
|
|
pte = pte_alloc_map(mm, pmd, proc);
|
|
if (!pte)
|
|
goto out_pte;
|
|
|
|
/* There's an interaction between the skas0 stub pages, stack
|
|
* randomization, and the BUG at the end of exit_mmap. exit_mmap
|
|
* checks that the number of page tables freed is the same as had
|
|
* been allocated. If the stack is on the last page table page,
|
|
* then the stack pte page will be freed, and if not, it won't. To
|
|
* avoid having to know where the stack is, or if the process mapped
|
|
* something at the top of its address space for some other reason,
|
|
* we set TASK_SIZE to end at the start of the last page table.
|
|
* This keeps exit_mmap off the last page, but introduces a leak
|
|
* of that page. So, we hang onto it here and free it in
|
|
* destroy_context_skas.
|
|
*/
|
|
|
|
mm->context.skas.last_page_table = pmd_page_kernel(*pmd);
|
|
#ifdef CONFIG_3_LEVEL_PGTABLES
|
|
mm->context.skas.last_pmd = (unsigned long) __va(pud_val(*pud));
|
|
#endif
|
|
|
|
*pte = mk_pte(virt_to_page(kernel), __pgprot(_PAGE_PRESENT));
|
|
*pte = pte_mkexec(*pte);
|
|
*pte = pte_wrprotect(*pte);
|
|
return(0);
|
|
|
|
out_pmd:
|
|
pud_free(pud);
|
|
out_pte:
|
|
pmd_free(pmd);
|
|
out:
|
|
return(-ENOMEM);
|
|
}
|
|
|
|
int init_new_context_skas(struct task_struct *task, struct mm_struct *mm)
|
|
{
|
|
struct mm_struct *cur_mm = current->mm;
|
|
struct mm_id *cur_mm_id = &cur_mm->context.skas.id;
|
|
struct mm_id *mm_id = &mm->context.skas.id;
|
|
unsigned long stack = 0;
|
|
int from, ret = -ENOMEM;
|
|
|
|
if(!proc_mm || !ptrace_faultinfo){
|
|
stack = get_zeroed_page(GFP_KERNEL);
|
|
if(stack == 0)
|
|
goto out;
|
|
|
|
/* This zeros the entry that pgd_alloc didn't, needed since
|
|
* we are about to reinitialize it, and want mm.nr_ptes to
|
|
* be accurate.
|
|
*/
|
|
mm->pgd[USER_PTRS_PER_PGD] = __pgd(0);
|
|
|
|
ret = init_stub_pte(mm, CONFIG_STUB_CODE,
|
|
(unsigned long) &__syscall_stub_start);
|
|
if(ret)
|
|
goto out_free;
|
|
|
|
ret = init_stub_pte(mm, CONFIG_STUB_DATA, stack);
|
|
if(ret)
|
|
goto out_free;
|
|
|
|
mm->nr_ptes--;
|
|
}
|
|
mm_id->stack = stack;
|
|
|
|
if(proc_mm){
|
|
if((cur_mm != NULL) && (cur_mm != &init_mm))
|
|
from = cur_mm_id->u.mm_fd;
|
|
else from = -1;
|
|
|
|
ret = new_mm(from, stack);
|
|
if(ret < 0){
|
|
printk("init_new_context_skas - new_mm failed, "
|
|
"errno = %d\n", ret);
|
|
goto out_free;
|
|
}
|
|
mm_id->u.mm_fd = ret;
|
|
}
|
|
else {
|
|
if((cur_mm != NULL) && (cur_mm != &init_mm))
|
|
mm_id->u.pid = copy_context_skas0(stack,
|
|
cur_mm_id->u.pid);
|
|
else mm_id->u.pid = start_userspace(stack);
|
|
}
|
|
|
|
return 0;
|
|
|
|
out_free:
|
|
if(mm_id->stack != 0)
|
|
free_page(mm_id->stack);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
void destroy_context_skas(struct mm_struct *mm)
|
|
{
|
|
struct mmu_context_skas *mmu = &mm->context.skas;
|
|
|
|
if(proc_mm)
|
|
os_close_file(mmu->id.u.mm_fd);
|
|
else
|
|
os_kill_ptraced_process(mmu->id.u.pid, 1);
|
|
|
|
if(!proc_mm || !ptrace_faultinfo){
|
|
free_page(mmu->id.stack);
|
|
pte_lock_deinit(virt_to_page(mmu->last_page_table));
|
|
pte_free_kernel((pte_t *) mmu->last_page_table);
|
|
dec_page_state(nr_page_table_pages);
|
|
#ifdef CONFIG_3_LEVEL_PGTABLES
|
|
pmd_free((pmd_t *) mmu->last_pmd);
|
|
#endif
|
|
}
|
|
}
|