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#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/bug.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/uaccess.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/desc.h>
#ifdef CONFIG_KAISER
__visible DEFINE_PER_CPU_USER_MAPPED(unsigned long, unsafe_stack_register_backup);
/**
* Get the real ppn from a address in kernel mapping.
* @param address The virtual adrress
* @return the physical address
*/
static inline unsigned long get_pa_from_mapping (unsigned long address)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
pgd = pgd_offset_k(address);
BUG_ON(pgd_none(*pgd) || pgd_large(*pgd));
pud = pud_offset(pgd, address);
BUG_ON(pud_none(*pud));
if (pud_large(*pud)) {
return (pud_pfn(*pud) << PAGE_SHIFT) | (address & ~PUD_PAGE_MASK);
}
pmd = pmd_offset(pud, address);
BUG_ON(pmd_none(*pmd));
if (pmd_large(*pmd)) {
return (pmd_pfn(*pmd) << PAGE_SHIFT) | (address & ~PMD_PAGE_MASK);
}
pte = pte_offset_kernel(pmd, address);
BUG_ON(pte_none(*pte));
return (pte_pfn(*pte) << PAGE_SHIFT) | (address & ~PAGE_MASK);
}
void _kaiser_copy (unsigned long start_addr, unsigned long size,
unsigned long flags)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
unsigned long address;
unsigned long end_addr = start_addr + size;
unsigned long target_address;
for (address = PAGE_ALIGN(start_addr - (PAGE_SIZE - 1));
address < PAGE_ALIGN(end_addr); address += PAGE_SIZE) {
target_address = get_pa_from_mapping(address);
pgd = native_get_shadow_pgd(pgd_offset_k(address));
BUG_ON(pgd_none(*pgd) && "All shadow pgds should be mapped at this time\n");
BUG_ON(pgd_large(*pgd));
pud = pud_offset(pgd, address);
if (pud_none(*pud)) {
set_pud(pud, __pud(_PAGE_TABLE | __pa(pmd_alloc_one(0, address))));
}
BUG_ON(pud_large(*pud));
pmd = pmd_offset(pud, address);
if (pmd_none(*pmd)) {
set_pmd(pmd, __pmd(_PAGE_TABLE | __pa(pte_alloc_one_kernel(0, address))));
}
BUG_ON(pmd_large(*pmd));
pte = pte_offset_kernel(pmd, address);
if (pte_none(*pte)) {
set_pte(pte, __pte(flags | target_address));
} else {
BUG_ON(__pa(pte_page(*pte)) != target_address);
}
}
}
// at first, add a pmd for every pgd entry in the shadowmem-kernel-part of the kernel mapping
static inline void __init _kaiser_init(void)
{
pgd_t *pgd;
int i = 0;
pgd = native_get_shadow_pgd(pgd_offset_k((unsigned long )0));
for (i = PTRS_PER_PGD / 2; i < PTRS_PER_PGD; i++) {
set_pgd(pgd + i, __pgd(_PAGE_TABLE |__pa(pud_alloc_one(0, 0))));
}
}
extern char __per_cpu_user_mapped_start[], __per_cpu_user_mapped_end[];
spinlock_t shadow_table_lock;
void __init kaiser_init(void)
{
int cpu;
spin_lock_init(&shadow_table_lock);
spin_lock(&shadow_table_lock);
_kaiser_init();
for_each_possible_cpu(cpu) {
// map the per cpu user variables
_kaiser_copy(
(unsigned long) (__per_cpu_user_mapped_start + per_cpu_offset(cpu)),
(unsigned long) __per_cpu_user_mapped_end - (unsigned long) __per_cpu_user_mapped_start,
__PAGE_KERNEL);
}
// map the entry/exit text section, which is responsible to switch between user- and kernel mode
_kaiser_copy(
(unsigned long) __entry_text_start,
(unsigned long) __entry_text_end - (unsigned long) __entry_text_start,
__PAGE_KERNEL_RX);
// the fixed map address of the idt_table
_kaiser_copy(
(unsigned long) idt_descr.address,
sizeof(gate_desc) * NR_VECTORS,
__PAGE_KERNEL_RO);
spin_unlock(&shadow_table_lock);
}
// add a mapping to the shadow-mapping, and synchronize the mappings
void kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags)
{
spin_lock(&shadow_table_lock);
_kaiser_copy(addr, size, flags);
spin_unlock(&shadow_table_lock);
}
extern void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end);
void kaiser_remove_mapping(unsigned long start, unsigned long size)
{
pgd_t *pgd = native_get_shadow_pgd(pgd_offset_k(start));
spin_lock(&shadow_table_lock);
do {
unmap_pud_range(pgd, start, start + size);
} while (pgd++ != native_get_shadow_pgd(pgd_offset_k(start + size)));
spin_unlock(&shadow_table_lock);
}
#endif /* CONFIG_KAISER */
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