static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
unsigned long virt, phys_addr_t size,
pgprot_t prot,
phys_addr_t (*alloc)(void))
{
init_pgd(pgd_offset_raw(pgdir, virt), phys, virt, size, prot, alloc);
}
/*
* Copy the current shadow region into a new pgdir.
*/
void __init kasan_copy_shadow(pgd_t *pgdir)
{
pgd_t *pgd, *pgd_new, *pgd_end;
pgd = pgd_offset_k(KASAN_SHADOW_START);
pgd_end = pgd_offset_k(KASAN_SHADOW_END);
pgd_new = pgd_offset_raw(pgdir, KASAN_SHADOW_START);
do {
set_pgd(pgd_new, *pgd);
} while (pgd++, pgd_new++, pgd != pgd_end);
}
/*
* Copy the current shadow region into a new pgdir.
*/
void __init kasan_copy_shadow(pgd_t *pgdir)
{
pgd_t *pgdp, *pgdp_new, *pgdp_end;
pgdp = pgd_offset_k(KASAN_SHADOW_START);
pgdp_end = pgd_offset_k(KASAN_SHADOW_END);
pgdp_new = pgd_offset_raw(pgdir, KASAN_SHADOW_START);
do {
set_pgd(pgdp_new, READ_ONCE(*pgdp));
} while (pgdp++, pgdp_new++, pgdp != pgdp_end);
}
static int copy_page_tables(pgd_t *dst_pgdp, unsigned long start,
unsigned long end)
{
unsigned long next;
unsigned long addr = start;
pgd_t *src_pgdp = pgd_offset_k(start);
dst_pgdp = pgd_offset_raw(dst_pgdp, start);
do {
next = pgd_addr_end(addr, end);
if (pgd_none(READ_ONCE(*src_pgdp)))
continue;
if (copy_pud(dst_pgdp, src_pgdp, addr, next))
return -ENOMEM;
} while (dst_pgdp++, src_pgdp++, addr = next, addr != end);
return 0;
}
/*
* Copies length bytes, starting at src_start into an new page,
* perform cache maintentance, then maps it at the specified address low
* address as executable.
*
* This is used by hibernate to copy the code it needs to execute when
* overwriting the kernel text. This function generates a new set of page
* tables, which it loads into ttbr0.
*
* Length is provided as we probably only want 4K of data, even on a 64K
* page system.
*/
static int create_safe_exec_page(void *src_start, size_t length,
unsigned long dst_addr,
phys_addr_t *phys_dst_addr,
void *(*allocator)(gfp_t mask),
gfp_t mask)
{
int rc = 0;
pgd_t *pgdp;
pud_t *pudp;
pmd_t *pmdp;
pte_t *ptep;
unsigned long dst = (unsigned long)allocator(mask);
if (!dst) {
rc = -ENOMEM;
goto out;
}
memcpy((void *)dst, src_start, length);
flush_icache_range(dst, dst + length);
pgdp = pgd_offset_raw(allocator(mask), dst_addr);
if (pgd_none(READ_ONCE(*pgdp))) {
pudp = allocator(mask);
if (!pudp) {
rc = -ENOMEM;
goto out;
}
pgd_populate(&init_mm, pgdp, pudp);
}
pudp = pud_offset(pgdp, dst_addr);
if (pud_none(READ_ONCE(*pudp))) {
pmdp = allocator(mask);
if (!pmdp) {
rc = -ENOMEM;
goto out;
}
pud_populate(&init_mm, pudp, pmdp);
}
pmdp = pmd_offset(pudp, dst_addr);
if (pmd_none(READ_ONCE(*pmdp))) {
ptep = allocator(mask);
if (!ptep) {
rc = -ENOMEM;
goto out;
}
pmd_populate_kernel(&init_mm, pmdp, ptep);
}
ptep = pte_offset_kernel(pmdp, dst_addr);
set_pte(ptep, pfn_pte(virt_to_pfn(dst), PAGE_KERNEL_EXEC));
/*
* Load our new page tables. A strict BBM approach requires that we
* ensure that TLBs are free of any entries that may overlap with the
* global mappings we are about to install.
*
* For a real hibernate/resume cycle TTBR0 currently points to a zero
* page, but TLBs may contain stale ASID-tagged entries (e.g. for EFI
* runtime services), while for a userspace-driven test_resume cycle it
* points to userspace page tables (and we must point it at a zero page
* ourselves). Elsewhere we only (un)install the idmap with preemption
* disabled, so T0SZ should be as required regardless.
*/
cpu_set_reserved_ttbr0();
local_flush_tlb_all();
write_sysreg(phys_to_ttbr(virt_to_phys(pgdp)), ttbr0_el1);
isb();
*phys_dst_addr = virt_to_phys((void *)dst);
out:
return rc;
}
