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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2019 SiFive
*/
#include <linux/pagewalk.h>
#include <linux/pgtable.h>
#include <linux/vmalloc.h>
#include <asm/tlbflush.h>
#include <asm/bitops.h>
#include <asm/set_memory.h>
struct pageattr_masks {
pgprot_t set_mask;
pgprot_t clear_mask;
};
static unsigned long set_pageattr_masks(unsigned long val, struct mm_walk *walk)
{
struct pageattr_masks *masks = walk->private;
unsigned long new_val = val;
new_val &= ~(pgprot_val(masks->clear_mask));
new_val |= (pgprot_val(masks->set_mask));
return new_val;
}
static int pageattr_p4d_entry(p4d_t *p4d, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
p4d_t val = p4dp_get(p4d);
if (p4d_leaf(val)) {
val = __p4d(set_pageattr_masks(p4d_val(val), walk));
set_p4d(p4d, val);
}
return 0;
}
static int pageattr_pud_entry(pud_t *pud, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
pud_t val = pudp_get(pud);
if (pud_leaf(val)) {
val = __pud(set_pageattr_masks(pud_val(val), walk));
set_pud(pud, val);
}
return 0;
}
static int pageattr_pmd_entry(pmd_t *pmd, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
pmd_t val = pmdp_get(pmd);
if (pmd_leaf(val)) {
val = __pmd(set_pageattr_masks(pmd_val(val), walk));
set_pmd(pmd, val);
}
return 0;
}
static int pageattr_pte_entry(pte_t *pte, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
pte_t val = ptep_get(pte);
val = __pte(set_pageattr_masks(pte_val(val), walk));
set_pte(pte, val);
return 0;
}
static int pageattr_pte_hole(unsigned long addr, unsigned long next,
int depth, struct mm_walk *walk)
{
/* Nothing to do here */
return 0;
}
static const struct mm_walk_ops pageattr_ops = {
.p4d_entry = pageattr_p4d_entry,
.pud_entry = pageattr_pud_entry,
.pmd_entry = pageattr_pmd_entry,
.pte_entry = pageattr_pte_entry,
.pte_hole = pageattr_pte_hole,
.walk_lock = PGWALK_RDLOCK,
};
#ifdef CONFIG_64BIT
static int __split_linear_mapping_pmd(pud_t *pudp,
unsigned long vaddr, unsigned long end)
{
pmd_t *pmdp;
unsigned long next;
pmdp = pmd_offset(pudp, vaddr);
do {
next = pmd_addr_end(vaddr, end);
if (next - vaddr >= PMD_SIZE &&
vaddr <= (vaddr & PMD_MASK) && end >= next)
continue;
if (pmd_leaf(pmdp_get(pmdp))) {
struct page *pte_page;
unsigned long pfn = _pmd_pfn(pmdp_get(pmdp));
pgprot_t prot = __pgprot(pmd_val(pmdp_get(pmdp)) & ~_PAGE_PFN_MASK);
pte_t *ptep_new;
int i;
pte_page = alloc_page(GFP_KERNEL);
if (!pte_page)
return -ENOMEM;
ptep_new = (pte_t *)page_address(pte_page);
for (i = 0; i < PTRS_PER_PTE; ++i, ++ptep_new)
set_pte(ptep_new, pfn_pte(pfn + i, prot));
smp_wmb();
set_pmd(pmdp, pfn_pmd(page_to_pfn(pte_page), PAGE_TABLE));
}
} while (pmdp++, vaddr = next, vaddr != end);
return 0;
}
static int __split_linear_mapping_pud(p4d_t *p4dp,
unsigned long vaddr, unsigned long end)
{
pud_t *pudp;
unsigned long next;
int ret;
pudp = pud_offset(p4dp, vaddr);
do {
next = pud_addr_end(vaddr, end);
if (next - vaddr >= PUD_SIZE &&
vaddr <= (vaddr & PUD_MASK) && end >= next)
continue;
if (pud_leaf(pudp_get(pudp))) {
struct page *pmd_page;
unsigned long pfn = _pud_pfn(pudp_get(pudp));
pgprot_t prot = __pgprot(pud_val(pudp_get(pudp)) & ~_PAGE_PFN_MASK);
pmd_t *pmdp_new;
int i;
pmd_page = alloc_page(GFP_KERNEL);
if (!pmd_page)
return -ENOMEM;
pmdp_new = (pmd_t *)page_address(pmd_page);
for (i = 0; i < PTRS_PER_PMD; ++i, ++pmdp_new)
set_pmd(pmdp_new,
pfn_pmd(pfn + ((i * PMD_SIZE) >> PAGE_SHIFT), prot));
smp_wmb();
set_pud(pudp, pfn_pud(page_to_pfn(pmd_page), PAGE_TABLE));
}
ret = __split_linear_mapping_pmd(pudp, vaddr, next);
if (ret)
return ret;
} while (pudp++, vaddr = next, vaddr != end);
return 0;
}
static int __split_linear_mapping_p4d(pgd_t *pgdp,
unsigned long vaddr, unsigned long end)
{
p4d_t *p4dp;
unsigned long next;
int ret;
p4dp = p4d_offset(pgdp, vaddr);
do {
next = p4d_addr_end(vaddr, end);
/*
* If [vaddr; end] contains [vaddr & P4D_MASK; next], we don't
* need to split, we'll change the protections on the whole P4D.
*/
if (next - vaddr >= P4D_SIZE &&
vaddr <= (vaddr & P4D_MASK) && end >= next)
continue;
if (p4d_leaf(p4dp_get(p4dp))) {
struct page *pud_page;
unsigned long pfn = _p4d_pfn(p4dp_get(p4dp));
pgprot_t prot = __pgprot(p4d_val(p4dp_get(p4dp)) & ~_PAGE_PFN_MASK);
pud_t *pudp_new;
int i;
pud_page = alloc_page(GFP_KERNEL);
if (!pud_page)
return -ENOMEM;
/*
* Fill the pud level with leaf puds that have the same
* protections as the leaf p4d.
*/
pudp_new = (pud_t *)page_address(pud_page);
for (i = 0; i < PTRS_PER_PUD; ++i, ++pudp_new)
set_pud(pudp_new,
pfn_pud(pfn + ((i * PUD_SIZE) >> PAGE_SHIFT), prot));
/*
* Make sure the pud filling is not reordered with the
* p4d store which could result in seeing a partially
* filled pud level.
*/
smp_wmb();
set_p4d(p4dp, pfn_p4d(page_to_pfn(pud_page), PAGE_TABLE));
}
ret = __split_linear_mapping_pud(p4dp, vaddr, next);
if (ret)
return ret;
} while (p4dp++, vaddr = next, vaddr != end);
return 0;
}
static int __split_linear_mapping_pgd(pgd_t *pgdp,
unsigned long vaddr,
unsigned long end)
{
unsigned long next;
int ret;
do {
next = pgd_addr_end(vaddr, end);
/* We never use PGD mappings for the linear mapping */
ret = __split_linear_mapping_p4d(pgdp, vaddr, next);
if (ret)
return ret;
} while (pgdp++, vaddr = next, vaddr != end);
return 0;
}
static int split_linear_mapping(unsigned long start, unsigned long end)
{
return __split_linear_mapping_pgd(pgd_offset_k(start), start, end);
}
#endif /* CONFIG_64BIT */
static int __set_memory(unsigned long addr, int numpages, pgprot_t set_mask,
pgprot_t clear_mask)
{
int ret;
unsigned long start = addr;
unsigned long end = start + PAGE_SIZE * numpages;
unsigned long __maybe_unused lm_start;
unsigned long __maybe_unused lm_end;
struct pageattr_masks masks = {
.set_mask = set_mask,
.clear_mask = clear_mask
};
if (!numpages)
return 0;
mmap_write_lock(&init_mm);
#ifdef CONFIG_64BIT
/*
* We are about to change the permissions of a kernel mapping, we must
* apply the same changes to its linear mapping alias, which may imply
* splitting a huge mapping.
*/
if (is_vmalloc_or_module_addr((void *)start)) {
struct vm_struct *area = NULL;
int i, page_start;
area = find_vm_area((void *)start);
page_start = (start - (unsigned long)area->addr) >> PAGE_SHIFT;
for (i = page_start; i < page_start + numpages; ++i) {
lm_start = (unsigned long)page_address(area->pages[i]);
lm_end = lm_start + PAGE_SIZE;
ret = split_linear_mapping(lm_start, lm_end);
if (ret)
goto unlock;
ret = walk_page_range_novma(&init_mm, lm_start, lm_end,
&pageattr_ops, NULL, &masks);
if (ret)
goto unlock;
}
} else if (is_kernel_mapping(start) || is_linear_mapping(start)) {
lm_start = (unsigned long)lm_alias(start);
lm_end = (unsigned long)lm_alias(end);
ret = split_linear_mapping(lm_start, lm_end);
if (ret)
goto unlock;
ret = walk_page_range_novma(&init_mm, lm_start, lm_end,
&pageattr_ops, NULL, &masks);
if (ret)
goto unlock;
}
ret = walk_page_range_novma(&init_mm, start, end, &pageattr_ops, NULL,
&masks);
unlock:
mmap_write_unlock(&init_mm);
/*
* We can't use flush_tlb_kernel_range() here as we may have split a
* hugepage that is larger than that, so let's flush everything.
*/
flush_tlb_all();
#else
ret = walk_page_range_novma(&init_mm, start, end, &pageattr_ops, NULL,
&masks);
mmap_write_unlock(&init_mm);
flush_tlb_kernel_range(start, end);
#endif
return ret;
}
int set_memory_rw_nx(unsigned long addr, int numpages)
{
return __set_memory(addr, numpages, __pgprot(_PAGE_READ | _PAGE_WRITE),
__pgprot(_PAGE_EXEC));
}
int set_memory_ro(unsigned long addr, int numpages)
{
return __set_memory(addr, numpages, __pgprot(_PAGE_READ),
__pgprot(_PAGE_WRITE));
}
int set_memory_rw(unsigned long addr, int numpages)
{
return __set_memory(addr, numpages, __pgprot(_PAGE_READ | _PAGE_WRITE),
__pgprot(0));
}
int set_memory_x(unsigned long addr, int numpages)
{
return __set_memory(addr, numpages, __pgprot(_PAGE_EXEC), __pgprot(0));
}
int set_memory_nx(unsigned long addr, int numpages)
{
return __set_memory(addr, numpages, __pgprot(0), __pgprot(_PAGE_EXEC));
}
int set_direct_map_invalid_noflush(struct page *page)
{
return __set_memory((unsigned long)page_address(page), 1,
__pgprot(0), __pgprot(_PAGE_PRESENT));
}
int set_direct_map_default_noflush(struct page *page)
{
return __set_memory((unsigned long)page_address(page), 1,
PAGE_KERNEL, __pgprot(0));
}
#ifdef CONFIG_DEBUG_PAGEALLOC
void __kernel_map_pages(struct page *page, int numpages, int enable)
{
if (!debug_pagealloc_enabled())
return;
if (enable)
__set_memory((unsigned long)page_address(page), numpages,
__pgprot(_PAGE_PRESENT), __pgprot(0));
else
__set_memory((unsigned long)page_address(page), numpages,
__pgprot(0), __pgprot(_PAGE_PRESENT));
}
#endif
bool kernel_page_present(struct page *page)
{
unsigned long addr = (unsigned long)page_address(page);
pgd_t *pgd;
pud_t *pud;
p4d_t *p4d;
pmd_t *pmd;
pte_t *pte;
pgd = pgd_offset_k(addr);
if (!pgd_present(pgdp_get(pgd)))
return false;
if (pgd_leaf(pgdp_get(pgd)))
return true;
p4d = p4d_offset(pgd, addr);
if (!p4d_present(p4dp_get(p4d)))
return false;
if (p4d_leaf(p4dp_get(p4d)))
return true;
pud = pud_offset(p4d, addr);
if (!pud_present(pudp_get(pud)))
return false;
if (pud_leaf(pudp_get(pud)))
return true;
pmd = pmd_offset(pud, addr);
if (!pmd_present(pmdp_get(pmd)))
return false;
if (pmd_leaf(pmdp_get(pmd)))
return true;
pte = pte_offset_kernel(pmd, addr);
return pte_present(ptep_get(pte));
}
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