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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2019 SiFive
*/
#include <linux/pagewalk.h>
#include <linux/pgtable.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_pgd_entry(pgd_t *pgd, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
pgd_t val = READ_ONCE(*pgd);
if (pgd_leaf(val)) {
val = __pgd(set_pageattr_masks(pgd_val(val), walk));
set_pgd(pgd, val);
}
return 0;
}
static int pageattr_p4d_entry(p4d_t *p4d, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
p4d_t val = READ_ONCE(*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 = READ_ONCE(*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 = READ_ONCE(*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 = READ_ONCE(*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 = {
.pgd_entry = pageattr_pgd_entry,
.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,
};
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;
struct pageattr_masks masks = {
.set_mask = set_mask,
.clear_mask = clear_mask
};
if (!numpages)
return 0;
mmap_read_lock(&init_mm);
ret = walk_page_range_novma(&init_mm, start, end, &pageattr_ops, NULL,
&masks);
mmap_read_unlock(&init_mm);
flush_tlb_kernel_range(start, end);
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)
{
int ret;
unsigned long start = (unsigned long)page_address(page);
unsigned long end = start + PAGE_SIZE;
struct pageattr_masks masks = {
.set_mask = __pgprot(0),
.clear_mask = __pgprot(_PAGE_PRESENT)
};
mmap_read_lock(&init_mm);
ret = walk_page_range(&init_mm, start, end, &pageattr_ops, &masks);
mmap_read_unlock(&init_mm);
return ret;
}
int set_direct_map_default_noflush(struct page *page)
{
int ret;
unsigned long start = (unsigned long)page_address(page);
unsigned long end = start + PAGE_SIZE;
struct pageattr_masks masks = {
.set_mask = PAGE_KERNEL,
.clear_mask = __pgprot(0)
};
mmap_read_lock(&init_mm);
ret = walk_page_range(&init_mm, start, end, &pageattr_ops, &masks);
mmap_read_unlock(&init_mm);
return ret;
}
#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(*pgd))
return false;
p4d = p4d_offset(pgd, addr);
if (!p4d_present(*p4d))
return false;
pud = pud_offset(p4d, addr);
if (!pud_present(*pud))
return false;
pmd = pmd_offset(pud, addr);
if (!pmd_present(*pmd))
return false;
pte = pte_offset_kernel(pmd, addr);
return pte_present(*pte);
}
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