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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_RISCV_KFENCE_H
#define _ASM_RISCV_KFENCE_H
#include <linux/kfence.h>
#include <linux/pfn.h>
#include <asm-generic/pgalloc.h>
#include <asm/pgtable.h>
static inline int split_pmd_page(unsigned long addr)
{
int i;
unsigned long pfn = PFN_DOWN(__pa((addr & PMD_MASK)));
pmd_t *pmd = pmd_off_k(addr);
pte_t *pte = pte_alloc_one_kernel(&init_mm);
if (!pte)
return -ENOMEM;
for (i = 0; i < PTRS_PER_PTE; i++)
set_pte(pte + i, pfn_pte(pfn + i, PAGE_KERNEL));
set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa(pte)), PAGE_TABLE));
flush_tlb_kernel_range(addr, addr + PMD_SIZE);
return 0;
}
static inline bool arch_kfence_init_pool(void)
{
int ret;
unsigned long addr;
pmd_t *pmd;
for (addr = (unsigned long)__kfence_pool; is_kfence_address((void *)addr);
addr += PAGE_SIZE) {
pmd = pmd_off_k(addr);
if (pmd_leaf(*pmd)) {
ret = split_pmd_page(addr);
if (ret)
return false;
}
}
return true;
}
static inline bool kfence_protect_page(unsigned long addr, bool protect)
{
pte_t *pte = virt_to_kpte(addr);
if (protect)
set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT));
else
set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT));
flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
return true;
}
#endif /* _ASM_RISCV_KFENCE_H */
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