cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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kfence.h (1312B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2
      3#ifndef _ASM_RISCV_KFENCE_H
      4#define _ASM_RISCV_KFENCE_H
      5
      6#include <linux/kfence.h>
      7#include <linux/pfn.h>
      8#include <asm-generic/pgalloc.h>
      9#include <asm/pgtable.h>
     10
     11static inline int split_pmd_page(unsigned long addr)
     12{
     13	int i;
     14	unsigned long pfn = PFN_DOWN(__pa((addr & PMD_MASK)));
     15	pmd_t *pmd = pmd_off_k(addr);
     16	pte_t *pte = pte_alloc_one_kernel(&init_mm);
     17
     18	if (!pte)
     19		return -ENOMEM;
     20
     21	for (i = 0; i < PTRS_PER_PTE; i++)
     22		set_pte(pte + i, pfn_pte(pfn + i, PAGE_KERNEL));
     23	set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa(pte)), PAGE_TABLE));
     24
     25	flush_tlb_kernel_range(addr, addr + PMD_SIZE);
     26	return 0;
     27}
     28
     29static inline bool arch_kfence_init_pool(void)
     30{
     31	int ret;
     32	unsigned long addr;
     33	pmd_t *pmd;
     34
     35	for (addr = (unsigned long)__kfence_pool; is_kfence_address((void *)addr);
     36	     addr += PAGE_SIZE) {
     37		pmd = pmd_off_k(addr);
     38
     39		if (pmd_leaf(*pmd)) {
     40			ret = split_pmd_page(addr);
     41			if (ret)
     42				return false;
     43		}
     44	}
     45
     46	return true;
     47}
     48
     49static inline bool kfence_protect_page(unsigned long addr, bool protect)
     50{
     51	pte_t *pte = virt_to_kpte(addr);
     52
     53	if (protect)
     54		set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT));
     55	else
     56		set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT));
     57
     58	flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
     59
     60	return true;
     61}
     62
     63#endif /* _ASM_RISCV_KFENCE_H */