Revert "arm64: remove page granularity limitation from KFENCE"

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4XWBS

--------------------------------

This reverts commit d3d0ca13

We found that this patch may lead to a TLB conflicts abort. This may results by
the changes from block<->table mappings. This problem may have something to do
with the Break-Before-Make sequence rule but not yet clear.
Signed-off-by: NLiu Shixin <liushixin2@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

arch/arm64/include/asm/kfence.h

@@ -8,77 +8,9 @@
 #ifndef __ASM_KFENCE_H
 #define __ASM_KFENCE_H
 
-#include <linux/kfence.h>
 #include <asm/cacheflush.h>
-#include <asm/pgalloc.h>
 
-static inline int split_pud_page(pud_t *pud, unsigned long addr)
-{
-	int i;
-	pmd_t *pmd = pmd_alloc_one(&init_mm, addr);
-	unsigned long pfn = PFN_DOWN(__pa(addr));
-
-	if (!pmd)
-		return -ENOMEM;
-
-	for (i = 0; i < PTRS_PER_PMD; i++)
-		set_pmd(pmd + i, pmd_mkhuge(pfn_pmd(pfn + i * PTRS_PER_PTE, PAGE_KERNEL)));
-
-	smp_wmb(); /* See comment in __pte_alloc */
-	pud_populate(&init_mm, pud, pmd);
-
-	flush_tlb_kernel_range(addr, addr + PUD_SIZE);
-	return 0;
-}
-
-static inline int split_pmd_page(pmd_t *pmd, unsigned long addr)
-{
-	int i;
-	pte_t *pte = pte_alloc_one_kernel(&init_mm);
-	unsigned long pfn = PFN_DOWN(__pa(addr));
-
-	if (!pte)
-		return -ENOMEM;
-
-	for (i = 0; i < PTRS_PER_PTE; i++)
-		set_pte(pte + i, pfn_pte(pfn + i, PAGE_KERNEL));
-
-	smp_wmb(); /* See comment in __pte_alloc */
-	pmd_populate_kernel(&init_mm, pmd, pte);
-
-	flush_tlb_kernel_range(addr, addr + PMD_SIZE);
-	return 0;
-}
-
-static inline bool arch_kfence_init_pool(void)
-{
-	unsigned long addr;
-	pgd_t *pgd;
-	p4d_t *p4d;
-	pud_t *pud;
-	pmd_t *pmd;
-
-	for (addr = (unsigned long)__kfence_pool; is_kfence_address((void *)addr);
-	     addr += PAGE_SIZE) {
-		pgd = pgd_offset(&init_mm, addr);
-		if (pgd_leaf(*pgd))
-			return false;
-		p4d = p4d_offset(pgd, addr);
-		if (p4d_leaf(*p4d))
-			return false;
-		pud = pud_offset(p4d, addr);
-		if (pud_leaf(*pud)) {
-			if (split_pud_page(pud, addr & PUD_MASK))
-				return false;
-		}
-		pmd = pmd_offset(pud, addr);
-		if (pmd_leaf(*pmd)) {
-			if (split_pmd_page(pmd, addr & PMD_MASK))
-				return false;
-		}
-	}
-	return true;
-}
+static inline bool arch_kfence_init_pool(void) { return true; }
 
 static inline bool kfence_protect_page(unsigned long addr, bool protect)
 {

arch/arm64/mm/mmu.c

@@ -477,7 +477,8 @@ static void __init map_mem(pgd_t *pgdp)
 	int flags = 0, eflags = 0;
 	u64 i;
 
-	if (rodata_full || debug_pagealloc_enabled())
+	if (rodata_full || debug_pagealloc_enabled() ||
+	    IS_ENABLED(CONFIG_KFENCE))
 		flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
 
 	/*
@@ -1486,7 +1487,8 @@ int arch_add_memory(int nid, u64 start, u64 size,
 	 * KFENCE requires linear map to be mapped at page granularity, so that
 	 * it is possible to protect/unprotect single pages in the KFENCE pool.
 	 */
-	if (rodata_full || debug_pagealloc_enabled())
+	if (rodata_full || debug_pagealloc_enabled() ||
+	    IS_ENABLED(CONFIG_KFENCE))
 		flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
 
 	__create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start),