powerpc/8xx: Implement dedicated kasan_init_region()

// SPDX-License-Identifier: GPL-2.0

#define DISABLE_BRANCH_PROFILING

#include <linux/kasan.h>

#include <linux/memblock.h>

#include <linux/hugetlb.h>

#include <asm/pgalloc.h>

static int __init

kasan_init_shadow_8M(unsigned long k_start, unsigned long k_end, void *block)

{

	pmd_t *pmd = pmd_ptr_k(k_start);

	unsigned long k_cur, k_next;

	for (k_cur = k_start; k_cur != k_end; k_cur = k_next, pmd += 2, block += SZ_8M) {

		pte_basic_t *new;

		k_next = pgd_addr_end(k_cur, k_end);

		k_next = pgd_addr_end(k_next, k_end);

		if ((void *)pmd_page_vaddr(*pmd) != kasan_early_shadow_pte)

			continue;

		new = memblock_alloc(sizeof(pte_basic_t), SZ_4K);

		if (!new)

			return -ENOMEM;

		*new = pte_val(pte_mkhuge(pfn_pte(PHYS_PFN(__pa(block)), PAGE_KERNEL)));

		hugepd_populate_kernel((hugepd_t *)pmd, (pte_t *)new, PAGE_SHIFT_8M);

		hugepd_populate_kernel((hugepd_t *)pmd + 1, (pte_t *)new, PAGE_SHIFT_8M);

	}

	return 0;

}

int __init kasan_init_region(void *start, size_t size)

{

	unsigned long k_start = (unsigned long)kasan_mem_to_shadow(start);

	unsigned long k_end = (unsigned long)kasan_mem_to_shadow(start + size);

	unsigned long k_cur;

	int ret;

	void *block;

	block = memblock_alloc(k_end - k_start, SZ_8M);

	if (!block)

		return -ENOMEM;

	if (IS_ALIGNED(k_start, SZ_8M)) {

		kasan_init_shadow_8M(k_start, ALIGN_DOWN(k_end, SZ_8M), block);

		k_cur = ALIGN_DOWN(k_end, SZ_8M);

		if (k_cur == k_end)

			goto finish;

	} else {

		k_cur = k_start;

	}

	ret = kasan_init_shadow_page_tables(k_start, k_end);

	if (ret)

		return ret;

	for (; k_cur < k_end; k_cur += PAGE_SIZE) {

		pmd_t *pmd = pmd_ptr_k(k_cur);

		void *va = block + k_cur - k_start;

		pte_t pte = pfn_pte(PHYS_PFN(__pa(va)), PAGE_KERNEL);

		if (k_cur < ALIGN_DOWN(k_end, SZ_512K))

			pte = pte_mkhuge(pte);

		__set_pte_at(&init_mm, k_cur, pte_offset_kernel(pmd, k_cur), pte, 0);

	}

finish:

	flush_tlb_kernel_range(k_start, k_end);

	return 0;

}

KASAN_SANITIZE := n

KASAN_SANITIZE := n

obj-$(CONFIG_PPC32)           += kasan_init_32.o

obj-$(CONFIG_PPC32)           += kasan_init_32.o

obj-$(CONFIG_PPC_8xx)		+= 8xx.o