xref: /src/sys/arch/aarch64/include/asan.h

/*	$NetBSD: asan.h,v 1.1 2018/11/01 20:34:50 maxv Exp $	*/

/*
 * Copyright (c) 2018 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Maxime Villard.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/atomic.h>
#include <aarch64/pmap.h>
#include <aarch64/vmparam.h>
#include <aarch64/cpufunc.h>
#include <aarch64/armreg.h>

#define __MD_VIRTUAL_SHIFT	48	/* 49bit address space, cut half */
#define __MD_CANONICAL_BASE	0xFFFF000000000000

#define __MD_SHADOW_SIZE	(1ULL << (__MD_VIRTUAL_SHIFT - KASAN_SHADOW_SCALE_SHIFT))
#define KASAN_MD_SHADOW_START	(AARCH64_KSEG_END)
#define KASAN_MD_SHADOW_END	(KASAN_MD_SHADOW_START + __MD_SHADOW_SIZE)

static inline int8_t *
kasan_md_addr_to_shad(const void *addr)
{
	vaddr_t va = (vaddr_t)addr;
	return (int8_t *)(KASAN_MD_SHADOW_START +
	    ((va - __MD_CANONICAL_BASE) >> KASAN_SHADOW_SCALE_SHIFT));
}

static inline bool
kasan_md_unsupported(vaddr_t addr)
{
	return (addr < VM_MIN_KERNEL_ADDRESS) ||
	    (addr >= VM_KERNEL_IO_ADDRESS);
}

static paddr_t
__md_palloc(void)
{
	paddr_t pa;

	pmap_alloc_pdp(pmap_kernel(), &pa);

	return pa;
}

static void
kasan_md_shadow_map_page(vaddr_t va)
{
	pd_entry_t *l0, *l1, *l2, *l3;
	paddr_t l0pa, pa;
	pd_entry_t pde;
	size_t idx;

	l0pa = reg_ttbr1_el1_read();
	l0 = (void *)AARCH64_PA_TO_KVA(l0pa);

	idx = l0pde_index(va);
	pde = l0[idx];
	if (!l0pde_valid(pde)) {
		pa = __md_palloc();
		atomic_swap_64(&l0[idx], pa | L0_TABLE);
	} else {
		pa = l0pde_pa(pde);
	}
	l1 = (void *)AARCH64_PA_TO_KVA(pa);

	idx = l1pde_index(va);
	pde = l1[idx];
	if (!l1pde_valid(pde)) {
		pa = __md_palloc();
		atomic_swap_64(&l1[idx], pa | L1_TABLE);
	} else {
		pa = l1pde_pa(pde);
	}
	l2 = (void *)AARCH64_PA_TO_KVA(pa);

	idx = l2pde_index(va);
	pde = l2[idx];
	if (!l2pde_valid(pde)) {
		pa = __md_palloc();
		atomic_swap_64(&l2[idx], pa | L2_TABLE);
	} else {
		pa = l2pde_pa(pde);
	}
	l3 = (void *)AARCH64_PA_TO_KVA(pa);

	idx = l3pte_index(va);
	pde = l3[idx];
	if (!l3pte_valid(pde)) {
		pa = __md_palloc();
		atomic_swap_64(&l3[idx], pa | L3_PAGE | LX_BLKPAG_UXN |
		    LX_BLKPAG_PXN | LX_BLKPAG_AF | LX_BLKPAG_AP_RW);
		aarch64_tlbi_by_va(va);
	}
}

#define kasan_md_early_init(a)	__nothing

static void
kasan_md_init(void)
{
	vaddr_t eva, dummy;

	CTASSERT((__MD_SHADOW_SIZE / L0_SIZE) == 64);

	/* The VAs we've created until now. */
	pmap_virtual_space(&eva, &dummy);
	kasan_shadow_map((void *)VM_MIN_KERNEL_ADDRESS,
	    eva - VM_MIN_KERNEL_ADDRESS);
}

#define kasan_md_unwind()	__nothing