/*-
 * Copyright (c) 2014, 2015 The FreeBSD Foundation.
 * Copyright (c) 2014 Andrew Turner.
 * All rights reserved.
 *
 * This software was developed by Andrew Turner under
 * sponsorship from the FreeBSD Foundation.
 *
 * Portions of this software were developed by Konstantin Belousov
 * under sponsorship from the FreeBSD Foundation.
 *
 * 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 AUTHOR 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 AUTHOR 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/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/exec.h>
#include <sys/imgact.h>
#include <sys/linker.h>
#include <sys/proc.h>
#include <sys/reg.h>
#include <sys/sysent.h>
#include <sys/imgact_elf.h>
#include <sys/syscall.h>
#include <sys/signalvar.h>
#include <sys/vnode.h>

#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_param.h>
#include <vm/vm_map.h>

#include <machine/elf.h>
#include <machine/md_var.h>

#include "linker_if.h"

u_long __read_frequently elf_hwcap;
u_long __read_frequently elf_hwcap2;
u_long __read_frequently elf_hwcap3;
u_long __read_frequently elf_hwcap4;
/* TODO: Move to a better location */
u_long __read_frequently linux_elf_hwcap;
u_long __read_frequently linux_elf_hwcap2;
u_long __read_frequently linux_elf_hwcap3;
u_long __read_frequently linux_elf_hwcap4;

struct arm64_addr_mask elf64_addr_mask = {
    .code = TBI_ADDR_MASK,
    .data = TBI_ADDR_MASK,
};
#ifdef COMPAT_FREEBSD14
struct arm64_addr_mask elf64_addr_mask_14;
#endif

static void arm64_exec_protect(struct image_params *, int);

static struct sysentvec elf64_freebsd_sysvec = {
        .sv_size        = SYS_MAXSYSCALL,
        .sv_table       = sysent,
        .sv_fixup       = __elfN(freebsd_fixup),
        .sv_sendsig     = sendsig,
        .sv_sigcode     = sigcode,
        .sv_szsigcode   = &szsigcode,
        .sv_name        = "FreeBSD ELF64",
        .sv_coredump    = __elfN(coredump),
        .sv_elf_core_osabi = ELFOSABI_FREEBSD,
        .sv_elf_core_abi_vendor = FREEBSD_ABI_VENDOR,
        .sv_elf_core_prepare_notes = __elfN(prepare_notes),
        .sv_minsigstksz = MINSIGSTKSZ,
        .sv_minuser     = VM_MIN_ADDRESS,
        .sv_maxuser     = VM_MAXUSER_ADDRESS,
        .sv_usrstack    = USRSTACK,
        .sv_psstrings   = PS_STRINGS,
        .sv_psstringssz = sizeof(struct ps_strings),
        .sv_stackprot   = VM_PROT_READ | VM_PROT_WRITE,
        .sv_copyout_auxargs = __elfN(freebsd_copyout_auxargs),
        .sv_copyout_strings = exec_copyout_strings,
        .sv_setregs     = exec_setregs,
        .sv_fixlimit    = NULL,
        .sv_maxssiz     = NULL,
        .sv_flags       = SV_SHP | SV_TIMEKEEP | SV_ABI_FREEBSD | SV_LP64 |
            SV_ASLR | SV_RNG_SEED_VER | SV_SIGSYS,
        .sv_set_syscall_retval = cpu_set_syscall_retval,
        .sv_fetch_syscall_args = cpu_fetch_syscall_args,
        .sv_syscallnames = syscallnames,
        .sv_shared_page_base = SHAREDPAGE,
        .sv_shared_page_len = PAGE_SIZE,
        .sv_schedtail   = NULL,
        .sv_thread_detach = NULL,
        .sv_trap        = NULL,
        .sv_hwcap       = &elf_hwcap,
        .sv_hwcap2      = &elf_hwcap2,
        .sv_hwcap3      = &elf_hwcap3,
        .sv_hwcap4      = &elf_hwcap4,
        .sv_onexec_old  = exec_onexec_old,
        .sv_protect     = arm64_exec_protect,
        .sv_onexit      = exit_onexit,
        .sv_regset_begin = SET_BEGIN(__elfN(regset)),
        .sv_regset_end  = SET_LIMIT(__elfN(regset)),
};
INIT_SYSENTVEC(elf64_sysvec, &elf64_freebsd_sysvec);

static const Elf64_Brandinfo freebsd_brand_info = {
        .brand          = ELFOSABI_FREEBSD,
        .machine        = EM_AARCH64,
        .compat_3_brand = "FreeBSD",
        .interp_path    = "/libexec/ld-elf.so.1",
        .sysvec         = &elf64_freebsd_sysvec,
        .interp_newpath = NULL,
        .brand_note     = &elf64_freebsd_brandnote,
        .flags          = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
};
C_SYSINIT(elf64, SI_SUB_EXEC, SI_ORDER_FIRST,
    (sysinit_cfunc_t)elf64_insert_brand_entry, &freebsd_brand_info);

static bool
get_arm64_addr_mask(struct regset *rs, struct thread *td, void *buf,
    size_t *sizep)
{
        if (buf != NULL) {
                KASSERT(*sizep == sizeof(elf64_addr_mask),
                    ("%s: invalid size", __func__));
#ifdef COMPAT_FREEBSD14
                /* running an old binary use the old address mask */
                if (td->td_proc->p_osrel < TBI_VERSION)
                        memcpy(buf, &elf64_addr_mask_14,
                            sizeof(elf64_addr_mask_14));
                else
#endif
                        memcpy(buf, &elf64_addr_mask, sizeof(elf64_addr_mask));
        }
        *sizep = sizeof(elf64_addr_mask);

        return (true);
}

static struct regset regset_arm64_addr_mask = {
        .note = NT_ARM_ADDR_MASK,
        .size = sizeof(struct arm64_addr_mask),
        .get = get_arm64_addr_mask,
};
ELF_REGSET(regset_arm64_addr_mask);

void
elf64_dump_thread(struct thread *td __unused, void *dst __unused,
    size_t *off __unused)
{
}

bool
elf_is_ifunc_reloc(Elf_Size r_info __unused)
{

        return (ELF_R_TYPE(r_info) == R_AARCH64_IRELATIVE);
}

static int
reloc_instr_imm(Elf32_Addr *where, Elf_Addr val, u_int msb, u_int lsb)
{

        /* Check bounds: upper bits must be all ones or all zeros. */
        if ((uint64_t)((int64_t)val >> (msb + 1)) + 1 > 1)
                return (-1);
        val >>= lsb;
        val &= (1 << (msb - lsb + 1)) - 1;
        *where |= (Elf32_Addr)val;
        return (0);
}

/*
 * Process a relocation.  Support for some static relocations is required
 * in order for the -zifunc-noplt optimization to work.
 */
static int
elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
    int type, int flags, elf_lookup_fn lookup)
{
#define ARM64_ELF_RELOC_LOCAL           (1 << 0)
#define ARM64_ELF_RELOC_LATE_IFUNC      (1 << 1)
        Elf_Addr *where, addr, addend, val;
        Elf_Word rtype, symidx;
        const Elf_Rel *rel;
        const Elf_Rela *rela;
        int error;

        switch (type) {
        case ELF_RELOC_REL:
                rel = (const Elf_Rel *)data;
                where = (Elf_Addr *) (relocbase + rel->r_offset);
                addend = *where;
                rtype = ELF_R_TYPE(rel->r_info);
                symidx = ELF_R_SYM(rel->r_info);
                break;
        case ELF_RELOC_RELA:
                rela = (const Elf_Rela *)data;
                where = (Elf_Addr *) (relocbase + rela->r_offset);
                addend = rela->r_addend;
                rtype = ELF_R_TYPE(rela->r_info);
                symidx = ELF_R_SYM(rela->r_info);
                break;
        default:
                panic("unknown reloc type %d\n", type);
        }

        if ((flags & ARM64_ELF_RELOC_LATE_IFUNC) != 0) {
                KASSERT(type == ELF_RELOC_RELA,
                    ("Only RELA ifunc relocations are supported"));
                if (rtype != R_AARCH64_IRELATIVE)
                        return (0);
        }

        if ((flags & ARM64_ELF_RELOC_LOCAL) != 0) {
                if (rtype == R_AARCH64_RELATIVE)
                        *where = elf_relocaddr(lf, relocbase + addend);
                return (0);
        }

        error = 0;
        switch (rtype) {
        case R_AARCH64_NONE:
        case R_AARCH64_RELATIVE:
                break;
        case R_AARCH64_TSTBR14:
                error = lookup(lf, symidx, 1, &addr);
                if (error != 0)
                        return (-1);
                error = reloc_instr_imm((Elf32_Addr *)where,
                    addr + addend - (Elf_Addr)where, 15, 2);
                break;
        case R_AARCH64_CONDBR19:
                error = lookup(lf, symidx, 1, &addr);
                if (error != 0)
                        return (-1);
                error = reloc_instr_imm((Elf32_Addr *)where,
                    addr + addend - (Elf_Addr)where, 20, 2);
                break;
        case R_AARCH64_JUMP26:
        case R_AARCH64_CALL26:
                error = lookup(lf, symidx, 1, &addr);
                if (error != 0)
                        return (-1);
                error = reloc_instr_imm((Elf32_Addr *)where,
                    addr + addend - (Elf_Addr)where, 27, 2);
                break;
        case R_AARCH64_ABS64:
        case R_AARCH64_GLOB_DAT:
        case R_AARCH64_JUMP_SLOT:
                error = lookup(lf, symidx, 1, &addr);
                if (error != 0)
                        return (-1);
                *where = addr + addend;
                break;
        case R_AARCH64_IRELATIVE:
                addr = relocbase + addend;
                val = ((Elf64_Addr (*)(void))addr)();
                if (*where != val)
                        *where = val;
                break;
        default:
                printf("kldload: unexpected relocation type %d, "
                    "symbol index %d\n", rtype, symidx);
                return (-1);
        }
        return (error);
}

int
elf_reloc_local(linker_file_t lf, Elf_Addr relocbase, const void *data,
    int type, elf_lookup_fn lookup)
{

        return (elf_reloc_internal(lf, relocbase, data, type,
            ARM64_ELF_RELOC_LOCAL, lookup));
}

/* Process one elf relocation with addend. */
int
elf_reloc(linker_file_t lf, Elf_Addr relocbase, const void *data, int type,
    elf_lookup_fn lookup)
{

        return (elf_reloc_internal(lf, relocbase, data, type, 0, lookup));
}

int
elf_reloc_late(linker_file_t lf, Elf_Addr relocbase, const void *data,
    int type, elf_lookup_fn lookup)
{

        return (elf_reloc_internal(lf, relocbase, data, type,
            ARM64_ELF_RELOC_LATE_IFUNC, lookup));
}

int
elf_cpu_load_file(linker_file_t lf)
{

        if (lf->id != 1)
                cpu_icache_sync_range(lf->address, lf->size);
        return (0);
}

int
elf_cpu_unload_file(linker_file_t lf __unused)
{

        return (0);
}

int
elf_cpu_parse_dynamic(caddr_t loadbase __unused, Elf_Dyn *dynamic __unused)
{

        return (0);
}

static const Elf_Note gnu_property_note = {
        .n_namesz = sizeof(GNU_ABI_VENDOR),
        .n_descsz = 16,
        .n_type = NT_GNU_PROPERTY_TYPE_0,
};

static bool
gnu_property_cb(const Elf_Note *note, void *arg0, bool *res)
{
        const uint32_t *data;
        uintptr_t p;

        *res = false;
        p = (uintptr_t)(note + 1);
        p += roundup2(note->n_namesz, 4);
        data = (const uint32_t *)p;
        if (data[0] != GNU_PROPERTY_AARCH64_FEATURE_1_AND)
                return (false);
        /*
         * The data length should be at least the size of a uint32, and be
         * a multiple of uint32_t's
         */
        if (data[1] < sizeof(uint32_t) || (data[1] % sizeof(uint32_t)) != 0)
                return (false);
        if ((data[2] & GNU_PROPERTY_AARCH64_FEATURE_1_BTI) != 0)
                *res = true;

        return (true);
}

static void
arm64_exec_protect(struct image_params *imgp, int flags __unused)
{
        const Elf_Ehdr *hdr;
        const Elf_Phdr *phdr;
        vm_offset_t sva, eva;
        int i;
        bool found;

        /* Skip if BTI is not supported */
        if ((elf_hwcap2 & HWCAP2_BTI) == 0)
                return;

        hdr = (const Elf_Ehdr *)imgp->image_header;
        phdr = (const Elf_Phdr *)(imgp->image_header + hdr->e_phoff);

        found = false;
        for (i = 0; i < hdr->e_phnum; i++) {
                if (phdr[i].p_type == PT_NOTE && __elfN(parse_notes)(imgp,
                    &gnu_property_note, GNU_ABI_VENDOR, &phdr[i],
                    gnu_property_cb, NULL)) {
                        found = true;
                        break;
                }
        }
        if (!found)
                return;

        for (i = 0; i < hdr->e_phnum; i++) {
                if (phdr[i].p_type != PT_LOAD || phdr[i].p_memsz == 0)
                        continue;

                sva = phdr[i].p_vaddr + imgp->et_dyn_addr;
                eva = sva + phdr[i].p_memsz;
                pmap_bti_set(vmspace_pmap(imgp->proc->p_vmspace), sva, eva);
        }
}