/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright 1996-1998 John D. Polstra.
 * All rights reserved.
 *
 * 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 ``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 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/reg.h>
#include <sys/sysent.h>
#include <sys/imgact_elf.h>
#include <sys/proc.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 <machine/elf.h>
#include <machine/md_var.h>
#include <machine/stack.h>
#ifdef VFP
#include <machine/vfp.h>
#endif

#include "opt_ddb.h"            /* for OPT_DDB */
#include "opt_global.h"         /* for OPT_KDTRACE_HOOKS */
#include "opt_stack.h"          /* for OPT_STACK */

static bool elf32_arm_abi_supported(const struct image_params *,
    const int32_t *, const uint32_t *);

u_long elf_hwcap;
u_long elf_hwcap2;

struct sysentvec elf32_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 ELF32",
        .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_ALL,
        .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_ASLR | SV_SHP | SV_TIMEKEEP | SV_RNG_SEED_VER |
                          SV_ABI_FREEBSD | SV_ILP32 | 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      = NULL,
        .sv_hwcap4      = NULL,
        .sv_onexec_old  = exec_onexec_old,
        .sv_onexit      = exit_onexit,
        .sv_regset_begin = SET_BEGIN(__elfN(regset)),
        .sv_regset_end  = SET_LIMIT(__elfN(regset)),
};
INIT_SYSENTVEC(elf32_sysvec, &elf32_freebsd_sysvec);

static const Elf32_Brandinfo freebsd_brand_info = {
        .brand          = ELFOSABI_FREEBSD,
        .machine        = EM_ARM,
        .compat_3_brand = "FreeBSD",
        .interp_path    = "/libexec/ld-elf.so.1",
        .sysvec         = &elf32_freebsd_sysvec,
        .interp_newpath = NULL,
        .brand_note     = &elf32_freebsd_brandnote,
        .flags          = BI_CAN_EXEC_DYN | BI_BRAND_NOTE,
        .header_supported= elf32_arm_abi_supported,
};

C_SYSINIT(elf32, SI_SUB_EXEC, SI_ORDER_FIRST,
        (sysinit_cfunc_t) elf32_insert_brand_entry,
        &freebsd_brand_info);

static bool
elf32_arm_abi_supported(const struct image_params *imgp,
    const int32_t *osrel __unused, const uint32_t *fctl0 __unused)
{
        const Elf_Ehdr *hdr = (const Elf_Ehdr *)imgp->image_header;

        /*
         * When configured for EABI, FreeBSD supports EABI vesions 4 and 5.
         */
        if (EF_ARM_EABI_VERSION(hdr->e_flags) < EF_ARM_EABI_FREEBSD_MIN) {
                if (bootverbose)
                        uprintf("Attempting to execute non EABI binary (rev %d) image %s",
                            EF_ARM_EABI_VERSION(hdr->e_flags), imgp->args->fname);
                return (false);
        }
        return (true);
}

void
elf32_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_ARM_IRELATIVE);
}

/*
 * It is possible for the compiler to emit relocations for unaligned data.
 * We handle this situation with these inlines.
 */
#define RELOC_ALIGNED_P(x) \
        (((uintptr_t)(x) & (sizeof(void *) - 1)) == 0)

static __inline Elf_Addr
load_ptr(Elf_Addr *where)
{
        Elf_Addr res;

        if (RELOC_ALIGNED_P(where))
                return *where;
        memcpy(&res, where, sizeof(res));
        return (res);
}

static __inline void
store_ptr(Elf_Addr *where, Elf_Addr val)
{
        if (RELOC_ALIGNED_P(where))
                *where = val;
        else
                memcpy(where, &val, sizeof(val));
}
#undef RELOC_ALIGNED_P

/* Process one elf relocation with addend. */
static int
elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
    int type, int local, elf_lookup_fn lookup)
{
        Elf_Addr *where;
        Elf_Addr addr;
        Elf_Addr addend;
        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 = load_ptr(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 (local) {
                if (rtype == R_ARM_RELATIVE) {  /* A + B */
                        addr = elf_relocaddr(lf, relocbase + addend);
                        if (load_ptr(where) != addr)
                                store_ptr(where, addr);
                }
                return (0);
        }

        switch (rtype) {
                case R_ARM_NONE:        /* none */
                        break;

                case R_ARM_ABS32:
                        error = lookup(lf, symidx, 1, &addr);
                        if (error != 0)
                                return (-1);
                        store_ptr(where, addr + load_ptr(where));
                        break;

                case R_ARM_COPY:        /* none */
                        /*
                         * There shouldn't be copy relocations in kernel
                         * objects.
                         */
                        printf("kldload: unexpected R_COPY relocation, "
                            "symbol index %d\n", symidx);
                        return (-1);
                        break;

                case R_ARM_JUMP_SLOT:
                        error = lookup(lf, symidx, 1, &addr);
                        if (error == 0) {
                                store_ptr(where, addr);
                                return (0);
                        }
                        return (-1);
                case R_ARM_RELATIVE:
                        break;

                case R_ARM_IRELATIVE:
                        addr = relocbase + addend;
                        addr = ((Elf_Addr (*)(void))addr)();
                        if (*where != addr)
                                *where = addr;
                        break;
                default:
                        printf("kldload: unexpected relocation type %d, "
                            "symbol index %d\n", rtype, symidx);
                        return (-1);
        }
        return(0);
}

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_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, 1, lookup));
}

int
elf_cpu_load_file(linker_file_t lf)
{

        /*
         * The pmap code does not do an icache sync upon establishing executable
         * mappings in the kernel pmap.  It's an optimization based on the fact
         * that kernel memory allocations always have EXECUTABLE protection even
         * when the memory isn't going to hold executable code.  The only time
         * kernel memory holding instructions does need a sync is after loading
         * a kernel module, and that's when this function gets called.
         *
         * This syncs data and instruction caches after loading a module.  We
         * don't worry about the kernel itself (lf->id is 1) as locore.S did
         * that on entry.  Even if data cache maintenance was done by IO code,
         * the relocation fixup process creates dirty cache entries that we must
         * write back before doing icache sync. The instruction cache sync also
         * invalidates the branch predictor cache on platforms that have one.
         */
        if (lf->id == 1)
                return (0);
        dcache_wb_pou((vm_offset_t)lf->address, (vm_size_t)lf->size);
        icache_inv_all();

#if defined(DDB) || defined(KDTRACE_HOOKS) || defined(STACK)
        /*
         * Inform the stack(9) code of the new module, so it can acquire its
         * per-module unwind data.
         */
        unwind_module_loaded(lf);
#endif

        return (0);
}

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

        return (0);
}

int
elf_cpu_unload_file(linker_file_t lf)
{

#if defined(DDB) || defined(KDTRACE_HOOKS) || defined(STACK)
        /* Inform the stack(9) code that this module is gone. */
        unwind_module_unloaded(lf);
#endif
        return (0);
}