/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Copyright 2020 Joyent, Inc.
 */

#include <sys/types.h>
#include <sys/inttypes.h>
#include <sys/systm.h>
#include <sys/elf.h>
#include <sys/elf_notes.h>

#include <util/memcpy.h>

#include "dboot_xboot.h"
#include "dboot_elfload.h"
#include "dboot_printf.h"

static caddr_t elf_file = 0;

#define PGETBYTES(offset)       ((void *)(elf_file + (offset)))

static void *
getehdr(void)
{
        uchar_t *ident;
        void *hdr = NULL;

        ident = PGETBYTES(0);
        if (ident == NULL)
                dboot_panic("Cannot read kernel ELF header");

        if (ident[EI_MAG0] != ELFMAG0 || ident[EI_MAG1] != ELFMAG1 ||
            ident[EI_MAG2] != ELFMAG2 || ident[EI_MAG3] != ELFMAG3)
                dboot_panic("not an ELF file!");

        if (ident[EI_CLASS] == ELFCLASS32)
                hdr = PGETBYTES(0);
        else if (ident[EI_CLASS] == ELFCLASS64)
                hdr = PGETBYTES(0);
        else
                dboot_panic("Unknown ELF class");

        return (hdr);
}


/*
 * parse the elf file for program information
 */
int
dboot_elfload64(uintptr_t file_image)
{
        Elf64_Ehdr *eh;
        Elf64_Phdr *phdr;
        caddr_t allphdrs;
        int i;
        paddr_t src;
        paddr_t dst;

        elf_file = (caddr_t)file_image;

        allphdrs = NULL;

        eh = getehdr();
        if (eh == NULL)
                dboot_panic("getehdr() failed");

        if (eh->e_type != ET_EXEC)
                dboot_panic("not ET_EXEC, e_type = 0x%x", eh->e_type);

        if (eh->e_phnum == 0 || eh->e_phoff == 0)
                dboot_panic("no program headers");

        /*
         * Get the program headers.
         */
        allphdrs = PGETBYTES(eh->e_phoff);
        if (allphdrs == NULL)
                dboot_panic("Failed to get program headers e_phnum = %d",
                    eh->e_phnum);

        /*
         * Next look for interesting program headers.
         */
        for (i = 0; i < eh->e_phnum; i++) {
                /*LINTED [ELF program header alignment]*/
                phdr = (Elf64_Phdr *)(allphdrs + eh->e_phentsize * i);

                /*
                 * Dynamically-linked executable.
                 * Complain.
                 */
                if (phdr->p_type == PT_INTERP) {
                        dboot_printf("warning: PT_INTERP section\n");
                        continue;
                }

                /*
                 * at this point we only care about PT_LOAD segments
                 */
                if (phdr->p_type != PT_LOAD)
                        continue;

                if (phdr->p_flags == (PF_R | PF_W) && phdr->p_vaddr == 0) {
                        dboot_printf("warning: krtld reloc info?\n");
                        continue;
                }

                /*
                 * If memory size is zero just ignore this header.
                 */
                if (phdr->p_memsz == 0)
                        continue;

                /*
                 * If load address 1:1 then ignore this header.
                 */
                if (phdr->p_paddr == phdr->p_vaddr) {
                        if (prom_debug)
                                dboot_printf("Skipping PT_LOAD segment for "
                                    "paddr = 0x%lx\n", (ulong_t)phdr->p_paddr);
                        continue;
                }

                /*
                 * copy the data to kernel area
                 */
                if (phdr->p_paddr != FOUR_MEG && phdr->p_paddr != 2 * FOUR_MEG)
                        dboot_panic("Bad paddr for kernel nucleus segment");
                src = (uintptr_t)PGETBYTES(phdr->p_offset);
                dst = ktext_phys + phdr->p_paddr - FOUR_MEG;
                if (prom_debug)
                        dboot_printf("copying %ld bytes from ELF offset 0x%lx "
                            "to physaddr 0x%lx (va=0x%lx)\n",
                            (ulong_t)phdr->p_filesz, (ulong_t)phdr->p_offset,
                            (ulong_t)dst, (ulong_t)phdr->p_vaddr);
                (void) memcpy((void *)(uintptr_t)dst,
                    (void *)(uintptr_t)src, (size_t)phdr->p_filesz);

                /*
                 * Clear space from oversized segments, bss.
                 * Note, the bss actual start is
                 * P2ROUNDUP(dst + phdr->p_filesz, shdr->sh_addralign),
                 * but we can wipe everything from phdr->p_filesz to
                 * phdr->p_memsz.
                 */
                if (phdr->p_filesz < phdr->p_memsz) {
                        if (prom_debug) {
                                dboot_printf("zeroing BSS %zu bytes from "
                                    "physaddr 0x%" PRIx64
                                    " (end=0x%" PRIx64 ")\n",
                                    (size_t)(phdr->p_memsz - phdr->p_filesz),
                                    dst + phdr->p_filesz,
                                    dst + phdr->p_memsz - 1);
                        }
                        (void) memset((void *)(uintptr_t)(dst + phdr->p_filesz),
                            0, phdr->p_memsz - phdr->p_filesz);
                }
        }

        /*
         * Ignore the intepreter (or should we die if there is one??)
         */
        return (0);
}