/*
 * This file is part of the coreboot project.
 *
 * Copyright (C) 2003 Eric W. Biederman <ebiederm@xmission.com>
 * Copyright (C) 2009 Ron Minnich <rminnich@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA, 02110-1301 USA
 */

#include <console/console.h>
#include <part/fallback_boot.h>
#include <boot/elf.h>
#include <boot/elf_boot.h>
#include <boot/coreboot_tables.h>
#include <ip_checksum.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <cbfs.h>
#include <lib.h>

#ifndef CONFIG_BIG_ENDIAN
#define ntohl(x) ( ((x&0xff)<<24) | ((x&0xff00)<<8) | \
                ((x&0xff0000) >> 8) | ((x&0xff000000) >> 24) )
#else
#define ntohl(x) (x)
#endif

/* Maximum physical address we can use for the coreboot bounce buffer.
 */
#ifndef MAX_ADDR
#define MAX_ADDR -1UL
#endif

extern unsigned char _ram_seg;
extern unsigned char _eram_seg;

struct segment {
        struct segment *next;
        struct segment *prev;
        struct segment *phdr_next;
        struct segment *phdr_prev;
        unsigned long s_dstaddr;
        unsigned long s_srcaddr;
        unsigned long s_memsz;
        unsigned long s_filesz;
        int compression;
};

struct verify_callback {
        struct verify_callback *next;
        int (*callback)(struct verify_callback *vcb, 
                Elf_ehdr *ehdr, Elf_phdr *phdr, struct segment *head);
        unsigned long desc_offset;
        unsigned long desc_addr;
};

struct ip_checksum_vcb {
        struct verify_callback data;
        unsigned short ip_checksum;
};

static int selfboot(struct lb_memory *mem, struct cbfs_payload *payload);

void * cbfs_load_payload(struct lb_memory *lb_mem, const char *name)
{
        struct cbfs_payload *payload;

        payload = (struct cbfs_payload *)cbfs_find_file(name, CBFS_TYPE_PAYLOAD);
        if (payload == NULL)
                return (void *) -1;
        printk_debug("Got a payload\n");

        selfboot(lb_mem, payload);
        printk_emerg("SELFBOOT RETURNED!\n");

        return (void *) -1;
}

/* The problem:  
 * Static executables all want to share the same addresses
 * in memory because only a few addresses are reliably present on
 * a machine, and implementing general relocation is hard.
 *
 * The solution:
 * - Allocate a buffer the size of the coreboot image plus additional
 *   required space.
 * - Anything that would overwrite coreboot copy into the lower part of
 *   the buffer. 
 * - After loading an ELF image copy coreboot to the top of the buffer.
 * - Then jump to the loaded image.
 * 
 * Benefits:
 * - Nearly arbitrary standalone executables can be loaded.
 * - Coreboot is preserved, so it can be returned to.
 * - The implementation is still relatively simple,
 *   and much simpler then the general case implemented in kexec.
 * 
 */

static unsigned long bounce_size, bounce_buffer;

static void get_bounce_buffer(struct lb_memory *mem, unsigned long req_size)
{
        unsigned long lb_size;
        unsigned long mem_entries;
        unsigned long buffer;
        int i;
        lb_size = (unsigned long)(&_eram_seg - &_ram_seg);
        /* Double coreboot size so I have somewhere to place a copy to return to */
        lb_size = req_size + lb_size;
        mem_entries = (mem->size - sizeof(*mem))/sizeof(mem->map[0]);
        buffer = 0;
        for(i = 0; i < mem_entries; i++) {
                unsigned long mstart, mend;
                unsigned long msize;
                unsigned long tbuffer;
                if (mem->map[i].type != LB_MEM_RAM)
                        continue;
                if (unpack_lb64(mem->map[i].start) > MAX_ADDR)
                        continue;
                if (unpack_lb64(mem->map[i].size) < lb_size)
                        continue;
                mstart = unpack_lb64(mem->map[i].start);
                msize = MAX_ADDR - mstart +1;
                if (msize > unpack_lb64(mem->map[i].size))
                        msize = unpack_lb64(mem->map[i].size);
                mend = mstart + msize;
                tbuffer = mend - lb_size;
                if (tbuffer < buffer) 
                        continue;
                buffer = tbuffer;
        }
        bounce_buffer = buffer;
        bounce_size = req_size;
}

static int valid_area(struct lb_memory *mem, unsigned long buffer,
        unsigned long start, unsigned long len)
{
        /* Check through all of the memory segments and ensure
         * the segment that was passed in is completely contained
         * in RAM.
         */
        int i;
        unsigned long end = start + len;
        unsigned long mem_entries = (mem->size - sizeof(*mem))/sizeof(mem->map[0]);

        /* See if I conflict with the bounce buffer */
        if (end >= buffer) {
                return 0;
        }

        /* Walk through the table of valid memory ranges and see if I
         * have a match.
         */
        for(i = 0; i < mem_entries; i++) {
                uint64_t mstart, mend;
                uint32_t mtype;
                mtype = mem->map[i].type;
                mstart = unpack_lb64(mem->map[i].start);
                mend = mstart + unpack_lb64(mem->map[i].size);
                if ((mtype == LB_MEM_RAM) && (start < mend) && (end > mstart)) {
                        break;
                }
                if ((mtype == LB_MEM_TABLE) && (start < mend) && (end > mstart)) {
                        printk_err("Payload is overwriting Coreboot tables.\n");
                        break;
                }
        }
        if (i == mem_entries) {
                printk_err("No matching ram area found for range:\n");
                printk_err("  [0x%016lx, 0x%016lx)\n", start, end);
                printk_err("Ram areas\n");
                for(i = 0; i < mem_entries; i++) {
                        uint64_t mstart, mend;
                        uint32_t mtype;
                        mtype = mem->map[i].type;
                        mstart = unpack_lb64(mem->map[i].start);
                        mend = mstart + unpack_lb64(mem->map[i].size);
                        printk_err("  [0x%016lx, 0x%016lx) %s\n",
                                (unsigned long)mstart, 
                                (unsigned long)mend, 
                                (mtype == LB_MEM_RAM)?"RAM":"Reserved");
                        
                }
                return 0;
        }
        return 1;
}

static const unsigned long lb_start = (unsigned long)&_ram_seg;
static const unsigned long lb_end = (unsigned long)&_eram_seg;

static int overlaps_coreboot(struct segment *seg)
{
        unsigned long start, end;
        start = seg->s_dstaddr;
        end = start + seg->s_memsz;
        return !((end <= lb_start) || (start >= lb_end));
}

static void relocate_segment(unsigned long buffer, struct segment *seg)
{
        /* Modify all segments that want to load onto coreboot
         * to load onto the bounce buffer instead.
         */
        unsigned long start, middle, end;

        printk_spew("lb: [0x%016lx, 0x%016lx)\n", 
                lb_start, lb_end);

        /* I don't conflict with coreboot so get out of here */
        if (!overlaps_coreboot(seg))
                return;

        start = seg->s_dstaddr;
        middle = start + seg->s_filesz;
        end = start + seg->s_memsz;

        printk_spew("segment: [0x%016lx, 0x%016lx, 0x%016lx)\n", 
                start, middle, end);

        if (seg->compression == CBFS_COMPRESS_NONE) {
                /* Slice off a piece at the beginning
                 * that doesn't conflict with coreboot.
                 */
                if (start < lb_start) {
                        struct segment *new;
                        unsigned long len = lb_start - start;
                        new = malloc(sizeof(*new));
                        *new = *seg;
                        new->s_memsz = len;
                        seg->s_memsz -= len;
                        seg->s_dstaddr += len;
                        seg->s_srcaddr += len;
                        if (seg->s_filesz > len) {
                                new->s_filesz = len;
                                seg->s_filesz -= len;
                        } else {
                                seg->s_filesz = 0;
                        }

                        /* Order by stream offset */
                        new->next = seg;
                        new->prev = seg->prev;
                        seg->prev->next = new;
                        seg->prev = new;
                        /* Order by original program header order */
                        new->phdr_next = seg;
                        new->phdr_prev = seg->phdr_prev;
                        seg->phdr_prev->phdr_next = new;
                        seg->phdr_prev = new;

                        /* compute the new value of start */
                        start = seg->s_dstaddr;
                        
                        printk_spew("   early: [0x%016lx, 0x%016lx, 0x%016lx)\n", 
                                new->s_dstaddr, 
                                new->s_dstaddr + new->s_filesz,
                                new->s_dstaddr + new->s_memsz);
                }
                        
                /* Slice off a piece at the end 
                 * that doesn't conflict with coreboot 
                 */
                if (end > lb_end) {
                        unsigned long len = lb_end - start;
                        struct segment *new;
                        new = malloc(sizeof(*new));
                        *new = *seg;
                        seg->s_memsz = len;
                        new->s_memsz -= len;
                        new->s_dstaddr += len;
                        new->s_srcaddr += len;
                        if (seg->s_filesz > len) {
                                seg->s_filesz = len;
                                new->s_filesz -= len;
                        } else {
                                new->s_filesz = 0;
                        }
                        /* Order by stream offset */
                        new->next = seg->next;
                        new->prev = seg;
                        seg->next->prev = new;
                        seg->next = new;
                        /* Order by original program header order */
                        new->phdr_next = seg->phdr_next;
                        new->phdr_prev = seg;
                        seg->phdr_next->phdr_prev = new;
                        seg->phdr_next = new;

                        printk_spew("   late: [0x%016lx, 0x%016lx, 0x%016lx)\n", 
                                new->s_dstaddr, 
                                new->s_dstaddr + new->s_filesz,
                                new->s_dstaddr + new->s_memsz);
                }
        }

        /* Now retarget this segment onto the bounce buffer */
        /* sort of explanation: the buffer is a 1:1 mapping to coreboot. 
         * so you will make the dstaddr be this buffer, and it will get copied
         * later to where coreboot lives.
         */
        seg->s_dstaddr = buffer + (seg->s_dstaddr - lb_start);

        printk_spew(" bounce: [0x%016lx, 0x%016lx, 0x%016lx)\n", 
                seg->s_dstaddr, 
                seg->s_dstaddr + seg->s_filesz, 
                seg->s_dstaddr + seg->s_memsz);
}


static int build_self_segment_list(
        struct segment *head, 
        struct lb_memory *mem,
        struct cbfs_payload *payload, u32 *entry)
{
        struct segment *new;
        struct segment *ptr;
        struct cbfs_payload_segment *segment, *first_segment;
        memset(head, 0, sizeof(*head));
        head->phdr_next = head->phdr_prev = head;
        head->next = head->prev = head;
        first_segment = segment = &payload->segments;

        while(1) {
                printk_debug("Loading segment from rom address 0x%p\n", segment);
                switch(segment->type) {
                case PAYLOAD_SEGMENT_PARAMS:
                        printk_debug("  parameter section (skipped)\n");
                        segment++;
                        continue;

                case PAYLOAD_SEGMENT_CODE:
                case PAYLOAD_SEGMENT_DATA:
                        printk_debug("  %s (compression=%x)\n", 
                                        segment->type == PAYLOAD_SEGMENT_CODE ?  "code" : "data",
                                        ntohl(segment->compression));
                        new = malloc(sizeof(*new));
                        new->s_dstaddr = ntohl((u32) segment->load_addr);
                        new->s_memsz = ntohl(segment->mem_len);
                        new->compression = ntohl(segment->compression);

                        new->s_srcaddr = (u32) ((unsigned char *) first_segment) + ntohl(segment->offset);
                        new->s_filesz = ntohl(segment->len);
                        printk_debug("  New segment dstaddr 0x%lx memsize 0x%lx srcaddr 0x%lx filesize 0x%lx\n",
                                new->s_dstaddr, new->s_memsz, new->s_srcaddr, new->s_filesz);
                        /* Clean up the values */
                        if (new->s_filesz > new->s_memsz)  {
                                new->s_filesz = new->s_memsz;
                        }
                        printk_debug("  (cleaned up) New segment addr 0x%lx size 0x%lx offset 0x%lx filesize 0x%lx\n",
                                new->s_dstaddr, new->s_memsz, new->s_srcaddr, new->s_filesz);
                        break;

                case PAYLOAD_SEGMENT_BSS:
                        printk_debug("  BSS 0x%p (%d byte)\n", (void *) ntohl((u32) segment->load_addr),
                                 ntohl(segment->mem_len));
                        new = malloc(sizeof(*new));
                        new->s_filesz = 0;
                        new->s_dstaddr = ntohl((u32) segment->load_addr);
                        new->s_memsz = ntohl(segment->mem_len);
                        break;

                case PAYLOAD_SEGMENT_ENTRY:
                        printk_debug("  Entry Point 0x%p\n", (void *) ntohl((u32) segment->load_addr));
                        *entry =  ntohl((u32) segment->load_addr);
                        /* Per definition, a payload always has the entry point
                         * as last segment. Thus, we use the occurence of the
                         * entry point as break condition for the loop.
                         * Can we actually just look at the number of section?
                         */
                        return 1;

                default:
                        /* We found something that we don't know about. Throw
                         * hands into the sky and run away!
                         */
                        printk_emerg("Bad segment type %x\n", segment->type);
                        return -1;
                }

                segment++;

                // FIXME: Explain what this is 
                for(ptr = head->next; ptr != head; ptr = ptr->next) {
                        if (new->s_srcaddr < ntohl((u32) segment->load_addr))
                                break;
                }

                /* Order by stream offset */
                new->next = ptr;
                new->prev = ptr->prev;
                ptr->prev->next = new;
                ptr->prev = new;

                /* Order by original program header order */
                new->phdr_next = head;
                new->phdr_prev = head->phdr_prev;
                head->phdr_prev->phdr_next  = new;
                head->phdr_prev = new;
        }

        return 1;
}

static int load_self_segments(
        struct segment *head,
        struct lb_memory *mem,
        struct cbfs_payload *payload)
{
        struct segment *ptr;
        
        unsigned long bounce_high = lb_end;
        for(ptr = head->next; ptr != head; ptr = ptr->next) {
                if (!overlaps_coreboot(ptr)) continue;
                if (ptr->s_dstaddr + ptr->s_memsz > bounce_high)
                        bounce_high = ptr->s_dstaddr + ptr->s_memsz;
        }
        get_bounce_buffer(mem, bounce_high - lb_start);
        if (!bounce_buffer) {
                printk_err("Could not find a bounce buffer...\n");
                return 0;
        }
        for(ptr = head->next; ptr != head; ptr = ptr->next) {
                /* Verify the memory addresses in the segment are valid */
                if (!valid_area(mem, bounce_buffer, ptr->s_dstaddr, ptr->s_memsz))
                        return 0;
        }
        for(ptr = head->next; ptr != head; ptr = ptr->next) {
                unsigned char *dest, *src;
                printk_debug("Loading Segment: addr: 0x%016lx memsz: 0x%016lx filesz: 0x%016lx\n",
                        ptr->s_dstaddr, ptr->s_memsz, ptr->s_filesz);
                
                /* Modify the segment to load onto the bounce_buffer if necessary.
                 */
                relocate_segment(bounce_buffer, ptr);

                printk_debug("Post relocation: addr: 0x%016lx memsz: 0x%016lx filesz: 0x%016lx\n",
                        ptr->s_dstaddr, ptr->s_memsz, ptr->s_filesz);

                /* Compute the boundaries of the segment */
                dest = (unsigned char *)(ptr->s_dstaddr);
                src = (unsigned char *)(ptr->s_srcaddr);
                
                /* Copy data from the initial buffer */
                if (ptr->s_filesz) {
                        unsigned char *middle, *end;
                        size_t len;
                        len = ptr->s_filesz;
                        switch(ptr->compression) {
                                case CBFS_COMPRESS_LZMA: {
                                        printk_debug("using LZMA\n");
                                        len = ulzma(src, dest);
                                        break;
                                }
#if CONFIG_COMPRESSED_PAYLOAD_NRV2B==1
                                case CBFS_COMPRESS_NRV2B: {
                                        printk_debug("using NRV2B\n");
                                        unsigned long unrv2b(u8 *src, u8 *dst, unsigned long *ilen_p);
                                        unsigned long tmp;
                                        len = unrv2b(src, dest, &tmp);
                                        break;
                                }
#endif
                                case CBFS_COMPRESS_NONE: {
                                        printk_debug("it's not compressed!\n");
                                        memcpy(dest, src, len);
                                        break;
                                }
                                default:
                                        printk_info( "CBFS:  Unknown compression type %d\n", ptr->compression);
                                        return -1;
                        }
                        end = dest + ptr->s_memsz;
                        middle = dest + len;
                        printk_spew("[ 0x%016lx, %016lx, 0x%016lx) <- %016lx\n",
                                (unsigned long)dest,
                                (unsigned long)middle,
                                (unsigned long)end,
                                (unsigned long)src);

                        /* Zero the extra bytes between middle & end */
                        if (middle < end) {
                                printk_debug("Clearing Segment: addr: 0x%016lx memsz: 0x%016lx\n",
                                        (unsigned long)middle, (unsigned long)(end - middle));
                        
                                /* Zero the extra bytes */
                                memset(middle, 0, end - middle);
                        }
                        /* Copy the data that's outside the area that shadows coreboot_ram */
                        printk_debug("dest %p, end %p, bouncebuffer %lx\n", dest, end, bounce_buffer);
                        if ((unsigned long)end > bounce_buffer) {
                                if ((unsigned long)dest < bounce_buffer) {
                                        unsigned char *from = dest;
                                        unsigned char *to = (unsigned char*)(lb_start-(bounce_buffer-(unsigned long)dest));
                                        unsigned long amount = bounce_buffer-(unsigned long)dest;
                                        printk_debug("move prefix around: from %p, to %p, amount: %lx\n", from, to, amount);
                                        memcpy(to, from, amount);
                                }
                                if ((unsigned long)end > bounce_buffer + (lb_end - lb_start)) {
                                        unsigned long from = bounce_buffer + (lb_end - lb_start);
                                        unsigned long to = lb_end;
                                        unsigned long amount = (unsigned long)end - from;
                                        printk_debug("move suffix around: from %lx, to %lx, amount: %lx\n", from, to, amount);
                                        memcpy((char*)to, (char*)from, amount);
                                }
                        }
                }
        }
        return 1;
}

static int selfboot(struct lb_memory *mem, struct cbfs_payload *payload)
{
        u32 entry=0;
        struct segment head;

        /* Preprocess the self segments */
        if (!build_self_segment_list(&head, mem, payload, &entry))
                goto out;

        /* Load the segments */
        if (!load_self_segments(&head, mem, payload))
                goto out;

        printk_spew("Loaded segments\n");

        /* Reset to booting from this image as late as possible */
        boot_successful();

        printk_debug("Jumping to boot code at %x\n", entry);
        post_code(0xfe);

        /* Jump to kernel */
        jmp_to_elf_entry((void*)entry, bounce_buffer, bounce_size);
        return 1;

 out:
        return 0;
}