lib/prog_loading: introduce prog_segment_loaded()

[coreboot.git] / src / lib / selfboot.c

/*
 * 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.
 */

#include <commonlib/compression.h>
#include <console/console.h>
#include <cpu/cpu.h>
#include <endian.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <symbols.h>
#include <cbfs.h>
#include <lib.h>
#include <bootmem.h>
#include <program_loading.h>
#include <timestamp.h>

static const unsigned long lb_start = (unsigned long)&_program;
static const unsigned long lb_end = (unsigned long)&_eprogram;

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

/* 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 than the general case implemented in kexec.
 */

static unsigned long bounce_size, bounce_buffer;

static void get_bounce_buffer(unsigned long req_size)
{
        unsigned long lb_size;
        void *buffer;

        /* When the ramstage is relocatable there is no need for a bounce
         * buffer. All payloads should not overlap the ramstage.
         */
        if (IS_ENABLED(CONFIG_RELOCATABLE_RAMSTAGE)) {
                bounce_buffer = ~0UL;
                bounce_size = 0;
                return;
        }

        lb_size = lb_end - lb_start;
        /* Plus coreboot size so I have somewhere
         * to place a copy to return to.
         */
        lb_size = req_size + lb_size;

        buffer = bootmem_allocate_buffer(lb_size);

        printk(BIOS_SPEW, "Bounce Buffer at %p, %lu bytes\n", buffer, lb_size);

        bounce_buffer = (uintptr_t)buffer;
        bounce_size = req_size;
}

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 int relocate_segment(unsigned long buffer, struct segment *seg)
{
        /* Modify all segments that want to load onto coreboot
         * to load onto the bounce buffer instead.
         */
        /* ret:  1 : A new segment is inserted before the seg.
         *       0 : A new segment is inserted after the seg, or no new one.
         */
        unsigned long start, middle, end, ret = 0;

        printk(BIOS_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 0;

        if (!arch_supports_bounce_buffer())
                die ("bounce buffer not supported");

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

        printk(BIOS_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;

                        /* compute the new value of start */
                        start = seg->s_dstaddr;

                        printk(BIOS_SPEW, "   early: [0x%016lx, 0x%016lx, 0x%016lx)\n",
                                new->s_dstaddr,
                                new->s_dstaddr + new->s_filesz,
                                new->s_dstaddr + new->s_memsz);

                        ret = 1;
                }

                /* 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;

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

        return ret;
}


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

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

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

                        new->s_srcaddr = (uintptr_t)
                                ((unsigned char *)first_segment)
                                + ntohl(segment->offset);
                        new->s_filesz = ntohl(segment->len);
                        printk(BIOS_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(BIOS_DEBUG,
                                       "  cleaned up filesize 0x%lx\n",
                                       new->s_filesz);
                        }
                        break;

                case PAYLOAD_SEGMENT_BSS:
                        printk(BIOS_DEBUG, "  BSS 0x%p (%d byte)\n", (void *)
                                        (intptr_t)ntohll(segment->load_addr),
                                        ntohl(segment->mem_len));
                        new = malloc(sizeof(*new));
                        new->s_filesz = 0;
                        new->s_srcaddr = (uintptr_t)
                                ((unsigned char *)first_segment)
                                + ntohl(segment->offset);
                        new->s_dstaddr = ntohll(segment->load_addr);
                        new->s_memsz = ntohl(segment->mem_len);
                        break;

                case PAYLOAD_SEGMENT_ENTRY:
                        printk(BIOS_DEBUG, "  Entry Point 0x%p\n",
                               (void *)(intptr_t)ntohll(segment->load_addr));
                        *entry =  ntohll(segment->load_addr);
                        /* Per definition, a payload always has the entry point
                         * as last segment. Thus, we use the occurrence 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(BIOS_EMERG, "Bad segment type %x\n", segment->type);
                        return -1;
                }

                /* We have found another CODE, DATA or BSS segment */
                segment++;

                /* Find place where to insert our segment */
                for(ptr = head->next; ptr != head; ptr = ptr->next) {
                        if (new->s_srcaddr < ntohll(segment->load_addr))
                                break;
                }

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

        return 1;
}

static int load_self_segments(
        struct segment *head,
        struct prog *payload)
{
        struct segment *ptr;
        struct segment *last_non_empty;
        const unsigned long one_meg = (1UL << 20);
        unsigned long bounce_high = lb_end;

        /* Determine last non-empty loaded segment. */
        last_non_empty = NULL;
        for(ptr = head->next; ptr != head; ptr = ptr->next)
                if (ptr->s_filesz != 0)
                        last_non_empty = ptr;

        for(ptr = head->next; ptr != head; ptr = ptr->next) {
                if (bootmem_region_targets_usable_ram(ptr->s_dstaddr,
                                                        ptr->s_memsz))
                        continue;

                if (ptr->s_dstaddr < one_meg &&
                    (ptr->s_dstaddr + ptr->s_memsz) <= one_meg) {
                        printk(BIOS_DEBUG,
                                "Payload being loaded below 1MiB "
                                "without region being marked as RAM usable.\n");
                        continue;
                }

                /* Payload segment not targeting RAM. */
                printk(BIOS_ERR, "SELF Payload doesn't target RAM:\n");
                printk(BIOS_ERR, "Failed Segment: 0x%lx, %lu bytes\n",
                        ptr->s_dstaddr, ptr->s_memsz);
                bootmem_dump_ranges();
                return 0;
        }

        for(ptr = head->next; ptr != head; ptr = ptr->next) {
                /*
                 * Add segments to bootmem memory map before a bounce buffer is
                 * allocated so that there aren't conflicts with the actual
                 * payload.
                 */
                bootmem_add_range(ptr->s_dstaddr, ptr->s_memsz,
                                        LB_MEM_UNUSABLE);

                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(bounce_high - lb_start);
        if (!bounce_buffer) {
                printk(BIOS_ERR, "Could not find a bounce buffer...\n");
                return 0;
        }

        for(ptr = head->next; ptr != head; ptr = ptr->next) {
                unsigned char *dest, *src;
                printk(BIOS_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.
                 */
                if (relocate_segment(bounce_buffer, ptr)) {
                        ptr = (ptr->prev)->prev;
                        continue;
                }

                printk(BIOS_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 = ptr->s_filesz;
                        size_t memsz = ptr->s_memsz;
                        switch(ptr->compression) {
                                case CBFS_COMPRESS_LZMA: {
                                        printk(BIOS_DEBUG, "using LZMA\n");
                                        timestamp_add_now(TS_START_ULZMA);
                                        len = ulzman(src, len, dest, memsz);
                                        timestamp_add_now(TS_END_ULZMA);
                                        if (!len) /* Decompression Error. */
                                                return 0;
                                        break;
                                }
                                case CBFS_COMPRESS_LZ4: {
                                        printk(BIOS_DEBUG, "using LZ4\n");
                                        timestamp_add_now(TS_START_ULZ4F);
                                        len = ulz4fn(src, len, dest, memsz);
                                        timestamp_add_now(TS_END_ULZ4F);
                                        if (!len) /* Decompression Error. */
                                                return 0;
                                        break;
                                }
                                case CBFS_COMPRESS_NONE: {
                                        printk(BIOS_DEBUG, "it's not compressed!\n");
                                        memcpy(dest, src, len);
                                        break;
                                }
                                default:
                                        printk(BIOS_INFO,  "CBFS:  Unknown compression type %d\n", ptr->compression);
                                        return -1;
                        }
                        end = dest + memsz;
                        middle = dest + len;
                        printk(BIOS_SPEW, "[ 0x%08lx, %08lx, 0x%08lx) <- %08lx\n",
                                (unsigned long)dest,
                                (unsigned long)middle,
                                (unsigned long)end,
                                (unsigned long)src);

                        /* Zero the extra bytes between middle & end */
                        if (middle < end) {
                                printk(BIOS_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 ramstage */
                        printk(BIOS_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(BIOS_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(BIOS_DEBUG, "move suffix around: from %lx, to %lx, amount: %lx\n", from, to, amount);
                                        memcpy((char*)to, (char*)from, amount);
                                }
                        }

                        /*
                         * Each architecture can perform additonal operations
                         * on the loaded segment
                         */
                        prog_segment_loaded((uintptr_t)dest, ptr->s_memsz,
                                        last_non_empty == ptr ? SEG_FINAL : 0);
                }
        }

        return 1;
}

void *selfload(struct prog *payload)
{
        uintptr_t entry = 0;
        struct segment head;
        void *data;

        data = rdev_mmap_full(prog_rdev(payload));

        if (data == NULL)
                return NULL;

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

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

        printk(BIOS_SPEW, "Loaded segments\n");

        rdev_munmap(prog_rdev(payload), data);

        /* Update the payload's area with the bounce buffer information. */
        prog_set_area(payload, (void *)(uintptr_t)bounce_buffer, bounce_size);

        /* Update the payload's area with the bounce buffer information. */
        prog_set_area(payload, (void *)(uintptr_t)bounce_buffer, bounce_size);

        return (void *)entry;

out:
        rdev_munmap(prog_rdev(payload), data);
        return NULL;
}