rush: Enable dp display

[coreboot.git] / util / cbfstool / rmodule.c

/*
 ;* Copyright (C) 2014 Google, Inc.
 *
 * 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 <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "elfparsing.h"
#include "rmodule.h"
#include "../../src/include/rmodule-defs.h"

struct rmod_context;

struct arch_ops {
        int arch;
        /* Determine if relocation is a valid type for the architecture. */
        int (*valid_type)(struct rmod_context *ctx, Elf64_Rela *rel);
        /* Determine if relocation should be emitted. */
        int (*should_emit)(struct rmod_context *ctx, Elf64_Rela *rel);
};

struct rmod_context {
        /* Ops to process relocations. */
        struct arch_ops *ops;

        /* endian conversion ops */
        struct xdr *xdr;

        /* Parsed ELF sturcture. */
        struct parsed_elf pelf;
        /* Program segment. */
        Elf64_Phdr *phdr;

        /* Collection of relocation addresses fixup in the module. */
        Elf64_Xword nrelocs;
        Elf64_Addr *emitted_relocs;

        /* The following fields are addresses within the linked program. */
        Elf64_Addr link_addr;
        Elf64_Addr entry;
        Elf64_Addr parameters_begin;
        Elf64_Addr parameters_end;
        Elf64_Addr bss_begin;
        Elf64_Addr bss_end;
        Elf64_Xword size;
};

/*
 * Architecture specific support operations.
 */
static int valid_reloc_386(struct rmod_context *ctx, Elf64_Rela *rel)
{
        int type;

        type = ELF64_R_TYPE(rel->r_info);

        /* Only these 2 relocations are expected to be found. */
        return (type == R_386_32 || type == R_386_PC32);
}

static int should_emit_386(struct rmod_context *ctx, Elf64_Rela *rel)
{
        int type;

        type = ELF64_R_TYPE(rel->r_info);

        /* R_386_32 relocations are absolute. Must emit these. */
        return (type == R_386_32);
}

static int valid_reloc_arm(struct rmod_context *ctx, Elf64_Rela *rel)
{
        int type;

        type = ELF64_R_TYPE(rel->r_info);

        /* Only these 6 relocations are expected to be found. */
        return (type == R_ARM_ABS32 || type == R_ARM_THM_PC22 ||
                type == R_ARM_THM_JUMP24 || type == R_ARM_V4BX ||
                type == R_ARM_CALL || type == R_ARM_JUMP24);
}

static int should_emit_arm(struct rmod_context *ctx, Elf64_Rela *rel)
{
        int type;

        type = ELF64_R_TYPE(rel->r_info);

        /* R_ARM_ABS32 relocations are absolute. Must emit these. */
        return (type == R_ARM_ABS32);
}

static int valid_reloc_aarch64(struct rmod_context *ctx, Elf64_Rela *rel)
{
        int type;

        type = ELF64_R_TYPE(rel->r_info);

        return (type == R_AARCH64_ADR_PREL_PG_HI21 ||
                type == R_AARCH64_ADD_ABS_LO12_NC  ||
                type == R_AARCH64_LDST8_ABS_LO12_NC ||
                type == R_AARCH64_JUMP26 ||
                type == R_AARCH64_LDST32_ABS_LO12_NC ||
                type == R_AARCH64_LDST64_ABS_LO12_NC ||
                type == R_AARCH64_CALL26 ||
                type == R_AARCH64_ABS64 ||
                type == R_AARCH64_LD_PREL_LO19 ||
                type == R_AARCH64_ADR_PREL_LO21);
}

static int should_emit_aarch64(struct rmod_context *ctx, Elf64_Rela *rel)
{
        int type;

        type = ELF64_R_TYPE(rel->r_info);

        return (type == R_AARCH64_ABS64);
}

static struct arch_ops reloc_ops[] = {
        {
                .arch = EM_386,
                .valid_type = valid_reloc_386,
                .should_emit = should_emit_386,
        },
        {
                .arch = EM_ARM,
                .valid_type = valid_reloc_arm,
                .should_emit = should_emit_arm,
        },
        {
                .arch = EM_AARCH64,
                .valid_type = valid_reloc_aarch64,
                .should_emit = should_emit_aarch64,
        },
};

/*
 * Relocation processing loops.
 */

static int for_each_reloc(struct rmod_context *ctx, int do_emit)
{
        Elf64_Half i;
        struct parsed_elf *pelf = &ctx->pelf;

        for (i = 0; i < pelf->ehdr.e_shnum; i++) {
                Elf64_Shdr *shdr;
                Elf64_Rela *relocs;
                Elf64_Xword nrelocs;
                Elf64_Xword j;

                relocs = pelf->relocs[i];

                /* No relocations in this section. */
                if (relocs == NULL)
                        continue;

                shdr = &pelf->shdr[i];
                nrelocs = shdr->sh_size / shdr->sh_entsize;

                for (j = 0; j < nrelocs; j++) {
                        Elf64_Rela *r = &relocs[j];

                        if (!ctx->ops->valid_type(ctx, r)) {
                                ERROR("Invalid reloc type: %u\n",
                                      (unsigned int)ELF64_R_TYPE(r->r_info));
                                return -1;
                        }

                        if (ctx->ops->should_emit(ctx, r)) {
                                int n = ctx->nrelocs;
                                if (do_emit)
                                        ctx->emitted_relocs[n] = r->r_offset;
                                ctx->nrelocs++;
                        }
                }
        }

        return 0;
}

static int find_program_segment(struct rmod_context *ctx)
{
        int i;
        int nsegments;
        struct parsed_elf *pelf;
        Elf64_Phdr *phdr;

        pelf = &ctx->pelf;

        /* There should only be a single loadable segment. */
        nsegments = 0;
        for (i = 0; i < pelf->ehdr.e_phnum; i++) {
                if (pelf->phdr[i].p_type != PT_LOAD)
                        continue;
                phdr = &pelf->phdr[i];
                nsegments++;
        }

        if (nsegments != 1) {
                ERROR("Unexepcted number of loadable segments: %d.\n",
                      nsegments);
                return -1;
        }

        INFO("Segment at 0x%0llx, file size 0x%0llx, mem size 0x%0llx.\n",
             (long long)phdr->p_vaddr, (long long)phdr->p_filesz,
             (long long)phdr->p_memsz);

        ctx->phdr = phdr;

        return 0;
}

static int
filter_relocation_sections(struct rmod_context *ctx)
{
        int i;
        const char *shstrtab;
        struct parsed_elf *pelf;
        const Elf64_Phdr *phdr;

        pelf = &ctx->pelf;
        phdr = ctx->phdr;
        shstrtab = buffer_get(pelf->strtabs[pelf->ehdr.e_shstrndx]);

        /*
         * Find all relocation sections that contain relocation entries
         * for sections that fall within the bounds of the segment. For
         * easier processing the pointer to the relocation array for the
         * sections that don't fall within the loadable program are NULL'd
         * out.
         */
        for (i = 0; i < pelf->ehdr.e_shnum; i++) {
                Elf64_Shdr *shdr;
                Elf64_Word sh_info;
                const char *section_name;

                shdr = &pelf->shdr[i];

                /* Ignore non-relocation sections. */
                if (shdr->sh_type != SHT_RELA && shdr->sh_type != SHT_REL)
                        continue;

                /* Obtain section which relocations apply. */
                sh_info = shdr->sh_info;
                shdr = &pelf->shdr[sh_info];

                section_name = &shstrtab[shdr->sh_name];
                DEBUG("Relocation section found for '%s' section.\n",
                      section_name);

                /* Do not process relocations for debug sections. */
                if (strstr(section_name, ".debug") != NULL) {
                        pelf->relocs[i] = NULL;
                        continue;
                }

                /*
                 * If relocations apply to a non program section ignore the
                 * relocations for future processing.
                 */
                if (shdr->sh_type != SHT_PROGBITS) {
                        pelf->relocs[i] = NULL;
                        continue;
                }

                if (shdr->sh_addr < phdr->p_vaddr ||
                    ((shdr->sh_addr + shdr->sh_size) >
                     (phdr->p_vaddr + phdr->p_memsz))) {
                        ERROR("Relocations being applied to section %d not "
                              "within segment region.\n", sh_info);
                        return -1;
                }
        }

        return 0;
}

static int vaddr_cmp(const void *a, const void *b)
{
        const Elf64_Addr *pa = a;
        const Elf64_Addr *pb = b;

        if (*pa < *pb)
                return -1;
        if (*pa > *pb)
                return 1;
        return 0;
}

static int collect_relocations(struct rmod_context *ctx)
{
        int nrelocs;

        /*
         * The relocs array in the pelf should only contain relocations that
         * apply to the program. Count the number relocations. Then collect
         * them into the allocated buffer.
         */
        if (for_each_reloc(ctx, 0))
                return -1;

        nrelocs = ctx->nrelocs;
        INFO("%d relocations to be emitted.\n", nrelocs);
        if (!nrelocs)
                return 0;

        /* Reset the counter for indexing into the array. */
        ctx->nrelocs = 0;
        ctx->emitted_relocs = calloc(nrelocs, sizeof(Elf64_Addr));
        /* Write out the relocations into the emitted_relocs array. */
        if (for_each_reloc(ctx, 1))
                return -1;

        if (ctx->nrelocs != nrelocs) {
                ERROR("Mismatch counted and emitted relocations: %zu vs %zu.\n",
                      (size_t)nrelocs, (size_t)ctx->nrelocs);
                return -1;
        }

        /* Sort the relocations by their address. */
        qsort(ctx->emitted_relocs, nrelocs, sizeof(Elf64_Addr), vaddr_cmp);

        return 0;
}

static int
populate_sym(struct rmod_context *ctx, const char *sym_name, Elf64_Addr *addr,
             int nsyms, const char *strtab)
{
        int i;
        Elf64_Sym *syms;

        syms = ctx->pelf.syms;

        for (i = 0; i < nsyms; i++) {
                if (syms[i].st_name == 0)
                        continue;
                if (strcmp(sym_name, &strtab[syms[i].st_name]))
                        continue;
                DEBUG("%s -> 0x%llx\n", sym_name, (long long)syms[i].st_value);
                *addr = syms[i].st_value;
                return 0;
        }
        ERROR("symbol '%s' not found.\n", sym_name);
        return -1;
}

static int populate_program_info(struct rmod_context *ctx)
{
        int i;
        const char *strtab;
        struct parsed_elf *pelf;
        Elf64_Ehdr *ehdr;
        int nsyms;

        pelf = &ctx->pelf;
        ehdr = &pelf->ehdr;

        /* Obtain the string table. */
        strtab = NULL;
        for (i = 0; i < ehdr->e_shnum; i++) {
                if (ctx->pelf.strtabs[i] == NULL)
                        continue;
                /* Don't use the section headers' string table. */
                if (i == ehdr->e_shstrndx)
                        continue;
                strtab = buffer_get(ctx->pelf.strtabs[i]);
                break;
        }

        if (strtab == NULL) {
                ERROR("No string table found.\n");
                return -1;
        }

        /* Determine number of symbols. */
        nsyms = 0;
        for (i = 0; i < ehdr->e_shnum; i++) {
                if (pelf->shdr[i].sh_type != SHT_SYMTAB)
                        continue;

                nsyms = pelf->shdr[i].sh_size / pelf->shdr[i].sh_entsize;
                break;
        }

        if (populate_sym(ctx, "_module_params_begin", &ctx->parameters_begin,
                         nsyms, strtab))
                return -1;

        if (populate_sym(ctx, "_module_params_end", &ctx->parameters_end,
                         nsyms, strtab))
                return -1;

        if (populate_sym(ctx, "_bss", &ctx->bss_begin, nsyms, strtab))
                return -1;

        if (populate_sym(ctx, "_ebss", &ctx->bss_end, nsyms, strtab))
                return -1;

        if (populate_sym(ctx, "__rmodule_entry", &ctx->entry, nsyms, strtab))
                return -1;

        /* Link address is the virtual address of the program segment. */
        ctx->link_addr = ctx->phdr->p_vaddr;

        /* The program size is the memsz of the program segment. */
        ctx->size = ctx->phdr->p_memsz;

        return 0;
}

static int
add_section(struct elf_writer *ew, struct buffer *data, const char *name,
            Elf64_Addr addr, Elf64_Word size)
{
        Elf64_Shdr shdr;
        int ret;

        memset(&shdr, 0, sizeof(shdr));
        if (data != NULL) {
                shdr.sh_type = SHT_PROGBITS;
                shdr.sh_flags = SHF_ALLOC | SHF_WRITE | SHF_EXECINSTR;
        } else {
                shdr.sh_type = SHT_NOBITS;
                shdr.sh_flags = SHF_ALLOC;
        }
        shdr.sh_addr = addr;
        shdr.sh_offset = addr;
        shdr.sh_size = size;

        ret = elf_writer_add_section(ew, &shdr, data, name);

        if (ret)
                ERROR("Could not add '%s' section.\n", name);

        return ret;
}

static int
write_elf(const struct rmod_context *ctx, const struct buffer *in,
          struct buffer *out)
{
        int i;
        int ret;
        int bit64;
        size_t loc;
        size_t rmod_data_size;
        struct elf_writer *ew;
        struct buffer rmod_data;
        struct buffer rmod_header;
        struct buffer program;
        struct buffer relocs;
        Elf64_Xword total_size;
        Elf64_Addr addr;
        Elf64_Ehdr ehdr;

        bit64 = ctx->pelf.ehdr.e_ident[EI_CLASS] == ELFCLASS64;

        /*
         * 3 sections will be added  to the ELF file.
         * +------------------+
         * |  rmodule header  |
         * +------------------+
         * |     program      |
         * +------------------+
         * |   relocations    |
         * +------------------+
         */

        /* Create buffer for header and relocations. */
        rmod_data_size = sizeof(struct rmodule_header);
        if (bit64)
                rmod_data_size += ctx->nrelocs * sizeof(Elf64_Addr);
        else
                rmod_data_size += ctx->nrelocs * sizeof(Elf32_Addr);

        if (buffer_create(&rmod_data, rmod_data_size, "rmod"))
                return -1;

        buffer_splice(&rmod_header, &rmod_data,
                      0, sizeof(struct rmodule_header));
        buffer_clone(&relocs, &rmod_data);
        buffer_seek(&relocs, sizeof(struct rmodule_header));

        /* Reset current location. */
        buffer_set_size(&rmod_header, 0);
        buffer_set_size(&relocs, 0);

        /* Program contents. */
        buffer_splice(&program, in, ctx->phdr->p_offset, ctx->phdr->p_filesz);

        /* Create ELF writer with modified entry point. */
        memcpy(&ehdr, &ctx->pelf.ehdr, sizeof(ehdr));
        ehdr.e_entry = ctx->entry;
        ew = elf_writer_init(&ehdr);

        if (ew == NULL) {
                ERROR("Failed to create ELF writer.\n");
                buffer_delete(&rmod_data);
                return -1;
        }

        /* Write out rmodule_header. */
        ctx->xdr->put16(&rmod_header, RMODULE_MAGIC);
        ctx->xdr->put8(&rmod_header, RMODULE_VERSION_1);
        ctx->xdr->put8(&rmod_header, 0);
        /* payload_begin_offset */
        loc = sizeof(struct rmodule_header);
        ctx->xdr->put32(&rmod_header, loc);
        /* payload_end_offset */
        loc += ctx->phdr->p_filesz;
        ctx->xdr->put32(&rmod_header, loc);
        /* relocations_begin_offset */
        ctx->xdr->put32(&rmod_header, loc);
        /* relocations_end_offset */
        if (bit64)
                loc += ctx->nrelocs * sizeof(Elf64_Addr);
        else
                loc += ctx->nrelocs * sizeof(Elf32_Addr);
        ctx->xdr->put32(&rmod_header, loc);
        /* module_link_start_address */
        ctx->xdr->put32(&rmod_header, ctx->link_addr);
        /* module_program_size */
        ctx->xdr->put32(&rmod_header, ctx->size);
        /* module_entry_point */
        ctx->xdr->put32(&rmod_header, ctx->entry);
        /* parameters_begin */
        ctx->xdr->put32(&rmod_header, ctx->parameters_begin);
        /* parameters_end */
        ctx->xdr->put32(&rmod_header, ctx->parameters_end);
        /* bss_begin */
        ctx->xdr->put32(&rmod_header, ctx->bss_begin);
        /* bss_end */
        ctx->xdr->put32(&rmod_header, ctx->bss_end);
        /* padding[4] */
        ctx->xdr->put32(&rmod_header, 0);
        ctx->xdr->put32(&rmod_header, 0);
        ctx->xdr->put32(&rmod_header, 0);
        ctx->xdr->put32(&rmod_header, 0);

        /* Write the relocations. */
        for (i = 0; i < ctx->nrelocs; i++) {
                if (bit64)
                        ctx->xdr->put64(&relocs, ctx->emitted_relocs[i]);
                else
                        ctx->xdr->put32(&relocs, ctx->emitted_relocs[i]);
        }

        total_size = 0;
        addr = 0;

        /*
         * There are 2 cases to deal with. The program has a large NOBITS
         * section and the relocations can fit entirely within occupied memory
         * region for the program. The other is that the relocations increase
         * the memory footprint of the program if it was loaded directly into
         * the region it would run. The rmdoule header is a fixed cost that
         * is considered a part of the program.
         */
        total_size += buffer_size(&rmod_header);
        if (buffer_size(&relocs) + ctx->phdr->p_filesz > ctx->phdr->p_memsz) {
                total_size += buffer_size(&relocs);
                total_size += ctx->phdr->p_filesz;
        } else {
                total_size += ctx->phdr->p_memsz;
        }

        ret = add_section(ew, &rmod_header, ".header", addr,
                          buffer_size(&rmod_header));
        if (ret < 0)
                goto out;
        addr += buffer_size(&rmod_header);

        ret = add_section(ew, &program, ".program", addr, ctx->phdr->p_filesz);
        if (ret < 0)
                goto out;
        addr += ctx->phdr->p_filesz;

        if (ctx->nrelocs) {
                ret = add_section(ew, &relocs, ".relocs", addr,
                                  buffer_size(&relocs));
                if (ret < 0)
                        goto out;
                addr += buffer_size(&relocs);
        }

        if (total_size != addr) {
                ret = add_section(ew, NULL, ".empty", addr, total_size - addr);
                if (ret < 0)
                        goto out;
        }

        /*
         * Ensure last section has a memory usage that meets the required
         * total size of the program in memory.
         */

        ret = elf_writer_serialize(ew, out);
        if (ret < 0)
                ERROR("Failed to serialize ELF to buffer.\n");

out:
        buffer_delete(&rmod_data);
        elf_writer_destroy(ew);

        return ret;
}

int rmodule_create(const struct buffer *elfin, struct buffer *elfout)
{
        struct rmod_context ctx;
        struct parsed_elf *pelf;
        int i;
        int ret;

        ret = -1;
        memset(&ctx, 0, sizeof(ctx));
        pelf = &ctx.pelf;

        if (parse_elf(elfin, pelf, ELF_PARSE_ALL)) {
                ERROR("Couldn't parse ELF!\n");
                return -1;
        }

        /* Only allow executables to be turned into rmodules. */
        if (pelf->ehdr.e_type != ET_EXEC) {
                ERROR("ELF is not an executable: %u.\n", pelf->ehdr.e_type);
                goto out;
        }

        /* Determine if architecture is supported. */
        for (i = 0; i < ARRAY_SIZE(reloc_ops); i++) {
                if (reloc_ops[i].arch == pelf->ehdr.e_machine) {
                        ctx.ops = &reloc_ops[i];
                        break;
                }
        }

        if (ctx.ops == NULL) {
                ERROR("ELF is unsupported arch: %u.\n", pelf->ehdr.e_machine);
                goto out;
        }

        /* Set the endian ops. */
        if (ctx.pelf.ehdr.e_ident[EI_DATA] == ELFDATA2MSB)
                ctx.xdr = &xdr_be;
        else
                ctx.xdr = &xdr_le;

        if (find_program_segment(&ctx))
                goto out;

        if (filter_relocation_sections(&ctx))
                goto out;

        if (collect_relocations(&ctx))
                goto out;

        if (populate_program_info(&ctx))
                goto out;

        if (write_elf(&ctx, elfin, elfout))
                goto out;

        ret = 0;

out:
        free(ctx.emitted_relocs);
        parsed_elf_destroy(pelf);
        return ret;
}