// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * OpenRISC module.c
 *
 * Linux architectural port borrowing liberally from similar works of
 * others.  All original copyrights apply as per the original source
 * declaration.
 *
 * Modifications for the OpenRISC architecture:
 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
 */

#include <linux/moduleloader.h>
#include <linux/elf.h>

int apply_relocate_add(Elf32_Shdr *sechdrs,
                       const char *strtab,
                       unsigned int symindex,
                       unsigned int relsec,
                       struct module *me)
{
        unsigned int i;
        Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
        Elf32_Sym *sym;
        uint32_t *location;
        uint32_t value;

        pr_debug("Applying relocate section %u to %u\n", relsec,
                 sechdrs[relsec].sh_info);
        for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
                /* This is where to make the change */
                location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
                        + rel[i].r_offset;

                /* This is the symbol it is referring to.  Note that all
                   undefined symbols have been resolved.  */
                sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
                        + ELF32_R_SYM(rel[i].r_info);
                value = sym->st_value + rel[i].r_addend;

                switch (ELF32_R_TYPE(rel[i].r_info)) {
                case R_OR1K_32:
                        *location = value;
                        break;
                case R_OR1K_LO_16_IN_INSN:
                        *((uint16_t *)location + 1) = value;
                        break;
                case R_OR1K_HI_16_IN_INSN:
                        *((uint16_t *)location + 1) = value >> 16;
                        break;
                case R_OR1K_INSN_REL_26:
                        value -= (uint32_t)location;
                        value >>= 2;
                        value &= 0x03ffffff;
                        value |= *location & 0xfc000000;
                        *location = value;
                        break;
                case R_OR1K_32_PCREL:
                        value -= (uint32_t)location;
                        *location = value;
                        break;
                case R_OR1K_AHI16:
                        /* Adjust the operand to match with a signed LO16.  */
                        value += 0x8000;
                        *((uint16_t *)location + 1) = value >> 16;
                        break;
                case R_OR1K_SLO16:
                        /* Split value lower 16-bits.  */
                        value = ((value & 0xf800) << 10) | (value & 0x7ff);
                        *location = (*location & ~0x3e007ff) | value;
                        break;
                default:
                        pr_err("module %s: Unknown relocation: %u\n",
                               me->name, ELF32_R_TYPE(rel[i].r_info));
                        break;
                }
        }

        return 0;
}