/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 2023 Free Software Foundation, Inc.
 *
 *  GRUB 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, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  GRUB 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 GRUB.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <grub/dl.h>
#include <grub/elf.h>
#include <grub/misc.h>
#include <grub/err.h>
#include <grub/types.h>
#include <grub/mm.h>
#include <grub/i18n.h>
#include <grub/cpu/reloc.h>

/* Check if EHDR is a valid ELF header.  */
grub_err_t
grub_arch_dl_check_header (void *ehdr)
{
  Elf_Ehdr *e = ehdr;

  /* Check the magic numbers.  */
  if (e->e_ident[EI_CLASS] != ELFCLASS64
      || e->e_ident[EI_DATA] != ELFDATA2LSB || e->e_machine != EM_LOONGARCH)
    return grub_error (GRUB_ERR_BAD_OS, N_("invalid arch-dependent ELF magic"));

  return GRUB_ERR_NONE;
}

#pragma GCC diagnostic ignored "-Wcast-align"

/*
 * Unified function for both REL and RELA.
 */
grub_err_t
grub_arch_dl_relocate_symbols (grub_dl_t mod, void *ehdr,
			       Elf_Shdr *s, grub_dl_segment_t seg)
{
  Elf_Rel *rel, *max;
  struct grub_loongarch64_stack stack;
  grub_loongarch64_stack_init (&stack);

  for (rel = (Elf_Rel *) ((char *) ehdr + s->sh_offset),
	 max = (Elf_Rel *) ((char *) rel + s->sh_size);
       rel < max;
       rel = (Elf_Rel *) ((char *) rel + s->sh_entsize))
    {
      Elf_Sym *sym;
      void *place;
      grub_uint64_t sym_addr;

      if (rel->r_offset >= seg->size)
	return grub_error (GRUB_ERR_BAD_MODULE,
			   "reloc offset is outside the segment");

      sym = (Elf_Sym *) ((char*) mod->symtab
			 + mod->symsize * ELF_R_SYM (rel->r_info));

      sym_addr = sym->st_value;
      if (s->sh_type == SHT_RELA)
	sym_addr += ((Elf_Rela *) rel)->r_addend;

      place = (void *) ((grub_addr_t) seg->addr + rel->r_offset);

      switch (ELF_R_TYPE (rel->r_info))
	{
	case R_LARCH_64:
	  {
	    grub_uint64_t *abs_place = place;

	    grub_dprintf ("dl", "reloc_abs64 %p => 0x%016llx, %p\n",
			  place, (unsigned long long) sym_addr, abs_place);

	    *abs_place += (grub_uint64_t) sym_addr;
	  }
	  break;
	case R_LARCH_MARK_LA:
	  break;
	case R_LARCH_SOP_PUSH_PCREL:
	case R_LARCH_SOP_PUSH_PLT_PCREL:
	  grub_loongarch64_sop_push (&stack, sym_addr - (grub_uint64_t)place);
	  break;
	case R_LARCH_B26:
	  {
	    grub_uint32_t *abs_place = place;
	    grub_ssize_t off = sym_addr - (grub_addr_t) place;

	    grub_loongarch64_b26 (abs_place, off);
	  }
	  break;
	case R_LARCH_ABS_HI20:
	  {
	    grub_uint32_t *abs_place = place;
	    grub_loongarch64_xxx_hi20 (abs_place, sym_addr);
	  }
	  break;
	case R_LARCH_ABS64_LO20:
	  {
	    grub_uint32_t *abs_place = place;
	    grub_loongarch64_abs64_lo20 (abs_place, sym_addr);
	  }
	  break;
	case R_LARCH_ABS64_HI12:
	  {
	    grub_uint32_t *abs_place = place;
	    grub_loongarch64_abs64_hi12 (abs_place, sym_addr);
	  }
	  break;
	case R_LARCH_PCALA_HI20:
	  {
	    grub_uint32_t *abs_place = place;
	    grub_int32_t off = (((sym_addr + 0x800) & ~0xfffULL) - ((grub_addr_t)place & ~0xfffULL));

	    grub_loongarch64_xxx_hi20 (abs_place, off);
	  }
	  break;
	case R_LARCH_ABS_LO12:
	case R_LARCH_PCALA_LO12:
	  {
	    grub_uint32_t *abs_place = place;
	    grub_loongarch64_xxx_lo12 (abs_place, sym_addr);
	  }
	  break;
	GRUB_LOONGARCH64_RELOCATION (&stack, place, sym_addr)
	default:
	  {
	    char rel_info[17]; /* log16(2^64) = 16, plus NUL.  */

	    grub_snprintf (rel_info, sizeof (rel_info) - 1, "%" PRIxGRUB_UINT64_T,
			   (grub_uint64_t) ELF_R_TYPE (rel->r_info));
	    return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
			       N_("relocation 0x%s is not implemented yet"), rel_info);
	  }
	  break;
	}
    }
  return GRUB_ERR_NONE;
}