diff mbox series

[v3,07/10] RISC-V: Add awareness for RISC-V reloations

Message ID 20181114172739.51640-8-agraf@suse.de
State Superseded
Headers show
Series Add RISC-V support | expand

Commit Message

Alexander Graf Nov. 14, 2018, 5:27 p.m. UTC
This patch adds awareness of RISC-V relocations throughout the grub tools
as well as dynamic linkage and elf->PE relocation conversion support.

Signed-off-by: Alexander Graf <agraf@suse.de>


---

v2 -> v3:

  - Fix riscv32 target
---
 grub-core/kern/dl.c         |   6 +-
 grub-core/kern/riscv/dl.c   | 335 ++++++++++++++++++++++++++++++++++++++++++++
 include/grub/dl.h           |   6 +-
 util/grub-mkimagexx.c       | 268 +++++++++++++++++++++++++++++++++++
 util/grub-module-verifier.c |  56 ++++++++
 5 files changed, 666 insertions(+), 5 deletions(-)
 create mode 100644 grub-core/kern/riscv/dl.c

-- 
2.12.3


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Comments

Daniel Kiper Nov. 21, 2018, 3:51 p.m. UTC | #1
On Wed, Nov 14, 2018 at 06:27:36PM +0100, Alexander Graf wrote:
> This patch adds awareness of RISC-V relocations throughout the grub tools

> as well as dynamic linkage and elf->PE relocation conversion support.

>

> Signed-off-by: Alexander Graf <agraf@suse.de>

>

> ---

>

> v2 -> v3:

>

>   - Fix riscv32 target

> ---

>  grub-core/kern/dl.c         |   6 +-

>  grub-core/kern/riscv/dl.c   | 335 ++++++++++++++++++++++++++++++++++++++++++++

>  include/grub/dl.h           |   6 +-

>  util/grub-mkimagexx.c       | 268 +++++++++++++++++++++++++++++++++++

>  util/grub-module-verifier.c |  56 ++++++++

>  5 files changed, 666 insertions(+), 5 deletions(-)

>  create mode 100644 grub-core/kern/riscv/dl.c

>

> diff --git a/grub-core/kern/dl.c b/grub-core/kern/dl.c

> index f8d58f029..48eb5e7b6 100644

> --- a/grub-core/kern/dl.c

> +++ b/grub-core/kern/dl.c

> @@ -225,7 +225,7 @@ grub_dl_load_segments (grub_dl_t mod, const Elf_Ehdr *e)

>    unsigned i;

>    const Elf_Shdr *s;

>    grub_size_t tsize = 0, talign = 1;

> -#if !defined (__i386__) && !defined (__x86_64__)

> +#if !defined (__i386__) && !defined (__x86_64__) && !defined(__riscv)


Could not we use __riscv__?

>    grub_size_t tramp;

>    grub_size_t got;

>    grub_err_t err;

> @@ -241,7 +241,7 @@ grub_dl_load_segments (grub_dl_t mod, const Elf_Ehdr *e)

>  	talign = s->sh_addralign;

>      }

>

> -#if !defined (__i386__) && !defined (__x86_64__)

> +#if !defined (__i386__) && !defined (__x86_64__) && !defined(__riscv)

>    err = grub_arch_dl_get_tramp_got_size (e, &tramp, &got);

>    if (err)

>      return err;

> @@ -304,7 +304,7 @@ grub_dl_load_segments (grub_dl_t mod, const Elf_Ehdr *e)

>  	  mod->segment = seg;

>  	}

>      }

> -#if !defined (__i386__) && !defined (__x86_64__)

> +#if !defined (__i386__) && !defined (__x86_64__) && !defined(__riscv)

>    ptr = (char *) ALIGN_UP ((grub_addr_t) ptr, GRUB_ARCH_DL_TRAMP_ALIGN);

>    mod->tramp = ptr;

>    mod->trampptr = ptr;

> diff --git a/grub-core/kern/riscv/dl.c b/grub-core/kern/riscv/dl.c

> new file mode 100644

> index 000000000..503b67df1

> --- /dev/null

> +++ b/grub-core/kern/riscv/dl.c

> @@ -0,0 +1,335 @@

> +/* dl.c - arch-dependent part of loadable module support */

> +/*

> + *  GRUB  --  GRand Unified Bootloader

> + *  Copyright (C) 2013  Free Software Foundation, Inc.


s/2013/2018/

> + *

> + *  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/mm.h>

> +#include <grub/i18n.h>

> +

> +#define LDR 0x58000050

> +#define BR 0xd61f0200

> +

> +


Please drop this empty line.

> +/*

> + * 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_DATA] != ELFDATA2LSB || e->e_machine != EM_RISCV)

> +    return grub_error (GRUB_ERR_BAD_OS,

> +		       N_("invalid arch-dependent ELF magic"));

> +

> +  return GRUB_ERR_NONE;

> +}

> +

> +#pragma GCC diagnostic ignored "-Wcast-align"


Why? Could you add a comment here?

> +/* Relocate symbols. */

> +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;

> +

> +  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_size_t sym_addr;

> +

> +      if (rel->r_offset >= seg->size)

> +	return grub_error (GRUB_ERR_BAD_MODULE,

> +			   "reloc offset is out of 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_RISCV_32:

> +	  {

> +	    grub_uint32_t *abs_place = place;

> +

> +	    grub_dprintf ("dl", "  reloc_abs32 %p => 0x%016llx\n",

> +			  place, (unsigned long long) sym_addr);

> +

> +	    *abs_place = (grub_uint32_t) sym_addr;

> +	  }

> +	  break;

> +	case R_RISCV_64:

> +	  {

> +	    grub_size_t *abs_place = place;

> +

> +	    grub_dprintf ("dl", "  reloc_abs64 %p => 0x%016llx\n",

> +			  place, (unsigned long long) sym_addr);

> +

> +	    *abs_place = (grub_size_t) sym_addr;

> +	  }

> +	  break;

> +

> +	case R_RISCV_ADD8:

> +	  {

> +	    grub_uint8_t *abs_place = place;

> +

> +	    *abs_place += (grub_uint8_t) sym_addr;

> +	  }

> +	  break;

> +	case R_RISCV_ADD16:

> +	  {

> +	    grub_uint16_t *abs_place = place;

> +

> +	    *abs_place += (grub_uint16_t) sym_addr;

> +	  }

> +	  break;

> +	case R_RISCV_ADD32:

> +	  {

> +	    grub_uint32_t *abs_place = place;

> +

> +	    *abs_place += (grub_uint32_t) sym_addr;

> +	  }

> +	  break;

> +	case R_RISCV_ADD64:

> +	  {

> +	    grub_size_t *abs_place = place;

> +

> +	    *abs_place += (grub_size_t) sym_addr;

> +	  }

> +	  break;

> +

> +	case R_RISCV_SUB8:

> +	  {

> +	    grub_uint8_t *abs_place = place;

> +

> +	    *abs_place -= (grub_uint8_t) sym_addr;

> +	  }

> +	  break;

> +	case R_RISCV_SUB16:

> +	  {

> +	    grub_uint16_t *abs_place = place;

> +

> +	    *abs_place -= (grub_uint16_t) sym_addr;

> +	  }

> +	  break;

> +	case R_RISCV_SUB32:

> +	  {

> +	    grub_uint32_t *abs_place = place;

> +

> +	    *abs_place -= (grub_uint32_t) sym_addr;

> +	  }

> +	  break;

> +	case R_RISCV_SUB64:

> +	  {

> +	    grub_size_t *abs_place = place;

> +

> +	    *abs_place -= (grub_size_t) sym_addr;

> +	  }

> +	  break;

> +

> +	case R_RISCV_BRANCH:

> +	  {

> +	    grub_uint32_t *abs_place = place;

> +	    grub_ssize_t off = sym_addr - (grub_addr_t) place;

> +	    grub_uint32_t imm12 = (off & 0x1000) << (31 - 12);

> +	    grub_uint32_t imm11 = (off & 0x800) >> (11 - 7);

> +	    grub_uint32_t imm10_5 = (off & 0x7e0) << (30 - 10);

> +	    grub_uint32_t imm4_1 = (off & 0x1e) << (11 - 4);

> +	    *abs_place = (*abs_place & 0x1fff07f)

> +			 | imm12 | imm11 | imm10_5 | imm4_1;


Could not we use some constants instead of numbers here?
If this does not make sense than please name the source of this numbers.

> +	  }

> +	  break;

> +

> +	case R_RISCV_JAL:

> +	  {

> +	    grub_uint32_t *abs_place = place;

> +	    grub_ssize_t off = sym_addr - (grub_addr_t) place;

> +	    grub_uint32_t imm20 = (off & 0x100000) << (31 - 20);

> +	    grub_uint32_t imm19_12 = (off & 0xff000);

> +	    grub_uint32_t imm11 = (off & 0x800) << (20 - 11);

> +	    grub_uint32_t imm10_1 = (off & 0x7fe) << (30 - 10);

> +	    *abs_place = (*abs_place & 0xfff)

> +			 | imm20 | imm19_12 | imm11 | imm10_1;


Ditto.

> +	  }

> +	  break;

> +

> +	case R_RISCV_CALL:

> +	  {

> +	    grub_uint32_t *abs_place = place;

> +	    grub_ssize_t off = sym_addr - (grub_addr_t) place;

> +	    grub_uint32_t hi20, lo12;

> +

> +	    if (off != (grub_int32_t) off)

> +	      return grub_error (GRUB_ERR_BAD_MODULE, "relocation overflow");

> +

> +	    hi20 = (off + 0x800) & 0xfffff000;

> +	    lo12 = (off - hi20) & 0xfff;

> +	    abs_place[0] = (abs_place[0] & 0xfff) | hi20;

> +	    abs_place[1] = (abs_place[1] & 0xfffff) | (lo12 << 20);


Ditto and below...

> +	  }

> +	  break;

> +

> +	case R_RISCV_RVC_BRANCH:

> +	  {

> +	    grub_uint16_t *abs_place = place;

> +	    grub_ssize_t off = sym_addr - (grub_addr_t) place;

> +	    grub_uint16_t imm8 = (off & 0x100) << (12 - 8);

> +	    grub_uint16_t imm7_6 = (off & 0xc0) >> (6 - 5);

> +	    grub_uint16_t imm5 = (off & 0x20) >> (5 - 2);

> +	    grub_uint16_t imm4_3 = (off & 0x18) << (12 - 5);

> +	    grub_uint16_t imm2_1 = (off & 0x6) << (12 - 10);

> +	    *abs_place = (*abs_place & 0xe383)

> +			 | imm8 | imm7_6 | imm5 | imm4_3 | imm2_1;

> +	  }

> +	  break;

> +

> +	case R_RISCV_RVC_JUMP:

> +	  {

> +	    grub_uint16_t *abs_place = place;

> +	    grub_ssize_t off = sym_addr - (grub_addr_t) place;

> +	    grub_uint16_t imm11 = (off & 0x800) << (12 - 11);

> +	    grub_uint16_t imm10 = (off & 0x400) >> (10 - 8);

> +	    grub_uint16_t imm9_8 = (off & 0x300) << (12 - 11);

> +	    grub_uint16_t imm7 = (off & 0x80) >> (7 - 6);

> +	    grub_uint16_t imm6 = (off & 0x40) << (12 - 11);

> +	    grub_uint16_t imm5 = (off & 0x20) >> (5 - 2);

> +	    grub_uint16_t imm4 = (off & 0x10) << (12 - 5);

> +	    grub_uint16_t imm3_1 = (off & 0xe) << (12 - 10);

> +	    *abs_place = ((*abs_place & 0xe003)

> +			  | imm11 | imm10 | imm9_8 | imm7 | imm6

> +			  | imm5 | imm4 | imm3_1);

> +	  }

> +	  break;

> +

> +	case R_RISCV_PCREL_HI20:

> +	  {

> +	    grub_uint32_t *abs_place = place;

> +	    grub_ssize_t off = sym_addr - (grub_addr_t) place;

> +	    grub_int32_t hi20;

> +

> +	    if (off != (grub_int32_t)off)

> +	      return grub_error (GRUB_ERR_BAD_MODULE, "relocation overflow");

> +

> +	    hi20 = (off + 0x800) & 0xfffff000;

> +	    *abs_place = (*abs_place & 0xfff) | hi20;

> +	  }

> +	break;

> +

> +	case R_RISCV_PCREL_LO12_I:

> +	case R_RISCV_PCREL_LO12_S:

> +	  {

> +	    grub_uint32_t *t32 = place;

> +	    Elf_Rela *rel2;

> +	    /* Search backwards for matching HI20 reloc.  */


Why "backwards"?

> +	    for (rel2 = (Elf_Rela *) ((char *) rel - s->sh_entsize);

> +		    (unsigned long)rel2 >= ((unsigned long)ehdr + s->sh_offset);

> +		    rel2 = (Elf_Rela *) ((char *) rel2 - s->sh_entsize))

> +	      {

> +		Elf_Addr rel2_info;

> +		Elf_Addr rel2_offset;

> +		Elf_Addr rel2_sym_addr;

> +		Elf_Addr rel2_loc;

> +		grub_ssize_t rel2_off;

> +		grub_ssize_t off;

> +		Elf_Sym *sym2;

> +

> +		rel2_offset = rel2->r_offset;

> +		rel2_info = rel2->r_info;

> +		rel2_loc = (grub_addr_t) seg->addr + rel2_offset;

> +

> +		if (ELF_R_TYPE (rel2_info) == R_RISCV_PCREL_HI20

> +		    && rel2_loc == sym_addr)

> +		  {

> +		    sym2 = (Elf_Sym *) ((char *) mod->symtab

> +				+ mod->symsize * ELF_R_SYM (rel2->r_info));

> +		    rel2_sym_addr = sym2->st_value;

> +		    if (s->sh_type == SHT_RELA)

> +		      rel2_sym_addr += ((Elf_Rela *) rel2)->r_addend;

> +

> +		    rel2_off = rel2_sym_addr - rel2_loc;

> +		    off = rel2_off - ((rel2_off + 0x800) & 0xfffff000);

> +

> +		    if (ELF_R_TYPE (rel->r_info) == R_RISCV_PCREL_LO12_I)

> +		      *t32 = (*t32 & 0xfffff) | (off & 0xfff) << 20;

> +		    else

> +		      {

> +			grub_uint32_t imm11_5 = (off & 0xfe0) << (31 - 11);

> +			grub_uint32_t imm4_0 = (off & 0x1f) << (11 - 4);

> +			*t32 = (*t32 & 0x1fff07f) | imm11_5 | imm4_0;

> +		      }

> +		    break;

> +		  }

> +	      }

> +	    if ((unsigned long)rel2 < ((unsigned long)ehdr + s->sh_offset))

> +	      return grub_error (GRUB_ERR_BAD_MODULE, "cannot find matching HI20 relocation");

> +	  }

> +	  break;

> +

> +	case R_RISCV_HI20:

> +	  {

> +	    grub_uint32_t *abs_place = place;

> +	    *abs_place = (*abs_place & 0xfff) |

> +			 (((grub_int32_t) sym_addr + 0x800) & 0xfffff000);

> +	  }

> +	  break;

> +

> +	case R_RISCV_LO12_I:

> +	  {

> +	    grub_uint32_t *abs_place = place;

> +	    grub_int32_t lo12 = (grub_int32_t) sym_addr -

> +				(((grub_int32_t) sym_addr + 0x800) & 0xfffff000);

> +	    *abs_place = (*abs_place & 0xfffff) | ((lo12 & 0xfff) << 20);

> +	  }

> +	  break;

> +

> +	case R_RISCV_LO12_S:

> +	  {

> +	    grub_uint32_t *abs_place = place;

> +	    grub_int32_t lo12 = (grub_int32_t) sym_addr -

> +				(((grub_int32_t) sym_addr + 0x800) & 0xfffff000);

> +	    grub_uint32_t imm11_5 = (lo12 & 0xfe0) << (31 - 11);

> +	    grub_uint32_t imm4_0 = (lo12 & 0x1f) << (11 - 4);

> +	    *abs_place = (*abs_place & 0x1fff07f) | imm11_5 | imm4_0;


Again, why not constants? And below...

Daniel

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Andreas Schwab Nov. 21, 2018, 4:08 p.m. UTC | #2
On Nov 21 2018, Daniel Kiper <dkiper@net-space.pl> wrote:

>> +	case R_RISCV_BRANCH:

>> +	  {

>> +	    grub_uint32_t *abs_place = place;

>> +	    grub_ssize_t off = sym_addr - (grub_addr_t) place;

>> +	    grub_uint32_t imm12 = (off & 0x1000) << (31 - 12);

>> +	    grub_uint32_t imm11 = (off & 0x800) >> (11 - 7);

>> +	    grub_uint32_t imm10_5 = (off & 0x7e0) << (30 - 10);

>> +	    grub_uint32_t imm4_1 = (off & 0x1e) << (11 - 4);

>> +	    *abs_place = (*abs_place & 0x1fff07f)

>> +			 | imm12 | imm11 | imm10_5 | imm4_1;

>

> Could not we use some constants instead of numbers here?


These are just where the insn encoding puts the bits.

> If this does not make sense than please name the source of this numbers.


https://github.com/riscv/riscv-isa-manual/blob/master/release/riscv-spec-v2.2.pdf

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

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Daniel Kiper Nov. 21, 2018, 4:31 p.m. UTC | #3
On Wed, Nov 21, 2018 at 05:08:09PM +0100, Andreas Schwab wrote:
> On Nov 21 2018, Daniel Kiper <dkiper@net-space.pl> wrote:

>

> >> +	case R_RISCV_BRANCH:

> >> +	  {

> >> +	    grub_uint32_t *abs_place = place;

> >> +	    grub_ssize_t off = sym_addr - (grub_addr_t) place;

> >> +	    grub_uint32_t imm12 = (off & 0x1000) << (31 - 12);

> >> +	    grub_uint32_t imm11 = (off & 0x800) >> (11 - 7);

> >> +	    grub_uint32_t imm10_5 = (off & 0x7e0) << (30 - 10);

> >> +	    grub_uint32_t imm4_1 = (off & 0x1e) << (11 - 4);

> >> +	    *abs_place = (*abs_place & 0x1fff07f)

> >> +			 | imm12 | imm11 | imm10_5 | imm4_1;

> >

> > Could not we use some constants instead of numbers here?

>

> These are just where the insn encoding puts the bits.

>

> > If this does not make sense than please name the source of this numbers.

>

> https://github.com/riscv/riscv-isa-manual/blob/master/release/riscv-spec-v2.2.pdf


OK, please add the document title and link to it into relevant source files.

Daniel

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Alexander Graf Nov. 25, 2018, 10:12 p.m. UTC | #4
On 21.11.18 16:51, Daniel Kiper wrote:
> On Wed, Nov 14, 2018 at 06:27:36PM +0100, Alexander Graf wrote:
>> This patch adds awareness of RISC-V relocations throughout the grub tools
>> as well as dynamic linkage and elf->PE relocation conversion support.
>>
>> Signed-off-by: Alexander Graf <agraf@suse.de>
>>
>> ---
>>
>> v2 -> v3:
>>
>>   - Fix riscv32 target
>> ---
>>  grub-core/kern/dl.c         |   6 +-
>>  grub-core/kern/riscv/dl.c   | 335 ++++++++++++++++++++++++++++++++++++++++++++
>>  include/grub/dl.h           |   6 +-
>>  util/grub-mkimagexx.c       | 268 +++++++++++++++++++++++++++++++++++
>>  util/grub-module-verifier.c |  56 ++++++++
>>  5 files changed, 666 insertions(+), 5 deletions(-)
>>  create mode 100644 grub-core/kern/riscv/dl.c
>>
>> diff --git a/grub-core/kern/dl.c b/grub-core/kern/dl.c
>> index f8d58f029..48eb5e7b6 100644
>> --- a/grub-core/kern/dl.c
>> +++ b/grub-core/kern/dl.c
>> @@ -225,7 +225,7 @@ grub_dl_load_segments (grub_dl_t mod, const Elf_Ehdr *e)
>>    unsigned i;
>>    const Elf_Shdr *s;
>>    grub_size_t tsize = 0, talign = 1;
>> -#if !defined (__i386__) && !defined (__x86_64__)
>> +#if !defined (__i386__) && !defined (__x86_64__) && !defined(__riscv)
> 
> Could not we use __riscv__?

Unfortunately __riscv__ is not defined in recent versions of gcc:


https://github.com/riscv/riscv-toolchain-conventions#cc-preprocessor-definitions

> 
>>    grub_size_t tramp;
>>    grub_size_t got;
>>    grub_err_t err;
>> @@ -241,7 +241,7 @@ grub_dl_load_segments (grub_dl_t mod, const Elf_Ehdr *e)
>>  	talign = s->sh_addralign;
>>      }
>>
>> -#if !defined (__i386__) && !defined (__x86_64__)
>> +#if !defined (__i386__) && !defined (__x86_64__) && !defined(__riscv)
>>    err = grub_arch_dl_get_tramp_got_size (e, &tramp, &got);
>>    if (err)
>>      return err;
>> @@ -304,7 +304,7 @@ grub_dl_load_segments (grub_dl_t mod, const Elf_Ehdr *e)
>>  	  mod->segment = seg;
>>  	}
>>      }
>> -#if !defined (__i386__) && !defined (__x86_64__)
>> +#if !defined (__i386__) && !defined (__x86_64__) && !defined(__riscv)
>>    ptr = (char *) ALIGN_UP ((grub_addr_t) ptr, GRUB_ARCH_DL_TRAMP_ALIGN);
>>    mod->tramp = ptr;
>>    mod->trampptr = ptr;
>> diff --git a/grub-core/kern/riscv/dl.c b/grub-core/kern/riscv/dl.c
>> new file mode 100644
>> index 000000000..503b67df1
>> --- /dev/null
>> +++ b/grub-core/kern/riscv/dl.c
>> @@ -0,0 +1,335 @@
>> +/* dl.c - arch-dependent part of loadable module support */
>> +/*
>> + *  GRUB  --  GRand Unified Bootloader
>> + *  Copyright (C) 2013  Free Software Foundation, Inc.
> 
> s/2013/2018/
> 
>> + *
>> + *  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/mm.h>
>> +#include <grub/i18n.h>
>> +
>> +#define LDR 0x58000050
>> +#define BR 0xd61f0200
>> +
>> +
> 
> Please drop this empty line.
> 
>> +/*
>> + * 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_DATA] != ELFDATA2LSB || e->e_machine != EM_RISCV)
>> +    return grub_error (GRUB_ERR_BAD_OS,
>> +		       N_("invalid arch-dependent ELF magic"));
>> +
>> +  return GRUB_ERR_NONE;
>> +}
>> +
>> +#pragma GCC diagnostic ignored "-Wcast-align"
> 
> Why? Could you add a comment here?

Mostly because all other targets have that as well?

I assume it's to silence warnings that the alignment could be mismatched
now, because offsets to elf data pointers could potentially be odd. In
practice, it never is though.

If I remove it, I get the following compile errors:

kern/riscv/dl.c: In function ‘grub_arch_dl_relocate_symbols’:
kern/riscv/dl.c:59:14: error: cast increases required alignment of
target type [-Werror=cast-align]
   for (rel = (Elf_Rel *) ((char *) ehdr + s->sh_offset),
              ^
kern/riscv/dl.c:60:9: error: cast increases required alignment of target
type [-Werror=cast-align]
   max = (Elf_Rel *) ((char *) rel + s->sh_size);
         ^
kern/riscv/dl.c:62:14: error: cast increases required alignment of
target type [-Werror=cast-align]
        rel = (Elf_Rel *) ((char *) rel + s->sh_entsize))
              ^
kern/riscv/dl.c:72:13: error: cast increases required alignment of
target type [-Werror=cast-align]
       sym = (Elf_Sym *) ((char *) mod->symtab
             ^
kern/riscv/dl.c:256:18: error: cast increases required alignment of
target type [-Werror=cast-align]
      for (rel2 = (Elf_Rela *) ((char *) rel - s->sh_entsize);
                  ^
kern/riscv/dl.c:258:14: error: cast increases required alignment of
target type [-Werror=cast-align]
       rel2 = (Elf_Rela *) ((char *) rel2 - s->sh_entsize))
              ^
kern/riscv/dl.c:275:14: error: cast increases required alignment of
target type [-Werror=cast-align]
       sym2 = (Elf_Sym *) ((char *) mod->symtab
              ^

> 
>> +/* Relocate symbols. */
>> +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;
>> +
>> +  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_size_t sym_addr;
>> +
>> +      if (rel->r_offset >= seg->size)
>> +	return grub_error (GRUB_ERR_BAD_MODULE,
>> +			   "reloc offset is out of 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_RISCV_32:
>> +	  {
>> +	    grub_uint32_t *abs_place = place;
>> +
>> +	    grub_dprintf ("dl", "  reloc_abs32 %p => 0x%016llx\n",
>> +			  place, (unsigned long long) sym_addr);
>> +
>> +	    *abs_place = (grub_uint32_t) sym_addr;
>> +	  }
>> +	  break;
>> +	case R_RISCV_64:
>> +	  {
>> +	    grub_size_t *abs_place = place;
>> +
>> +	    grub_dprintf ("dl", "  reloc_abs64 %p => 0x%016llx\n",
>> +			  place, (unsigned long long) sym_addr);
>> +
>> +	    *abs_place = (grub_size_t) sym_addr;
>> +	  }
>> +	  break;
>> +
>> +	case R_RISCV_ADD8:
>> +	  {
>> +	    grub_uint8_t *abs_place = place;
>> +
>> +	    *abs_place += (grub_uint8_t) sym_addr;
>> +	  }
>> +	  break;
>> +	case R_RISCV_ADD16:
>> +	  {
>> +	    grub_uint16_t *abs_place = place;
>> +
>> +	    *abs_place += (grub_uint16_t) sym_addr;
>> +	  }
>> +	  break;
>> +	case R_RISCV_ADD32:
>> +	  {
>> +	    grub_uint32_t *abs_place = place;
>> +
>> +	    *abs_place += (grub_uint32_t) sym_addr;
>> +	  }
>> +	  break;
>> +	case R_RISCV_ADD64:
>> +	  {
>> +	    grub_size_t *abs_place = place;
>> +
>> +	    *abs_place += (grub_size_t) sym_addr;
>> +	  }
>> +	  break;
>> +
>> +	case R_RISCV_SUB8:
>> +	  {
>> +	    grub_uint8_t *abs_place = place;
>> +
>> +	    *abs_place -= (grub_uint8_t) sym_addr;
>> +	  }
>> +	  break;
>> +	case R_RISCV_SUB16:
>> +	  {
>> +	    grub_uint16_t *abs_place = place;
>> +
>> +	    *abs_place -= (grub_uint16_t) sym_addr;
>> +	  }
>> +	  break;
>> +	case R_RISCV_SUB32:
>> +	  {
>> +	    grub_uint32_t *abs_place = place;
>> +
>> +	    *abs_place -= (grub_uint32_t) sym_addr;
>> +	  }
>> +	  break;
>> +	case R_RISCV_SUB64:
>> +	  {
>> +	    grub_size_t *abs_place = place;
>> +
>> +	    *abs_place -= (grub_size_t) sym_addr;
>> +	  }
>> +	  break;
>> +
>> +	case R_RISCV_BRANCH:
>> +	  {
>> +	    grub_uint32_t *abs_place = place;
>> +	    grub_ssize_t off = sym_addr - (grub_addr_t) place;
>> +	    grub_uint32_t imm12 = (off & 0x1000) << (31 - 12);
>> +	    grub_uint32_t imm11 = (off & 0x800) >> (11 - 7);
>> +	    grub_uint32_t imm10_5 = (off & 0x7e0) << (30 - 10);
>> +	    grub_uint32_t imm4_1 = (off & 0x1e) << (11 - 4);
>> +	    *abs_place = (*abs_place & 0x1fff07f)
>> +			 | imm12 | imm11 | imm10_5 | imm4_1;
> 
> Could not we use some constants instead of numbers here?
> If this does not make sense than please name the source of this numbers.

As Andreas already mentioned, these are just taken from the spec. I
agree that it looks quite unreadable, but putting the numbers into
constants would only make things worse I guess.

I'll add the spec reference into the head of this file.

> 
>> +	  }
>> +	  break;
>> +
>> +	case R_RISCV_JAL:
>> +	  {
>> +	    grub_uint32_t *abs_place = place;
>> +	    grub_ssize_t off = sym_addr - (grub_addr_t) place;
>> +	    grub_uint32_t imm20 = (off & 0x100000) << (31 - 20);
>> +	    grub_uint32_t imm19_12 = (off & 0xff000);
>> +	    grub_uint32_t imm11 = (off & 0x800) << (20 - 11);
>> +	    grub_uint32_t imm10_1 = (off & 0x7fe) << (30 - 10);
>> +	    *abs_place = (*abs_place & 0xfff)
>> +			 | imm20 | imm19_12 | imm11 | imm10_1;
> 
> Ditto.
> 
>> +	  }
>> +	  break;
>> +
>> +	case R_RISCV_CALL:
>> +	  {
>> +	    grub_uint32_t *abs_place = place;
>> +	    grub_ssize_t off = sym_addr - (grub_addr_t) place;
>> +	    grub_uint32_t hi20, lo12;
>> +
>> +	    if (off != (grub_int32_t) off)
>> +	      return grub_error (GRUB_ERR_BAD_MODULE, "relocation overflow");
>> +
>> +	    hi20 = (off + 0x800) & 0xfffff000;
>> +	    lo12 = (off - hi20) & 0xfff;
>> +	    abs_place[0] = (abs_place[0] & 0xfff) | hi20;
>> +	    abs_place[1] = (abs_place[1] & 0xfffff) | (lo12 << 20);
> 
> Ditto and below...
> 
>> +	  }
>> +	  break;
>> +
>> +	case R_RISCV_RVC_BRANCH:
>> +	  {
>> +	    grub_uint16_t *abs_place = place;
>> +	    grub_ssize_t off = sym_addr - (grub_addr_t) place;
>> +	    grub_uint16_t imm8 = (off & 0x100) << (12 - 8);
>> +	    grub_uint16_t imm7_6 = (off & 0xc0) >> (6 - 5);
>> +	    grub_uint16_t imm5 = (off & 0x20) >> (5 - 2);
>> +	    grub_uint16_t imm4_3 = (off & 0x18) << (12 - 5);
>> +	    grub_uint16_t imm2_1 = (off & 0x6) << (12 - 10);
>> +	    *abs_place = (*abs_place & 0xe383)
>> +			 | imm8 | imm7_6 | imm5 | imm4_3 | imm2_1;
>> +	  }
>> +	  break;
>> +
>> +	case R_RISCV_RVC_JUMP:
>> +	  {
>> +	    grub_uint16_t *abs_place = place;
>> +	    grub_ssize_t off = sym_addr - (grub_addr_t) place;
>> +	    grub_uint16_t imm11 = (off & 0x800) << (12 - 11);
>> +	    grub_uint16_t imm10 = (off & 0x400) >> (10 - 8);
>> +	    grub_uint16_t imm9_8 = (off & 0x300) << (12 - 11);
>> +	    grub_uint16_t imm7 = (off & 0x80) >> (7 - 6);
>> +	    grub_uint16_t imm6 = (off & 0x40) << (12 - 11);
>> +	    grub_uint16_t imm5 = (off & 0x20) >> (5 - 2);
>> +	    grub_uint16_t imm4 = (off & 0x10) << (12 - 5);
>> +	    grub_uint16_t imm3_1 = (off & 0xe) << (12 - 10);
>> +	    *abs_place = ((*abs_place & 0xe003)
>> +			  | imm11 | imm10 | imm9_8 | imm7 | imm6
>> +			  | imm5 | imm4 | imm3_1);
>> +	  }
>> +	  break;
>> +
>> +	case R_RISCV_PCREL_HI20:
>> +	  {
>> +	    grub_uint32_t *abs_place = place;
>> +	    grub_ssize_t off = sym_addr - (grub_addr_t) place;
>> +	    grub_int32_t hi20;
>> +
>> +	    if (off != (grub_int32_t)off)
>> +	      return grub_error (GRUB_ERR_BAD_MODULE, "relocation overflow");
>> +
>> +	    hi20 = (off + 0x800) & 0xfffff000;
>> +	    *abs_place = (*abs_place & 0xfff) | hi20;
>> +	  }
>> +	break;
>> +
>> +	case R_RISCV_PCREL_LO12_I:
>> +	case R_RISCV_PCREL_LO12_S:
>> +	  {
>> +	    grub_uint32_t *t32 = place;
>> +	    Elf_Rela *rel2;
>> +	    /* Search backwards for matching HI20 reloc.  */
> 
> Why "backwards"?

Because then the chance is higher that we hit a matching relocation
quickly :).


Alex
diff mbox series

Patch

diff --git a/grub-core/kern/dl.c b/grub-core/kern/dl.c
index f8d58f029..48eb5e7b6 100644
--- a/grub-core/kern/dl.c
+++ b/grub-core/kern/dl.c
@@ -225,7 +225,7 @@  grub_dl_load_segments (grub_dl_t mod, const Elf_Ehdr *e)
   unsigned i;
   const Elf_Shdr *s;
   grub_size_t tsize = 0, talign = 1;
-#if !defined (__i386__) && !defined (__x86_64__)
+#if !defined (__i386__) && !defined (__x86_64__) && !defined(__riscv)
   grub_size_t tramp;
   grub_size_t got;
   grub_err_t err;
@@ -241,7 +241,7 @@  grub_dl_load_segments (grub_dl_t mod, const Elf_Ehdr *e)
 	talign = s->sh_addralign;
     }
 
-#if !defined (__i386__) && !defined (__x86_64__)
+#if !defined (__i386__) && !defined (__x86_64__) && !defined(__riscv)
   err = grub_arch_dl_get_tramp_got_size (e, &tramp, &got);
   if (err)
     return err;
@@ -304,7 +304,7 @@  grub_dl_load_segments (grub_dl_t mod, const Elf_Ehdr *e)
 	  mod->segment = seg;
 	}
     }
-#if !defined (__i386__) && !defined (__x86_64__)
+#if !defined (__i386__) && !defined (__x86_64__) && !defined(__riscv)
   ptr = (char *) ALIGN_UP ((grub_addr_t) ptr, GRUB_ARCH_DL_TRAMP_ALIGN);
   mod->tramp = ptr;
   mod->trampptr = ptr;
diff --git a/grub-core/kern/riscv/dl.c b/grub-core/kern/riscv/dl.c
new file mode 100644
index 000000000..503b67df1
--- /dev/null
+++ b/grub-core/kern/riscv/dl.c
@@ -0,0 +1,335 @@ 
+/* dl.c - arch-dependent part of loadable module support */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2013  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/mm.h>
+#include <grub/i18n.h>
+
+#define LDR 0x58000050
+#define BR 0xd61f0200
+
+
+/*
+ * 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_DATA] != ELFDATA2LSB || e->e_machine != EM_RISCV)
+    return grub_error (GRUB_ERR_BAD_OS,
+		       N_("invalid arch-dependent ELF magic"));
+
+  return GRUB_ERR_NONE;
+}
+
+#pragma GCC diagnostic ignored "-Wcast-align"
+
+/* Relocate symbols. */
+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;
+
+  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_size_t sym_addr;
+
+      if (rel->r_offset >= seg->size)
+	return grub_error (GRUB_ERR_BAD_MODULE,
+			   "reloc offset is out of 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_RISCV_32:
+	  {
+	    grub_uint32_t *abs_place = place;
+
+	    grub_dprintf ("dl", "  reloc_abs32 %p => 0x%016llx\n",
+			  place, (unsigned long long) sym_addr);
+
+	    *abs_place = (grub_uint32_t) sym_addr;
+	  }
+	  break;
+	case R_RISCV_64:
+	  {
+	    grub_size_t *abs_place = place;
+
+	    grub_dprintf ("dl", "  reloc_abs64 %p => 0x%016llx\n",
+			  place, (unsigned long long) sym_addr);
+
+	    *abs_place = (grub_size_t) sym_addr;
+	  }
+	  break;
+
+	case R_RISCV_ADD8:
+	  {
+	    grub_uint8_t *abs_place = place;
+
+	    *abs_place += (grub_uint8_t) sym_addr;
+	  }
+	  break;
+	case R_RISCV_ADD16:
+	  {
+	    grub_uint16_t *abs_place = place;
+
+	    *abs_place += (grub_uint16_t) sym_addr;
+	  }
+	  break;
+	case R_RISCV_ADD32:
+	  {
+	    grub_uint32_t *abs_place = place;
+
+	    *abs_place += (grub_uint32_t) sym_addr;
+	  }
+	  break;
+	case R_RISCV_ADD64:
+	  {
+	    grub_size_t *abs_place = place;
+
+	    *abs_place += (grub_size_t) sym_addr;
+	  }
+	  break;
+
+	case R_RISCV_SUB8:
+	  {
+	    grub_uint8_t *abs_place = place;
+
+	    *abs_place -= (grub_uint8_t) sym_addr;
+	  }
+	  break;
+	case R_RISCV_SUB16:
+	  {
+	    grub_uint16_t *abs_place = place;
+
+	    *abs_place -= (grub_uint16_t) sym_addr;
+	  }
+	  break;
+	case R_RISCV_SUB32:
+	  {
+	    grub_uint32_t *abs_place = place;
+
+	    *abs_place -= (grub_uint32_t) sym_addr;
+	  }
+	  break;
+	case R_RISCV_SUB64:
+	  {
+	    grub_size_t *abs_place = place;
+
+	    *abs_place -= (grub_size_t) sym_addr;
+	  }
+	  break;
+
+	case R_RISCV_BRANCH:
+	  {
+	    grub_uint32_t *abs_place = place;
+	    grub_ssize_t off = sym_addr - (grub_addr_t) place;
+	    grub_uint32_t imm12 = (off & 0x1000) << (31 - 12);
+	    grub_uint32_t imm11 = (off & 0x800) >> (11 - 7);
+	    grub_uint32_t imm10_5 = (off & 0x7e0) << (30 - 10);
+	    grub_uint32_t imm4_1 = (off & 0x1e) << (11 - 4);
+	    *abs_place = (*abs_place & 0x1fff07f)
+			 | imm12 | imm11 | imm10_5 | imm4_1;
+	  }
+	  break;
+
+	case R_RISCV_JAL:
+	  {
+	    grub_uint32_t *abs_place = place;
+	    grub_ssize_t off = sym_addr - (grub_addr_t) place;
+	    grub_uint32_t imm20 = (off & 0x100000) << (31 - 20);
+	    grub_uint32_t imm19_12 = (off & 0xff000);
+	    grub_uint32_t imm11 = (off & 0x800) << (20 - 11);
+	    grub_uint32_t imm10_1 = (off & 0x7fe) << (30 - 10);
+	    *abs_place = (*abs_place & 0xfff)
+			 | imm20 | imm19_12 | imm11 | imm10_1;
+	  }
+	  break;
+
+	case R_RISCV_CALL:
+	  {
+	    grub_uint32_t *abs_place = place;
+	    grub_ssize_t off = sym_addr - (grub_addr_t) place;
+	    grub_uint32_t hi20, lo12;
+
+	    if (off != (grub_int32_t) off)
+	      return grub_error (GRUB_ERR_BAD_MODULE, "relocation overflow");
+
+	    hi20 = (off + 0x800) & 0xfffff000;
+	    lo12 = (off - hi20) & 0xfff;
+	    abs_place[0] = (abs_place[0] & 0xfff) | hi20;
+	    abs_place[1] = (abs_place[1] & 0xfffff) | (lo12 << 20);
+	  }
+	  break;
+
+	case R_RISCV_RVC_BRANCH:
+	  {
+	    grub_uint16_t *abs_place = place;
+	    grub_ssize_t off = sym_addr - (grub_addr_t) place;
+	    grub_uint16_t imm8 = (off & 0x100) << (12 - 8);
+	    grub_uint16_t imm7_6 = (off & 0xc0) >> (6 - 5);
+	    grub_uint16_t imm5 = (off & 0x20) >> (5 - 2);
+	    grub_uint16_t imm4_3 = (off & 0x18) << (12 - 5);
+	    grub_uint16_t imm2_1 = (off & 0x6) << (12 - 10);
+	    *abs_place = (*abs_place & 0xe383)
+			 | imm8 | imm7_6 | imm5 | imm4_3 | imm2_1;
+	  }
+	  break;
+
+	case R_RISCV_RVC_JUMP:
+	  {
+	    grub_uint16_t *abs_place = place;
+	    grub_ssize_t off = sym_addr - (grub_addr_t) place;
+	    grub_uint16_t imm11 = (off & 0x800) << (12 - 11);
+	    grub_uint16_t imm10 = (off & 0x400) >> (10 - 8);
+	    grub_uint16_t imm9_8 = (off & 0x300) << (12 - 11);
+	    grub_uint16_t imm7 = (off & 0x80) >> (7 - 6);
+	    grub_uint16_t imm6 = (off & 0x40) << (12 - 11);
+	    grub_uint16_t imm5 = (off & 0x20) >> (5 - 2);
+	    grub_uint16_t imm4 = (off & 0x10) << (12 - 5);
+	    grub_uint16_t imm3_1 = (off & 0xe) << (12 - 10);
+	    *abs_place = ((*abs_place & 0xe003)
+			  | imm11 | imm10 | imm9_8 | imm7 | imm6
+			  | imm5 | imm4 | imm3_1);
+	  }
+	  break;
+
+	case R_RISCV_PCREL_HI20:
+	  {
+	    grub_uint32_t *abs_place = place;
+	    grub_ssize_t off = sym_addr - (grub_addr_t) place;
+	    grub_int32_t hi20;
+
+	    if (off != (grub_int32_t)off)
+	      return grub_error (GRUB_ERR_BAD_MODULE, "relocation overflow");
+
+	    hi20 = (off + 0x800) & 0xfffff000;
+	    *abs_place = (*abs_place & 0xfff) | hi20;
+	  }
+	break;
+
+	case R_RISCV_PCREL_LO12_I:
+	case R_RISCV_PCREL_LO12_S:
+	  {
+	    grub_uint32_t *t32 = place;
+	    Elf_Rela *rel2;
+	    /* Search backwards for matching HI20 reloc.  */
+	    for (rel2 = (Elf_Rela *) ((char *) rel - s->sh_entsize);
+		    (unsigned long)rel2 >= ((unsigned long)ehdr + s->sh_offset);
+		    rel2 = (Elf_Rela *) ((char *) rel2 - s->sh_entsize))
+	      {
+		Elf_Addr rel2_info;
+		Elf_Addr rel2_offset;
+		Elf_Addr rel2_sym_addr;
+		Elf_Addr rel2_loc;
+		grub_ssize_t rel2_off;
+		grub_ssize_t off;
+		Elf_Sym *sym2;
+
+		rel2_offset = rel2->r_offset;
+		rel2_info = rel2->r_info;
+		rel2_loc = (grub_addr_t) seg->addr + rel2_offset;
+
+		if (ELF_R_TYPE (rel2_info) == R_RISCV_PCREL_HI20
+		    && rel2_loc == sym_addr)
+		  {
+		    sym2 = (Elf_Sym *) ((char *) mod->symtab
+				+ mod->symsize * ELF_R_SYM (rel2->r_info));
+		    rel2_sym_addr = sym2->st_value;
+		    if (s->sh_type == SHT_RELA)
+		      rel2_sym_addr += ((Elf_Rela *) rel2)->r_addend;
+
+		    rel2_off = rel2_sym_addr - rel2_loc;
+		    off = rel2_off - ((rel2_off + 0x800) & 0xfffff000);
+
+		    if (ELF_R_TYPE (rel->r_info) == R_RISCV_PCREL_LO12_I)
+		      *t32 = (*t32 & 0xfffff) | (off & 0xfff) << 20;
+		    else
+		      {
+			grub_uint32_t imm11_5 = (off & 0xfe0) << (31 - 11);
+			grub_uint32_t imm4_0 = (off & 0x1f) << (11 - 4);
+			*t32 = (*t32 & 0x1fff07f) | imm11_5 | imm4_0;
+		      }
+		    break;
+		  }
+	      }
+	    if ((unsigned long)rel2 < ((unsigned long)ehdr + s->sh_offset))
+	      return grub_error (GRUB_ERR_BAD_MODULE, "cannot find matching HI20 relocation");
+	  }
+	  break;
+
+	case R_RISCV_HI20:
+	  {
+	    grub_uint32_t *abs_place = place;
+	    *abs_place = (*abs_place & 0xfff) |
+			 (((grub_int32_t) sym_addr + 0x800) & 0xfffff000);
+	  }
+	  break;
+
+	case R_RISCV_LO12_I:
+	  {
+	    grub_uint32_t *abs_place = place;
+	    grub_int32_t lo12 = (grub_int32_t) sym_addr -
+				(((grub_int32_t) sym_addr + 0x800) & 0xfffff000);
+	    *abs_place = (*abs_place & 0xfffff) | ((lo12 & 0xfff) << 20);
+	  }
+	  break;
+
+	case R_RISCV_LO12_S:
+	  {
+	    grub_uint32_t *abs_place = place;
+	    grub_int32_t lo12 = (grub_int32_t) sym_addr -
+				(((grub_int32_t) sym_addr + 0x800) & 0xfffff000);
+	    grub_uint32_t imm11_5 = (lo12 & 0xfe0) << (31 - 11);
+	    grub_uint32_t imm4_0 = (lo12 & 0x1f) << (11 - 4);
+	    *abs_place = (*abs_place & 0x1fff07f) | imm11_5 | imm4_0;
+	  }
+	  break;
+
+	case R_RISCV_RELAX:
+	  break;
+	default:
+	  return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
+			     N_("relocation 0x%x is not implemented yet"),
+			     ELF_R_TYPE (rel->r_info));
+	}
+    }
+
+  return GRUB_ERR_NONE;
+}
diff --git a/include/grub/dl.h b/include/grub/dl.h
index fee27a14c..f03c03561 100644
--- a/include/grub/dl.h
+++ b/include/grub/dl.h
@@ -292,12 +292,14 @@  grub_arch_dl_get_tramp_got_size (const void *ehdr, grub_size_t *tramp,
 				 grub_size_t *got);
 #endif
 
-#if defined (__powerpc__) || defined (__mips__) || defined (__arm__)
+#if defined (__powerpc__) || defined (__mips__) || defined (__arm__) || \
+    (defined(__riscv) && (__riscv_xlen == 32))
 #define GRUB_ARCH_DL_TRAMP_ALIGN 4
 #define GRUB_ARCH_DL_GOT_ALIGN 4
 #endif
 
-#if defined (__aarch64__) || defined (__sparc__)
+#if defined (__aarch64__) || defined (__sparc__) || \
+    (defined(__riscv) && (__riscv_xlen == 64))
 #define GRUB_ARCH_DL_TRAMP_ALIGN 8
 #define GRUB_ARCH_DL_GOT_ALIGN 8
 #endif
diff --git a/util/grub-mkimagexx.c b/util/grub-mkimagexx.c
index a483c674c..a94d03540 100644
--- a/util/grub-mkimagexx.c
+++ b/util/grub-mkimagexx.c
@@ -1188,6 +1188,205 @@  SUFFIX (relocate_addrs) (Elf_Ehdr *e, struct section_metadata *smd,
 		 break;
 	       }
 #endif /* MKIMAGE_ELF32 */
+	     case EM_RISCV:
+	       {
+		 grub_uint64_t *t64 = (grub_uint64_t *) target;
+		 grub_uint32_t *t32 = (grub_uint32_t *) target;
+		 grub_uint16_t *t16 = (grub_uint16_t *) target;
+		 grub_uint8_t *t8 = (grub_uint8_t *) target;
+		 grub_int64_t off = (long)sym_addr - target_section_addr - offset
+				    - image_target->vaddr_offset;
+
+		 sym_addr += addend;
+
+		 switch (ELF_R_TYPE (info))
+		   {
+		   case R_RISCV_ADD8:
+		     {
+		       *t8 = *t8 + sym_addr;
+		     }
+		     break;
+		   case R_RISCV_ADD16:
+		     {
+		       *t16 = grub_host_to_target16 (grub_target_to_host16 (*t16) + sym_addr);
+		     }
+		     break;
+		   case R_RISCV_32:
+		   case R_RISCV_ADD32:
+		     {
+		       *t32 = grub_host_to_target32 (grub_target_to_host32 (*t32) + sym_addr);
+		     }
+		     break;
+		   case R_RISCV_64:
+		   case R_RISCV_ADD64:
+		     {
+		       *t64 = grub_host_to_target64 (grub_target_to_host64 (*t64) + sym_addr);
+		     }
+		     break;
+
+		   case R_RISCV_SUB8:
+		     {
+		       *t8 = sym_addr - *t8;
+		     }
+		     break;
+		   case R_RISCV_SUB16:
+		     {
+		       *t16 = grub_host_to_target16 (grub_target_to_host16 (*t16) - sym_addr);
+		     }
+		     break;
+		   case R_RISCV_SUB32:
+		     {
+		       *t32 = grub_host_to_target32 (grub_target_to_host32 (*t32) - sym_addr);
+		     }
+		     break;
+		   case R_RISCV_SUB64:
+		     {
+		       *t64 = grub_host_to_target64 (grub_target_to_host64 (*t64) - sym_addr);
+		     }
+		     break;
+		   case R_RISCV_BRANCH:
+		     {
+		       grub_uint32_t imm12 = (off & 0x1000) << (31 - 12);
+		       grub_uint32_t imm11 = (off & 0x800) >> (11 - 7);
+		       grub_uint32_t imm10_5 = (off & 0x7e0) << (30 - 10);
+		       grub_uint32_t imm4_1 = (off & 0x1e) << (11 - 4);
+		       *t32 = grub_host_to_target32 ((grub_target_to_host32 (*t32) & 0x1fff07f)
+						     | imm12 | imm11 | imm10_5 | imm4_1);
+		     }
+		     break;
+		   case R_RISCV_JAL:
+		     {
+		       grub_uint32_t imm20 = (off & 0x100000) << (31 - 20);
+		       grub_uint32_t imm19_12 = (off & 0xff000);
+		       grub_uint32_t imm11 = (off & 0x800) << (20 - 11);
+		       grub_uint32_t imm10_1 = (off & 0x7fe) << (30 - 10);
+		       *t32 = grub_host_to_target32 ((grub_target_to_host32 (*t32) & 0xfff)
+						     | imm20 | imm19_12 | imm11 | imm10_1);
+		     }
+		     break;
+		   case R_RISCV_CALL:
+		     {
+		       grub_uint32_t hi20, lo12;
+
+		       if (off != (grub_int32_t)off)
+			 grub_util_error ("target %lx not reachable from pc=%lx", (long)sym_addr, (long)target);
+
+		       hi20 = (off + 0x800) & 0xfffff000;
+		       lo12 = (off - hi20) & 0xfff;
+		       t32[0] = grub_host_to_target32 ((grub_target_to_host32 (t32[0]) & 0xfff) | hi20);
+		       t32[1] = grub_host_to_target32 ((grub_target_to_host32 (t32[1]) & 0xfffff) | (lo12 << 20));
+		     }
+		     break;
+		   case R_RISCV_RVC_BRANCH:
+		     {
+		       grub_uint16_t imm8 = (off & 0x100) << (12 - 8);
+		       grub_uint16_t imm7_6 = (off & 0xc0) >> (6 - 5);
+		       grub_uint16_t imm5 = (off & 0x20) >> (5 - 2);
+		       grub_uint16_t imm4_3 = (off & 0x18) << (12 - 5);
+		       grub_uint16_t imm2_1 = (off & 0x6) << (12 - 10);
+		       *t16 = grub_host_to_target16 ((grub_target_to_host16 (*t16) & 0xe383)
+						     | imm8 | imm7_6 | imm5 | imm4_3 | imm2_1);
+		     }
+		     break;
+		   case R_RISCV_RVC_JUMP:
+		     {
+		       grub_uint16_t imm11 = (off & 0x800) << (12 - 11);
+		       grub_uint16_t imm10 = (off & 0x400) >> (10 - 8);
+		       grub_uint16_t imm9_8 = (off & 0x300) << (12 - 11);
+		       grub_uint16_t imm7 = (off & 0x80) >> (7 - 6);
+		       grub_uint16_t imm6 = (off & 0x40) << (12 - 11);
+		       grub_uint16_t imm5 = (off & 0x20) >> (5 - 2);
+		       grub_uint16_t imm4 = (off & 0x10) << (12 - 5);
+		       grub_uint16_t imm3_1 = (off & 0xe) << (12 - 10);
+		       *t16 = grub_host_to_target16 ((grub_target_to_host16 (*t16) & 0xe003)
+						     | imm11 | imm10 | imm9_8 | imm7 | imm6
+						     | imm5 | imm4 | imm3_1);
+		     }
+		     break;
+		   case R_RISCV_PCREL_HI20:
+		     {
+		       grub_int32_t hi20;
+
+		       if (off != (grub_int32_t)off)
+			 grub_util_error ("target %lx not reachable from pc=%lx", (long)sym_addr, (long)target);
+
+		       hi20 = (off + 0x800) & 0xfffff000;
+		       *t32 = grub_host_to_target32 ((grub_target_to_host32 (*t32) & 0xfff) | hi20);
+		     }
+		     break;
+		   case R_RISCV_PCREL_LO12_I:
+		   case R_RISCV_PCREL_LO12_S:
+		     {
+		       Elf_Rela *rel2;
+		       Elf_Word k;
+		       /* Search backwards for matching HI20 reloc.  */
+		       for (k = j, rel2 = (Elf_Rela *) ((char *) r - r_size);
+			    k > 0;
+			    k--, rel2 = (Elf_Rela *) ((char *) rel2 - r_size))
+			 {
+			   Elf_Addr rel2_info;
+			   Elf_Addr rel2_offset;
+			   Elf_Addr rel2_sym_addr;
+			   Elf_Addr rel2_addend;
+			   Elf_Addr rel2_loc;
+			   grub_int64_t rel2_off;
+
+			   rel2_offset = grub_target_to_host (rel2->r_offset);
+			   rel2_info = grub_target_to_host (rel2->r_info);
+			   rel2_loc = target_section_addr + rel2_offset + image_target->vaddr_offset;
+
+			   if (ELF_R_TYPE (rel2_info) == R_RISCV_PCREL_HI20
+			       && rel2_loc == sym_addr)
+			     {
+			       rel2_sym_addr = SUFFIX (get_symbol_address)
+				 (e, smd->symtab, ELF_R_SYM (rel2_info),
+				  image_target);
+			       rel2_addend = (s->sh_type == grub_target_to_host32 (SHT_RELA)) ?
+				 grub_target_to_host (rel2->r_addend) : 0;
+			       rel2_off = rel2_sym_addr + rel2_addend - rel2_loc;
+			       off = rel2_off - ((rel2_off + 0x800) & 0xfffff000);
+
+			       if (ELF_R_TYPE (info) == R_RISCV_PCREL_LO12_I)
+				 *t32 = grub_host_to_target32 ((grub_target_to_host32 (*t32) & 0xfffff) | (off & 0xfff) << 20);
+			       else
+				 {
+				   grub_uint32_t imm11_5 = (off & 0xfe0) << (31 - 11);
+				   grub_uint32_t imm4_0 = (off & 0x1f) << (11 - 4);
+				   *t32 = grub_host_to_target32 ((grub_target_to_host32 (*t32) & 0x1fff07f) | imm11_5 | imm4_0);
+				 }
+			       break;
+			     }
+			 }
+		       if (k == 0)
+			 grub_util_error ("cannot find matching HI20 relocation");
+		     }
+		     break;
+		   case R_RISCV_HI20:
+		     *t32 = grub_host_to_target32 ((grub_target_to_host32 (*t32) & 0xfff) | (((grub_int32_t) sym_addr + 0x800) & 0xfffff000));
+		     break;
+		   case R_RISCV_LO12_I:
+		     {
+		       grub_int32_t lo12 = (grub_int32_t) sym_addr - (((grub_int32_t) sym_addr + 0x800) & 0xfffff000);
+		       *t32 = grub_host_to_target32 ((grub_target_to_host32 (*t32) & 0xfffff) | ((lo12 & 0xfff) << 20));
+		     }
+		     break;
+		   case R_RISCV_LO12_S:
+		     {
+		       grub_int32_t lo12 = (grub_int32_t) sym_addr - (((grub_int32_t) sym_addr + 0x800) & 0xfffff000);
+		       grub_uint32_t imm11_5 = (lo12 & 0xfe0) << (31 - 11);
+		       grub_uint32_t imm4_0 = (lo12 & 0x1f) << (11 - 4);
+		       *t32 = grub_host_to_target32 ((grub_target_to_host32 (*t32) & 0x1fff07f) | imm11_5 | imm4_0);
+		     }
+		     break;
+		   case R_RISCV_RELAX:
+		     break;
+		   default:
+		     grub_util_error (_("relocation 0x%x is not implemented yet"),
+				      (unsigned int) ELF_R_TYPE (info));
+		     break;
+		   }
+	       break;
+	       }
 	     default:
 	       grub_util_error ("unknown architecture type %d",
 				image_target->elf_target);
@@ -1472,6 +1671,75 @@  translate_relocation_pe (struct translate_context *ctx,
 	}
       break;
 #endif /* defined(MKIMAGE_ELF32) */
+    case EM_RISCV:
+      switch (ELF_R_TYPE (info))
+	{
+	case R_RISCV_32:
+	  {
+	    ctx->current_address
+	      = add_fixup_entry (&ctx->lst,
+				 GRUB_PE32_REL_BASED_HIGHLOW,
+				 addr, 0, ctx->current_address,
+				 image_target);
+	  }
+	  break;
+	case R_RISCV_64:
+	  {
+	    ctx->current_address
+	      = add_fixup_entry (&ctx->lst,
+				 GRUB_PE32_REL_BASED_DIR64,
+				 addr, 0, ctx->current_address,
+				 image_target);
+	  }
+	  break;
+	  /* Relative relocations do not require fixup entries. */
+	case R_RISCV_BRANCH:
+	case R_RISCV_JAL:
+	case R_RISCV_CALL:
+	case R_RISCV_PCREL_HI20:
+	case R_RISCV_PCREL_LO12_I:
+	case R_RISCV_PCREL_LO12_S:
+	case R_RISCV_RVC_BRANCH:
+	case R_RISCV_RVC_JUMP:
+	case R_RISCV_ADD32:
+	case R_RISCV_SUB32:
+	  grub_util_info ("  %s:  not adding fixup: 0x%08x : 0x%08x", __FUNCTION__, (unsigned int) addr, (unsigned int) ctx->current_address);
+	  break;
+	case R_RISCV_HI20:
+	  {
+	    ctx->current_address
+	      = add_fixup_entry (&ctx->lst,
+				 GRUB_PE32_REL_BASED_RISCV_HI20,
+				 addr, 0, ctx->current_address,
+				 image_target);
+	  }
+	  break;
+	case R_RISCV_LO12_I:
+	  {
+	    ctx->current_address
+	      = add_fixup_entry (&ctx->lst,
+				 GRUB_PE32_REL_BASED_RISCV_LOW12I,
+				 addr, 0, ctx->current_address,
+				 image_target);
+	  }
+	  break;
+	case R_RISCV_LO12_S:
+	  {
+	    ctx->current_address
+	      = add_fixup_entry (&ctx->lst,
+				 GRUB_PE32_REL_BASED_RISCV_LOW12S,
+				 addr, 0, ctx->current_address,
+				 image_target);
+	  }
+	  break;
+	case R_RISCV_RELAX:
+	  break;
+	default:
+	  grub_util_error (_("relocation 0x%x is not implemented yet"),
+			   (unsigned int) ELF_R_TYPE (info));
+	  break;
+	}
+      break;
     default:
       grub_util_error ("unknown machine type 0x%x", image_target->elf_target);
     }
diff --git a/util/grub-module-verifier.c b/util/grub-module-verifier.c
index 03ba1ab43..7a32b010c 100644
--- a/util/grub-module-verifier.c
+++ b/util/grub-module-verifier.c
@@ -117,6 +117,62 @@  struct grub_module_verifier_arch archs[] = {
       R_AARCH64_LDST64_ABS_LO12_NC,
       R_AARCH64_PREL32,
       -1
+    } },
+  { "riscv32", 4, 0, EM_RISCV, GRUB_MODULE_VERIFY_SUPPORTS_REL | GRUB_MODULE_VERIFY_SUPPORTS_RELA, (int[]){
+      R_RISCV_32,
+      R_RISCV_64,
+      R_RISCV_ADD8,
+      R_RISCV_ADD16,
+      R_RISCV_ADD32,
+      R_RISCV_ADD64,
+      R_RISCV_SUB8,
+      R_RISCV_SUB16,
+      R_RISCV_SUB32,
+      R_RISCV_SUB64,
+      R_RISCV_ALIGN,
+      R_RISCV_BRANCH,
+      R_RISCV_CALL,
+      R_RISCV_CALL_PLT,
+      R_RISCV_GOT_HI20,
+      R_RISCV_HI20,
+      R_RISCV_JAL,
+      R_RISCV_LO12_I,
+      R_RISCV_LO12_S,
+      R_RISCV_PCREL_HI20,
+      R_RISCV_PCREL_LO12_I,
+      R_RISCV_PCREL_LO12_S,
+      R_RISCV_RELAX,
+      R_RISCV_RVC_BRANCH,
+      R_RISCV_RVC_JUMP,
+      -1
+    } },
+  { "riscv64", 8, 0, EM_RISCV, GRUB_MODULE_VERIFY_SUPPORTS_REL | GRUB_MODULE_VERIFY_SUPPORTS_RELA, (int[]){
+      R_RISCV_32,
+      R_RISCV_64,
+      R_RISCV_ADD8,
+      R_RISCV_ADD16,
+      R_RISCV_ADD32,
+      R_RISCV_ADD64,
+      R_RISCV_SUB8,
+      R_RISCV_SUB16,
+      R_RISCV_SUB32,
+      R_RISCV_SUB64,
+      R_RISCV_ALIGN,
+      R_RISCV_BRANCH,
+      R_RISCV_CALL,
+      R_RISCV_CALL_PLT,
+      R_RISCV_GOT_HI20,
+      R_RISCV_HI20,
+      R_RISCV_JAL,
+      R_RISCV_LO12_I,
+      R_RISCV_LO12_S,
+      R_RISCV_PCREL_HI20,
+      R_RISCV_PCREL_LO12_I,
+      R_RISCV_PCREL_LO12_S,
+      R_RISCV_RELAX,
+      R_RISCV_RVC_BRANCH,
+      R_RISCV_RVC_JUMP,
+      -1
     }
   },
 };