loongarch: Add support for ELF psABI v1.00 relocations

This patch adds support of the stack-based LoongArch relocations
throughout GRUB, including tools, dynamic linkage, and support for
conversion of ELF relocations into PE ones. A stack machine is required
to handle these per the spec [1] (see the R_LARCH_SOP types), of which
a simple implementation is included.

These relocations are produced by binutils 2.38 and 2.39, while the newer
v2.00 relocs require more recent toolchain (binutils 2.40+ & gcc 13+, or
LLVM 16+). GCC 13 has not been officially released as of early 2023, so
support for v1.00 relocs are expected to stay relevant for a while.

[1] https://loongson.github.io/LoongArch-Documentation/LoongArch-ELF-ABI-EN.html#_relocations

Signed-off-by: Zhou Yang <zhouyang@loongson.cn>
Signed-off-by: Xiaotian Wu <wuxiaotian@loongson.cn>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Wentao Guan <guanwentao@uniontech.com>

GRUB2/MOD_SRC/grub-2.04/grub-core/kern/dl.c

@@ -225,7 +225,8 @@ 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__) && !defined(__riscv)
+#if !defined (__i386__) && !defined (__x86_64__) && !defined(__riscv) && \
+  !defined (__loongarch__)
   grub_size_t tramp;
   grub_size_t got;
   grub_err_t err;
@@ -241,7 +242,8 @@ grub_dl_load_segments (grub_dl_t mod, const Elf_Ehdr *e)
 	talign = s->sh_addralign;
     }
 
-#if !defined (__i386__) && !defined (__x86_64__) && !defined(__riscv)
+#if !defined (__i386__) && !defined (__x86_64__) && !defined(__riscv) && \
+  !defined (__loongarch__)
   err = grub_arch_dl_get_tramp_got_size (e, &tramp, &got);
   if (err)
     return err;
@@ -304,7 +306,8 @@ grub_dl_load_segments (grub_dl_t mod, const Elf_Ehdr *e)
 	  mod->segment = seg;
 	}
     }
-#if !defined (__i386__) && !defined (__x86_64__) && !defined(__riscv)
+#if !defined (__i386__) && !defined (__x86_64__) && !defined(__riscv) && \
+  !defined (__loongarch__)
   ptr = (char *) ALIGN_UP ((grub_addr_t) ptr, GRUB_ARCH_DL_TRAMP_ALIGN);
   mod->tramp = ptr;
   mod->trampptr = ptr;

GRUB2/MOD_SRC/grub-2.04/grub-core/kern/loongarch64/dl.c

@@ -0,0 +1,102 @@
+/*
+ *  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;
+      grub_uint64_t *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 = (grub_uint64_t *) ((grub_addr_t) seg->addr + rel->r_offset);
+
+      switch (ELF_R_TYPE (rel->r_info))
+	{
+	case R_LARCH_64:
+	  *place = 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;
+	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;
+}

GRUB2/MOD_SRC/grub-2.04/grub-core/kern/loongarch64/dl_helper.c

@@ -0,0 +1,201 @@
+/*
+ *  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/mm.h>
+#include <grub/i18n.h>
+#include <grub/loongarch64/reloc.h>
+
+static void grub_loongarch64_stack_push (grub_loongarch64_stack_t stack, grub_uint64_t x);
+static grub_uint64_t grub_loongarch64_stack_pop (grub_loongarch64_stack_t stack);
+
+void
+grub_loongarch64_stack_init (grub_loongarch64_stack_t stack)
+{
+  stack->top = -1;
+  stack->count = LOONGARCH64_STACK_MAX;
+}
+
+static void
+grub_loongarch64_stack_push (grub_loongarch64_stack_t stack, grub_uint64_t x)
+{
+  if (stack->top == stack->count)
+    return;
+  stack->data[++stack->top] = x;
+}
+
+static grub_uint64_t
+grub_loongarch64_stack_pop (grub_loongarch64_stack_t stack)
+{
+  if (stack->top == -1)
+    return -1;
+  return stack->data[stack->top--];
+}
+
+void
+grub_loongarch64_sop_push (grub_loongarch64_stack_t stack, grub_int64_t offset)
+{
+  grub_loongarch64_stack_push (stack, offset);
+}
+
+/* opr2 = pop (), opr1 = pop (), push (opr1 - opr2) */
+void
+grub_loongarch64_sop_sub (grub_loongarch64_stack_t stack)
+{
+  grub_uint64_t a, b;
+  b = grub_loongarch64_stack_pop (stack);
+  a = grub_loongarch64_stack_pop (stack);
+  grub_loongarch64_stack_push (stack, a - b);
+}
+
+/* opr2 = pop (), opr1 = pop (), push (opr1 << opr2) */
+void
+grub_loongarch64_sop_sl (grub_loongarch64_stack_t stack)
+{
+  grub_uint64_t a, b;
+  b = grub_loongarch64_stack_pop (stack);
+  a = grub_loongarch64_stack_pop (stack);
+  grub_loongarch64_stack_push (stack, a << b);
+}
+
+/* opr2 = pop (), opr1 = pop (), push (opr1 >> opr2) */
+void
+grub_loongarch64_sop_sr (grub_loongarch64_stack_t stack)
+{
+  grub_uint64_t a, b;
+  b = grub_loongarch64_stack_pop (stack);
+  a = grub_loongarch64_stack_pop (stack);
+  grub_loongarch64_stack_push (stack, a >> b);
+}
+
+/* opr2 = pop (), opr1 = pop (), push (opr1 + opr2) */
+void
+grub_loongarch64_sop_add (grub_loongarch64_stack_t stack)
+{
+  grub_uint64_t a, b;
+  b = grub_loongarch64_stack_pop (stack);
+  a = grub_loongarch64_stack_pop (stack);
+  grub_loongarch64_stack_push (stack, a + b);
+}
+
+/* opr2 = pop (), opr1 = pop (), push (opr1 & opr2) */
+void
+grub_loongarch64_sop_and (grub_loongarch64_stack_t stack)
+{
+  grub_uint64_t a, b;
+  b = grub_loongarch64_stack_pop (stack);
+  a = grub_loongarch64_stack_pop (stack);
+  grub_loongarch64_stack_push (stack, a & b);
+}
+
+/* opr3 = pop (), opr2 = pop (), opr1 = pop (), push (opr1 ? opr2 : opr3) */
+void
+grub_loongarch64_sop_if_else (grub_loongarch64_stack_t stack)
+{
+  grub_uint64_t a, b, c;
+  c = grub_loongarch64_stack_pop (stack);
+  b = grub_loongarch64_stack_pop (stack);
+  a = grub_loongarch64_stack_pop (stack);
+
+  if (a) {
+      grub_loongarch64_stack_push (stack, b);
+  } else {
+      grub_loongarch64_stack_push (stack, c);
+  }
+}
+
+/* opr1 = pop (), (*(uint32_t *) PC) [14 ... 10] = opr1 [4 ... 0] */
+void
+grub_loongarch64_sop_32_s_10_5 (grub_loongarch64_stack_t stack,
+				grub_uint64_t *place)
+{
+  grub_uint64_t a = grub_loongarch64_stack_pop (stack);
+  *place |= ((a & 0x1f) << 10);
+}
+
+/* opr1 = pop (), (*(uint32_t *) PC) [21 ... 10] = opr1 [11 ... 0] */
+void
+grub_loongarch64_sop_32_u_10_12 (grub_loongarch64_stack_t stack,
+				 grub_uint64_t *place)
+{
+  grub_uint64_t a = grub_loongarch64_stack_pop (stack);
+  *place = *place | ((a & 0xfff) << 10);
+}
+
+/* opr1 = pop (), (*(uint32_t *) PC) [21 ... 10] = opr1 [11 ... 0] */
+void
+grub_loongarch64_sop_32_s_10_12 (grub_loongarch64_stack_t stack,
+				 grub_uint64_t *place)
+{
+  grub_uint64_t a = grub_loongarch64_stack_pop (stack);
+  *place = (*place) | ((a & 0xfff) << 10);
+}
+
+/* opr1 = pop (), (*(uint32_t *) PC) [25 ... 10] = opr1 [15 ... 0] */
+void
+grub_loongarch64_sop_32_s_10_16 (grub_loongarch64_stack_t stack,
+				 grub_uint64_t *place)
+{
+  grub_uint64_t a = grub_loongarch64_stack_pop (stack);
+  *place = (*place) | ((a & 0xffff) << 10);
+}
+
+/* opr1 = pop (), (*(uint32_t *) PC) [25 ... 10] = opr1 [17 ... 2] */
+void
+grub_loongarch64_sop_32_s_10_16_s2 (grub_loongarch64_stack_t stack,
+				    grub_uint64_t *place)
+{
+  grub_uint64_t a = grub_loongarch64_stack_pop (stack);
+  *place = (*place) | (((a >> 2) & 0xffff) << 10);
+}
+
+/* opr1 = pop (), (*(uint32_t *) PC) [24 ... 5] = opr1 [19 ... 0] */
+void
+grub_loongarch64_sop_32_s_5_20 (grub_loongarch64_stack_t stack, grub_uint64_t *place)
+{
+  grub_uint64_t a = grub_loongarch64_stack_pop (stack);
+  *place = (*place) | ((a & 0xfffff)<<5);
+}
+
+/* opr1 = pop (), (*(uint32_t *) PC) [4 ... 0] = opr1 [22 ... 18] */
+void
+grub_loongarch64_sop_32_s_0_5_10_16_s2 (grub_loongarch64_stack_t stack,
+					grub_uint64_t *place)
+{
+  grub_uint64_t a = grub_loongarch64_stack_pop (stack);
+
+  *place =(*place) | (((a >> 2) & 0xffff) << 10);
+  *place =(*place) | ((a >> 18) & 0x1f);
+}
+
+/*
+ * opr1 = pop ()
+ * (*(uint32_t *) PC) [9 ... 0] = opr1 [27 ... 18],
+ * (*(uint32_t *) PC) [25 ... 10] = opr1 [17 ... 2]
+ */
+void
+grub_loongarch64_sop_32_s_0_10_10_16_s2 (grub_loongarch64_stack_t stack,
+					 grub_uint64_t *place)
+{
+  grub_uint64_t a = grub_loongarch64_stack_pop (stack);
+  *place =(*place) | (((a >> 2) & 0xffff) << 10);
+  *place =(*place) | ((a >> 18) & 0x3ff);
+}