arch/x86_64: add basic support for R_X86_64_REX_GOTPCRELX relocation

GOTPCRELX reloc available only for CONFIG_ARCH_ADDRENV=y

when CONFIG_ARCH_ADDRENV is not set, CONFIG_ARCH_TEXT_VBASE is not specified
so we can't relocate

Signed-off-by: p-szafonimateusz <p-szafonimateusz@xiaomi.com>

arch/x86_64/include/elf.h

@@ -32,6 +32,7 @@
 #define R_X86_64_32             10
 #define R_X86_64_32S            11
 #define R_X86_64_PC64           24
+#define R_X86_64_REX_GOTPCRELX  42
 
 /* 4.3.1 ELF Identification.  Should have:
  *

libs/libc/machine/x86_64/arch_elf64.c

@@ -37,6 +37,13 @@
 
 #include <nuttx/elf.h>
 
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#define OPCODE_MOV    0x8b
+#define OPCODE_LEA    0x8d
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -174,6 +181,26 @@ int up_relocateadd(const Elf64_Rela *rel, const Elf64_Sym *sym,
 
         *(uint32_t *)addr = value;
         break;
+#ifdef CONFIG_ARCH_ADDRENV
+      case R_X86_64_REX_GOTPCRELX:
+
+        /* Handle like R_X86_64_PC32 but with load offset */
+
+        value = (sym->st_value + rel->r_addend - addr +
+                 CONFIG_ARCH_TEXT_VBASE);
+
+        /* Convert MOV to LEA - other relocations not suported */
+
+        if (*(uint8_t *)(addr - 2) != OPCODE_MOV)
+          {
+            berr("ERROR: not supported REX_GOTPCRELX relocation\n");
+            return -EINVAL;
+          }
+
+        *(uint8_t *)(addr - 2) = OPCODE_LEA;
+        *(uint32_t *)(addr)    = value;
+        break;
+#endif
       default:
         berr("ERROR: Unsupported relocation: %d\n", relotype);
         return -EINVAL;