--- a/pr/include/md/_linux.cfg
+++ b/pr/include/md/_linux.cfg
@@ -1107,16 +1107,61 @@
 #define PR_ALIGN_OF_FLOAT   4
 #define PR_ALIGN_OF_DOUBLE  8
 #define PR_ALIGN_OF_POINTER 8
 #define PR_ALIGN_OF_WORD    8
 
 #define PR_BYTES_PER_WORD_LOG2  3
 #define PR_BYTES_PER_DWORD_LOG2 3
 
+#elif defined(__arc__)
+
+#define IS_LITTLE_ENDIAN 1
+#undef  IS_BIG_ENDIAN
+
+#define PR_BYTES_PER_BYTE   1
+#define PR_BYTES_PER_SHORT  2
+#define PR_BYTES_PER_INT    4
+#define PR_BYTES_PER_INT64  8
+#define PR_BYTES_PER_LONG   4
+#define PR_BYTES_PER_FLOAT  4
+#define PR_BYTES_PER_DOUBLE 8
+#define PR_BYTES_PER_WORD   4
+#define PR_BYTES_PER_DWORD  8
+
+#define PR_BITS_PER_BYTE    8
+#define PR_BITS_PER_SHORT   16
+#define PR_BITS_PER_INT     32
+#define PR_BITS_PER_INT64   64
+#define PR_BITS_PER_LONG    32
+#define PR_BITS_PER_FLOAT   32
+#define PR_BITS_PER_DOUBLE  64
+#define PR_BITS_PER_WORD    32
+
+#define PR_BITS_PER_BYTE_LOG2   3
+#define PR_BITS_PER_SHORT_LOG2  4
+#define PR_BITS_PER_INT_LOG2    5
+#define PR_BITS_PER_INT64_LOG2  6
+#define PR_BITS_PER_LONG_LOG2   5
+#define PR_BITS_PER_FLOAT_LOG2  5
+#define PR_BITS_PER_DOUBLE_LOG2 6
+#define PR_BITS_PER_WORD_LOG2   5
+
+#define PR_ALIGN_OF_SHORT   2
+#define PR_ALIGN_OF_INT     4
+#define PR_ALIGN_OF_LONG    4
+#define PR_ALIGN_OF_INT64   4
+#define PR_ALIGN_OF_FLOAT   4
+#define PR_ALIGN_OF_DOUBLE  4
+#define PR_ALIGN_OF_POINTER 4
+#define PR_ALIGN_OF_WORD    4
+
+#define PR_BYTES_PER_WORD_LOG2   2
+#define PR_BYTES_PER_DWORD_LOG2  3
+
 #else
 
 #error "Unknown CPU architecture"
 
 #endif
 
 #ifndef HAVE_LONG_LONG
 #define	HAVE_LONG_LONG

--- a/pr/include/md/_linux.h
+++ b/pr/include/md/_linux.h
@@ -56,16 +56,18 @@
 #elif defined(__m32r__)
 #define _PR_SI_ARCHITECTURE "m32r"
 #elif defined(__or1k__)
 #define _PR_SI_ARCHITECTURE "or1k"
 #elif defined(__riscv) && (__riscv_xlen == 32)
 #define _PR_SI_ARCHITECTURE "riscv32"
 #elif defined(__riscv) && (__riscv_xlen == 64)
 #define _PR_SI_ARCHITECTURE "riscv64"
+#elif defined(__arc__)
+#define _PR_SI_ARCHITECTURE "arc"
 #else
 #error "Unknown CPU architecture"
 #endif
 #define PR_DLL_SUFFIX		".so"
 
 #define _PR_VMBASE              0x30000000
 #define _PR_STACK_VMBASE	0x50000000
 #define _MD_DEFAULT_STACK_SIZE	65536L