kpatch/LoongArch: Add initial support for kpatch

Add initial support for LoongArch.

Signed-off-by: George Guo <[email protected]>

Author: georgejguo

kpatch-build/create-diff-object.c

@@ -180,6 +180,8 @@ static bool is_gcc6_localentry_bundled_sym(struct kpatch_elf *kelf,
 		return false;
 	case S390:
 		return false;
+	case LOONGARCH64:
+		return false;
 	default:
 		ERROR("unsupported arch");
 	}
@@ -694,6 +696,11 @@ static bool insn_is_load_immediate(struct kpatch_elf *kelf, void *addr)
 
 		break;
 
+	case LOONGARCH64:
+		/* to be done */
+
+		break;
+
 	case S390:
 		/* arg2: lghi %r3, imm */
 		if (insn[0] == 0xa7 && insn[1] == 0x39)
@@ -2420,22 +2427,22 @@ static bool static_call_sites_group_filter(struct lookup_table *lookup,
 static struct special_section special_sections[] = {
 	{
 		.name		= "__bug_table",
-		.arch		= X86_64 | PPC64 | S390,
+		.arch		= X86_64 | PPC64 | S390 | LOONGARCH64,
 		.group_size	= bug_table_group_size,
 	},
 	{
 		.name		= ".fixup",
-		.arch		= X86_64 | PPC64 | S390,
+		.arch		= X86_64 | PPC64 | S390 | LOONGARCH64,
 		.group_size	= fixup_group_size,
 	},
 	{
 		.name		= "__ex_table", /* must come after .fixup */
-		.arch		= X86_64 | PPC64 | S390,
+		.arch		= X86_64 | PPC64 | S390 | LOONGARCH64,
 		.group_size	= ex_table_group_size,
 	},
 	{
 		.name		= "__jump_table",
-		.arch		= X86_64 | PPC64 | S390,
+		.arch		= X86_64 | PPC64 | S390 | LOONGARCH64,
 		.group_size	= jump_table_group_size,
 		.group_filter	= jump_table_group_filter,
 	},
@@ -2456,7 +2463,7 @@ static struct special_section special_sections[] = {
 	},
 	{
 		.name		= ".altinstructions",
-		.arch		= X86_64 | S390,
+		.arch		= X86_64 | S390 | LOONGARCH64,
 		.group_size	= altinstructions_group_size,
 	},
 	{

kpatch-build/kpatch-elf.c

@@ -142,6 +142,8 @@ unsigned int absolute_rela_type(struct kpatch_elf *kelf)
 		return R_X86_64_64;
 	case S390:
 		return R_390_64;
+	case LOONGARCH64:
+		return R_LARCH_64;
 	default:
 		ERROR("unsupported arch");
 	}
@@ -206,6 +208,7 @@ long rela_target_offset(struct kpatch_elf *kelf, struct section *relasec,
 
 	switch(kelf->arch) {
 	case PPC64:
+	case LOONGARCH64:
 		add_off = 0;
 		break;
 	case X86_64:
@@ -261,6 +264,7 @@ unsigned int insn_length(struct kpatch_elf *kelf, void *addr)
 		return decoded_insn.length;
 
 	case PPC64:
+	case LOONGARCH64:
 		return 4;
 
 	case S390:
@@ -593,6 +597,9 @@ struct kpatch_elf *kpatch_elf_open(const char *name)
 	case EM_S390:
 		kelf->arch = S390;
 		break;
+	case EM_LOONGARCH:
+		kelf->arch = LOONGARCH64;
+		break;
 	default:
 		ERROR("Unsupported target architecture");
 	}

kpatch-build/kpatch-elf.h

@@ -116,6 +116,7 @@ enum architecture {
 	PPC64  = 0x1 << 0,
 	X86_64 = 0x1 << 1,
 	S390   = 0x1 << 2,
+	LOONGARCH64 = 0x1 << 3,
 };
 
 struct kpatch_elf {