[PATCH v2 11/12] objtool: Introduce objtool for arm64

[Josh Poimboeuf <jpoimboe@kernel.org>]

Add basic support for arm64 on objtool.  Only --checksum is currently
supported.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 arch/arm64/Kconfig                            |   2 +
 tools/objtool/Makefile                        |   4 +
 tools/objtool/arch/arm64/Build                |   2 +
 tools/objtool/arch/arm64/decode.c             | 116 ++++++++++++++++++
 .../arch/arm64/include/arch/cfi_regs.h        |  11 ++
 tools/objtool/arch/arm64/include/arch/elf.h   |  13 ++
 .../objtool/arch/arm64/include/arch/special.h |  21 ++++
 tools/objtool/arch/arm64/special.c            |  21 ++++
 8 files changed, 190 insertions(+)
 create mode 100644 tools/objtool/arch/arm64/Build
 create mode 100644 tools/objtool/arch/arm64/decode.c
 create mode 100644 tools/objtool/arch/arm64/include/arch/cfi_regs.h
 create mode 100644 tools/objtool/arch/arm64/include/arch/elf.h
 create mode 100644 tools/objtool/arch/arm64/include/arch/special.h
 create mode 100644 tools/objtool/arch/arm64/special.c

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 38dba5f7e4d2..354aa80c5b4b 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -236,9 +236,11 @@ config ARM64
 	select HAVE_HW_BREAKPOINT if PERF_EVENTS
 	select HAVE_IOREMAP_PROT
 	select HAVE_IRQ_TIME_ACCOUNTING
+	select HAVE_KLP_BUILD
 	select HAVE_LIVEPATCH
 	select HAVE_MOD_ARCH_SPECIFIC
 	select HAVE_NMI
+	select HAVE_OBJTOOL
 	select HAVE_PERF_EVENTS
 	select HAVE_PERF_EVENTS_NMI if ARM64_PSEUDO_NMI
 	select HAVE_PERF_REGS
diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index b71d1886022e..66b04172b79a 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -11,6 +11,10 @@ ifeq ($(SRCARCH),loongarch)
 	BUILD_ORC	   := y
 endif
 
+ifeq ($(SRCARCH),arm64)
+	ARCH_HAS_KLP := y
+endif
+
 ifeq ($(ARCH_HAS_KLP),y)
 	HAVE_XXHASH = $(shell printf "$(pound)include <xxhash.h>\nXXH3_state_t *state;int main() {}" | \
 		      $(HOSTCC) $(HOSTCFLAGS) -xc - -o /dev/null -lxxhash 2> /dev/null && echo y || echo n)
diff --git a/tools/objtool/arch/arm64/Build b/tools/objtool/arch/arm64/Build
new file mode 100644
index 000000000000..d24d5636a5b8
--- /dev/null
+++ b/tools/objtool/arch/arm64/Build
@@ -0,0 +1,2 @@
+objtool-y += decode.o
+objtool-y += special.o
diff --git a/tools/objtool/arch/arm64/decode.c b/tools/objtool/arch/arm64/decode.c
new file mode 100644
index 000000000000..ee93c096243f
--- /dev/null
+++ b/tools/objtool/arch/arm64/decode.c
@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <objtool/check.h>
+#include <objtool/disas.h>
+#include <objtool/elf.h>
+#include <objtool/arch.h>
+#include <objtool/warn.h>
+#include <objtool/builtin.h>
+
+const char *arch_reg_name[CFI_NUM_REGS] = {};
+
+int arch_ftrace_match(const char *name)
+{
+	return 0;
+}
+
+s64 arch_insn_adjusted_addend(struct instruction *insn, struct reloc *reloc)
+{
+	return reloc_addend(reloc);
+}
+
+bool arch_callee_saved_reg(unsigned char reg)
+{
+	return false;
+}
+
+int arch_decode_hint_reg(u8 sp_reg, int *base)
+{
+	exit(-1);
+}
+
+const char *arch_nop_insn(int len)
+{
+	exit(-1);
+}
+
+const char *arch_ret_insn(int len)
+{
+	exit(-1);
+}
+
+int arch_decode_instruction(struct objtool_file *file, const struct section *sec,
+			    unsigned long offset, unsigned int maxlen,
+			    struct instruction *insn)
+{
+	u32 i = *((u32 *)(sec->data->d_buf + offset));
+
+	insn->len = 4;
+
+	/*
+	 * These are the bare minimum needed for static branch detection and
+	 * checksum calculations.
+	 */
+	if (i == 0xd503201f || i == 0x2a1f03f7) {
+		/* For static branches */
+		insn->type = INSN_NOP;
+	} else if ((i & 0xfc000000) == 0x14000000) {
+		/* For static branches and intra-TU sibling calls */
+		insn->type = INSN_JUMP_UNCONDITIONAL;
+		insn->immediate = sign_extend64(i & 0x03ffffff, 25);
+	} else if ((i & 0xfc000000) == 0x94000000) {
+		/* For intra-TU calls */
+		insn->type = INSN_CALL;
+		insn->immediate = sign_extend64(i & 0x03ffffff, 25);
+	} else if ((i & 0xff000000) == 0x54000000) {
+		/* For intra-TU conditional sibling calls */
+		insn->type = INSN_JUMP_CONDITIONAL;
+		insn->immediate = sign_extend64((i & 0xffffe0) >> 5, 18);
+	} else {
+		insn->type = INSN_OTHER;
+	}
+
+	return 0;
+}
+
+u64 arch_adjusted_addend(struct reloc *reloc)
+{
+	return reloc_addend(reloc);
+}
+
+unsigned long arch_jump_destination(struct instruction *insn)
+{
+	return insn->offset + (insn->immediate << 2);
+}
+
+bool arch_pc_relative_reloc(struct reloc *reloc)
+{
+	return false;
+}
+
+void arch_initial_func_cfi_state(struct cfi_init_state *state)
+{
+	state->cfa.base = CFI_UNDEFINED;
+}
+
+unsigned int arch_reloc_size(struct reloc *reloc)
+{
+	switch (reloc_type(reloc)) {
+	case R_AARCH64_ABS64:
+	case R_AARCH64_PREL64:
+		return 8;
+	default:
+		return 4;
+	}
+}
+
+#ifdef DISAS
+int arch_disas_info_init(struct disassemble_info *dinfo)
+{
+	return disas_info_init(dinfo, bfd_arch_aarch64,
+			       bfd_mach_arm_unknown, bfd_mach_aarch64,
+			       NULL);
+}
+#endif /* DISAS */
diff --git a/tools/objtool/arch/arm64/include/arch/cfi_regs.h b/tools/objtool/arch/arm64/include/arch/cfi_regs.h
new file mode 100644
index 000000000000..49c81cbb6646
--- /dev/null
+++ b/tools/objtool/arch/arm64/include/arch/cfi_regs.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _OBJTOOL_ARCH_CFI_REGS_H
+#define _OBJTOOL_ARCH_CFI_REGS_H
+
+/* These aren't actually used for arm64 */
+#define CFI_BP 0
+#define CFI_SP 0
+#define CFI_RA 0
+#define CFI_NUM_REGS 2
+
+#endif /* _OBJTOOL_ARCH_CFI_REGS_H */
diff --git a/tools/objtool/arch/arm64/include/arch/elf.h b/tools/objtool/arch/arm64/include/arch/elf.h
new file mode 100644
index 000000000000..80a1bc479930
--- /dev/null
+++ b/tools/objtool/arch/arm64/include/arch/elf.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _OBJTOOL_ARCH_ELF_H
+#define _OBJTOOL_ARCH_ELF_H
+
+#define R_NONE		R_AARCH64_NONE
+#define R_ABS64		R_AARCH64_ABS64
+#define R_ABS32		R_AARCH64_ABS32
+#define R_DATA32	R_AARCH64_PREL32
+#define R_DATA64	R_AARCH64_PREL64
+#define R_TEXT32	R_AARCH64_PREL32
+#define R_TEXT64	R_AARCH64_PREL64
+
+#endif /* _OBJTOOL_ARCH_ELF_H */
diff --git a/tools/objtool/arch/arm64/include/arch/special.h b/tools/objtool/arch/arm64/include/arch/special.h
new file mode 100644
index 000000000000..8ae804a83ea4
--- /dev/null
+++ b/tools/objtool/arch/arm64/include/arch/special.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _OBJTOOL_ARCH_SPECIAL_H
+#define _OBJTOOL_ARCH_SPECIAL_H
+
+#define EX_ENTRY_SIZE 12
+#define EX_ORIG_OFFSET 0
+#define EX_NEW_OFFSET 4
+
+#define JUMP_ENTRY_SIZE 16
+#define JUMP_ORIG_OFFSET 0
+#define JUMP_NEW_OFFSET 4
+#define JUMP_KEY_OFFSET 8
+
+#define ALT_ENTRY_SIZE 12
+#define ALT_ORIG_OFFSET 0
+#define ALT_NEW_OFFSET 4
+#define ALT_FEATURE_OFFSET 8
+#define ALT_ORIG_LEN_OFFSET 10
+#define ALT_NEW_LEN_OFFSET 11
+
+#endif /* _OBJTOOL_ARCH_SPECIAL_H */
diff --git a/tools/objtool/arch/arm64/special.c b/tools/objtool/arch/arm64/special.c
new file mode 100644
index 000000000000..3c2b83d94939
--- /dev/null
+++ b/tools/objtool/arch/arm64/special.c
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <objtool/special.h>
+
+bool arch_support_alt_relocation(struct special_alt *special_alt,
+				 struct instruction *insn,
+				 struct reloc *reloc)
+{
+	return false;
+}
+
+struct reloc *arch_find_switch_table(struct objtool_file *file,
+				     struct instruction *insn,
+				     unsigned long *table_size)
+{
+	return NULL;
+}
+
+const char *arch_cpu_feature_name(int feature_number)
+{
+	return NULL;
+}
-- 
2.53.0