Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Julien Thierry <jthierry@redhat.com>
To:     linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc:     catalin.marinas@arm.com, will@kernel.org, ardb@kernel.org,
        masahiroy@kernel.org, keescook@chromium.org,
        michal.lkml@markovi.net, jpoimboe@redhat.com, peterz@infradead.org,
        mark.rutland@arm.com, broonie@kernel.org,
        linux-efi@vger.kernel.org, linux-hardening@vger.kernel.org,
        Julien Thierry <jthierry@redhat.com>
Subject: [RFC PATCH 06/17] objtool: arm64: Decode jump and call related instructions
Date:   Wed, 20 Jan 2021 18:37:49 +0100
Message-Id: <20210120173800.1660730-7-jthierry@redhat.com>
In-Reply-To: <20210120173800.1660730-1-jthierry@redhat.com>
References: <20210120173800.1660730-1-jthierry@redhat.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Decode branch, branch and link (aarch64's call) and return instructions.

Signed-off-by: Julien Thierry <jthierry@redhat.com>
---
 tools/objtool/arch/arm64/decode.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/tools/objtool/arch/arm64/decode.c b/tools/objtool/arch/arm64/decode.c
index 0f312dd1b146..924121b4b466 100644
--- a/tools/objtool/arch/arm64/decode.c
+++ b/tools/objtool/arch/arm64/decode.c
@@ -205,6 +205,28 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec,
 		}
 		*type = INSN_OTHER;
 		break;
+	case AARCH64_INSN_CLS_BR_SYS:
+		if (aarch64_insn_is_ret(insn) &&
+		    aarch64_insn_decode_register(AARCH64_INSN_REGTYPE_RN, insn) == AARCH64_INSN_REG_LR) {
+			*type = INSN_RETURN;
+		} else if (aarch64_insn_is_bl(insn)) {
+			*type = INSN_CALL;
+			*immediate = aarch64_get_branch_offset(insn);
+		} else if (aarch64_insn_is_blr(insn)) {
+			*type = INSN_CALL_DYNAMIC;
+		} else if (aarch64_insn_is_b(insn)) {
+			*type = INSN_JUMP_UNCONDITIONAL;
+			*immediate = aarch64_get_branch_offset(insn);
+		} else if (aarch64_insn_is_br(insn)) {
+			*type = INSN_JUMP_DYNAMIC;
+		} else if (aarch64_insn_is_branch_imm(insn)) {
+			/* Remaining branch opcodes are conditional */
+			*type = INSN_JUMP_CONDITIONAL;
+			*immediate = aarch64_get_branch_offset(insn);
+		} else {
+			*type = INSN_OTHER;
+		}
+		break;
 	default:
 		*type = INSN_OTHER;
 		break;
-- 
2.25.4