linux-kernel - [PATCH 5/8] arm64: insn: add encoder for MOV (register)

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Date:   Mon, 21 Oct 2019 17:34:23 +0100
From:   Mark Rutland <mark.rutland@....com>
To:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:     amit.kachhap@....com, ard.biesheuvel@...aro.org,
        catalin.marinas@....com, deller@....de, duwe@...e.de,
        james.morse@....com, jeyu@...nel.org, jpoimboe@...hat.com,
        jthierry@...hat.com, mark.rutland@....com, mingo@...hat.com,
        peterz@...radead.org, rostedt@...dmis.org, svens@...ckframe.org,
        takahiro.akashi@...aro.org, will@...nel.org
Subject: [PATCH 5/8] arm64: insn: add encoder for MOV (register)

For FTRACE_WITH_REGS, we're going to want to generate a MOV (register)
instruction as part of the callsite intialization. As MOV (register) is
an alias for ORR (shifted register), we can generate this with
aarch64_insn_gen_logical_shifted_reg(), but it's somewhat verbose and
difficult to read in-context.

Add a aarch64_insn_gen_move_reg() wrapper for this case so that we can
write callers in a more straightforward way.

Signed-off-by: Mark Rutland <mark.rutland@....com>
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will@...nel.org>
---
 arch/arm64/include/asm/insn.h |  3 +++
 arch/arm64/kernel/insn.c      | 13 +++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h
index 39e7780bedd6..bb313dde58a4 100644
--- a/arch/arm64/include/asm/insn.h
+++ b/arch/arm64/include/asm/insn.h
@@ -440,6 +440,9 @@ u32 aarch64_insn_gen_logical_shifted_reg(enum aarch64_insn_register dst,
 					 int shift,
 					 enum aarch64_insn_variant variant,
 					 enum aarch64_insn_logic_type type);
+u32 aarch64_insn_gen_move_reg(enum aarch64_insn_register dst,
+			      enum aarch64_insn_register src,
+			      enum aarch64_insn_variant variant);
 u32 aarch64_insn_gen_logical_immediate(enum aarch64_insn_logic_type type,
 				       enum aarch64_insn_variant variant,
 				       enum aarch64_insn_register Rn,
diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c
index d801a7094076..513b29c3e735 100644
--- a/arch/arm64/kernel/insn.c
+++ b/arch/arm64/kernel/insn.c
@@ -1268,6 +1268,19 @@ u32 aarch64_insn_gen_logical_shifted_reg(enum aarch64_insn_register dst,
 	return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_6, insn, shift);
 }
 
+/*
+ * MOV (register) is architecturally an alias of ORR (shifted register) where
+ * MOV <*d>, <*m> is equivalent to ORR <*d>, <*ZR>, <*m>
+ */
+u32 aarch64_insn_gen_move_reg(enum aarch64_insn_register dst,
+			      enum aarch64_insn_register src,
+			      enum aarch64_insn_variant variant)
+{
+	return aarch64_insn_gen_logical_shifted_reg(dst, AARCH64_INSN_REG_ZR,
+						    src, 0, variant,
+						    AARCH64_INSN_LOGIC_ORR);
+}
+
 u32 aarch64_insn_gen_adr(unsigned long pc, unsigned long addr,
 			 enum aarch64_insn_register reg,
 			 enum aarch64_insn_adr_type type)
-- 
2.11.0