linux-kernel - [RFC PATCH 11/16] arm64/insn: always inline aarch64_insn_gen

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Message-ID: <20250923174903.76283-12-ada.coupriediaz@arm.com>
Date: Tue, 23 Sep 2025 18:48:58 +0100
From: Ada Couprie Diaz <ada.coupriediaz@....com>
To: linux-arm-kernel@...ts.infradead.org
Cc: Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>,
	Marc Zyngier <maz@...nel.org>,
	Oliver Upton <oliver.upton@...ux.dev>,
	Ard Biesheuvel <ardb@...nel.org>,
	Joey Gouly <joey.gouly@....com>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Zenghui Yu <yuzenghui@...wei.com>,
	Andrey Ryabinin <ryabinin.a.a@...il.com>,
	Alexander Potapenko <glider@...gle.com>,
	Andrey Konovalov <andreyknvl@...il.com>,
	Dmitry Vyukov <dvyukov@...gle.com>,
	Vincenzo Frascino <vincenzo.frascino@....com>,
	linux-kernel@...r.kernel.org,
	kvmarm@...ts.linux.dev,
	kasan-dev@...glegroups.com,
	Mark Rutland <mark.rutland@....com>,
	Ada Couprie Diaz <ada.coupriediaz@....com>
Subject: [RFC PATCH 11/16] arm64/insn: always inline aarch64_insn_gen_extr()

As it is always called with an explicit variant, we can check for
its validity at compile time and remove the runtime error print.

This makes `aarch64_insn_gen_extr()` safe for inlining
and usage from patching callbacks, as both
`aarch64_insn_encode_immediate()` and `aarch64_insn_encode_register()`
have been made safe in previous commits.

Signed-off-by: Ada Couprie Diaz <ada.coupriediaz@....com>
---
 arch/arm64/include/asm/insn.h | 39 ++++++++++++++++++++++++++++++-----
 arch/arm64/lib/insn.c         | 32 ----------------------------
 2 files changed, 34 insertions(+), 37 deletions(-)

diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h
index 6e6a53d4d750..4ba4d5c50137 100644
--- a/arch/arm64/include/asm/insn.h
+++ b/arch/arm64/include/asm/insn.h
@@ -1111,12 +1111,41 @@ static __always_inline u32 aarch64_insn_gen_logical_immediate(
 	return aarch64_encode_immediate(imm, variant, insn);
 }
 
+static __always_inline u32 aarch64_insn_gen_extr(
+			 enum aarch64_insn_variant variant,
+			 enum aarch64_insn_register Rm,
+			 enum aarch64_insn_register Rn,
+			 enum aarch64_insn_register Rd,
+			 u8 lsb)
+{
+	compiletime_assert(variant == AARCH64_INSN_VARIANT_32BIT ||
+		variant == AARCH64_INSN_VARIANT_64BIT,
+		"unknown variant encoding");
+	u32 insn;
+
+	insn = aarch64_insn_get_extr_value();
+
+	switch (variant) {
+	case AARCH64_INSN_VARIANT_32BIT:
+		if (lsb > 31)
+			return AARCH64_BREAK_FAULT;
+		break;
+	case AARCH64_INSN_VARIANT_64BIT:
+		if (lsb > 63)
+			return AARCH64_BREAK_FAULT;
+		insn |= AARCH64_INSN_SF_BIT;
+		insn = aarch64_insn_encode_immediate(AARCH64_INSN_IMM_N, insn, 1);
+		break;
+	default:
+		return AARCH64_BREAK_FAULT;
+	}
+
+	insn = aarch64_insn_encode_immediate(AARCH64_INSN_IMM_S, insn, lsb);
+	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, Rd);
+	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, Rn);
+	return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RM, insn, Rm);
+}
 
-u32 aarch64_insn_gen_extr(enum aarch64_insn_variant variant,
-			  enum aarch64_insn_register Rm,
-			  enum aarch64_insn_register Rn,
-			  enum aarch64_insn_register Rd,
-			  u8 lsb);
 #ifdef CONFIG_ARM64_LSE_ATOMICS
 u32 aarch64_insn_gen_atomic_ld_op(enum aarch64_insn_register result,
 				  enum aarch64_insn_register address,
diff --git a/arch/arm64/lib/insn.c b/arch/arm64/lib/insn.c
index 8d38bf4bf203..71df4d72ac81 100644
--- a/arch/arm64/lib/insn.c
+++ b/arch/arm64/lib/insn.c
@@ -1021,38 +1021,6 @@ u32 aarch32_insn_mcr_extract_crm(u32 insn)
 	return insn & CRM_MASK;
 }
 
-u32 aarch64_insn_gen_extr(enum aarch64_insn_variant variant,
-			  enum aarch64_insn_register Rm,
-			  enum aarch64_insn_register Rn,
-			  enum aarch64_insn_register Rd,
-			  u8 lsb)
-{
-	u32 insn;
-
-	insn = aarch64_insn_get_extr_value();
-
-	switch (variant) {
-	case AARCH64_INSN_VARIANT_32BIT:
-		if (lsb > 31)
-			return AARCH64_BREAK_FAULT;
-		break;
-	case AARCH64_INSN_VARIANT_64BIT:
-		if (lsb > 63)
-			return AARCH64_BREAK_FAULT;
-		insn |= AARCH64_INSN_SF_BIT;
-		insn = aarch64_insn_encode_immediate(AARCH64_INSN_IMM_N, insn, 1);
-		break;
-	default:
-		pr_err("%s: unknown variant encoding %d\n", __func__, variant);
-		return AARCH64_BREAK_FAULT;
-	}
-
-	insn = aarch64_insn_encode_immediate(AARCH64_INSN_IMM_S, insn, lsb);
-	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RD, insn, Rd);
-	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn, Rn);
-	return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RM, insn, Rm);
-}
-
 static u32 __get_barrier_crm_val(enum aarch64_insn_mb_type type)
 {
 	switch (type) {
-- 
2.43.0