linux-kernel - [RFC PATCH 15/16] arm64/insn: always inline aarch64_insn_gen_load_acq_store

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Message-ID: <20250923174903.76283-16-ada.coupriediaz@arm.com>
Date: Tue, 23 Sep 2025 18:49:02 +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 15/16] arm64/insn: always inline aarch64_insn_gen_load_acq_store_rel()

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

This makes `aarch64_insn_gen_load_acq_store_rel()` safe for inlining
and usage from patching callbacks, as both
`aarch64_insn_encode_ldst_size()` 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 | 36 +++++++++++++++++++++++++++++++----
 arch/arm64/lib/insn.c         | 29 ----------------------------
 2 files changed, 32 insertions(+), 33 deletions(-)

diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h
index 46d4d452e2e2..b7abc9b3e74c 100644
--- a/arch/arm64/include/asm/insn.h
+++ b/arch/arm64/include/asm/insn.h
@@ -882,10 +882,38 @@ u32 aarch64_insn_gen_load_store_pair(enum aarch64_insn_register reg1,
 				     int offset,
 				     enum aarch64_insn_variant variant,
 				     enum aarch64_insn_ldst_type type);
-u32 aarch64_insn_gen_load_acq_store_rel(enum aarch64_insn_register reg,
-					enum aarch64_insn_register base,
-					enum aarch64_insn_size_type size,
-					enum aarch64_insn_ldst_type type);
+
+static __always_inline u32 aarch64_insn_gen_load_acq_store_rel(
+					 enum aarch64_insn_register reg,
+					 enum aarch64_insn_register base,
+					 enum aarch64_insn_size_type size,
+					 enum aarch64_insn_ldst_type type)
+{
+	compiletime_assert(type == AARCH64_INSN_LDST_LOAD_ACQ ||
+					type == AARCH64_INSN_LDST_STORE_REL,
+		"unknown load-acquire/store-release encoding");
+	u32 insn;
+
+	switch (type) {
+	case AARCH64_INSN_LDST_LOAD_ACQ:
+		insn = aarch64_insn_get_load_acq_value();
+		break;
+	case AARCH64_INSN_LDST_STORE_REL:
+		insn = aarch64_insn_get_store_rel_value();
+		break;
+	default:
+		return AARCH64_BREAK_FAULT;
+	}
+
+	insn = aarch64_insn_encode_ldst_size(size, insn);
+
+	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, insn,
+					    reg);
+
+	return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn,
+					    base);
+}
+
 u32 aarch64_insn_gen_load_store_ex(enum aarch64_insn_register reg,
 				   enum aarch64_insn_register base,
 				   enum aarch64_insn_register state,
diff --git a/arch/arm64/lib/insn.c b/arch/arm64/lib/insn.c
index 63564d236235..6ee298f96d47 100644
--- a/arch/arm64/lib/insn.c
+++ b/arch/arm64/lib/insn.c
@@ -328,35 +328,6 @@ u32 aarch64_insn_gen_load_store_pair(enum aarch64_insn_register reg1,
 					     offset >> shift);
 }
 
-u32 aarch64_insn_gen_load_acq_store_rel(enum aarch64_insn_register reg,
-					enum aarch64_insn_register base,
-					enum aarch64_insn_size_type size,
-					enum aarch64_insn_ldst_type type)
-{
-	u32 insn;
-
-	switch (type) {
-	case AARCH64_INSN_LDST_LOAD_ACQ:
-		insn = aarch64_insn_get_load_acq_value();
-		break;
-	case AARCH64_INSN_LDST_STORE_REL:
-		insn = aarch64_insn_get_store_rel_value();
-		break;
-	default:
-		pr_err("%s: unknown load-acquire/store-release encoding %d\n",
-		       __func__, type);
-		return AARCH64_BREAK_FAULT;
-	}
-
-	insn = aarch64_insn_encode_ldst_size(size, insn);
-
-	insn = aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, insn,
-					    reg);
-
-	return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RN, insn,
-					    base);
-}
-
 u32 aarch64_insn_gen_load_store_ex(enum aarch64_insn_register reg,
 				   enum aarch64_insn_register base,
 				   enum aarch64_insn_register state,
-- 
2.43.0