KVM: arm64: Move __smccc_workaround_1_smc to .rodata

This snippet of assembly is used by cpu_errata.c to overwrite parts of KVM hyp
vector. Move it to its own source file and change its ELF section to .rodata.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200625131420.71444-3-dbrazdil@google.com

arch/arm64/kvm/hyp/Makefile

@@ -7,6 +7,7 @@ ccflags-y += -fno-stack-protector -DDISABLE_BRANCH_PROFILING \
 		$(DISABLE_STACKLEAK_PLUGIN)
 
 obj-$(CONFIG_KVM) += hyp.o
+obj-$(CONFIG_KVM_INDIRECT_VECTORS) += smccc_wa.o
 
 hyp-y := vgic-v3-sr.o timer-sr.o aarch32.o vgic-v2-cpuif-proxy.o sysreg-sr.o \
 	 debug-sr.o entry.o switch.o fpsimd.o tlb.o hyp-entry.o

arch/arm64/kvm/hyp/hyp-entry.S

@@ -318,20 +318,4 @@ SYM_CODE_START(__bp_harden_hyp_vecs)
 1:	.org __bp_harden_hyp_vecs + __BP_HARDEN_HYP_VECS_SZ
 	.org 1b
 SYM_CODE_END(__bp_harden_hyp_vecs)
-
-	.popsection
-
-SYM_CODE_START(__smccc_workaround_1_smc)
-	esb
-	sub	sp, sp, #(8 * 4)
-	stp	x2, x3, [sp, #(8 * 0)]
-	stp	x0, x1, [sp, #(8 * 2)]
-	mov	w0, #ARM_SMCCC_ARCH_WORKAROUND_1
-	smc	#0
-	ldp	x2, x3, [sp, #(8 * 0)]
-	ldp	x0, x1, [sp, #(8 * 2)]
-	add	sp, sp, #(8 * 4)
-1:	.org __smccc_workaround_1_smc + __SMCCC_WORKAROUND_1_SMC_SZ
-	.org 1b
-SYM_CODE_END(__smccc_workaround_1_smc)
 #endif

arch/arm64/kvm/hyp/smccc_wa.S

+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2015-2018 - ARM Ltd
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/linkage.h>
+
+#include <asm/kvm_asm.h>
+#include <asm/kvm_mmu.h>
+
+	/*
+	 * This is not executed directly and is instead copied into the vectors
+	 * by install_bp_hardening_cb().
+	 */
+	.data
+	.pushsection	.rodata
+	.global		__smccc_workaround_1_smc
+SYM_DATA_START(__smccc_workaround_1_smc)
+	esb
+	sub	sp, sp, #(8 * 4)
+	stp	x2, x3, [sp, #(8 * 0)]
+	stp	x0, x1, [sp, #(8 * 2)]
+	mov	w0, #ARM_SMCCC_ARCH_WORKAROUND_1
+	smc	#0
+	ldp	x2, x3, [sp, #(8 * 0)]
+	ldp	x0, x1, [sp, #(8 * 2)]
+	add	sp, sp, #(8 * 4)
+1:	.org __smccc_workaround_1_smc + __SMCCC_WORKAROUND_1_SMC_SZ
+	.org 1b
+SYM_DATA_END(__smccc_workaround_1_smc)