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Subject[PATCH 4.4 26/75] ARM: 8479/2: add implementation for arm-smccc
Date
From: Jens Wiklander <jens.wiklander@linaro.org>

Commit b329f95d70f3f955093e9a2b18ac1ed3587a8f73 upstream.

Adds implementation for arm-smccc and enables CONFIG_HAVE_SMCCC for
architectures that may support arm-smccc. It's the responsibility of the
caller to know if the SMC instruction is supported by the platform.

Reviewed-by: Lars Persson <lars.persson@axis.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/arm/Kconfig | 1
arch/arm/kernel/Makefile | 2 +
arch/arm/kernel/armksyms.c | 6 ++++
arch/arm/kernel/smccc-call.S | 62 +++++++++++++++++++++++++++++++++++++++++++
4 files changed, 71 insertions(+)

--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -37,6 +37,7 @@ config ARM
select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32
select HAVE_ARCH_SECCOMP_FILTER if (AEABI && !OABI_COMPAT)
select HAVE_ARCH_TRACEHOOK
+ select HAVE_ARM_SMCCC if CPU_V7
select HAVE_BPF_JIT
select HAVE_CC_STACKPROTECTOR
select HAVE_CONTEXT_TRACKING
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -91,4 +91,6 @@ obj-y += psci-call.o
obj-$(CONFIG_SMP) += psci_smp.o
endif

+obj-$(CONFIG_HAVE_ARM_SMCCC) += smccc-call.o
+
extra-y := $(head-y) vmlinux.lds
--- a/arch/arm/kernel/armksyms.c
+++ b/arch/arm/kernel/armksyms.c
@@ -16,6 +16,7 @@
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include <linux/io.h>
+#include <linux/arm-smccc.h>

#include <asm/checksum.h>
#include <asm/ftrace.h>
@@ -175,3 +176,8 @@ EXPORT_SYMBOL(__gnu_mcount_nc);
EXPORT_SYMBOL(__pv_phys_pfn_offset);
EXPORT_SYMBOL(__pv_offset);
#endif
+
+#ifdef CONFIG_HAVE_ARM_SMCCC
+EXPORT_SYMBOL(arm_smccc_smc);
+EXPORT_SYMBOL(arm_smccc_hvc);
+#endif
--- /dev/null
+++ b/arch/arm/kernel/smccc-call.S
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2015, Linaro Limited
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/linkage.h>
+
+#include <asm/opcodes-sec.h>
+#include <asm/opcodes-virt.h>
+#include <asm/unwind.h>
+
+ /*
+ * Wrap c macros in asm macros to delay expansion until after the
+ * SMCCC asm macro is expanded.
+ */
+ .macro SMCCC_SMC
+ __SMC(0)
+ .endm
+
+ .macro SMCCC_HVC
+ __HVC(0)
+ .endm
+
+ .macro SMCCC instr
+UNWIND( .fnstart)
+ mov r12, sp
+ push {r4-r7}
+UNWIND( .save {r4-r7})
+ ldm r12, {r4-r7}
+ \instr
+ pop {r4-r7}
+ ldr r12, [sp, #(4 * 4)]
+ stm r12, {r0-r3}
+ bx lr
+UNWIND( .fnend)
+ .endm
+
+/*
+ * void smccc_smc(unsigned long a0, unsigned long a1, unsigned long a2,
+ * unsigned long a3, unsigned long a4, unsigned long a5,
+ * unsigned long a6, unsigned long a7, struct arm_smccc_res *res)
+ */
+ENTRY(arm_smccc_smc)
+ SMCCC SMCCC_SMC
+ENDPROC(arm_smccc_smc)
+
+/*
+ * void smccc_hvc(unsigned long a0, unsigned long a1, unsigned long a2,
+ * unsigned long a3, unsigned long a4, unsigned long a5,
+ * unsigned long a6, unsigned long a7, struct arm_smccc_res *res)
+ */
+ENTRY(arm_smccc_hvc)
+ SMCCC SMCCC_HVC
+ENDPROC(arm_smccc_hvc)

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