[PATCH 2/4] ARM: Add smc call support

Sascha Hauer s.hauer at pengutronix.de
Tue Feb 7 00:43:25 PST 2017 

Taken from the Kernel: A wrapper to make a smc call from C.

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 arch/arm/cpu/Makefile            |   2 +
 arch/arm/cpu/smccc-call.S        |  64 ++++++++++++++++++++++++
 arch/arm/include/asm/arm-smccc.h | 104 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 170 insertions(+)
 create mode 100644 arch/arm/cpu/smccc-call.S
 create mode 100644 arch/arm/include/asm/arm-smccc.h

diff --git a/arch/arm/cpu/Makefile b/arch/arm/cpu/Makefile
index d8cb1871a..e542f1741 100644
--- a/arch/arm/cpu/Makefile
+++ b/arch/arm/cpu/Makefile
@@ -34,6 +34,8 @@ ifeq ($(CONFIG_MMU),)
 obj-y += no-mmu.o
 endif
 
+obj-$(CONFIG_ARM_SECURE_MONITOR) += smccc-call.o
+
 obj-$(CONFIG_CPU_32v4T) += cache-armv4.o
 pbl-$(CONFIG_CPU_32v4T) += cache-armv4.o
 obj-$(CONFIG_CPU_32v5) += cache-armv5.o
diff --git a/arch/arm/cpu/smccc-call.S b/arch/arm/cpu/smccc-call.S
new file mode 100644
index 000000000..c2781b1ab
--- /dev/null
+++ b/arch/arm/cpu/smccc-call.S
@@ -0,0 +1,64 @@
+/*
+ * 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/unwind.h>
+
+    .arch_extension sec
+    .arch_extension virt
+	.arm
+
+	/*
+	 * 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)
diff --git a/arch/arm/include/asm/arm-smccc.h b/arch/arm/include/asm/arm-smccc.h
new file mode 100644
index 000000000..b5abfda80
--- /dev/null
+++ b/arch/arm/include/asm/arm-smccc.h
@@ -0,0 +1,104 @@
+/*
+ * 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.
+ *
+ */
+#ifndef __LINUX_ARM_SMCCC_H
+#define __LINUX_ARM_SMCCC_H
+
+#include <linux/linkage.h>
+#include <linux/types.h>
+
+/*
+ * This file provides common defines for ARM SMC Calling Convention as
+ * specified in
+ * http://infocenter.arm.com/help/topic/com.arm.doc.den0028a/index.html
+ */
+
+#define ARM_SMCCC_STD_CALL		0
+#define ARM_SMCCC_FAST_CALL		1
+#define ARM_SMCCC_TYPE_SHIFT		31
+
+#define ARM_SMCCC_SMC_32		0
+#define ARM_SMCCC_SMC_64		1
+#define ARM_SMCCC_CALL_CONV_SHIFT	30
+
+#define ARM_SMCCC_OWNER_MASK		0x3F
+#define ARM_SMCCC_OWNER_SHIFT		24
+
+#define ARM_SMCCC_FUNC_MASK		0xFFFF
+
+#define ARM_SMCCC_IS_FAST_CALL(smc_val)	\
+	((smc_val) & (ARM_SMCCC_FAST_CALL << ARM_SMCCC_TYPE_SHIFT))
+#define ARM_SMCCC_IS_64(smc_val) \
+	((smc_val) & (ARM_SMCCC_SMC_64 << ARM_SMCCC_CALL_CONV_SHIFT))
+#define ARM_SMCCC_FUNC_NUM(smc_val)	((smc_val) & ARM_SMCCC_FUNC_MASK)
+#define ARM_SMCCC_OWNER_NUM(smc_val) \
+	(((smc_val) >> ARM_SMCCC_OWNER_SHIFT) & ARM_SMCCC_OWNER_MASK)
+
+#define ARM_SMCCC_CALL_VAL(type, calling_convention, owner, func_num) \
+	(((type) << ARM_SMCCC_TYPE_SHIFT) | \
+	((calling_convention) << ARM_SMCCC_CALL_CONV_SHIFT) | \
+	(((owner) & ARM_SMCCC_OWNER_MASK) << ARM_SMCCC_OWNER_SHIFT) | \
+	((func_num) & ARM_SMCCC_FUNC_MASK))
+
+#define ARM_SMCCC_OWNER_ARCH		0
+#define ARM_SMCCC_OWNER_CPU		1
+#define ARM_SMCCC_OWNER_SIP		2
+#define ARM_SMCCC_OWNER_OEM		3
+#define ARM_SMCCC_OWNER_STANDARD	4
+#define ARM_SMCCC_OWNER_TRUSTED_APP	48
+#define ARM_SMCCC_OWNER_TRUSTED_APP_END	49
+#define ARM_SMCCC_OWNER_TRUSTED_OS	50
+#define ARM_SMCCC_OWNER_TRUSTED_OS_END	63
+
+/**
+ * struct arm_smccc_res - Result from SMC/HVC call
+ * @a0-a3 result values from registers 0 to 3
+ */
+struct arm_smccc_res {
+	unsigned long a0;
+	unsigned long a1;
+	unsigned long a2;
+	unsigned long a3;
+};
+
+/**
+ * arm_smccc_smc() - make SMC calls
+ * @a0-a7: arguments passed in registers 0 to 7
+ * @res: result values from registers 0 to 3
+ *
+ * This function is used to make SMC calls following SMC Calling Convention.
+ * The content of the supplied param are copied to registers 0 to 7 prior
+ * to the SMC instruction. The return values are updated with the content
+ * from register 0 to 3 on return from the SMC instruction.
+ */
+asmlinkage void arm_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);
+
+/**
+ * arm_smccc_hvc() - make HVC calls
+ * @a0-a7: arguments passed in registers 0 to 7
+ * @res: result values from registers 0 to 3
+ *
+ * This function is used to make HVC calls following SMC Calling
+ * Convention.  The content of the supplied param are copied to registers 0
+ * to 7 prior to the HVC instruction. The return values are updated with
+ * the content from register 0 to 3 on return from the HVC instruction.
+ */
+asmlinkage void arm_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);
+
+#endif /*__LINUX_ARM_SMCCC_H*/
-- 
2.11.0

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