[RFC PATCH 16/31] arm: add SMC wrapper that is compatible with SMCCC

[Oleksandr Tyshchenko <olekstysh@gmail.com>]

From: Volodymyr Babchuk <volodymyr_babchuk@epam.com>

Existing SMC wrapper call_smc() allows only 4 parameters and
returns only one value. This is enough for existing
use in PSCI code, but TEE mediator will need a call that is
fully compatible with ARM SMCCC.
This patch adds this call for both arm32 and arm64.

There was similar patch by Edgar E. Iglesias ([1]), but looks
like it is abandoned.

[1] https://lists.xenproject.org/archives/html/xen-devel/2017-02/msg00636.html

CC: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com>

Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Julien Grall <julien.grall@linaro.org>
---
 xen/arch/arm/arm32/Makefile     |  1 +
 xen/arch/arm/arm32/smc.S        | 32 ++++++++++++++++++++++++++++++++
 xen/arch/arm/arm64/Makefile     |  1 +
 xen/arch/arm/arm64/smc.S        | 29 +++++++++++++++++++++++++++++
 xen/include/asm-arm/processor.h |  4 ++++
 5 files changed, 67 insertions(+)
 create mode 100644 xen/arch/arm/arm32/smc.S
 create mode 100644 xen/arch/arm/arm64/smc.S

diff --git a/xen/arch/arm/arm32/Makefile b/xen/arch/arm/arm32/Makefile
index 0ac254f..a2362f3 100644
--- a/xen/arch/arm/arm32/Makefile
+++ b/xen/arch/arm/arm32/Makefile
@@ -8,6 +8,7 @@ obj-y += insn.o
 obj-$(CONFIG_LIVEPATCH) += livepatch.o
 obj-y += proc-v7.o proc-caxx.o
 obj-y += smpboot.o
+obj-y += smc.o
 obj-y += traps.o
 obj-y += vfp.o
 
diff --git a/xen/arch/arm/arm32/smc.S b/xen/arch/arm/arm32/smc.S
new file mode 100644
index 0000000..1cc9528
--- /dev/null
+++ b/xen/arch/arm/arm32/smc.S
@@ -0,0 +1,32 @@
+/*
+ * xen/arch/arm/arm32/smc.S
+ *
+ * Wrapper for Secure Monitors Calls
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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 <asm/macros.h>
+
+/*
+ * void call_smccc_smc(register_t a0, register_t a1, register_t a2,
+ *                     register_t a3, register_t a4, register_t a5,
+ *                     register_t a6, register_t a7, register_t res[4])
+ */
+ENTRY(call_smccc_smc)
+        mov     r12, sp
+        push    {r4-r7}
+        ldm     r12, {r4-r7}
+        smc     #0
+        pop     {r4-r7}
+        ldr     r12, [sp, #(4 * 4)]
+        stm     r12, {r0-r3}
+        bx      lr
diff --git a/xen/arch/arm/arm64/Makefile b/xen/arch/arm/arm64/Makefile
index 149b6b3..7831dc1 100644
--- a/xen/arch/arm/arm64/Makefile
+++ b/xen/arch/arm/arm64/Makefile
@@ -8,5 +8,6 @@ obj-y += entry.o
 obj-y += insn.o
 obj-$(CONFIG_LIVEPATCH) += livepatch.o
 obj-y += smpboot.o
+obj-y += smc.o
 obj-y += traps.o
 obj-y += vfp.o
diff --git a/xen/arch/arm/arm64/smc.S b/xen/arch/arm/arm64/smc.S
new file mode 100644
index 0000000..aa44fba
--- /dev/null
+++ b/xen/arch/arm/arm64/smc.S
@@ -0,0 +1,29 @@
+/*
+ * xen/arch/arm/arm64/smc.S
+ *
+ * Wrapper for Secure Monitors Calls
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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 <asm/macros.h>
+
+/*
+ * void call_smccc_smc(register_t a0, register_t a1, register_t a2,
+ *                     register_t a3, register_t a4, register_t a5,
+ *                     register_t a6, register_t a7, register_t res[4])
+ */
+ENTRY(call_smccc_smc)
+        smc     #0
+        ldr     x4, [sp]
+        stp     x0, x1, [x4, 0]
+        stp     x2, x3, [x4, 16]
+        ret
diff --git a/xen/include/asm-arm/processor.h b/xen/include/asm-arm/processor.h
index 9f7a42f..4ce5bb6 100644
--- a/xen/include/asm-arm/processor.h
+++ b/xen/include/asm-arm/processor.h
@@ -786,6 +786,10 @@ void vcpu_regs_user_to_hyp(struct vcpu *vcpu,
 int call_smc(register_t function_id, register_t arg0, register_t arg1,
              register_t arg2);
 
+void call_smccc_smc(register_t a0, register_t a1, register_t a2,
+                    register_t a3, register_t a4, register_t a5,
+                    register_t a6, register_t a7, register_t res[4]);
+
 void do_trap_hyp_serror(struct cpu_user_regs *regs);
 
 void do_trap_guest_serror(struct cpu_user_regs *regs);
-- 
2.7.4


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