[OpenWrt-Devel] [PATCH] kernel: arm64: psci: move psci firmware calls out of line

[Dirk Neukirchen]

- fixes build error on arm64 with FTRACE enabled
- upstream ticket says gcc5 but both linaro gcc variants
OpenWrt is using seem to be affected

backport upstream change f5e0a12ca2d939e47995f73428d9bf1ad372b289
for Kernel 3.18

only compile tested

Signed-off-by: Dirk Neukirchen <dirkneukirchen at web.de>
---
 ...psci_move_psci_firmware_calls_out_of_line.patch | 124 +++++++++++++++++++++
 1 file changed, 124 insertions(+)
 create mode 100644 target/linux/generic/patches-3.18/090-from_4.0_arm64_psci_move_psci_firmware_calls_out_of_line.patch

diff --git a/target/linux/generic/patches-3.18/090-from_4.0_arm64_psci_move_psci_firmware_calls_out_of_line.patch b/target/linux/generic/patches-3.18/090-from_4.0_arm64_psci_move_psci_firmware_calls_out_of_line.patch
new file mode 100644
index 0000000..1db9d5f
--- /dev/null
+++ b/target/linux/generic/patches-3.18/090-from_4.0_arm64_psci_move_psci_firmware_calls_out_of_line.patch
@@ -0,0 +1,124 @@
+From f5e0a12ca2d939e47995f73428d9bf1ad372b289 Mon Sep 17 00:00:00 2001
+From: Will Deacon <will.deacon at arm.com>
+Date: Wed, 25 Feb 2015 12:10:35 +0000
+Subject: arm64: psci: move psci firmware calls out of line
+
+An arm64 allmodconfig fails to build with GCC 5 due to __asmeq
+assertions in the PSCI firmware calling code firing due to mcount
+preambles breaking our assumptions about register allocation of function
+arguments:
+
+  /tmp/ccDqJsJ6.s: Assembler messages:
+  /tmp/ccDqJsJ6.s:60: Error: .err encountered
+  /tmp/ccDqJsJ6.s:61: Error: .err encountered
+  /tmp/ccDqJsJ6.s:62: Error: .err encountered
+  /tmp/ccDqJsJ6.s:99: Error: .err encountered
+  /tmp/ccDqJsJ6.s:100: Error: .err encountered
+  /tmp/ccDqJsJ6.s:101: Error: .err encountered
+
+This patch fixes the issue by moving the PSCI calls out-of-line into
+their own assembly files, which are safe from the compiler's meddling
+fingers.
+
+Reported-by: Andy Whitcroft <apw at canonical.com>
+Signed-off-by: Will Deacon <will.deacon at arm.com>
+Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
+
+--- /dev/null
++++ b/arch/arm64/kernel/psci-call.S
+@@ -0,0 +1,28 @@
++/*
++ * This program is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License version 2 as
++ * published by the Free Software Foundation.
++ *
++ * 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.
++ *
++ * Copyright (C) 2015 ARM Limited
++ *
++ * Author: Will Deacon <will.deacon at arm.com>
++ */
++
++#include <linux/linkage.h>
++
++/* int __invoke_psci_fn_hvc(u64 function_id, u64 arg0, u64 arg1, u64 arg2) */
++ENTRY(__invoke_psci_fn_hvc)
++	hvc	#0
++	ret
++ENDPROC(__invoke_psci_fn_hvc)
++
++/* int __invoke_psci_fn_smc(u64 function_id, u64 arg0, u64 arg1, u64 arg2) */
++ENTRY(__invoke_psci_fn_smc)
++	smc	#0
++	ret
++ENDPROC(__invoke_psci_fn_smc)
+--- a/arch/arm64/kernel/psci.c
++++ b/arch/arm64/kernel/psci.c
+@@ -57,6 +57,9 @@ static struct psci_operations psci_ops;
+ static int (*invoke_psci_fn)(u64, u64, u64, u64);
+ typedef int (*psci_initcall_t)(const struct device_node *);
+ 
++asmlinkage int __invoke_psci_fn_hvc(u64, u64, u64, u64);
++asmlinkage int __invoke_psci_fn_smc(u64, u64, u64, u64);
++
+ enum psci_function {
+ 	PSCI_FN_CPU_SUSPEND,
+ 	PSCI_FN_CPU_ON,
+@@ -109,40 +112,6 @@ static void psci_power_state_unpack(u32
+ 			PSCI_0_2_POWER_STATE_AFFL_SHIFT;
+ }
+ 
+-/*
+- * The following two functions are invoked via the invoke_psci_fn pointer
+- * and will not be inlined, allowing us to piggyback on the AAPCS.
+- */
+-static noinline int __invoke_psci_fn_hvc(u64 function_id, u64 arg0, u64 arg1,
+-					 u64 arg2)
+-{
+-	asm volatile(
+-			__asmeq("%0", "x0")
+-			__asmeq("%1", "x1")
+-			__asmeq("%2", "x2")
+-			__asmeq("%3", "x3")
+-			"hvc	#0\n"
+-		: "+r" (function_id)
+-		: "r" (arg0), "r" (arg1), "r" (arg2));
+-
+-	return function_id;
+-}
+-
+-static noinline int __invoke_psci_fn_smc(u64 function_id, u64 arg0, u64 arg1,
+-					 u64 arg2)
+-{
+-	asm volatile(
+-			__asmeq("%0", "x0")
+-			__asmeq("%1", "x1")
+-			__asmeq("%2", "x2")
+-			__asmeq("%3", "x3")
+-			"smc	#0\n"
+-		: "+r" (function_id)
+-		: "r" (arg0), "r" (arg1), "r" (arg2));
+-
+-	return function_id;
+-}
+-
+ static int psci_get_version(void)
+ {
+ 	int err;
+--- a/arch/arm64/kernel/Makefile
++++ b/arch/arm64/kernel/Makefile
+@@ -14,8 +14,9 @@ CFLAGS_REMOVE_return_address.o = -pg
+ arm64-obj-y		:= cputable.o debug-monitors.o entry.o irq.o fpsimd.o	\
+ 			   entry-fpsimd.o process.o ptrace.o setup.o signal.o	\
+ 			   sys.o stacktrace.o time.o traps.o io.o vdso.o	\
+-			   hyp-stub.o psci.o cpu_ops.o insn.o return_address.o	\
+-			   cpuinfo.o cpu_errata.o alternative.o
++			   hyp-stub.o psci.o psci-call.o cpu_ops.o insn.o	\
++			   return_address.o cpuinfo.o cpu_errata.o		\
++			   alternative.o
+ 
+ arm64-obj-$(CONFIG_COMPAT)		+= sys32.o kuser32.o signal32.o 	\
+ 					   sys_compat.o
-- 
2.4.1
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