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@canonical.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
(cherry picked from commit f5e0a12ca2d939e47995f73428d9bf1ad372b289)
Signed-off-by: Jon Medhurst <tixy@linaro.org>

diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index a8ad571c4758fd06593b6b2ac0dff8307379c9e9..12618cbd1bab20330da1ecf5f9cd92252175a2de 100644 (file)
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -15,7 +15,7 @@ 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
+                          hyp-stub.o psci.o psci-call.o cpu_ops.o insn.o return_address.o
 
 arm64-obj-$(CONFIG_COMPAT)             += sys32.o kuser32.o signal32.o         \
                                           sys_compat.o

diff --git a/arch/arm64/kernel/psci-call.S b/arch/arm64/kernel/psci-call.S
new file mode 100644 (file)
index 0000000..cf83e61
--- /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@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)

diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c
index 4d827dd6219933f6160f3aec70ad832e169a48cc..fc457d0fee9c84540891e1e771242c86a0718a0e 100644 (file)
--- a/arch/arm64/kernel/psci.c
+++ b/arch/arm64/kernel/psci.c
@@ -58,6 +58,9 @@ 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 power_state,
                        & PSCI_0_2_POWER_STATE_AFFL_MASK;
 }
 
-/*
- * 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;