3.16.36-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Will Deacon <will.deacon@xxxxxxx>
commit f5e0a12ca2d939e47995f73428d9bf1ad372b289 upstream.
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@xxxxxxxxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
---
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -15,7 +15,8 @@ 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
--- /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@xxxxxxx>
+ */
+
+#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
@@ -55,6 +55,9 @@ 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,
@@ -93,40 +96,6 @@ static u32 psci_power_state_pack(struct
& 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;
--
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