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Commit f5e0a12c authored by Will Deacon's avatar Will Deacon Committed by Catalin Marinas
Browse files

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: default avatarAndy Whitcroft <apw@canonical.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent e1b6b6ce

arch/arm64/kernel/Makefile

+3 −2
Original line number Diff line number Diff line
@@ -15,8 +15,9 @@ 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 cacheinfo.o

			   hyp-stub.o psci.o psci-call.o cpu_ops.o insn.o	\

			   return_address.o cpuinfo.o cpu_errata.o		\

			   alternative.o cacheinfo.o



arm64-obj-$(CONFIG_COMPAT)		+= sys32.o kuser32.o signal32.o 	\

					   sys_compat.o entry32.o		\

arch/arm64/kernel/psci-call.S

0 → 100644
+28 −0
Original line number Diff line number Diff line 
/*

 * 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)

arch/arm64/kernel/psci.c

+3 −34
Original line number Diff line number Diff line
@@ -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 power_state, 
			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;