[linux-yocto] [PATCH] arm64: psci: move psci firmware calls out of line

[Bruce Ashfield]

Dropping the non-yocto interested parties from my reply, looks
like you git-send-email was picking up cc: folks.

Obviously this is for ARM and gcc5 ... but my question is, with
this, what do we have ? ARM building with gcc5 ?

And to confirm, this is for 3.19 ? or 3.14 ?

Bruce

On 2015-05-16 12:07 PM, Armin Kuster wrote:
> From: Will Deacon <will.deacon at arm.com>
>
> 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>
> Signed-off-by: Armin Kuter <akuster at mvista.com>
> ---
>   arch/arm64/kernel/Makefile    |  6 ++++--
>   arch/arm64/kernel/psci-call.S | 28 ++++++++++++++++++++++++++++
>   arch/arm64/kernel/psci.c      | 37 +++----------------------------------
>   3 files changed, 35 insertions(+), 36 deletions(-)
>   create mode 100644 arch/arm64/kernel/psci-call.S
>
> diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
> index eaa77ed..c8e9adc 100644
> --- a/arch/arm64/kernel/Makefile
> +++ b/arch/arm64/kernel/Makefile
> @@ -15,8 +15,10 @@ 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 			\
> diff --git a/arch/arm64/kernel/psci-call.S b/arch/arm64/kernel/psci-call.S
> new file mode 100644
> 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 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)
> diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c
> index f1dbca7..38c12f4 100644
> --- 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 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;
>