Re: [PATCH] arm64: annotate psci invoke functions as notrace

[Richard W.M. Jones]

On Wed, Feb 18, 2015 at 12:26:38PM -0500, Kyle McMartin wrote:
> Using GCC 5 to build the kernel with ftrace enabled, we encounter the
> following error as a result of the mcount prologue changing the expected
> register use of the function parameters,
> 
> /tmp/cc8Kpn7A.s: Assembler messages:
> /tmp/cc8Kpn7A.s:41: Error: .err encountered
> /tmp/cc8Kpn7A.s:42: Error: .err encountered
> /tmp/cc8Kpn7A.s:43: Error: .err encountered
> /tmp/cc8Kpn7A.s:101: Error: .err encountered
> /tmp/cc8Kpn7A.s:102: Error: .err encountered
> /tmp/cc8Kpn7A.s:103: Error: .err encountered
> scripts/Makefile.build:257: recipe for target 'arch/arm64/kernel/psci.o' failed
> 
> Fix this by annotating the function as notrace, to suppress the
> generation of profiling prologues and epilogues on the function.
> 
> Signed-off-by: Kyle McMartin <kyle@xxxxxxxxxx>
> 
> --- a/arch/arm64/kernel/psci.c
> +++ b/arch/arm64/kernel/psci.c
> @@ -113,7 +113,7 @@ static void psci_power_state_unpack(u32 power_state,
>   * 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,
> +static noinline notrace int __invoke_psci_fn_hvc(u64 function_id, u64 arg0, u64 arg1,
>  					 u64 arg2)
>  {
>  	asm volatile(
> @@ -128,7 +128,7 @@ static noinline int __invoke_psci_fn_hvc(u64 function_id, u64 arg0, u64 arg1,
>  	return function_id;
>  }
>  
> -static noinline int __invoke_psci_fn_smc(u64 function_id, u64 arg0, u64 arg1,
> +static noinline notrace int __invoke_psci_fn_smc(u64 function_id, u64 arg0, u64 arg1,
>  					 u64 arg2)
>  {
>  	asm volatile(

I need this patch in order to compile the upstream kernel on aarch64
using gcc 5.  Can it not be added temporarily while the longer term
fix, whatever that is, is worked out?

Rich.

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