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SubjectRe: [PATCH] arm64: annotate psci invoke functions as notrace
Hi Kyle,

On Wed, Feb 18, 2015 at 05:26:38PM +0000, 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@redhat.com>

Will and I have patches for arm64 and arm, moving the invocations out to
separate assembly files as discussed when Andy Whitcroft reported the
issue previously [1].

Given that GCC 5 is still in development we were planning to post those
when -rc1 arrives.

Thanks,
Mark.

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-January/319344.html

>
> --- 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(
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>


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