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SubjectRe: [PATCH] arch/x86/realmode: make trampoline code conditional for x86-32
On Thu, Oct 16, 2014 at 11:05:50AM +0200, Jarkko Sakkinen wrote:
> Trampoline code is only needed for SMP and in x86-64 for wakeup
> code. Make it conditional in order to minimize the kernel size.
> Added a new hidden config option CONFIG_X86_TRAMPOLINE as
> suggested by H. Peter Anvin.
>
> The justification for this patch is tinyfication effort run by
> Josh Triplett. In embedded world a 32-bit processor without SMP
> is not uncommon phenomenon.
>
> I think the trampoline code could be completely ripped off if
> ACPI_SLEEP and INTEL_TXT are not enabled but did not want to
> include that yet into this patch.
>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
> arch/x86/Kconfig | 4 ++++
> arch/x86/realmode/rm/Makefile | 10 +++++-----
> 2 files changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index f2327e8..9603ca3 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -2488,6 +2488,10 @@ config PMC_ATOM
> def_bool y
> depends on PCI
>
> +config X86_TRAMPOLINE
> + def_bool y
> + depends on X86_64 || SMP

I think this could be just as well

depends on (X86_64 && (INTEL_TXT || ACPI_SLEEP)) || SMP

Should I send an updated patch?

> +
> source "net/Kconfig"
>
> source "drivers/Kconfig"
> diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile
> index 7c0d7be..299e450 100644
> --- a/arch/x86/realmode/rm/Makefile
> +++ b/arch/x86/realmode/rm/Makefile
> @@ -19,11 +19,11 @@ wakeup-objs += video-vga.o
> wakeup-objs += video-vesa.o
> wakeup-objs += video-bios.o
>
> -realmode-y += header.o
> -realmode-y += trampoline_$(BITS).o
> -realmode-y += stack.o
> -realmode-y += reboot.o
> -realmode-$(CONFIG_ACPI_SLEEP) += $(wakeup-objs)
> +realmode-y += header.o
> +realmode-$(CONFIG_X86_TRAMPOLINE) += trampoline_$(BITS).o
> +realmode-y += stack.o
> +realmode-y += reboot.o
> +realmode-$(CONFIG_ACPI_SLEEP) += $(wakeup-objs)
>
> targets += $(realmode-y)
>
> --
> 2.1.0
>

/Jarkko


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