* [PATCH] arch/x86/realmode: make trampoline code conditional for x86-32
@ 2014-10-15 15:38 Jarkko Sakkinen
2014-10-15 15:47 ` H. Peter Anvin
0 siblings, 1 reply; 5+ messages in thread
From: Jarkko Sakkinen @ 2014-10-15 15:38 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, H. Peter Anvin
Cc: x86, linux-kernel, Jarkko Sakkinen
Trampoline code is only needed for SMP and in x86-64 for wakeup
code. Make it conditional in order to minimize the kernel size.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
arch/x86/realmode/rm/Makefile | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile
index 7c0d7be..82b7312 100644
--- a/arch/x86/realmode/rm/Makefile
+++ b/arch/x86/realmode/rm/Makefile
@@ -20,7 +20,11 @@ wakeup-objs += video-vesa.o
wakeup-objs += video-bios.o
realmode-y += header.o
+ifdef CONFIG_X86_64
realmode-y += trampoline_$(BITS).o
+else
+realmode-$(CONFIG_SMP) += trampoline_$(BITS).o
+endif
realmode-y += stack.o
realmode-y += reboot.o
realmode-$(CONFIG_ACPI_SLEEP) += $(wakeup-objs)
--
2.1.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] arch/x86/realmode: make trampoline code conditional for x86-32
2014-10-15 15:38 [PATCH] arch/x86/realmode: make trampoline code conditional for x86-32 Jarkko Sakkinen
@ 2014-10-15 15:47 ` H. Peter Anvin
2014-10-16 6:59 ` Jarkko Sakkinen
0 siblings, 1 reply; 5+ messages in thread
From: H. Peter Anvin @ 2014-10-15 15:47 UTC (permalink / raw)
To: Jarkko Sakkinen, Thomas Gleixner, Ingo Molnar; +Cc: x86, linux-kernel
On 10/15/2014 08:38 AM, Jarkko Sakkinen wrote:
> Trampoline code is only needed for SMP and in x86-64 for wakeup
> code. Make it conditional in order to minimize the kernel size.
>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
> arch/x86/realmode/rm/Makefile | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile
> index 7c0d7be..82b7312 100644
> --- a/arch/x86/realmode/rm/Makefile
> +++ b/arch/x86/realmode/rm/Makefile
> @@ -20,7 +20,11 @@ wakeup-objs += video-vesa.o
> wakeup-objs += video-bios.o
>
> realmode-y += header.o
> +ifdef CONFIG_X86_64
> realmode-y += trampoline_$(BITS).o
> +else
> +realmode-$(CONFIG_SMP) += trampoline_$(BITS).o
> +endif
> realmode-y += stack.o
> realmode-y += reboot.o
> realmode-$(CONFIG_ACPI_SLEEP) += $(wakeup-objs)
>
It is usually preferred to make this a hidden config option (e.g.
CONFIG_X86_TRAMPOLINE) rather than use ifdef, especially since your
ifdef has another conditional inside it.
-hpa
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] arch/x86/realmode: make trampoline code conditional for x86-32
2014-10-15 15:47 ` H. Peter Anvin
@ 2014-10-16 6:59 ` Jarkko Sakkinen
0 siblings, 0 replies; 5+ messages in thread
From: Jarkko Sakkinen @ 2014-10-16 6:59 UTC (permalink / raw)
To: H. Peter Anvin; +Cc: Thomas Gleixner, Ingo Molnar, x86, linux-kernel
On Wed, Oct 15, 2014 at 08:47:11AM -0700, H. Peter Anvin wrote:
> On 10/15/2014 08:38 AM, Jarkko Sakkinen wrote:
> > Trampoline code is only needed for SMP and in x86-64 for wakeup
> > code. Make it conditional in order to minimize the kernel size.
> >
> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> > ---
> > arch/x86/realmode/rm/Makefile | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile
> > index 7c0d7be..82b7312 100644
> > --- a/arch/x86/realmode/rm/Makefile
> > +++ b/arch/x86/realmode/rm/Makefile
> > @@ -20,7 +20,11 @@ wakeup-objs += video-vesa.o
> > wakeup-objs += video-bios.o
> >
> > realmode-y += header.o
> > +ifdef CONFIG_X86_64
> > realmode-y += trampoline_$(BITS).o
> > +else
> > +realmode-$(CONFIG_SMP) += trampoline_$(BITS).o
> > +endif
> > realmode-y += stack.o
> > realmode-y += reboot.o
> > realmode-$(CONFIG_ACPI_SLEEP) += $(wakeup-objs)
> >
>
> It is usually preferred to make this a hidden config option (e.g.
> CONFIG_X86_TRAMPOLINE) rather than use ifdef, especially since your
> ifdef has another conditional inside it.
OK, I'll revise the patch, thanks.
> -hpa
/Jarkko
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH] arch/x86/realmode: make trampoline code conditional for x86-32
@ 2014-10-16 9:05 Jarkko Sakkinen
2014-10-16 20:03 ` Jarkko Sakkinen
0 siblings, 1 reply; 5+ messages in thread
From: Jarkko Sakkinen @ 2014-10-16 9:05 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, H. Peter Anvin
Cc: x86, linux-kernel, Jarkko Sakkinen
Trampoline code is only needed for SMP and in x86-64 for wakeup
code. Make it conditional in order to minimize the kernel size.
Added a new hidden config option CONFIG_X86_TRAMPOLINE as
suggested by H. Peter Anvin.
The justification for this patch is tinyfication effort run by
Josh Triplett. In embedded world a 32-bit processor without SMP
is not uncommon phenomenon.
I think the trampoline code could be completely ripped off if
ACPI_SLEEP and INTEL_TXT are not enabled but did not want to
include that yet into this patch.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
arch/x86/Kconfig | 4 ++++
arch/x86/realmode/rm/Makefile | 10 +++++-----
2 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index f2327e8..9603ca3 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2488,6 +2488,10 @@ config PMC_ATOM
def_bool y
depends on PCI
+config X86_TRAMPOLINE
+ def_bool y
+ depends on X86_64 || SMP
+
source "net/Kconfig"
source "drivers/Kconfig"
diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile
index 7c0d7be..299e450 100644
--- a/arch/x86/realmode/rm/Makefile
+++ b/arch/x86/realmode/rm/Makefile
@@ -19,11 +19,11 @@ wakeup-objs += video-vga.o
wakeup-objs += video-vesa.o
wakeup-objs += video-bios.o
-realmode-y += header.o
-realmode-y += trampoline_$(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
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] arch/x86/realmode: make trampoline code conditional for x86-32
2014-10-16 9:05 Jarkko Sakkinen
@ 2014-10-16 20:03 ` Jarkko Sakkinen
0 siblings, 0 replies; 5+ messages in thread
From: Jarkko Sakkinen @ 2014-10-16 20:03 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, H. Peter Anvin; +Cc: x86, linux-kernel
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
^ permalink raw reply [flat|nested] 5+ messages in thread
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