[Mini-OS] -fpic?

[Mini-OS] -fpic?

[Samuel Thibault]

Is there a reason for using -fpic when compiling mini-os?

I'm asking because that actually causes linking troubles in my
stubdomain work, and just dropping it works fine (and I don't see why
we'd need it)

Samuel

Re: [Mini-OS] -fpic?

[Keir Fraser]

If it builds without it then it should be fine, I believe.

 -- Keir

On 27/11/07 11:16, "Samuel Thibault" <samuel.thibault@eu.citrix.com> wrote:

> Is there a reason for using -fpic when compiling mini-os?
> 
> I'm asking because that actually causes linking troubles in my
> stubdomain work, and just dropping it works fine (and I don't see why
> we'd need it)
> 
> Samuel
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel

Re: [Mini-OS] Drop useless -fpic flag

[Samuel Thibault]

Keir Fraser, le Tue 27 Nov 2007 12:33:23 +0000, a écrit :
> If it builds without it then it should be fine, I believe.

And nobody raised his hand, so here is a patch:

Drop useless -fpic flag.

Signed-off-by: Samuel Thibault <samuel.thibault@citrix.com>

diff -r c555a5f97982 extras/mini-os/arch/x86/arch.mk
--- a/extras/mini-os/arch/x86/arch.mk	Wed Nov 28 13:36:56 2007 +0000
+++ b/extras/mini-os/arch/x86/arch.mk	Wed Nov 28 16:33:37 2007 +0000
@@ -17,7 +17,7 @@ endif
 endif
 
 ifeq ($(TARGET_ARCH),x86_64)
-ARCH_CFLAGS := -m64 -mno-red-zone -fpic -fno-reorder-blocks
+ARCH_CFLAGS := -m64 -mno-red-zone -fno-reorder-blocks
 ARCH_CFLAGS += -fno-asynchronous-unwind-tables
 ARCH_ASFLAGS := -m64
 ARCH_LDFLAGS := -m elf_x86_64

Re: [Mini-OS] Drop useless -fpic flag

[Keir Fraser]

Ah yes, I think the -fpic was inherited from Xen's Makefile. Xen has to be
built -fpic because it is not linked sufficiently close to address 0x0 to
use absolute addressing the 32-bit displacements. This isn't the case for
minios.

 -- Keir

On 28/11/07 16:35, "Samuel Thibault" <samuel.thibault@eu.citrix.com> wrote:

> Keir Fraser, le Tue 27 Nov 2007 12:33:23 +0000, a écrit :
>> If it builds without it then it should be fine, I believe.
> 
> And nobody raised his hand, so here is a patch:
> 
> Drop useless -fpic flag.
> 
> Signed-off-by: Samuel Thibault <samuel.thibault@citrix.com>
> 
> diff -r c555a5f97982 extras/mini-os/arch/x86/arch.mk
> --- a/extras/mini-os/arch/x86/arch.mk Wed Nov 28 13:36:56 2007 +0000
> +++ b/extras/mini-os/arch/x86/arch.mk Wed Nov 28 16:33:37 2007 +0000
> @@ -17,7 +17,7 @@ endif
>  endif
>  
>  ifeq ($(TARGET_ARCH),x86_64)
> -ARCH_CFLAGS := -m64 -mno-red-zone -fpic -fno-reorder-blocks
> +ARCH_CFLAGS := -m64 -mno-red-zone -fno-reorder-blocks
>  ARCH_CFLAGS += -fno-asynchronous-unwind-tables
>  ARCH_ASFLAGS := -m64
>  ARCH_LDFLAGS := -m elf_x86_64

Re: [Mini-OS] Drop useless -fpic flag

[Grzegorz Miłoś]

Yes, that's right. At the time I was writing the first version I just  
copied all the flags. I, too, believe -fpic acn be discarded.

Cheers
Gregor

On 28 Nov 2007, at 16:42, Keir Fraser wrote:

> Ah yes, I think the -fpic was inherited from Xen's Makefile. Xen has  
> to be
> built -fpic because it is not linked sufficiently close to address  
> 0x0 to
> use absolute addressing the 32-bit displacements. This isn't the  
> case for
> minios.
>
> -- Keir
>
> On 28/11/07 16:35, "Samuel Thibault" <samuel.thibault@eu.citrix.com>  
> wrote:
>
>> Keir Fraser, le Tue 27 Nov 2007 12:33:23 +0000, a écrit :
>>> If it builds without it then it should be fine, I believe.
>>
>> And nobody raised his hand, so here is a patch:
>>
>> Drop useless -fpic flag.
>>
>> Signed-off-by: Samuel Thibault <samuel.thibault@citrix.com>
>>
>> diff -r c555a5f97982 extras/mini-os/arch/x86/arch.mk
>> --- a/extras/mini-os/arch/x86/arch.mk Wed Nov 28 13:36:56 2007 +0000
>> +++ b/extras/mini-os/arch/x86/arch.mk Wed Nov 28 16:33:37 2007 +0000
>> @@ -17,7 +17,7 @@ endif
>> endif
>>
>> ifeq ($(TARGET_ARCH),x86_64)
>> -ARCH_CFLAGS := -m64 -mno-red-zone -fpic -fno-reorder-blocks
>> +ARCH_CFLAGS := -m64 -mno-red-zone -fno-reorder-blocks
>> ARCH_CFLAGS += -fno-asynchronous-unwind-tables
>> ARCH_ASFLAGS := -m64
>> ARCH_LDFLAGS := -m elf_x86_64
>
>
>
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