| Message ID | 1378262667.32360.6.camel@phoenix |
|---|---|
| State | Rejected |
| Delegated to: | Thomas Petazzoni |
| Headers | show |
Dear Axel Lin, On Wed, 04 Sep 2013 10:44:27 +0800, Axel Lin wrote: > diff --git a/arch/Config.in b/arch/Config.in > index 14899ca..31c23ec 100644 > --- a/arch/Config.in > +++ b/arch/Config.in > @@ -223,8 +223,9 @@ config BR2_GCC_TARGET_MODE > # Set up target binary format > choice > prompt "Target Binary Format" > - depends on BR2_bfin || BR2_m68k > - default BR2_BINFMT_FDPIC > + depends on BR2_arm || BR2_bfin || BR2_m68k > + default BR2_BINFMT_ELF if BR2_arm > + default BR2_BINFMT_FDPIC if (BR2_bfin || BR2_m68k) I know it was broken before, but FDPIC isn't supported on BR2_m68k, so I guess we should have something like: prompt "Target Binary Format" depends on BR2_arm || BR2_m68k || BR2_bfin default BR2_BINFMT_ELF if BR2_arm default BR2_BINFMT_FDPIC if BR2_bfin default BR2_BINFMT_FLAT if BR2_m68k But I'm wondering if we shouldn't go further than that, and make BR2_BINFMT_FLAT available only for non-MMU ARMs. Something like: prompt "Target Binary Format" depends on BR2_arm7tmdi || BR2_arm_cortex_m3 || BR2_arm_cortex_m4 || BR2_m68k || BR2_bfin default BR2_BINFMT_FLAT if BR2_arm7tmdi || BR2_arm_cortex_m3 || BR2_arm_cortex_m4 || BR2_m68k default BR2_BINFMT_FDPIC if BR2_bfin or something like this. This way, users of MMU-capable ARM variants wouldn't be confused by the availability of FLAT and ELF as binary formats. Of course, BR2_BINFMT_ELF should gain some !BR2_arm7tmdi && !BR2_arm_cortex_m3 && !BR2_arm_cortex_m4 dependencies, or maybe even a !BR2_USE_MMU dependency. I think there's quite some room for improvement around the definition of which CPU has an MMU or not, and which architectures support which binary formats. Best regards, Thomas
Op 5-sep.-2013 23:48 schreef "Thomas Petazzoni" < thomas.petazzoni@free-electrons.com> het volgende: > But I'm wondering if we shouldn't go further than that, and make > BR2_BINFMT_FLAT available only for non-MMU ARMs. Something like: > > prompt "Target Binary Format" > depends on BR2_arm7tmdi || BR2_arm_cortex_m3 || BR2_arm_cortex_m4 || BR2_m68k || BR2_bfin > default BR2_BINFMT_FLAT if BR2_arm7tmdi || BR2_arm_cortex_m3 || BR2_arm_cortex_m4 || BR2_m68k > default BR2_BINFMT_FDPIC if BR2_bfin > > or something like this. This way, users of MMU-capable ARM variants > wouldn't be confused by the availability of FLAT and ELF as binary > formats. Of course, BR2_BINFMT_ELF should gain some !BR2_arm7tmdi > && !BR2_arm_cortex_m3 && !BR2_arm_cortex_m4 dependencies, or maybe even > a !BR2_USE_MMU dependency. I think there's quite some room for > improvement around the definition of which CPU has an MMU or not, and > which architectures support which binary formats. Don't we/shouldn't we have something like ARCH_HAS_MMU and/or ARCH_SUPPORTS_FLAT_BINARY? Best regards, Thomas
Dear Thomas De Schampheleire, On Fri, 6 Sep 2013 03:08:10 +0200, Thomas De Schampheleire wrote: > > or something like this. This way, users of MMU-capable ARM variants > > wouldn't be confused by the availability of FLAT and ELF as binary > > formats. Of course, BR2_BINFMT_ELF should gain some !BR2_arm7tmdi > > && !BR2_arm_cortex_m3 && !BR2_arm_cortex_m4 dependencies, or maybe even > > a !BR2_USE_MMU dependency. I think there's quite some room for > > improvement around the definition of which CPU has an MMU or not, and > > which architectures support which binary formats. > > Don't we/shouldn't we have something like ARCH_HAS_MMU and/or > ARCH_SUPPORTS_FLAT_BINARY? Yes, we should probably have something like this (and ditto for other binary formats: ELF, FDPIC and so on). Thomas
On 09/06/2013 03:25 AM, Thomas Petazzoni wrote: > On Fri, 6 Sep 2013 03:08:10 +0200, Thomas De Schampheleire wrote: > >> Don't we/shouldn't we have something like ARCH_HAS_MMU and/or >> ARCH_SUPPORTS_FLAT_BINARY? > > Yes, we should probably have something like this (and ditto for other > binary formats: ELF, FDPIC and so on). On a side note, remember that HAS_MMU doesn't mean it's using it - from what i've read you can use MMU-bearing processors to test uclinux MMU-less scenarios (dunno if it can be done with every SOC out there, probably depends on the linux support for each one, at least a couple of Atmel ones were used this way for testing and/or masochism). Regards.
Dear Gustavo Zacarias, On Fri, 06 Sep 2013 07:08:16 -0300, Gustavo Zacarias wrote: > On 09/06/2013 03:25 AM, Thomas Petazzoni wrote: > > > On Fri, 6 Sep 2013 03:08:10 +0200, Thomas De Schampheleire wrote: > > > >> Don't we/shouldn't we have something like ARCH_HAS_MMU and/or > >> ARCH_SUPPORTS_FLAT_BINARY? > > > > Yes, we should probably have something like this (and ditto for other > > binary formats: ELF, FDPIC and so on). > > On a side note, remember that HAS_MMU doesn't mean it's using it - from > what i've read you can use MMU-bearing processors to test uclinux > MMU-less scenarios (dunno if it can be done with every SOC out there, > probably depends on the linux support for each one, at least a couple of > Atmel ones were used this way for testing and/or masochism). Right. We could distinguish what the hardware is capable of (i.e BR2_HAS_MMU vs. !BR2_HAS_MMU) and what the user wants to do (BR2_USE_MMU vs. !BR2_USE_MMU). Of course, BR2_USE_MMU depends on BR2_HAS_MMU. That said, until now, we've been hiding BR2_USE_MMU on many architectures for which !MMU doesn't exist/isn't supported. On ARM, I believe it doesn't make much sense to expose !MMU for MMU-capable variants. Best regards, Thomas
diff --git a/arch/Config.in b/arch/Config.in index 14899ca..31c23ec 100644 --- a/arch/Config.in +++ b/arch/Config.in @@ -223,8 +223,9 @@ config BR2_GCC_TARGET_MODE # Set up target binary format choice prompt "Target Binary Format" - depends on BR2_bfin || BR2_m68k - default BR2_BINFMT_FDPIC + depends on BR2_arm || BR2_bfin || BR2_m68k + default BR2_BINFMT_ELF if BR2_arm + default BR2_BINFMT_FDPIC if (BR2_bfin || BR2_m68k) config BR2_BINFMT_ELF bool "ELF" @@ -245,7 +246,7 @@ config BR2_BINFMT_FDPIC config BR2_BINFMT_FLAT bool "FLAT" - depends on BR2_bfin || BR2_m68k + depends on BR2_arm || BR2_bfin || BR2_m68k select BR2_PREFER_STATIC_LIB help FLAT binary is a relatively simple and lightweight executable format
Some noMMU ARM platforms need to select BR2_BINFMT_FLAT. Most ARM platforms have MMU, thus set default to BR2_BINFMT_ELF for ARM. Signed-off-by: Axel Lin <axel.lin@ingics.com> --- arch/Config.in | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)