The MMU option is currently located in the "Toolchain" menu, but it
doesn't make sense as it's really architecture related. In addition,
the selection of MMU has an impact on the choice of binary format
available, which is visible in the architecture menu.
Therefore, this commit moves the MMU option into the architecture
menu.
However, if we simply move it in arch/Config.in, it means that we
would have the following order of options:
Target architecture
Target architecture variant
ABI
MMU
Binary format
But really, the MMU option should be right below the Target
architecture variant, and the available ABIs derived from that.
The variant and ABI are arch-specfic, and defined in the per-arch
Config.in fragments; a Kconfig option can have only one prompt defined,
even under conditions, and appears at the place in the menu where its
prompt was defined. So, there is no (easy) possibility to have a
generic option appear where we want it.
Since in fact only 2 architectures show a visible prompt for the MMU
option (RISC-V and Xtensa), we move this option in
arch/Config.in.riscv and arch/Config.in.xtensa.
Some walkthrough the commit:
- BR2_ARCH_HAS_MMU_MANDATORY and BR2_ARCH_HAS_MMU_OPTIONAL are
removed as they are no longer needed
- BR2_USE_MMU becomes a hidden boolean
- All the places where we used to select BR2_ARCH_HAS_MMU_MANDATORY
now select BR2_USE_MMU directly.
- Introduce BR2_RISCV_USE_MMU and BR2_XTENSA_USE_MMU.
- All defconfigs that used "# BR2_USE_MMU is not set" are switched to
using the new option.
All in all, this simplifies things quite a bit, and allows to have a
good option ordering in the Target architecture menu.
This commit might raise a concern in terms of backward compatibility
with existing configurations. The only configurations that will be
broken by this change are RISC-V noMMU (which was very recently
introduced) and Xtensa noMMU (which we can probably agree is not such
a widely popular configuration).
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
[yann.morin.1998@free.fr:
- expand further why we need per-arch MMU options
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Even though that seems weird, the LP64F ABI is only supported when MMU
support is enabled. Indeed, as per commit
9a51381ced ("package/uclibc: prevent
config with unsupported RISC-V float ABI"), uClibc does not support
LP64F. But uClibc is the only C library that support RISC-V 64-bit
noMMU.
So the selection of LP64F and !MMU is impossible. Right now this
selection causes a build failure as no C library is enabled.
This commit fixes this by ensuring we cannot use LP64F when MMU
support is not available.
Fixes:
http://autobuild.buildroot.net/results/6320dcc655f1871eb8bf6a9689bddde7447385f5/
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
The variable 'KERNEL_ARCH' is actually a normalized version of
'ARCH'/'BR2_ARCH'. For example, 'arcle' and 'arceb' both become 'arc', just
as all powerpc variants become 'powerpc'.
It is presumably called 'KERNEL_ARCH' because the Linux kernel is typically
the first place where support for a new architecture is added, and thus is
the entity that defines the normalized name.
However, the term 'KERNEL_ARCH' can also be interpreted as 'the architecture
used by the kernel', which need not be exactly the same as 'the normalized
name for a certain arch'. In particular, for cases where a 64-bit
architecture is running a 64-bit kernel but 32-bit userspace. Examples
include:
* aarch64 architecture, with aarch64 kernel and 32-bit (ARM) userspace
* x86_64 architecture, with x86_64 kernel and 32-bit (i386) userspace
In such cases, the 'architecture used by the kernel' needs to refer to the
64-bit name (aarch64, x86_64), whereas all userspace applications need to
refer the, potentially normalized, 32-bit name.
This means that there need to be two different variables:
KERNEL_ARCH: the architecture used by the kernel
NORMALIZED_ARCH: the normalized name for the current userspace architecture
At this moment, both will actually have the same content. But a subsequent
patch will add basic support for situations described above, in which
KERNEL_ARCH may become overwritten to the 64-bit architecture, while
NORMALIZED_ARCH needs to remain the same (32-bit) case.
This commit replaces use of KERNEL_ARCH where actually the userspace arch is
needed. Places that use KERNEL_ARCH in combination with building of kernel
modules are not touched.
There may be cases where a package builds both a kernel module as userspace,
in which case it may need to know about both KERNEL_ARCH and
NORMALIZED_ARCH, for the case where they differ. But this is to be fixed on
a per-need basis.
Signed-off-by: Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
Reviewed-by: Romain Naour <romain.naour@gmail.com>
[Arnout: Also rename BR2_KERNEL_ARCH to BR2_NORMALIZED_ARCH]
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Similar to other arch-specific strings, the 'KERNEL_ARCH' variable can be
determined from Config.in.<arch> files.
Besides aligning with similar strings, this also means simplification: the
big 'sed' covers several architectures not even supported by Buildroot.
Signed-off-by: Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
Reviewed-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Linux supports No-MMU RISC-V 64-bits since kernel version 5.8. Make
MMU optional to enable building for RISC-V 64-bits boards that do not
have one. MMU use of RISC-V 32-bits builds remains mandatory for now.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
This patch sets the default floating point ABI based on the ISA
extensions that have been selected rather than defaulting to soft
float.
For 64-bit:
ISA 'D' selects lp64d
ISA 'F' selects lp64f
Otherwise select lp64
For 32-bit:
ISA 'D' selects ilp32d
ISA 'F' selects ilp32f
Otherwise select ilp32
This change was proposed by Palmer Dabbelt at SiFive.
Signed-off-by: Mark Corbin <mark.corbin@embecosm.com>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
It is too sad when an editor picks up the wrong syntax...
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
This enables a riscv32 system to be built with a Buildroot generated
toolchain (gcc >= 7.x, binutils >= 2.30, glibc only).
This requires a custom version of glibc 2.26 from the riscv-glibc
repository. Note that there are no tags in this repository, so the
glibc version just consists of the 40 character commit id string.
Thanks to Fabrice Bellard for pointing me towards the 32-bit glibc
repository and for providing the necessary patch to get it to build.
Signed-off-by: Mark Corbin <mark.corbin@embecosm.com>
Reviewed-by: Matt Weber <matthew.weber@rockwellcollins.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
This enables a riscv64 system to be built with a Buildroot generated
toolchain (gcc >= 7.x, binutils >= 2.30, glibc only).
This configuration has been used to successfully build a qemu-bootable
riscv-linux-4.15 kernel (https://github.com/riscv/riscv-linux.git).
Signed-off-by: Mark Corbin <mark.corbin@embecosm.com>
[Thomas:
- simplify arch.mk.riscv by directly setting GCC_TARGET_ARCH
- simplify glibc.mk changes by using GLIBC_CONF_ENV.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
