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>
As Guo explained, upstream gcc does not support abi-v1 (only abi-v2), but
ck610 needs abi-v1 [0] [1]
To simplify things, we make the whole C-SKY architecture require gcc-9
or later, and add a single exception in gcc to force the ck610 to use
the C-SKY port.
Note that this does not change the default gcc version to be used for
C-SKY: the C-SKY port is still always the default one; the gcc-9 version
is only proposed as an alternative (except for ck610, of course).
[0] http://lists.busybox.net/pipermail/buildroot/2019-July/254386.html
[1] package/Makefile.in#73
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Cc: Guo Ren <guoren@kernel.org>
Cc: Arnout Vandecappelle <arnout@mind.be>
Cc: Romain Naour <romain.naour@gmail.com>
Acked-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
ck860 is newest CPU core of C-SKY with high performance & SMP
supported.
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
The C-SKY architecture uses two different ABIs, depending on the core
being used:
- "abiv1" is a mcore based ISA with ELF_NUM:39 and does not support
FPU & VDSP. It is used only for the ck610 core.
- "abiv2" is C-SKY's own ISA with ELF_NUM:252 and supports FPU &
VDSP. It is used for the ck807, ck810, ck860 cores.
Since "abiv1" does not support FPU, BR2_GCC_TARGET_FLOAT_ABI will
always have the value "soft" for the ck610 core.
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
[Thomas: rework commit log]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
VDSP is C-SKY enhanced extension instruction set for SIMD, AI and DSP
operation. It is supported by abiv2, used by the ck807, ck810, ck860
cores.
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
[Thomas: update help text in Config.in.legacy about the BR2_CSKY_DSP
option.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
The DSP extention is in fact no longer used for C-SKY, nor supported
by C-SKY gcc, so we remove it.
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
[Thomas: split from the VDSP patch, add Config.in.legacy]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Calculating GCC_TARGET_CPU requires combining multiple flags, which
isn't very nicely expressed in Config.in, so let's move this into
arch.mk.csky, similarly to what is done in arch.mk.riscv.
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
[Thomas: rework commit log]
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 config option corresponds to the string returned by readelf for
the "Machine" field of the ELF header. It will be used to check if the
architecture of binaries built by Buildroot match the target
architecture.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
This commit provides basic support for the C-SKY architecture.
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
[Thomas: minor tweaks.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
