XScale cores either have a DSP coprocessor (which contains a single
40 bit accumulator register), or an iWMMXt coprocessor (which contains
eight 64 bit registers.)
Because of the small amount of state in the DSP coprocessor, access to
the DSP coprocessor (CP0) is always enabled, and DSP context switching
is done unconditionally on every task switch. Access to the iWMMXt
coprocessor (CP0/CP1) is enabled only when an iWMMXt instruction is
first issued, and iWMMXt context switching is done lazily.
CONFIG_IWMMXT is supposed to mean 'the cpu we will be running on will
have iWMMXt support', but boards are supposed to select this config
symbol by hand, and at least one pxa27x board doesn't get this right,
so on that board, proc-xscale.S will incorrectly assume that we have a
DSP coprocessor, enable CP0 on boot, and we will then only save the
first iWMMXt register (wR0) on context switches, which is Bad.
This patch redefines CONFIG_IWMMXT as 'the cpu we will be running on
might have iWMMXt support, and we will enable iWMMXt context switching
if it does.' This means that with this patch, running a CONFIG_IWMMXT=n
kernel on an iWMMXt-capable CPU will no longer potentially corrupt iWMMXt
state over context switches, and running a CONFIG_IWMMXT=y kernel on a
non-iWMMXt capable CPU will still do DSP context save/restore.
These changes should make iWMMXt work on PXA3xx, and as a side effect,
enable proper acc0 save/restore on non-iWMMXt capable xsc3 cores such
as IOP13xx and IXP23xx (which will not have CONFIG_CPU_XSCALE defined),
as well as setting and using HWCAP_IWMMXT properly.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Move HWCAP_* definitions into asm/elf.h, where they should belong.
Since userspace wants to get at these definitions by including
asm/procinfo.h, include asm/elf.h from this file if __KERNEL__
is not defined, and issue a warning suggesting to fix the program
up to use asm/elf.h instead.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Move kernel-only #includes into #ifdef __KERNEL__, so that
headers_install target can be used on ARM.
Signed-off-by: Ralph Siemsen <ralphs@netwinder.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Daniel Jacobowitz
Handle new EABI relocations when loading kernel modules. This is
necessary for CONFIG_AEABI kernels, and also for some broken
(since fixed) old ABI toolchains.
Signed-off-by: Daniel Jacobowitz <dan@codesourcery.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Daniel Jacobowitz
Thread flags are inherited on fork(). In order for a binary which has
the iWMMXt coprocessor enabled to run a binary which needs the FPA
emulation, we need to explicitly clear TIF_USING_IWMMXT if we are not
going to set it.
Signed-off-by: Daniel Jacobowitz <dan@codesourcery.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Mike Frysinger
the ELF_DATA define in both arm asm subdirs of linux/include/ contain a
semicolon at the end. this of course will cause any code that tries to use
ELF_DATA in assignment or comparison to fail. no other arch has a semicolon
in their ELF_DATA defines.
Signed-off-by: Mike Frysinger
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Lennert Buytenhek
Russell King
David Woodhouse
Ralph Siemsen
Daniel Jacobowitz
Mike Frysinger
Linus Torvalds