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>
Add the necessary call to register_isa_ports() so that glibc knows where these are found on Integrator platforms. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Lennert Buytenhek This patch makes the iWMMXt context switch hook use the generic thread notifier infrastructure that was recently merged in commit d6551e884cf66de072b81f8b6d23259462c40baf. Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Lennert Buytenhek Add the necessary kernel bits for crunch task switching. Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch fix compilation problem of start-up codes. (head-nommu.S, arch/arm/kernel/Makefile) Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Nicolas Pitre The difference between EABI and the legacy ABI may affect either structure member alignment and/or argument register selection. The patch has the details. Included are wrappers for the following syscalls: sys_stat64 sys_lstat64 sys_fstat64 sys_fcntl64 sys_epoll_ctl sys_epoll_wait sys_ipc sys_semop sys_semtimedop sys_pread64 sys_pwrite64 sys_truncate64 sys_ftruncate64 sys_readahead Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ISA_DMA_API tells the rest of the kernel if the ISA DMA API is available. Select this symbol only on machine types which make use of the ISA DMA API. Make building of arch/arm/kernel/dma.c depend on this symbol - if a machine does not support the ISA DMA API, it's pointless building this file. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
We are coding the kernel link address into the makefiles, which is invisibly dependent on PAGE_OFFSET. If PAGE_OFFSET is changed, the makefiles also need to be changed. Make adjustments such that the makefiles encode just the offset from PAGE_OFFSET for the kernel link address, and use PAGE_OFFSET in the linker scripts directly. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Nicolas Pitre Since vmlinux.lds.S is preprocessed, we can use the defines already present in asm/memory.h (allowed by patch #3060) for the XIP kernel link address instead of relying on a duplicated Makefile hardcoded value, and also get rid of its dependency on awk to handle it at the same time. While at it let's clean XIP stuff even further and make things clearer in head.S with a nice code reduction. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This is not used anymore - RiscPC now contains the necessary supporting code. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>