Shadow registers are part of the openrisc spec along with sr[cid], as
part of the fast context switching feature. When exceptions occur,
instead of having to save registers to the stack if enabled the CID will
increment and a new set of registers will be available.
This patch only implements shadow registers which can be used as extra
scratch registers via the mfspr and mtspr if required. This is
implemented in a way where it would be easy to add on the fast context
switching, currently cid is hardcoded to 0.
This is need for openrisc linux smp kernels to boot correctly.
Signed-off-by: Stafford Horne <shorne@gmail.com>
Threads work much better when you set the TLS register.
This was fixed in the upstream kernel for Linux 4.9.
Signed-off-by: Richard Henderson <rth@twiddle.net>
These headers all use TARGET_CPU_H as header guard symbol. Reuse of
the same guard symbol in multiple headers is okay as long as they
cannot be included together.
Since we can avoid guard symbol reuse easily, do so: use guard symbol
$target_TARGET_CPU_H for linux-user/$target/target_cpu.h.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
The OpenRISC kernel ignores CLONE_SETTLS in its copy_thread()
implementation, so a cpu_set_tls() implementation is a no-op.
cpu_clone_regs() was setting the syscall return value in the
wrong register -- it is gpr[11], not gpr[2]. With these two
things fixed, we can compile with NPTL enabled.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Jia Liu <proljc@gmail.com>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
The functions cpu_clone_regs() and cpu_set_tls() are not purely CPU
related -- they are specific to the TLS ABI for a a particular OS.
Move them into the linux-user/ tree where they belong.
target-lm32 had entirely unused implementations, since it has no
linux-user target; just drop them.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Laurent Vivier
Stafford Horne
Richard Henderson
Markus Armbruster
Peter Maydell