On 08/21/2012 10:52 AM, Aurelien Jarno wrote: > Le 21/08/2012 17:41, Meador Inge a écrit : >> On 08/21/2012 05:14 AM, Andreas Färber wrote: >>> So what about the non-MIPS32r2 case? IIUC then the SYNCI_Step register >>> would no longer be accessible, which your commit message does not >>> mention. Intentional? >> >> Yes, that is intentional. In Section 9.13 of [1] it is stated that these >> registers are only required starting at release 2 of the architecture. The >> Linux kernel follows the same approach. > > Remember this is linux user mode, as such you should not look at the > MIPS architecture, but rather at the behavour of MIPS architecture + > Linux kernel. SYNCI_Step is emulated by the Linux kernel for non R2 > CPUs, as such it should be available even for non R2 CPUs *in user mode > only*. At a first glance, it seems to be the same for CPUNum, CC and > CCRes, but someone has to check that more in details.
Ah, thanks Aurelien. I see that in the kernel sources now. Specifically, it seems that 'simulate_rdhwr' handles the emulation [1] and that it includes support for CPUNum, SYNCI_Step, CC, CCRes, and ULR (User Local register). So, I will remove the conditional. I am not quite sure how to handle ULR at the moment. [1] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob;f=arch/mips/kernel/traps.c;h=9be3df1fa8a461dc4e1e5563582f483e4ed7c103;hb=HEAD -- Meador Inge CodeSourcery / Mentor Embedded http://www.mentor.com/embedded-software
