This set of patches enable the use of scratch registers on XLR/XLS and XLP (cop0 reg 22, sel 0-7) to optimize the generated TLB handlers. The current code assumes scratch is 31, which is fixed by the first patch. The second patch fixes a minor issue in checking if scratch is allocated. The third patch enables use of a scratch register when it is available even on a 32-bit or non-r2 platform. The fourth patch is a cleanup to consolidate all the defines needed into one file, this patch does not have any change in logic. In the earlier scheme, if MIPS_PGD_C0_CONTEXT was defined, the Context register or a scratch register would contain the current PGD, and the Xcontext would contain the smp_processor_id shifted to index pointers. In the new scheme, the behavior when MIPS_PGD_C0_CONTEXT is defined remains the same. But when it is not defined, we still try to allocate a scratch register for the current pgd and the smp processor id remains in Context. There is also an additional change is to generate the tlbmiss_handler_setup_pgd() function even when MIPS_PGD_C0_CONTEXT is not defined. This function will save the PGD in pgd_current[] and also in the scratch register if one has been allocated. Comments/testing welcome. Thanks, JC. Changes in v3: * Add patch 2 - fix up check for a valid scratch register Changes in v2: * Update macros in thread-info.h, remove __ASSEMBLY__ part * add ASM_CPUID_MFC0 and UASM_i_CPUID_MFC0 which allows us to remove a lot of conditional compilation. * make c0_kscratch a inline function and remove global variable Jayachandran C (4): MIPS: Allow platform specific scratch registers MIPS: Fixup check for invalid scratch register MIPS: mm: Use scratch for PGD when !CONFIG_MIPS_PGD_C0_CONTEXT MIPS: Move definition of SMP processor id register to header file arch/mips/include/asm/mmu_context.h | 22 ++--- arch/mips/include/asm/stackframe.h | 24 ++--- arch/mips/include/asm/thread_info.h | 30 +++++- arch/mips/kernel/cpu-probe.c | 1 + arch/mips/mm/tlbex.c | 186 +++++++++++++++++------------------ 5 files changed, 132 insertions(+), 131 deletions(-) -- 1.7.9.5
