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* [PATCH 0/4] Use scratch registers on XLR/XLS/XLP
@ 2013-06-11 15:41 Jayachandran C
  2013-06-11 15:41 ` [PATCH 1/4] MIPS: Allow platform specific scratch registers Jayachandran C
                   ` (3 more replies)
  0 siblings, 4 replies; 10+ messages in thread
From: Jayachandran C @ 2013-06-11 15:41 UTC (permalink / raw)
  To: linux-mips, ralf; +Cc: Jayachandran C

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

^ permalink raw reply	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2013-06-20 15:41 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-06-11 15:41 [PATCH 0/4] Use scratch registers on XLR/XLS/XLP Jayachandran C
2013-06-11 15:41 ` [PATCH 1/4] MIPS: Allow platform specific scratch registers Jayachandran C
2013-06-11 15:41 ` [PATCH 2/4] MIPS: Fixup check for invalid scratch register Jayachandran C
2013-06-11 15:41 ` [PATCH 3/4] MIPS: mm: Use scratch for PGD when !CONFIG_MIPS_PGD_C0_CONTEXT Jayachandran C
2013-06-18 12:45   ` [PATCH UPDATED " Jayachandran C
2013-06-18 12:45     ` [PATCH UPDATED 4/4] MIPS: Move definition of SMP processor id register to header file Jayachandran C
2013-06-20 14:48       ` Ralf Baechle
2013-06-20 15:40         ` Maciej W. Rozycki
2013-06-20 15:19     ` [PATCH UPDATED 3/4] MIPS: mm: Use scratch for PGD when !CONFIG_MIPS_PGD_C0_CONTEXT Ralf Baechle
2013-06-11 15:41 ` [PATCH 4/4] MIPS: Move definition of SMP processor id register to header file Jayachandran C

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