[PATCH v2 0/2] change ARM linux memory layout to support 32 CPUs

Liu Hua sdu.liu at huawei.com
Fri Apr 11 01:00:50 PDT 2014


Hi Nicolas or Russell,

This patch series change fixmap mapping region to suppport 32 CPUs.
Because the "top_pmd" covers 0xfffe0000 - 0xffffffff(2M). And part 
is used by vector table. So I move this region down to 0xffc00000
 - 0xffdffff. 


I have tested the patches on arma9(2 CPUs) and arma15(16 CPUs) platforms

BTW, As we know we can configure NR_CPUS up to 32. So we need 2048K 
at most. But for ARM systems with less cpus, there is a waste 
of virtual address. So should we change its size according to
NR_CPUS, as what MIPS linux does ?

Changes from v1:
---------------
- changed documentation for ARM linux memory layout.
- moved fixmap mapping region, not just extended.

Liu Hua (2):
  ARM : DMA : remove useless information about DMA
  ARM : extend fixmap mapping region to support 32 CPUs

 Documentation/arm/memory.txt   |  8 ++------
 arch/arm/include/asm/fixmap.h  |  4 ++--
 arch/arm/include/asm/highmem.h |  1 +
 arch/arm/include/asm/memory.h  |  2 --
 arch/arm/mm/highmem.c          | 10 +++++-----
 arch/arm/mm/mm.h               |  7 +++++++
 arch/arm/mm/mmu.c              |  4 ++++
 mm/highmem.c                   |  1 +
 8 files changed, 22 insertions(+), 15 deletions(-)

-- 
1.9.0




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