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[SPARC64]: Eliminate NR_CPUS limitations.

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Cheetah systems can have cpuids as large as 1023, although physical
systems don't have that many cpus.

Only three limitations existed in the kernel preventing arbitrary
NR_CPUS values:

1) dcache dirty cpu state stored in page->flags on
   D-cache aliasing platforms.  With some build time
   calculations and some build-time BUG checks on
   page->flags layout, this one was easily solved.

2) The cheetah XCALL delivery code could only handle
   a cpumask with up to 32 cpus set.  Some simple looping
   logic clears that up too.

3) thread_info->cpu was a u8, easily changed to a u16.

There are a few spots in the kernel that still put NR_CPUS
sized arrays on the kernel stack, but that's not a sparc64
specific problem.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller
2007-05-26 01:14:43 -07:00
parent 5cbc307373
commit 22adb358e8
6 changed files with 43 additions and 16 deletions
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2
include/asm-sparc64/cpudata.h
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@@ -202,7 +202,7 @@ extern struct sun4v_2insn_patch_entry __sun4v_2insn_patch,
* the calculations done by the macro mid-stream.
*/
#define LOAD_PER_CPU_BASE(DEST, THR, REG1, REG2, REG3) \
ldub [THR + TI_CPU], REG1; \
lduh [THR + TI_CPU], REG1; \
sethi %hi(__per_cpu_shift), REG3; \
sethi %hi(__per_cpu_base), REG2; \
ldx [REG3 + %lo(__per_cpu_shift)], REG3; \