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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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19
arch/sparc64/kernel/smp.c
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@@ -400,7 +400,7 @@ static __inline__ void spitfire_xcall_deliver(u64 data0, u64 data1, u64 data2, c
static void cheetah_xcall_deliver(u64 data0, u64 data1, u64 data2, cpumask_t mask)
{
u64 pstate, ver;
int nack_busy_id, is_jbus;
int nack_busy_id, is_jbus, need_more;
if (cpus_empty(mask))
return;
@@ -416,6 +416,7 @@ static void cheetah_xcall_deliver(u64 data0, u64 data1, u64 data2, cpumask_t mas
__asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
retry:
need_more = 0;
__asm__ __volatile__("wrpr %0, %1, %%pstate\n\t"
: : "r" (pstate), "i" (PSTATE_IE));
@@ -444,6 +445,10 @@ retry:
: /* no outputs */
: "r" (target), "i" (ASI_INTR_W));
nack_busy_id++;
if (nack_busy_id == 32) {
need_more = 1;
break;
}
}
}
@@ -460,6 +465,16 @@ retry:
if (dispatch_stat == 0UL) {
__asm__ __volatile__("wrpr %0, 0x0, %%pstate"
: : "r" (pstate));
if (unlikely(need_more)) {
int i, cnt = 0;
for_each_cpu_mask(i, mask) {
cpu_clear(i, mask);
cnt++;
if (cnt == 32)
break;
}
goto retry;
}
return;
}
if (!--stuck)
@@ -497,6 +512,8 @@ retry:
if ((dispatch_stat & check_mask) == 0)
cpu_clear(i, mask);
this_busy_nack += 2;
if (this_busy_nack == 64)
break;
}
goto retry;