Author: nwhitehorn
Date: Sun Aug 29 18:17:38 2010
New Revision: 211967
URL: http://svn.freebsd.org/changeset/base/211967
Log:
Avoid a race in the allocation of new segment IDs that could result in
memory corruption on heavily loaded SMP systems.
MFC after: 2 weeks
Modified:
head/sys/powerpc/aim/mmu_oea64.c
Modified: head/sys/powerpc/aim/mmu_oea64.c
==============================================================================
--- head/sys/powerpc/aim/mmu_oea64.c Sun Aug 29 16:38:08 2010
(r211966)
+++ head/sys/powerpc/aim/mmu_oea64.c Sun Aug 29 18:17:38 2010
(r211967)
@@ -285,6 +285,7 @@ extern void bs_remap_earlyboot(void);
* Lock for the pteg and pvo tables.
*/
struct mtx moea64_table_mutex;
+struct mtx moea64_slb_mutex;
/*
* PTEG data.
@@ -1068,6 +1069,7 @@ moea64_bootstrap(mmu_t mmup, vm_offset_t
*/
mtx_init(&moea64_table_mutex, "pmap table", NULL, MTX_DEF |
MTX_RECURSE);
+ mtx_init(&moea64_slb_mutex, "SLB table", NULL, MTX_DEF);
/*
* Initialize the TLBIE lock. TLBIE can only be executed by one CPU.
@@ -2054,6 +2056,7 @@ moea64_get_unique_vsid(void) {
entropy = 0;
__asm __volatile("mftb %0" : "=r"(entropy));
+ mtx_lock(&moea64_slb_mutex);
for (i = 0; i < NVSIDS; i += VSID_NBPW) {
u_int n;
@@ -2083,9 +2086,11 @@ moea64_get_unique_vsid(void) {
hash |= i;
}
moea64_vsid_bitmap[n] |= mask;
+ mtx_unlock(&moea64_slb_mutex);
return (hash);
}
+ mtx_unlock(&moea64_slb_mutex);
panic("%s: out of segments",__func__);
}
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