Date: Sun, 29 Aug 2010 18:17:38 +0000 (UTC) From: Nathan Whitehorn <nwhitehorn@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r211967 - head/sys/powerpc/aim Message-ID: <201008291817.o7TIHcT5070979@svn.freebsd.org>
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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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