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| author | Balbir Singh <bsingharora@gmail.com> | 2018-04-06 08:24:23 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-05-01 22:58:22 +0300 |
| commit | f2acc8dc0644194efba8474d3a4dc13752430894 (patch) | |
| tree | c95201c2762fc2dacb1c4b0e2a34ddfb54d19185 /arch/powerpc/mm | |
| parent | 5a5ea34017993e6714dec7c741d1d9e263ec3638 (diff) | |
| download | linux-f2acc8dc0644194efba8474d3a4dc13752430894.tar.xz | |
powerpc/mm: Flush cache on memory hot(un)plug
commit fb5924fddf9ee31db04da7ad4e8c3434a387101b upstream.
This patch adds support for flushing potentially dirty cache lines
when memory is hot-plugged/hot-un-plugged. The support is currently
limited to 64 bit systems.
The bug was exposed when mappings for a device were actually
hot-unplugged and plugged in back later. A similar issue was observed
during the development of memtrace, but memtrace does it's own
flushing of region via a custom routine.
These patches do a flush both on hotplug/unplug to clear any stale
data in the cache w.r.t mappings, there is a small race window where a
clean cache line may be created again just prior to tearing down the
mapping.
The patches were tested by disabling the flush routines in memtrace
and doing I/O on the trace file. The system immediately
checkstops (quite reliablly if prior to the hot-unplug of the memtrace
region, we memset the regions we are about to hot unplug). After these
patches no custom flushing is needed in the memtrace code.
Fixes: 9d5171a8f248 ("powerpc/powernv: Enable removal of memory for in memory tracing")
Cc: stable@vger.kernel.org # v4.14+
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Acked-by: Reza Arbab <arbab@linux.ibm.com>
Reviewed-by: Rashmica Gupta <rashmica.g@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/powerpc/mm')
| -rw-r--r-- | arch/powerpc/mm/mem.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index 4362b86ef84c..9c2f83331e5b 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -143,6 +143,7 @@ int arch_add_memory(int nid, u64 start, u64 size, bool want_memblock) start, start + size, rc); return -EFAULT; } + flush_inval_dcache_range(start, start + size); return __add_pages(nid, start_pfn, nr_pages, want_memblock); } @@ -171,6 +172,7 @@ int arch_remove_memory(u64 start, u64 size) /* Remove htab bolted mappings for this section of memory */ start = (unsigned long)__va(start); + flush_inval_dcache_range(start, start + size); ret = remove_section_mapping(start, start + size); /* Ensure all vmalloc mappings are flushed in case they also |