diff options
| author | David Hildenbrand <david@redhat.com> | 2020-11-11 15:53:18 +0100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-11-19 16:56:59 +1100 |
| commit | e5b2af044f31bf18defa557a8cd11c23caefa34c (patch) | |
| tree | 85ef3702e092c9311d4d57112c3ed8710e6856e7 /arch/powerpc/mm/mem.c | |
| parent | 4abb1e5b63ac3281275315fc6b0cde0b9c2e2e42 (diff) | |
| download | linux-e5b2af044f31bf18defa557a8cd11c23caefa34c.tar.gz | |
powerpc/mm: protect linear mapping modifications by a mutex
This code currently relies on mem_hotplug_begin()/mem_hotplug_done() -
create_section_mapping()/remove_section_mapping() implementations
cannot tollerate getting called concurrently.
Let's prepare for callers (memtrace) not holding any such locks (and
don't force them to mess with memory hotplug locks).
Other parts in these functions don't seem to rely on external locking.
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201111145322.15793-5-david@redhat.com
Diffstat (limited to 'arch/powerpc/mm/mem.c')
| -rw-r--r-- | arch/powerpc/mm/mem.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index 8a86d81f8df02..ca5c4b54c366c 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -58,6 +58,7 @@ #define CPU_FTR_NOEXECUTE 0 #endif +static DEFINE_MUTEX(linear_mapping_mutex); unsigned long long memory_limit; bool init_mem_is_free; @@ -126,8 +127,10 @@ int __ref arch_create_linear_mapping(int nid, u64 start, u64 size, int rc; start = (unsigned long)__va(start); + mutex_lock(&linear_mapping_mutex); rc = create_section_mapping(start, start + size, nid, params->pgprot); + mutex_unlock(&linear_mapping_mutex); if (rc) { pr_warn("Unable to create linear mapping for 0x%llx..0x%llx: %d\n", start, start + size, rc); @@ -144,7 +147,9 @@ void __ref arch_remove_linear_mapping(u64 start, u64 size) start = (unsigned long)__va(start); flush_dcache_range_chunked(start, start + size, FLUSH_CHUNK_SIZE); + mutex_lock(&linear_mapping_mutex); ret = remove_section_mapping(start, start + size); + mutex_unlock(&linear_mapping_mutex); WARN_ON_ONCE(ret); /* Ensure all vmalloc mappings are flushed in case they also |