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| author | Brian Starkey <brian.starkey@arm.com> | 2016-03-22 14:27:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-03-22 15:36:02 -0700 |
| commit | cf61e2a1487d833e4748dead4096584de70bf742 (patch) | |
| tree | 311f4ff6e83253a858d583face5d5af9aedb4149 /kernel | |
| parent | 41b27154874b3a40d6673052d08c8e9fd0c6404f (diff) | |
| download | linux-cf61e2a1487d833e4748dead4096584de70bf742.tar.bz2 | |
memremap: don't modify flags
These patches implement a MEMREMAP_WC flag for memremap(), which can be
used to obtain writecombine mappings. This is then used for setting up
dma_coherent_mem regions which use the DMA_MEMORY_MAP flag.
The motivation is to fix an alignment fault on arm64, and the suggestion
to implement MEMREMAP_WC for this case was made at [1]. That particular
issue is handled in patch 4, which makes sure that the appropriate
memset function is used when zeroing allocations mapped as IO memory.
This patch (of 4):
Don't modify the flags input argument to memremap(). MEMREMAP_WB is
already a special case so we can check for it directly instead of
clearing flag bits in each mapper.
Signed-off-by: Brian Starkey <brian.starkey@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/memremap.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/kernel/memremap.c b/kernel/memremap.c index 584febd13e2e..e5e685e6ff2a 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -64,6 +64,9 @@ void *memremap(resource_size_t offset, size_t size, unsigned long flags) IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE); void *addr = NULL; + if (!flags) + return NULL; + if (is_ram == REGION_MIXED) { WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n", &offset, (unsigned long) size); @@ -72,7 +75,6 @@ void *memremap(resource_size_t offset, size_t size, unsigned long flags) /* Try all mapping types requested until one returns non-NULL */ if (flags & MEMREMAP_WB) { - flags &= ~MEMREMAP_WB; /* * MEMREMAP_WB is special in that it can be satisifed * from the direct map. Some archs depend on the @@ -86,21 +88,19 @@ void *memremap(resource_size_t offset, size_t size, unsigned long flags) } /* - * If we don't have a mapping yet and more request flags are - * pending then we will be attempting to establish a new virtual + * If we don't have a mapping yet and other request flags are + * present then we will be attempting to establish a new virtual * address mapping. Enforce that this mapping is not aliasing * System RAM. */ - if (!addr && is_ram == REGION_INTERSECTS && flags) { + if (!addr && is_ram == REGION_INTERSECTS && flags != MEMREMAP_WB) { WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n", &offset, (unsigned long) size); return NULL; } - if (!addr && (flags & MEMREMAP_WT)) { - flags &= ~MEMREMAP_WT; + if (!addr && (flags & MEMREMAP_WT)) addr = ioremap_wt(offset, size); - } return addr; } |