path: root/kernel/Makefile
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authorDan Williams <dan.j.williams@intel.com>2015-08-10 23:07:06 -0400
committerDan Williams <dan.j.williams@intel.com>2015-08-14 13:23:28 -0400
commit92281dee825f6d2eb07c441437e4196a44b0861c (patch)
tree2d8e24a39dfacf286ab66644545af853056d64f7 /kernel/Makefile
parent92b19ff50e8f242392d78b2aacc5b5b672f1796b (diff)
arch: introduce memremap()
Existing users of ioremap_cache() are mapping memory that is known in advance to not have i/o side effects. These users are forced to cast away the __iomem annotation, or otherwise neglect to fix the sparse errors thrown when dereferencing pointers to this memory. Provide memremap() as a non __iomem annotated ioremap_*() in the case when ioremap is otherwise a pointer to cacheable memory. Empirically, ioremap_<cacheable-type>() call sites are seeking memory-like semantics (e.g. speculative reads, and prefetching permitted). memremap() is a break from the ioremap implementation pattern of adding a new memremap_<type>() for each mapping type and having silent compatibility fall backs. Instead, the implementation defines flags that are passed to the central memremap() and if a mapping type is not supported by an arch memremap returns NULL. We introduce a memremap prototype as a trivial wrapper of ioremap_cache() and ioremap_wt(). Later, once all ioremap_cache() and ioremap_wt() usage has been removed from drivers we teach archs to implement arch_memremap() with the ability to strictly enforce the mapping type. Cc: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'kernel/Makefile')
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/Makefile b/kernel/Makefile
index 43c4c920f30a..92866d36e376 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -99,6 +99,8 @@ obj-$(CONFIG_JUMP_LABEL) += jump_label.o
obj-$(CONFIG_CONTEXT_TRACKING) += context_tracking.o
obj-$(CONFIG_TORTURE_TEST) += torture.o
+obj-$(CONFIG_HAS_IOMEM) += memremap.o
$(obj)/configs.o: $(obj)/config_data.h
# config_data.h contains the same information as ikconfig.h but gzipped.

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