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authorLinus Torvalds <torvalds@linux-foundation.org>2015-12-17 09:45:09 -0800
committerAlex Shi <alex.shi@linaro.org>2016-08-27 11:23:38 +0800
commit662dda1b7b258dc918933d57f9249a1b5f16512c (patch)
tree7458d516092ceb44d0b84bad5d49f5842cc1807f /lib
parent799abb4f9534fe9323c2f931c2989d4bc276b256 (diff)
x86: reorganize SMAP handling in user space accesses
This reorganizes how we do the stac/clac instructions in the user access code. Instead of adding the instructions directly to the same inline asm that does the actual user level access and exception handling, add them at a higher level. This is mainly preparation for the next step, where we will expose an interface to allow users to mark several accesses together as being user space accesses, but it does already clean up some code: - the inlined trivial cases of copy_in_user() now do stac/clac just once over the accesses: they used to do one pair around the user space read, and another pair around the write-back. - the {get,put}_user_ex() macros that are used with the catch/try handling don't do any stac/clac at all, because that happens in the try/catch surrounding them. Other than those two cleanups that happened naturally from the re-organization, this should not make any difference. Yet. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> (cherry picked from commit 11f1a4b9755f5dbc3e822a96502ebe9b044b14d8) Signed-off-by: Alex Shi <alex.shi@linaro.org>
Diffstat (limited to 'lib')
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