The architecture specification states that TLB operations are
guaranteed to be complete only after the execution of a DSB (Data
Synchronisation Barrier, former Data Write Barrier or Drain Write
Buffer). The branch target cache invalidation is also needed. The ISB
(Instruction Synchronisation Barrier, formerly Prefetch Flush) is
needed unless there will be a return from exception before the
corresponding mapping is used (i.e. user mappings).
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Daniel Jacobowitz
The ARM kernel has several uses of asm("foo%?"). %? is a GCC internal
modifier used to output conditional execution predicates. However, no
version of GCC supports conditionalizing asm statements. GCC 4.2 will
correctly expand %? to the empty string in user asms. Earlier versions may
reuse the condition from the previous instruction. In 'if (foo) asm
("bar%?");' this is somewhat likely to be right... but not reliable.
So, the only safe thing to do is to remove the uses of %?. I believe
the tlbflush.h occurances were supposed to be removed before, based
on the comment about %? not working at the top of that file.
Old versions of GCC could omit branches around user asms if the asm didn't
mark the condition codes as clobbered. This problem hasn't been seen on any
recent (3.x or 4.x) GCC, but it could theoretically happen. So, where
%? was removed a cc clobber was added.
Signed-off-by: Daniel Jacobowitz <dan@codesourcery.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch removes TLB related codes in nommu mode.
Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Catalin Marinas
Chapter B2.7.3 in the latest ARM ARM (with v6 information) states that
the completion of a TLB maintenance operation is only guaranteed by
the execution of a DSB (Data Syncronization Barrier, formerly Data
Write Barrier or Drain Write Buffer).
Note that a DSB is only needed in the flush_tlb_kernel_* functions
since the completion is guaranteed by a mode change (i.e. switching
back to user mode) for the flush_tlb_user_* functions.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Catalin Marinas