During cold boot, the initial translation tables are created with data
caches disabled, so all modifications go to memory directly. After the
MMU is enabled and data cache is enabled, any modification to the tables
goes to data cache, and eventually may get flushed to memory.
If CPU0 modifies the tables while CPU1 is off, CPU0 will have the
modified tables in its data cache. When CPU1 is powered on, the MMU is
enabled, then it enables coherency, and then it enables the data cache.
Until this is done, CPU1 isn't in coherency, and the translation tables
it sees can be outdated if CPU0 still has some modified entries in its
data cache.
This can be a problem in some cases. For example, the warm boot code
uses only the tables mapped during cold boot, which don't normally
change. However, if they are modified (and a RO page is made RW, or a XN
page is made executable) the CPU will see the old attributes and crash
when it tries to access it.
This doesn't happen in systems with HW_ASSISTED_COHERENCY or
WARMBOOT_ENABLE_DCACHE_EARLY. In these systems, the data cache is
enabled at the same time as the MMU. As soon as this happens, the CPU is
in coherency.
There was an attempt of a fix in psci_helpers.S, but it didn't solve the
problem. That code has been deleted. The code was introduced in commit
<264410306381> ("Invalidate TLB entries during warm boot").
Now, during a map or unmap operation, the memory associated to each
modified table is flushed. Traversing a table will also flush it's
memory, as there is no way to tell in the current implementation if the
table that has been traversed has also been modified.
Change-Id: I4b520bca27502f1018878061bc5fb82af740bb92
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
Changed the names for consistency with the rest of the library. Introduced
new helpers that manipulate the active translation tables context.
Change-Id: Icaca56b67fcf6a96e88aa3c7e47411162e8e6856
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
xlat_arch_tlbi_va_regime() isn't used, so it has been renamed to
xlat_arch_tlbi_va() and the previous implementation has been removed.
Change-Id: Ic118bed3fb68234748d86b2e9e95b25650289276
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
They only contained one function that is easily integrated in the private
library header and the existing architectural C files.
This also helps making the library more portable, as the Makefile of the
library now doesn't use the variable INCLUDES, which is specific to this
codebase and doesn't respect the namespace of the library.
Change-Id: I22228e6a97e9b4f346f5cd8947609263e8df71d8
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
It is useful to have LOG_LEVEL_VERBOSE because it prints the memory map
of each image, but that also means that the change_mem_attributes and
get_mem_attributes functions have verbose prints, and generate a too
long text output that hides other useful information.
As they were mostly there for debug purposes, this patch removes them.
Change-Id: I2986537377d1f78be2b79cc8a6cf230c380bdb55
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
The previous debug output for EL1&0 translation regimes was too verbose,
which makes it hard to read and hides the intent behind the parameters
assigned to each region. This patch simplifies this output and makes the
outputs for EL3 and EL1&0 mostly the same. The difference is that in
EL1&0 it is specified whether the region is exclusively accessible from
EL1 (PRIV) or both EL0 and EL1 (USER).
For example:
MEM-RW(PRIV)-NOACCESS(USER)-XN(PRIV)-XN(USER)-S
MEM-RO(PRIV)-NOACCESS(USER)-EXEC(PRIV)-EXEC(USER)-S
After the change, it becomes this:
MEM-RW-XN-PRIV-S
MEM-RO-EXEC-PRIV-S
Change-Id: I15f4b99058429d42107fbf89e15f4838a9b559a5
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
Instead of having one big file with all the code, it's better to have
a few smaller files that are more manageable:
- xlat_tables_core.c: Code related to the core functionality of the
library (map and unmap regions, initialize xlat context).
- xlat_tables_context.c: Instantiation of the active image context
as well as APIs to manipulate it.
- xlat_tables_utils.c: Helper code that isn't part of the core
functionality (change attributes, debug print messages).
Change-Id: I3ea956fc1afd7473c0bb5e7c6aab3b2e5d88c711
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
Antonio Nino Diaz