Since the necessary register values are now pre-computed and
stored in the memory domain struct, we can use them directly
in various assembly locations, thus replacing the function
call to xtensa_swap_update_page_tables().
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
When context switching and dealing with non-nested interrupts,
the context to be restored are saved in the thread stack.
When userspace is enabled, this means saving context into
the user stacks for user threads. This allows PS values to be
manipulated externally by setting PS.RING in the saved PS
value to 0, resulting in granting kernel access privilege when
the thread is restored. To prevent this, we store the PS value
into the thread struct instead, where user threads cannot
manipulate that. Note that nested interrupts and syscalls are
not using the user stack but the interrupt stack and thread
privileged stack respectively, where they are not accessible
under user mode.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
Userspace support for Xtensa architecture using Xtensa MMU.
Some considerations:
- Syscalls are not inline functions like in other architectures because
some compiler issues when using multiple registers to pass parameters
to the syscall. So here we have a function call so we can use
registers as we need.
- TLS is not supported by xcc in xtensa and reading PS register is
a privileged instruction. So, we have to use threadptr to know if a
thread is an user mode thread.
Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
There was a bunch of dead historical cruft floating around in the
arch/xtensa tree, left over from older code versions. It's time to do
a cleanup pass. This is entirely refactoring and size optimization,
no behavior changes on any in-tree devices should be present.
Among the more notable changes:
+ xtensa_context.h offered an elaborate API to deal with a stack frame
and context layout that we no longer use.
+ xtensa_rtos.h was entirely dead code
+ xtensa_timer.h was a parallel abstraction layer implementing in the
architecture layer what we're already doing in our timer driver.
+ The architecture thread structs (_callee_saved and _thread_arch)
aren't used by current code, and had dead fields that were removed.
Unfortunately for standards compliance and C++ compatibility it's
not possible to leave an empty struct here, so they have a single
byte field.
+ xtensa_api.h was really just some interrupt management inlines used
by irq.h, so fold that code into the outer header.
+ Remove the stale assembly offsets. This architecture doesn't use
that facility.
All told, more than a thousand lines have been removed. Not bad.
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
Any word started with underscore followed by and uppercase letter or a
second underscore is a reserved word according with C99.
Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
The issue was that cpStack was changed to a memory buffer by commit
https://gerrit.zephyrproject.org/r/#/c/12816
However the assembly code was expecting it to be a pointer and thus
issuing an indirection, that leads to wrong addresses.
The fix removed this unnecessary indirection and thus the inherent
invalid memory access exception.
Issue: ZEP-1997
Change-Id: I843f049212f2d116a01b05367a284209f463a5e7
Signed-off-by: Mazen NEIFER <mazen@nestwave.com>
Master branch changed requirements for license headers while this
branch has been in development.
Change-Id: I9bce16ff275057a4bb664019628fc9b6de7aef7c
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
