arch_user_string_nlen() did not exactly work correctly as any
invalid pointers being passed are de-referenced naively, which
results in DTLB misses (MMU) or access errors (MPU). However,
arch_user_string_nlen() should always return to the caller
with appropriate error code set, and should never result in
thread termination. Since we are usually going through syscalls
when arch_user_string_nlen() is called, for MMU, the DTLB miss
goes through double exception. Since the pointer is invalid,
there is a high chance there is not even a L2 page table
associated with that bad address. So the DTLB miss cannot be
handled and it just keeps looping in double exception until
there is another exception type where we get to the C handler.
However, the stack frame is no longer the frame associated
with the call to arch_user_string_nlen(), and the call return
address would be incorrect. Forcing this incorrect address as
the next PC would result in some other exceptions, e.g.
illegal instruction, which would go to the C handler again.
This time it will go to the end of handler and would result
in thread termination. For MPU systems, access errors would
simply result in thread terminal in the C handler. Because of
these reasons, change the arch_user_string_nlen() to check if
the memory region can be accessed under kernel mode first
before feeding it to strnlen().
Also remove the exception fixup arrays as there is nothing
there anymore.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
Namespaced the generated headers with `zephyr` to prevent
potential conflict with other headers.
Introduce a temporary Kconfig `LEGACY_GENERATED_INCLUDE_PATH`
that is enabled by default. This allows the developers to
continue the use of the old include paths for the time being
until it is deprecated and eventually removed. The Kconfig will
generate a build-time warning message, similar to the
`CONFIG_TIMER_RANDOM_GENERATOR`.
Updated the includes path of in-tree sources accordingly.
Most of the changes here are scripted, check the PR for more
info.
Signed-off-by: Yong Cong Sin <ycsin@meta.com>
- spill windows in the current context (before switching task) since
it will be erased.
- Remove unnucessary load/mov
Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
For CPU without THREADPTR, we need an alternative way to figure
out if we are in user context. This extends the user context
check to do that via a brief syscall.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
Calling z_mrsh_* functions require 7 arguments where the 7th is
the stack frame. Only the first 6 arguments are passed by
registers where the 7th must be done via stack. However, this
is not being done and an incorrect argument was being passed to
the z_mrsh_* functions as stack frame pointer. An obvious issue
would be dumping of stack during kernel oops, as incorrect data
was being printed or crashes due to inaccessible memory. So fix
it by properly populating the stack with correct stack frame
pointer as outgoing argument for the caller of z_mrsh_*
functions.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
There is no need to do a call4 and jx. Simply do a callx4
is enough.
Also amended the now incorrect comment about how syscall
trampoline is set up. It is now a straight call4 instead of
the old 2x call4.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
Adds the necessary code required to unconditionally save/restore the
HiFi AE registers. The macros xchal_cp1_load and xchal_cp1_store
are defined in the Xtensa HAL.
Signed-off-by: Peter Mitsis <peter.mitsis@intel.com>
Some Xtensa cores do not support NMI, so XCHAL_HAVE_NMI=0 and
XCHAL_NMILEVEL won't be defined at all causing
arch/xtensa/include/xtensa-asm2-s.h to throw compilation error.
Fixes: #67855
Signed-off-by: Maciej Kusio <maciejkusio@meta.com>
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
Simply to provide some consistencies on file naming under
arch/xtensa.
These are all internally used files and are not public.
So there is no need to provide a deprecation path for
them.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
Use thread local storage to check whether or not a thread is running
in user mode. This allows to use threadptr to properly support tls.
Signed-off-by: Flavio Ceolin <flavio.ceolin@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>
