This commit follows the parent commit work.
This commit introduces the following major changes.
1. Move all directories and files in 'include/zephyr/arch/arm/aarch32'
to the 'include/zephyr/arch/arm' directory.
2. Change the path string which is influenced by the changement 1.
Signed-off-by: Huifeng Zhang <Huifeng.Zhang@arm.com>
It doesn't make sense to keep the aarch32 directory in the
'arch/arm/core' directory as the aarch64 has been moved out.
This commit introduces the following major changes.
1. Move all directories and files in 'arch/arm/core/aarch32' to
'arch/arm/core' and remove the 'arch/arm/core/aarch32' directory.
2. Move all directories and files in 'arch/include/aarch32' to
'arch/include' and remove the 'arch/include/aarch32' directory.
3. Remove the nested including in the 'arch/include/kernel_arch_func.h'
and 'arch/include/offsets_short_arch.h' header files.
4. Change the path string which is influenced by the changement 1
and 2.
Signed-off-by: Huifeng Zhang <Huifeng.Zhang@arm.com>
Before introducing the code for ARM64 (AArch64) we need to relocate the
current ARM code to a new AArch32 sub-directory. For now we can assume
that no code is shared between ARM and ARM64.
There are no functional changes. The code is moved to the new location
and the file paths are fixed to reflect this change.
Signed-off-by: Carlo Caione <ccaione@baylibre.com>
Promote the private z_arch_* namespace, which specifies
the interface between the core kernel and the
architecture code, to a new top-level namespace named
arch_*.
This allows our documentation generation to create
online documentation for this set of interfaces,
and this set of interfaces is worth treating in a
more formal way anyway.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
In this commit we implement the assembly functions in userspace.S
- z_arm_userspace_enter()
- z_arm_do_syscall()
- z_arch_user_string_nlen()
for ARMv6-M and ARMv8-M Baseline architecture. We "inline" the
implementation for Baseline, along with the Mainline (ARMv7-M)
implementation, i.e. we rework only what is required to build
for Baseline Cortex-M.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
Add more documentation and inline explanatory comments in
assembly sources swap_helper.S and userspace.S and remove
redundant/wrong documentation when applicable.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
ARM user space requires ARM_MPU. We can, therefore,
remove the unnecessary #ifdef CONFIG_ARM_MPU blocks
in userspace.S. In addition, we do minor refactoring
in z_arm_userspace_enter(), and z_arm_pendsv(), and
z_arm_svc(), aiming at reducing the push/pop overhead
as much as possible.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
A clean-up commit that removes unnecessary inclusions from
assembly files in arm/core and arm/core/cortex_m. It also
ogranizes the inclusions based on the following order and
set of rules:
- never include kernel_structs.h
- include toolchain.h and linker/sections.h in all ASM files
- include offsets-short.h, if ASM accesses offset constants
- include arch/cpu.h, if ASM accesses CMSIS constants
(defined locally in include/arch/arm)
- include file-specific headers, if needed (e.g. vector-table.h)
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This patch re-namespaces global variables and functions
that are used only within the arch/arm/ code to be
prefixed with z_arm_.
Some instances of CamelCase have been corrected.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
z_arm_do_syscall is executing in privileged mode. This implies
that we shall not be allowed to use the thread's default
unprivileged stack, (i.e push to or pop from it), to avoid any
possible stack corruptions.
Note that since we execute in PRIV mode and no MPU guard or
PSPLIM register is guarding the end of the default stack, we
won't be able to detect any stack overflows.
This commit implement the above change, by forcing
z_arm_do_syscall() to FIRST switch to privileged
stack and then do all the preparations to execute
the system call.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
ip register holds the stack_info.size (it is passed as argument
into z_arch_user_mode_enter(.)). We trust that the value of
stack_info.size contains the accurate size of the writable
stack buffer, above stack_info.start (as specified in kernel.h).
Therefore, we do not need to subtract any bytes for the MPU
stack guard. This allows us to clean-up one more occurrence of
CONFIG_MPU_REQUIRES_POWER_OF_TWO_ALIGNMENT in userspace.S.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
Rename reserved function names in arch/ subdirectory. The Python
script gen_priv_stacks.py was updated to follow the 'z_' prefix
naming.
Signed-off-by: Patrik Flykt <patrik.flykt@intel.com>
This commit initializes the thread.mode variable, right before
dropping thread privilege level to user mode. This is required,
as we need to know the privilege level of the thread, in case
we need to context-switch it -out and -in again (e.g. in case
an interrupt triggers a context-switch).
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This commit updates the thread.mode variable, in system
calls, whenever we modify the execution privilege level.
We need to do this, in order to be able to properly handle
context-switching triggered by ISRs, while doing the system
calls. The commit ensures that a context-switch, triggered
by an ISR during or after,a system call will preserve the
right privilege level.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
Update reserved function names starting with one underscore, replacing
them as follows:
'_k_' with 'z_'
'_K_' with 'Z_'
'_handler_' with 'z_handl_'
'_Cstart' with 'z_cstart'
'_Swap' with 'z_swap'
This renaming is done on both global and those static function names
in kernel/include and include/. Other static function names in kernel/
are renamed by removing the leading underscore. Other function names
not starting with any prefix listed above are renamed starting with
a 'z_' or 'Z_' prefix.
Function names starting with two or three leading underscores are not
automatcally renamed since these names will collide with the variants
with two or three leading underscores.
Various generator scripts have also been updated as well as perf,
linker and usb files. These are
drivers/serial/uart_handlers.c
include/linker/kobject-text.ld
kernel/include/syscall_handler.h
scripts/gen_kobject_list.py
scripts/gen_syscall_header.py
Signed-off-by: Patrik Flykt <patrik.flykt@intel.com>
_arch_configure_dynamic_mpu_regions() may re-program the MPU
Stack Guard, to guard the privilege stack for overflows,
(if building with option CONFIG_MPU_STACK_GUARD). There is a
risk of actually overflowing the stack while doing the
re-programming. We minimize the risk by placing the
re-programming function immediately after we have switched to
the privileged stack so that the whole privilege stack area is
available for this critical operation.
Note that the risk for overflow is higher if using the normal
thread stack, since we do not control how much stack is actually
left, when user invokes _arm_userspace_enter().
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This commit moves the clearing of PSPLIM before determining the
privilege stack start and size. In this way the clearing can be
done without unnecessary pushing and popping r3 core register.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This commit provides two fixes for the ARMv8-M built-in stack
protection in userspace.S. First, it clears the PSPLIM register
before setting the PSP to the privileged stack. In the wake of
this, the privilege stack area can now be positioned enywhere,
i.e. does not have to be above the user stack area. Second, it
removes unncessary push/pop when clearing the PSPLIM register,
upon returning from the system call, since the r3 register is
not used anymore in this routine.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This patch adjusts the way we are doing push/pop operations before
making function calls inside of assembly routines. ARM requires 8
byte aligned stack operations across public interfaces. This means
that we need to be sure to push multiples of 2 registers.
Fixes#2108
Signed-off-by: Andy Gross <andy.gross@linaro.org>
This commit introduces an ARM API that allows the user to
program a set of dynamic MPU regions at run-time. The API
function is invoked every time the memory map needs to be
re-programmed (for example at thread context-switch). The
functionality is implementated in arm_core_mpu.c.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This commit extends the support of built-in thread stack
protection (i.e. based on the stack pointer limit registers)
in ARMv8-M, so that it works with user mode. The commit
does the following:
- enables and disables the stack limit checking on the
privileged stack, inside thread system calls, and upon
entering user mode,
- does not enable stack limit checking in context switch,
if the thread is in user mode.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
Before entering userspace, the MPU stack guard is
configured to guard the default (i.e. afterwards, the "user")
thread stack, as the privileged stack has not yet been set. Upon
entering userspace the MPU stack guard needs to be re-programmed
to the privileged stack, otherwise, there is a risk that the
first system call might be serviced without privileged stack
protection, if it occurs before any context-switch. This commit
fixes this issue, by calling configure_mpu_stack_guard(..) upon
userspace entering.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
_k_syscall_table is an array of function pointers and is declared as
such in C sources, this makes it an STT_OBJECT[0] in the symbol
table. But when the same symbol is declared in assembly, it is
declared to be a function, which would make the symbol an STT_FUNC.
When linking with LTO this type inconsistency results in the warning:
real-ld: Warning: type of symbol `_k_syscall_table' changed from 2 to
1 in /tmp/cc84ofK0.ltrans8.ltrans.o
To fix this warning we declare the table with GDATA instead of GTEXT,
which will change the type from 'function' to 'object'.
[0]
https://docs.oracle.com/cd/E19455-01/816-0559/chapter6-79797/index.html
Signed-off-by: Sebastian Bøe <sebastian.boe@nordicsemi.no>
There exist two symbols that became equivalent when PR #9383 was
merged; _SYSCALL_LIMIT and K_SYSCALL_LIMIT. This patch deprecates the
redundant _SYSCALL_LIMIT symbol.
_SYSCALL_LIMIT was initally introduced because before PR #9383 was
merged K_SYSCALL_LIMIT was an enum, which couldn't be included into
assembly files. PR #9383 converted it into a define, which can be
included into assembly files, making _SYSCALL_LIMIT redundant.
Likewise for _SYSCALL_BAD.
Signed-off-by: Sebastian Bøe <sebastian.boe@nordicsemi.no>
Uses fixup infrastructure to safely abort if we get an MPU
fault when examining a string passed in from user mode.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
The r7 register is used as a frame pointer on ARM Thumb. As result, it
cannot be modified by the assembly code in functions using stack frame.
This commit replaces r7 by r8, which is a general purpose register.
Also it fixes#7704.
Signed-off-by: Piotr Zięcik <piotr.ziecik@nordicsemi.no>
Upon return from a syscall handlers, the r1, r2, and r3 registers
could contain random kernel data that should not be leaked to user
mode. Zero these out before returning from _arm_do_syscall().
Fixes#7753.
The invocation macros need a clobber if r1, r2, or r3 are not used
to carry syscall arguments. This is a partial fix for #7754 but
there appear to be other issues.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This patch changes the ARM system calls to use registers for passing
or arguments. This removes the possibility of stack issues when
callers do not adhere to the AAPCS.
Fixes#6802
Signed-off-by: Andy Gross <andy.gross@linaro.org>
During the transition of privilege levels while performing syscalls,
the ARM documentation recommends flushing the pipeline to avoid
pre-fetched instructions from being executed with the previous
privilege level.
The manual says:
4.16 CONTROL register
(...) after programming the CONTROL register, an ISB instruction
should be used.
(...) This is not implemented in the Cortex M0 processor.
Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>
This patch adds support for userspace on ARM architectures. Arch
specific calls for transitioning threads to user mode, system calls,
and associated handlers.
Signed-off-by: Andy Gross <andy.gross@linaro.org>
