A quick look at "man syscall" shows that in Linux, all architectures
support at least 6 argument system calls, with a few supporting 7. We
can at least do 6 in Zephyr.
x86 port modified to use EBP register to carry the 6th system call
argument.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
* Instead of a common system call entry function, we instead create a
table mapping system call ids to handler skeleton functions which are
invoked directly by the architecture code which receives the system
call.
* system call handler prototype specified. All but the most trivial
system calls will implement one of these. They validate all the
arguments, including verifying kernel/device object pointers, ensuring
that the calling thread has appropriate access to any memory buffers
passed in, and performing other parameter checks that the base system
call implementation does not check, or only checks with __ASSERT().
It's only possible to install a system call implementation directly
inside this table if the implementation has a return value and requires
no validation of any of its arguments.
A sample handler implementation for k_mutex_unlock() might look like:
u32_t _syscall_k_mutex_unlock(u32_t mutex_arg, u32_t arg2, u32_t arg3,
u32_t arg4, u32_t arg5, void *ssf)
{
struct k_mutex *mutex = (struct k_mutex *)mutex_arg;
_SYSCALL_ARG1;
_SYSCALL_IS_OBJ(mutex, K_OBJ_MUTEX, 0, ssf);
_SYSCALL_VERIFY(mutex->lock_count > 0, ssf);
_SYSCALL_VERIFY(mutex->owner == _current, ssf);
k_mutex_unlock(mutex);
return 0;
}
* the x86 port modified to work with the system call table instead of
calling a common handler function. fixed an issue where registers being
changed could confuse the compiler has been fixed; all registers, even
ones used for parameters, must be preserved across the system call.
* a new arch API for producing a kernel oops when validating system call
arguments added. The debug information reported will be from the system
call site and not inside the handler function.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
- _arch_user_mode_enter() implemented
- _arch_is_user_context() implemented
- _new_thread() will honor K_USER option if passed in
- System call triggering macros implemented
- _thread_entry_wrapper moved and now looks for the next function to
call in EDI
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
- There's no point in building up "validity" (declared volatile for some
strange reason), just exit with false return value if any of the page
directory or page table checks don't come out as expected
- The function was returning the opposite value as its documentation
(0 on success, -EPERM on failure). Documentation updated.
- This function will only be used to verify buffers from user-space.
There's no need for a flags parameter, the only option that needs to
be passed in is whether the buffer has write permissions or not.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
The byte ones are required for ns16550 uart driver which is
present on some arm socs. Add half-word ones for completeness.
Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
This was felt to be necessary at one point but actually isn't.
- When a thread is initialized to use a particular stack, calls will be
made to the MMU/MPU to restrict access to that stack to only that
thread. Once a stack is in use, it will not be generally readable even
if the buffer exists in application memory space.
- If a user thread wants to create a thread, we will need to have some
way to ensure that whatever stack buffer passed in is unused and
appropriate. Since unused stacks in application memory will be generally
accessible, we can just check that the calling thread to
k_thread_create() has access to the stack buffer passed in, it won't if
the stack is in use.
On ARM we had a linker definition for .stacks, but currently stacks are
just tagged with __noinit (which is fine).
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Previously, this was only done if an essential thread self-exited,
and was a runtime check that generated a kernel panic.
Now if any thread has k_thread_abort() called on it, and that thread
is essential to the system operation, this check is made. It is now
an assertion.
_NANO_ERR_INVALID_TASK_EXIT checks and printouts removed since this
is now an assertion.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
All system calls made from userspace which involve pointers to kernel
objects (including device drivers) will need to have those pointers
validated; userspace should never be able to crash the kernel by passing
it garbage.
The actual validation with _k_object_validate() will be in the system
call receiver code, which doesn't exist yet.
- CONFIG_USERSPACE introduced. We are somewhat far away from having an
end-to-end implementation, but at least need a Kconfig symbol to
guard the incoming code with. Formal documentation doesn't exist yet
either, but will appear later down the road once the implementation is
mostly finalized.
- In the memory region for RAM, the data section has been moved last,
past bss and noinit. This ensures that inserting generated tables
with addresses of kernel objects does not change the addresses of
those objects (which would make the table invalid)
- The DWARF debug information in the generated ELF binary is parsed to
fetch the locations of all kernel objects and pass this to gperf to
create a perfect hash table of their memory addresses.
- The generated gperf code doesn't know that we are exclusively working
with memory addresses and uses memory inefficently. A post-processing
script process_gperf.py adjusts the generated code before it is
compiled to work with pointer values directly and not strings
containing them.
- _k_object_init() calls inserted into the init functions for the set of
kernel object types we are going to support so far
Issue: ZEP-2187
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This patch fixes a couple of issues with the stack guard size and
properly constructs the STACK_ALIGN and STACK_ALIGN_SIZE definitions.
The ARM AAPCS requires that the stack pointers be 8 byte aligned. The
STACK_ALIGN_SIZE definition is meant to contain the stack pointer
alignment requirements. This is the required alignment at public API
boundaries (ie stack frames).
The STACK_ALIGN definition is the required alignment for the start
address for stack buffer storage. STACK_ALIGN is used to validate
the allocation sizes for stack buffers.
The MPU_GUARD_ALIGN_AND_SIZE definition is the minimum alignment and
size for the MPU. The minimum size and alignment just so happen to be
32 bytes for vanilla ARM MPU implementations.
When defining stack buffers, the stack guard alignment requirements
must be taken into consideration when allocating the stack memory.
The __align() must be filled in with either STACK_ALIGN_SIZE or the
align/size of the MPU stack guard. The align/size for the guard region
will be 0 when CONFIG_MPU_STACK_GUARD is not set, and 32 bytes when it
is.
The _ARCH_THREAD_STACK_XXXXXX APIs need to know the minimum alignment
requirements for the stack buffer memory and the stack guard size to
correctly allocate and reference the stack memory. This is reflected
in the macros with the use of the STACK_ALIGN definition and the
MPU_GUARD_ALIGN_AND_SIZE definition.
Signed-off-by: Andy Gross <andy.gross@linaro.org>
* apply STACK_GUARD_SIZE, no extra space will be added if
MPU_STACK_GUARD is disabled
* When ARC_STACK_CHECKING is enabled, MPU_STACK_GUARD will be
disabled
* add two new api: arc_core_mpu_default and arc_core_mpu_region
to configure mpu regions
* improve arc_core_mpu_enable and arc_core_mpu_disable
Signed-off-by: Wayne Ren <wei.ren@synopsys.com>
* add arc mpu driver
* modify the corresponding kconfig and kbuild
* currently only em_starterkit 2.2's em7d configuration
has mpu feature (mpu version 2)
* as the minimum region size of arc mpu version 2 is 2048 bytes and
region size should be power of 2, the stack size of threads
(including main thread and idle thread) should be at least
2048 bytes and power of 2
* for mpu stack guard feature, a stack guard region of 2048 bytes
is generated. This brings more memory footprint
* For arc mpu version 3, the minimum region size is 32 bytes.
* the codes are tested by the mpu_stack_guard_test and stackprot
Signed-off-by: Wayne Ren <wei.ren@synopsys.com>
Fix misspellings in .h files missed during code reviews
and affecting generated API documentation
Signed-off-by: David B. Kinder <david.b.kinder@intel.com>
An abnormal crash was encountered in ARMv6-M SoCs that don't have flash
starting at 0. With Zephyr OS the reason for this crash is that, on
ARMv6-M the system requires an exception vector table at the 0 address.
We implement the relocate_vector_table function to move the vector table
code to address 0 on systems which don't have the start of code already
at 0.
[kumar.gala: reworderd commit message, tweaked how we check if we need
to copy vector table]
Signed-off-by: Xiaorui Hu <xiaorui.hu@linaro.org>
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
The Xtensa port was the only one remaining to be converted to the new
way of connecting interrupts in Zephyr. Some things are still
unconverted, mainly the exception table, and this will be performed
another time.
Of note: _irq_priority_set() isn't called on _ARCH_IRQ_CONNECT(), since
IRQs can't change priority on Xtensa: while the architecture has the
concept of interrupt priority levels, each line has a fixed level and
can't be changed.
Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>
This patch adjusts the ARM MPU implementation to be compliant to the
recent changes that introduced the opaque kernel data types.
Signed-off-by: Andy Gross <andy.gross@linaro.org>
This patch always defines the ARCH_THREAD_STACK_XXX macros/functions
regardless of the MPU_STACK_GUARD usage. Only use MPU_STACK_GUARD when
determining the minimum stack alignment.
Signed-off-by: Andy Gross <andy.gross@linaro.org>
The mimimum mpu size is 32 bytes, but requires mpu base address to be
aligned on 32 bytes to work. Define architecture thread macro when
MPU_STACK_GUARD config to allocate stack with 32 more bytes.
Signed-off-by: Michel Jaouen <michel.jaouen@st.com>
This patch adds the allow flash write CONFIG option to the ARM MPU
configuration in privileged mode.
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@linaro.org>
Signed-off-by: Michael Scott <michael.scott@linaro.org>
Signed-off-by: David Brown <david.brown@linaro.org>
This patch adds the allow flash write CONFIG option to the NXP MPU
configuration in privileged mode.
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@linaro.org>
Signed-off-by: David Brown <david.brown@linaro.org>
This is a simpler memory arrangement; RAM will start with
app data, and everything after it is either kernel data or
unclaimed memory reserved for the kernel's use.
New linker variables are also implemented here.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Kernel data size shifts in between linker passes due to the addition
of the page tables. We would like application memory bounds to
remain fixed so that we can program the MMU permissions for it
at build time.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Page faults will additionally dump out some interesting
page directory and page table flags for the faulting
memory address.
Intended to help determine whether the page tables have been
configured incorrectly as we enable memory protection features.
This only happens if CONFIG_EXCEPTION_DEBUG is turned on.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Historically, stacks were just character buffers and could be treated
as such if the user wanted to look inside the stack data, and also
declared as an array of the desired stack size.
This is no longer the case. Certain architectures will create a memory
region much larger to account for MPU/MMU guard pages. Unfortunately,
the kernel interfaces treat both the declared stack, and the valid
stack buffer within it as the same char * data type, even though these
absolutely cannot be used interchangeably.
We introduce an opaque k_thread_stack_t which gets instantiated by
K_THREAD_STACK_DECLARE(), this is no longer treated by the compiler
as a character pointer, even though it really is.
To access the real stack buffer within, the result of
K_THREAD_STACK_BUFFER() can be used, which will return a char * type.
This should catch a bunch of programming mistakes at build time:
- Declaring a character array outside of K_THREAD_STACK_DECLARE() and
passing it to K_THREAD_CREATE
- Directly examining the stack created by K_THREAD_STACK_DECLARE()
which is not actually the memory desired and may trigger a CPU
exception
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Subsequent patches will set this guard page as unmapped,
triggering a page fault on access. If this is due to
stack overflow, a double fault will be triggered,
which we are now capable of handling with a switch to
a know good stack.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
We now create a special IA hardware task for handling
double faults. This has a known good stack so that if
the kernel tries to push stack data onto an unmapped page,
we don't triple-fault and reset the system.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
We will need this for stack memory protection scenarios
where a writable GDT with Task State Segment descriptors
will be used. The addresses of the TSS segments cannot be
put in the GDT via preprocessor magic due to architecture
requirments that the address be split up into different
fields in the segment descriptor.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This has one use-case: configuring the double-fault #DF
exception handler to do an IA task switch to a special
IA task with a known good stack, such that we can dump
diagnostic information and then panic.
Will be used for stack overflow detection in kernel mode,
as otherwise the CPU will triple-fault and reset.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
A user space buffer must be validated before required operation
can proceed. This API will check the current MMU
configuration to determine if the buffer held by the user is valid.
Jira: ZEP-2326
Signed-off-by: Adithya Baglody <adithya.nagaraj.baglody@intel.com>
This needs to be in <arch/cpu.h> so that it can be called
from the k_panic()/k_oops() macros in kernel.h.
Fixes build errors on these arches when using k_panic() or
k_oops().
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Different areas of memory will need to have different access
policies programmed into the MMU. We introduce MMU page alignment
to the following areas:
- The boundaries of the image "ROM" area
- The beginning of RAM representing kernel datas/bss/nonit
- The beginning of RAM representing app datas/bss/noinit
Some old alignment directives that are no longer necessary have
been removed.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This patch splits out the application data and bss from the
rest of the kernel. Choosing CONFIG_APPLICATION_MEMORY will
result in the application and kernel being split.
Signed-off-by: Andy Gross <andy.gross@linaro.org>
Implements CONFIG_APPLICATION_MEMORY for x86. Working in
XIP and non-XIP configurations.
This patch does *not* implement any alignment constraints
imposed by the x86 MMU, such enabling will be done later.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
patch adds necessary files and does the modification to the existing
files to add device support for x86 based intel quark microcontroller
Signed-off-by: Savinay Dharmappa <savinay.dharmappa@intel.com>
This is unmaintained and currently has no known users. It was
added to support a Wind River project. If in the future we need it
again, we should re-introduce it with an exception-based mechanism
for catching out-of-bounds memory queries from the debugger.
The mem_safe subsystem is also removed, it is only used by the
GDB server. If its functionality is needed in the future, it
shoudl be replaced with an exception-based mechanism.
The _image_{ram, rom, text}_{start, end} linker variables have
been left in place, they will be re-purposed and expanded to
support memory protection.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
The porting of the TI CC2650 SoC introduces the need to
write a specific configuration area (CCFG) at the end of the
flash. It is read by the bootloader ROM of the SoC.
For now, this is a quick hack and not a generic solution;
similar needs may arise with other hardware.
Signed-off-by: Geoffrey Le Gourriérec <geoffrey.legourrierec@smile.fr>
Clearing fields in the region descriptor attributes doesn't always have
the expected effect of revoking permissions. In the case of bus master
supervisor mode fields (MxSM), setting to zero actually enables read,
write, and execute access.
When we reworked handling of region descriptor 0, we inadvertently
enabled execution from RAM by clearing the MxSM fields and enabling the
descriptor. This caused samples/mpu_test run to throw a usage fault
instead of an MPU-triggered bus fault.
Fix this by setting all the MxSM fields to 2'b11, which gives supervisor
mode the same access as user mode.
Signed-off-by: Maureen Helm <maureen.helm@nxp.com>
We need to make sure that __NVIC_PRIO_BITS & CONFIG_NUM_IRQ_PRIO_BITS
are set to the same value. Add a simple build time check to ensure
this is the case. This is to catch future cases of issues like
ZEP-2243. This is a stop gap til we resolve ZEP-2262, which covers use
of both __NVIC_PRIO_BITS & CONFIG_NUM_IRQ_PRIO_BITS.
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
Macro is used to create a structure to specify the boot time
page table configuration. Needed by the gen_mmu.py script to generate
the actual page tables.
Linker script is needed for the following:
1. To place the MMU page tables at 4KByte boundary.
2. To keep the configuration structure created by
the Macro(mentioned above).
Signed-off-by: Adithya Baglody <adithya.nagaraj.baglody@intel.com>
Fixes an issue where if a thread calls k_panic() or k_oops()
with interrupts locked, control would return to the thread
and it would only be aborted after interrupts were unlocked
again.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
The REGION bits (bit[3:0]) of MPU_RBAR register can specify the number
of the region to update if the VALID bit (bit[4]) is also set.
If the bit[3:0] of "region_addr" are not zero, might cause to update
unexpected region. This could happen since we might not declare stack
memory with specific alignment.
This patch will mask the bit[4:0] of "region_addr" to prevent updating
unexpected region.
Signed-off-by: Chunlin Han <chunlin.han@linaro.org>
Inserting the IDT results in any data afterwards being shifted.
We want the memory addresses between the zephyr_prebuilt.elf
and zephyr.elf to be as close as possible. Insert some dummy
data in the linker script the same size as the gen_idt data
structures. Needed for forthcoming patches which generate MMU
page tables at build time.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
