This commit partially reverts the changes introduced in
(bbe1a19786), where the PSP
modification, the interrupt enabling, and the branch to main
thread were refactored in C functions. This introduced an issue
with stack usage when compiling without any optimization.
Reverting to use assembly functions to jump to main thread
ensures, now, that the pointer to main() is preserved intact
while changing the PSP and passed correctly to z_thread_entry().
Fixes#14471.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This commit simply moves the MPU re-programming of
dynamic regions during initialization to occur right
before switching PSP to the main thread stack. As a
result, the MPU re-programming will execute using
the interrupt stack. No functional changes are
introduced.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
The clang ARM assembler is a bit stricter than GNU as, make a few
changes so things build with both
Signed-off-by: Peter Smith <peter.smith@linaro.org>
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
Architecture defconfigs are not used anymore and are stale. Remove them
to avoid confusion.
Related to #14442
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
The shared page is inherently used in multiprocessor contexts where
the compiler optimizer can trip us up (specifically, a spin on
num_active_pus was being hoisted out of the loop on some gcc's). Put
the volatile declartion into the struct pointer itself instead of
relying on the code to get it right.
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
Currently thread abort doesn't work if a thread is currently scheduled
on a different CPU, because we have no way of delivering an interrupt
to the other CPU to force the issue. This patch adds a simple
framework for an architecture to provide such an IPI, implements it
for x86_64, and uses it to implement a spin loop in abort for the case
where a thread is currently scheduled elsewhere.
On SMP architectures (xtensa) where no such IPI is implemented, we
fall back to waiting on an arbitrary interrupt to occur. This "works"
for typical code (and all current tests), but of course it cannot be
guaranteed on such an architecture that k_thread_abort() will return
in finite time (e.g. the other thread on the other CPU might have
taken a spinlock and entered an infinite loop, so it will never
receive an interrupt to terminate itself)!
On non-SMP architectures this patch changes no code paths at all.
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
Before we're initialized and can use proper synchronization, the CPU
initialization path spins on the thread entry function to be non-null.
But the data wasn't tagged volatile, and with gcc 8.2.1 (but not
6.2.0) the optimizer was hoisting the reads to SMP init would spin
forever.
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
The previous scheme where the xuk layer would call out to the to
"fetch" the stack for a SMP CPU at startup was sorta weird, and an
impedance mismatch with Zephyr which has a "start this CPU" call
instead. It also got broken when x86_64 started launching CPUs
(correctly) on their interrupt stacks instead of a temporary area;
they weren't ready yet when xuk initialization was happening and the
system would deadlock waiting for code that can't run yet to provide a
stack.
Note that this preserves the somewhat quirky behavior that Zephyr's
CPU numbering is just the order in which the SMP CPUs emerge from
initialization and not a hardware ID.
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
When this code was written, there was no "stack frame" struct defined.
There is now, so use that for clarity and concision. Also remove an
obvious comment (I mean, duh, we can put any segment selectors in
those fields we want).
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
There was a spot where the early boot code was logging using %p to
emit an integer, and Coverity doesn't like that. Fixes#14420 and
Fixes#14418
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
Speculative execution side channel attacks can read the
entire FPU/SIMD register state on affected Intel Core
processors, see CVE-2018-3665.
We now have two options for managing floating point
context between threads on x86: CONFIG_EAGER_FP_SHARING
and CONFIG_LAZY_FP_SHARING.
The mitigation is to unconditionally save/restore these
registers on context switch, instead of the lazy sharing
algorithm used by CONFIG_LAZY_FP_SHARING.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
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>
We add two points where we add lfences to disable
speculation:
* In the memory buffer validation code, which takes memory
addresses and sizes from userspace and determins whether
this memory is actually accessible.
* In the system call landing site, after the system call ID
has been validated but before it is used.
Kconfigs have been added to enable these checks if the CPU
is not known to be immune on X86.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
We introduce hidden Kconfigs for all speculative
side channel attacks that we plan to address in the
kernel and update the existing ones to indicate their
CVEs.
This list keeps growing, so introduce a new config
CONFIG_X86_NO_SPECULATIVE_VULNERABILITIES, for CPUs
which don't speculatively execute, or are otherwise
immune by design.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Commit 45a7e5d076 removed scripts/sysgen
and _k_task_list/_k_event_list sections are no longer being used.
So remove them.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
The commit adds an __ASSERT statement when configuring
the ARMv8-M build-in stack guard for supervisor thread
stack overflow protection, to catch the case when the
stack_info.start does not point to the beginning of the
thread stack allocated area, pointed by stack_obj.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This commit does the following:
- moves the reservation of the area for local thread data
inside the arch-specific _new_thread() function,
- aligns the end of the thread's stack with the granularity
of the MPU, already at thread's initialization, moving it
out of userspace_enter() function. In this way, the local
thread data are stored inside the thread stack area that
is, later, assigned unprivileged RW permissions (if thread
enters user mode).
- passes the right thread stack size information to function
_new_thread_init(), which stores it into stack_info.start.
As a result, the whole usable User Thread stack area (i.e.
excluding a possible guard area) falls inside the region
programmed as unprivileged RW, during context-switch.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
Appears within a menu that already has 'depends on ARM_SECURE_FIRMWARE'.
'depends on FOO' on a menu will add 'depends on FOO' to each item within
it. 'if FOO' work similarly.
Tip: When adding a symbol, check its dependencies in the menuconfig
('ninja menuconfig', then / to jump to the symbol). The menuconfig also
shows how the file with the symbol got included, so if you see
duplicated dependencies, it's easy to hunt down where they come from.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
Appears within a menu that already has a 'depends on ARCH_POSIX'.
'depends on FOO' on a menu will add 'depends on FOO' to each item within
it. 'if FOO' work similarly.
Tip: When adding a symbol, check its dependencies in the menuconfig
('ninja menuconfig', then / to jump to the symbol). The menuconfig also
shows how the file with the symbol got included, so if you see
duplicated dependencies, it's easy to hunt down where they come from.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
- The ARC CPU_HAS_MPU dependencies were added within the menu
menu "ARCH MPU Options"
depends on CPU_HAS_MPU
(arch/arc/core/mpu/Kconfig is source'd within it).
- The ARM CPU_HAS_MPU dependencies were redundantly added by
if CPU_HAS_MPU
source "arch/arm/core/cortex_m/mpu/Kconfig"
endif
and by some 'depends on CPU_HAS_MPU' within that file. Remove the
'depends on' and move the 'if' into the file instead.
Tip: Jump to symbols with '/' in the menuconfig and press '?' to check
their dependencies. If there are duplicated dependencies, the
'included via ...' path can be handy to discover where they are added.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
The lowest level of the x86_64 bit port supports the full 64 bit ABI
just fine, but Zephyr does not (yet) and builds under the x32 ABI
instead. The xuk layer can be built with or without the -mx32 switch,
and it had a configurable in a header to tell it what it was. At some
point during development I swept through and turned all those tunables
into kconfigs, but this one wasn't used by zephyr and so it got the
CONFIG_* rename but never had an entry added to a Kconfig file to
match it, and eventually got picked up by Ulf's unused symbol
detector.
Rename back. It will probably become a kconfig again someday when we
need it. Fixes#14059.
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
Refactor internal ARM v7m and v8m MPU region re-programming
functions to take as argument a pointer to k_mem_partition
objects, instead of the object itself.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
Refactor internal NXP MPU region re-programming functions
to take as argument a pointer to k_mem_partition objects,
instead of the object itself.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This commit refactors the MPU region re-programming functions,
to take as argument an array of pointers to memory partition
structures, instead of the whole array of the partitions. In
this way the stack usage can be minimized, if the actual
partition information is kept in statically allocated memory.
instead of the map itself.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
The "ARM Cortex-M options" menu is already within a 'if CPU_CORTEX_M',
so no need to put 'depends on CPU_CORTEX_M' on it.
Tip: Jump to symbols with '/' in the menuconfig and press '?' to check
their dependencies. If there are duplicated dependencies, the
'included via ...' path can be handy to discover where they are added.
Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
Based on the definition of _ARCH_THREAD_STACK_DEFINE() macro
for ARM, the MPU Stack Guard region is placed inside the
allocated stack object, only if
CONFIG_MPU_REQUIRES_POWER_OF_TWO_ALIGNMENT and CONFIG_USERSPACE
are both set. For ARM stack objects, allocated using the
_ARCH_THREAD_STACK_DEFINE() macro, such as the threads' stacks
and the interrupt stack, the above must be reflected on how we
set the initial start of the stacks.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
On x86, if a supervisor thread belonging to a memory domain
adds a new partition to that domain, subsequent context switches
to another thread in the same domain, or dropping itself to user
mode, does not have the correct setup in the page tables.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
We need a copy of the flags field for ever PTE we are
updating, we can't just keep OR-ing in the address
field.
Fixes issues seen when setting flags for memory regions
larger than a page.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
During speculative execution, non-present pages are treated
as valid, which may expose their contents through side
channels.
Any non-present PTE will now have its address bits zeroed,
such that any speculative reads to them will go to the NULL
page.
The expected hit on performance is so minor that this is
enabled at all times.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
The SOC code can set whether it's known that the CPU
is immune, don't default to turning this off.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Retpolines were never completely implemented, even on x86.
Move this particular Kconfig to only concern itself with
the assembly code, and don't default it on ever since we
prefer SSBD instead.
We can restore the common kernel-wide CONFIG_RETPOLINE once
we have an end-to-end implementation.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
PAE page tables (the only kind we support) have 512
entries per page directory, not 1024.
Fixes: #13838
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit introduces a generic arch/arm function to evaluate
thread stack corruption. The function shall be used upon
occurrence of MemManage and Bus Faults.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This commit adds an explanatory note in the places
where we manually adjust the PSP after stacking Bus
and MemManage errors, stressing that this is due to
the fact that interrupt tail-chaining cannot always
be guaranteed by the processor.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
The commit removes a redundant check for imprecise bus fault,
when a precise bus fault has occurred, now that we have
re-worked the BusFault handler to iterate through all possible
bus errors.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This commit reworks the logic, based on which we assess
thread stack corruptions upon BusFault exceptions triggered
by the NXP MPU module. BusFaults rely on calling external
function to assess whether a thread stack corruption due to
overflow has occurred. Upon detection of stack corruption,
the current stack pointer is manually adjusted upwards, to
prevent un-stacking errors from firing up upon returning from
the exception.
Additionally, the commit allows to be checking for all different
types of BusFault occurrences that are reported through BFSR,
without stopping after having spotted the first BusFault type.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This commit reworks the logic, based on which we assess
thread stack corruptions upon MemManageFault exceptions.
Furthermore, it takes out all kernel-related logic and relies
on calling external function 'evaluate_thread_stack_corruption'
to assess whether a thread stack overflow has occurred. Upon
detection of stack corruption, the current stack pointer is
manually adjusted upwards, to prevent un-stacking errors from
firing up upon returning from the exception.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This commit improves the debug message on UsageFaults
related to Stack overflow, stating that the context
area is not valid. An inline comment is added, with
more detailed explanation.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This commit fixes two Constant Expression Result errors,
in the NXP MPU driver due to incompatible integer types.
Fixes#13836.
Fixes#13865.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This commit fixes several essential inline comments in the
core assembly code for ARM, improving code readability.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This commit applies the same fixes, concering the Constant
Expression Result errors identified in the ARMv7-M and the
NXP MPU drivers, into the ARMv8-M MPU implementation.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This commit fixes two Constant Expression Result errors,
in the ARMv7-M MPU driver due to incompatible integer types.
Fixes#13844.
Fixes#13854.
Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
