Commit Graph

85 Commits

Author SHA1 Message Date
Marti Bolivar 449170548b arch: riscv32: support CONFIG_WDOG_INIT
Borrow from an Arm Cortex-M convention where each Kconfig.soc can
define a 'config WDOG_INIT' that does watchdog initialization early in
the boot process if that SoC needs it.

Some SoCs have watchdogs that are enabled by default and need to be
turned off during reset handling (to be re-enabled if necessary by a
Zephyr watchdog driver).

Signed-off-by: Marti Bolivar <marti@foundries.io>
2019-01-25 11:59:46 -05:00
Marti Bolivar ef765b28cb arch: riscv32: follow-on tweaks
A couple of follow-on patches suggested after previous RISCV32 arch
changes were merged.

Tweak some help in arch/riscv32/kconfig to better work with the RST
docs.

Take out all the CONFIG_PRINTK ifdeffery in fatal.c. The cause_str()
routine should get compiled out if PRINTK=n anyway.

Signed-off-by: Marti Bolivar <marti@foundries.io>
2019-01-25 11:59:46 -05:00
Marti Bolivar f4c3163d3b arch: riscv32: provide a general mechanism for saving SoC context
RISC-V permits myriad extensions to the ISA, any of which may imply
additional context that must be saved and restored on ISR entry and
exit. The current in-tree example is the Pulpino core, which has extra
registers used by ISA extensions for running loops that shouldn't get
clobbered by an ISR.

This is currently supported by including pulpino-specific definitions
in the generic architecture code. This works, but it's a bit inelegant
and is something of a layering violation. A more generic mechanism is
required to support other RISC-V SoCs with similar requirements
without cluttering the arch code too much.

Provide that by extending the semantics of the existing
CONFIG_RISCV_SOC_CONTEXT_SAVE option to allow other SoCs to allocate
space for saving and restoring their own state, promoting the
currently pulpino-specific __soc_save_context / __soc_restore_context
routines to a RISC-V arch API.

The cost of making this generic is two more instructions in each ISR
to pass the SoC specific context to these routines in a0 rather than
just assuming the stack points to the right place. This is minimal,
and should have been done anyway to keep with the ABI.

As a first (and currently only in-tree) customer, convert the Pulpino
SoC code to this new mechanism.

Signed-off-by: Marti Bolivar <marti@foundries.io>
2018-12-04 22:54:23 -05:00
Marti Bolivar b85d893d60 arch: riscv32: fix IRQ handling bugs when benchmarking
The way that CONFIG_EXECUTION_BENCHMARKING=y is handled on this
architecture is incorrect. The goals are:

- call read_timer_start_of_isr() as close as possible to the
  beginning of the ISR
- call read_timer_end_of_isr() after all preparations have
  been made to call the driver-level IRQ handler, but it hasn't
  been called yet

The current implementation could cause kernel crashes, though.

The read_timer_start_of_isr() call is made before saving MEPC or any
SoC-specific context. The MEPC issue is not that big of a deal, but
doing it before saving SoC context could clobber state that hasn't
been saved yet and corrupt the kernel.

One example is a pulpino style RISC-V SoC. Some Pulpino cores have
extra registers that are used for ISA extensions used to generate code
for C loops. There's no guarantee read_timer_start_of_isr() will never
have a loop inside: in fact, the RISC-V User-Level ISA v2.2 explicitly
recommends using a loop to get the 64-bit value of the "cycle" CSR. A
Pulpino-like SoC with a cycle CSR could thus naturally have a
read_timer_start_of_isr() implementation that involves loops. Saving
the loop state before reading the timer would then be needed.

Fix this issue by moving the call to read_timer_start_of_isr to after
all context saving is done. (This is a fairer comparison to Arm
Cortex-M SoCs anyway, since register stacking is performed in hardware
on Cortex M and is done before the first ISR instruction executes.)

The call to read_timer_end_of_isr() has an issue as well: it's called
after the ISR's argument has been stored in a0 and the ISR address is
in t1, but before actually calling the ISR itself.

In the standard RV32I calling convention, both t1 and a0 are caller
saved, so read_timer_end_of_isr() is within its rights to set them to
any garbage, which we'll happily treat as a function and its argument
and execute.

Avoid that possibility by saving the register values to the stack in
this configuration.

Signed-off-by: Marti Bolivar <marti@foundries.io>
2018-12-04 22:54:23 -05:00
Marti Bolivar eef071ebc3 arch: riscv32: fix comment in offsets.c
The structure names appear to have changed.

Signed-off-by: Marti Bolivar <marti@foundries.io>
2018-12-04 22:54:23 -05:00
Marti Bolivar 7425195a25 arch: riscv32: fix INCLUDE_RESET_VECTOR Kconfig help
The generated stub doesn't actually initialize the CPU or jump to
__start. All it does is set up the interrupt stack and jump to
_PrepC. Fix the help.

Signed-off-by: Marti Bolivar <marti@foundries.io>
2018-12-04 22:54:23 -05:00
Marti Bolivar 0b234f2518 arch: riscv32: fix fatal.c build without printk
If CONFIG_PRINTK=n, cause_str will not be defined, and _Fault() will
fail to build. Fix that by ifdeffing out the printk call in that case.

Signed-off-by: Marti Bolivar <marti@foundries.io>
2018-12-04 22:54:23 -05:00
Flavio Ceolin 46715faa5c kernel: Remove _IntLibInit function
There were many platforms where this function was doing nothing. Just
merging its functionality with _PrepC function.

Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
2018-11-28 14:59:10 -08:00
Andrew Boie 383c451214 riscv32: add _arch_irq_connect_dynamic()
Implements dynamic interrupts.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2018-11-10 11:01:22 -05:00
Flavio Ceolin 61a1057ea5 kernel: Remove redundant type name
struct k_thread already has a pointer type k_tid_t, there is no need for
this definition to tcs.

Less symbols/names make the code cleaner and more readable.

Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
2018-10-31 19:43:47 -04:00
Adithya Baglody e9cb0ae72a arch: kernel_arch_func.h: Fix MISRA violation
Always compare unsigned interger type with another unsigned
integer type. Currently in nios2, posix, riscv32, x86 and xtensa
we were comparing the _kernel.nested variable with a signed
interger type. Fixed this violation.

Signed-off-by: Adithya Baglody <adithya.nagaraj.baglody@intel.com>
2018-10-17 12:17:58 -04:00
Andy Ross 9098a45c84 kernel: New timeslicing implementation
Instead of checking every time we hit the low-level context switch
path to see if the new thread has a "partner" with which it needs to
share time, just run the slice timer always and reset it from the
scheduler at the points where it has already decided a switch needs to
happen.  In TICKLESS_KERNEL situations, we pay the cost of extra timer
interrupts at ~10Hz or whatever, which is low (note also that this
kind of regular wakeup architecture is required on SMP anyway so the
scheduler can "notice" threads scheduled by other CPUs).  Advantages:

1. Much simpler logic.  Significantly smaller code.  No variance or
   dependence on tickless modes or timer driver (beyond setting a
   simple timeout).

2. No arch-specific assembly integration with _Swap() needed

3. Better performance on many workloads, as the accounting now happens
   at most once per timer interrupt (~5 Hz) and true rescheduling and
   not on every unrelated context switch and interrupt return.

4. It's SMP-safe.  The previous scheme kept the slice ticks as a
   global variable, which was an unnoticed bug.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
2018-10-16 15:03:10 -04:00
Krzysztof Chruscinski 27459a13e4 arch: Add LOG_PANIC to fault handlers
Added LOG_PANIC to fault handlers to ensure that log is flush and
logger processes messages in a blocking way in fault handler.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
2018-09-27 13:11:26 +05:30
Flavio Ceolin 67ca176754 headers: Fix headers across the project
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>
2018-09-17 15:49:26 -04:00
Anas Nashif abcf2ad5a8 kconfig: move soc selection to ZEPHYR_BASE/soc/
Rather than do that for each architecture, source SoC Kconfigs where the
code is maintained, under ZEPHYR_BASE/soc.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2018-09-13 00:56:48 -04:00
Anas Nashif 279cc2e448 riscv32: move soc to top-level dir soc/
Move the SoC outside of the architecture tree and put them at the same
level as boards and architectures allowing both SoCs and boards to be
maintained outside the tree.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2018-09-13 00:56:48 -04:00
Anas Nashif 483910ab4b systemview: add support natively using tracing hooks
Add needed hooks as a subsystem that can be enabled in any application.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2018-08-21 05:45:47 -07:00
Anas Nashif a2248782a2 kernel: event_logger: remove kernel_event_logger
Move to more generic tracing hooks that can be implemented in different
ways and do not interfere with the kernel.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2018-08-21 05:45:47 -07:00
Adithya Baglody 1d27b404a6 tests: benchmarks: timing_info: Enable benchmarks for riscv32.
This patch provides support needed to get timing related
information from riscv32 based SOC.

Signed-off-by: Adithya Baglody <adithya.nagaraj.baglody@intel.com>
2018-08-20 06:51:25 -07:00
Flavio Ceolin 0866d18d03 irq: Fix irq_lock api usage
irq_lock returns an unsigned int, though, several places was using
signed int. This commit fix this behaviour.

In order to avoid this error happens again, a coccinelle script was
added and can be used to check violations.

Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
2018-08-16 19:47:41 -07:00
Nathaniel Graff 218d7a0aa9 riscv: Rename the FE310 SoC to Sifive Freedom
FE310 is the name of one SoC out of a range of products in the SiFive
Freedom line. The FE310 SoC port in Zephyr is compatible with all of
these products, so rename the SoC to SiFive Freedom

Signed-off-by: Nathaniel Graff <nathaniel.graff@sifive.com>
2018-08-16 06:23:01 -07:00
Nathaniel Graff 970cfdb88b arch: riscv32: Move MEPC increment in irq_wrapper
Move the MEPC increment logic in __irq_wrapper such that the saved MEPC
is only incremented on a syscall (ecall instruction).

Signed-off-by: Nathaniel Graff <nathaniel.graff@sifive.com>
2018-08-15 08:07:41 -05:00
Ulf Magnusson 17f1b0adec Kconfig: Switch to improved globbing statements
A design flaw of 'gsource' is that there's no way to require at least
one file to match the glob pattern. This could lead to silent errors.

Switch to a new design, where a plain 'source' is globbing and requires
at least one file to match. A separate 'osource' (optional source)
statement is available for cases where it's okay for a pattern (or plain
filename) to not match any files.

'orsource' combines 'osource' and 'rsource' (relative source).

This commit search-replaces 'gsource' with 'source', but backwards
compatibility with 'gsource' is still maintained by making it an alias
for 'osource' (and by making 'grsource' an alias for 'orsource').

The three Kconfig files arch/{nios2,posix,xtensa}/Kconfig source
arch/{nios2,posix,xtensa}/soc/*/Kconfig, which doesn't match any files.
Use 'osource' for those. The soc/*/Kconfig files seem to be for
additional SoC-specific symbols, only none exist yet on those ARCHes.

Also use 'osource' for the source of $ENV_VAR_BOARD_DIR/Kconfig in
boards/Kconfig, which doesn't exist for all boards.

Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
2018-08-15 04:07:44 -07:00
Nathaniel Graff 45d5d5db48 boards: riscv: Convert HiFive1 to DTS
Adds DTS bindings for sifive,pwm0, sifive,uart0, sifive,spi0, and
riscv,plic0.

Signed-off-by: Nathaniel Graff <nathaniel.graff@sifive.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-08-13 18:35:38 -05:00
Ulf Magnusson ec3eff57e0 Kconfig: Use the first default with a satisfied condition
Up until now, Zephyr has patched Kconfig to use the last 'default' with
a satisfied condition, instead of the first one. I'm not sure why the
patch was added (it predates Kconfiglib), but I suspect it's related to
Kconfig.defconfig files.

There are at least three problems with the patch:

  1. It's inconsistent with how Kconfig works in other projects, which
     might confuse newcomers.

  2. Due to oversights, earlier 'range' properties are still preferred,
     as well as earlier 'default' properties on choices.

     In addition to being inconsistent, this makes it impossible to
     override 'range' properties and choice 'default' properties if the
     base definition of the symbol/choice already has 'range'/'default'
     properties.

     I've seen errors caused by the inconsistency, and I suspect there
     are more.

  3. A fork of Kconfiglib that adds the patch needs to be maintained.

Get rid of the patch and go back to standard Kconfig behavior, as
follows:

  1. Include the Kconfig.defconfig files first instead of last in
     Kconfig.zephyr.

  2. Include boards/Kconfig and arch/<arch>/Kconfig first instead of
     last in arch/Kconfig.

  3. Include arch/<arch>/soc/*/Kconfig first instead of last in
     arch/<arch>/Kconfig.

  4. Swap a few other 'source's to preserve behavior for some scattered
     symbols with multiple definitions.

     Swap 'source's in some no-op cases too, where it might match the
     intent.

  5. Reverse the defaults on symbol definitions that have more than one
     default.

     Skip defaults that are mutually exclusive, e.g. where each default
     has an 'if <some board>' condition. They are already safe.

  6. Remove the prefer-later-defaults patch from Kconfiglib.

Testing was done with a Python script that lists all Kconfig
symbols/choices with multiple defaults, along with a whitelist of fixed
symbols. The script also verifies that there are no "unreachable"
defaults hidden by defaults without conditions

As an additional test, zephyr/.config was generated before and after the
change for several samples and checked to be identical (after sorting).

This commit includes some default-related cleanups as well:

  - Simplify some symbol definitions, e.g. where a default has 'if FOO'
    when the symbol already has 'depends on FOO'.

  - Remove some redundant 'default ""' for string symbols. This is the
    implicit default.

Piggyback fixes for swapped ranges on BT_L2CAP_RX_MTU and
BT_L2CAP_TX_MTU (caused by confusing inconsistency).

Piggyback some fixes for style nits too, e.g. unindented help texts.

Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
2018-08-10 12:38:28 -07:00
Sebastian Bøe 347f9a0a2d cmake: LD: Specify the entry point in the linker scripts
The entry point can and therefore should be set by linker
scripts. Whenever possible one should express things in the source
language, be it .c or .ld, and not in code generators or in the build
system.

This patch removes the flag -eCONFIG_KERNEL_ENTRY from the linker's
command line and replaces it with the linker script command

ENTRY(CONFIG_KERNEL_ENTRY)

Signed-off-by: Sebastian Bøe <sebastian.boe@nordicsemi.no>
2018-07-03 17:18:14 -04:00
Ulf Magnusson 81d61601a8 arch: riscv32: Kconfig: Remove redundant 'default n' properties
Bool symbols implicitly default to 'n'.

A 'default n' can make sense e.g. in a Kconfig.defconfig file, if you
want to override a 'default y' on the base definition of the symbol. It
isn't used like that on any of these symbols though.

Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
2018-06-26 11:07:57 -05:00
Karol Gugala 1765d75ff4 riscv32: riscv-privilege: Microsemi Mi-V support
This commit adds support for Microsemi Mi-V RISC-V softcore CPU
running on the M2GL025 IGLOO2 FPGA development board.

signed-off-by: Karol Gugala <kgugala@antmicro.com>
2018-06-20 11:57:07 -04:00
Karol Gugala 23a5b5d171 riscv32: riscv-privilege: integrate common code
This commit moves code from fe310 platform into RISC-V privilege common
folder. This way the code can be reused by other platforms in future.

signed-off-by: Karol Gugala <kgugala@antmicro.com>
2018-06-20 11:57:07 -04:00
Savinay Dharmappa b7c4c0302c dts: riscv32: riscv32-qemu: Add device tree support
add device tree support for riscv32-qemu

Signed-off-by: Savinay Dharmappa <savinay.dharmappa@intel.com>
2018-06-13 08:47:52 -04:00
Andrew Boie 2dd91eca0e kernel: move thread monitor init to common code
The original implementation of CONFIG_THREAD_MONITOR would
try to leverage a thread's initial stack layout to provide
the entry function with arguments for any given thread.

This is problematic:

- Some arches do not have a initial stack layout suitable for
this
- Some arches never enabled this at all (riscv32, nios2)
- Some arches did not enable this properly
- Dropping to user mode would erase or provide incorrect
information.

Just spend a few extra bytes to store this stuff directly
in the k_thread struct and get rid of all the arch-specific
code for this.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2018-06-06 14:26:45 -04:00
Andy Ross 3a0cb2d35d kernel: Remove legacy preemption checking
The metairq feature exposed the fact that all of our arch code (and a
few mistaken spots in the scheduler too) was trying to interpret
"preemptible" threads independently.

As of the scheduler rewrite, that logic is entirely within sched.c and
doing it externally is redundant.  And now that "cooperative" threads
can be preempted, it's wrong and produces test failures when used with
metairq threads.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
2018-05-25 09:40:55 -07:00
Tomasz Bursztyka 61ef30d10e drivers/uart: Use dts to set uart options for ns16550 driver
Fix the ns16550 uart driver and relevant SoCs accordingly.
All generic settings are now DTS based.

Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
2018-05-18 20:18:50 +03:00
Ulf Magnusson 547ed9b563 kconfig: Make 'source' non-globbing and use 'gsource'
Until now, Zephyr has used a patched Kconfiglib that turns 'source' into
a globbing source (by replacing 'source' with 'gsource' at the token
level). There's two problems with this:

  - The patch needs to be maintained separately

  - Misspelled filenames are silently ignored, as they look like glob
    patterns that don't match anything

Fix it as follows:

  1. Replace all 'source' statements that use wildcards with 'gsource'

  2. Remove the custom Kconfiglib patch so that 'source' no longer globs

The sed pattern '/source.*[*?]/s/source/gsource/' was run over all
Kconfig* files to do the replacement.

source's that use environment variables that might contain glob patterns
were manually changed to gsource.

Building the docs in doc/ is a good test, as doc/Makefile deliberately
sets the environment variables to glob up as many Kconfig files as
possible.

Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
2018-05-08 11:14:12 +02:00
Tomasz Jurtsch 6dae38cb98 arch: riscv32: fe310: Always-On domain adress definition
Added always-on domain address definition

Signed-off-by: Tomasz Michalak <tmichalak@antmicro.com>
Signed-off-by: Karol Gugala <kgugala@antmicro.com>
Signed-off-by: Tomasz Jurtsch <tjurtsch@antmicro.com>
2018-04-05 08:08:08 -05:00
Anas Nashif 8949233390 kconfig: fix more help spacing issues
Fix Kconfig help sections and add spacing to be consistent across all
Kconfig file. In a previous run we missed a few.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2018-02-15 23:20:55 -05:00
Ramakrishna Pallala 301acb8e1b kernel: include: rename nano_internal.h to kernel_internal.h
Rename the nano_internal.h to kernel_internal.h and modify the
header file name accordingly wherever it is used.

Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com>
2018-01-31 10:07:21 -06:00
Anas Nashif 5146dbbc58 arch: architecture defines kernel entry
Make defining the kernel entry architecture specific and move it to the
architecture domain.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2017-12-27 14:16:08 -05:00
Anas Nashif 429c2a4d9d kconfig: fix help syntax and add spaces
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2017-12-13 17:43:28 -06:00
Anas Nashif a372eaedcc kconfig: move IRQ_OFFLOAD to a more generic place
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2017-11-27 22:15:30 -05:00
Sebastian Bøe 0829ddfe9a kbuild: Removed KBuild
Signed-off-by: Sebastian Boe <sebastian.boe@nordicsemi.no>
2017-11-08 20:00:22 -05:00
Sebastian Bøe 12f8f76165 Introduce cmake-based rewrite of KBuild
Introducing CMake is an important step in a larger effort to make
Zephyr easy to use for application developers working on different
platforms with different development environment needs.

Simplified, this change retains Kconfig as-is, and replaces all
Makefiles with CMakeLists.txt. The DSL-like Make language that KBuild
offers is replaced by a set of CMake extentions. These extentions have
either provided simple one-to-one translations of KBuild features or
introduced new concepts that replace KBuild concepts.

This is a breaking change for existing test infrastructure and build
scripts that are maintained out-of-tree. But for FW itself, no porting
should be necessary.

For users that just want to continue their work with minimal
disruption the following should suffice:

Install CMake 3.8.2+

Port any out-of-tree Makefiles to CMake.

Learn the absolute minimum about the new command line interface:

$ cd samples/hello_world
$ mkdir build && cd build
$ cmake -DBOARD=nrf52_pca10040 ..

$ cd build
$ make

PR: zephyrproject-rtos#4692
docs: http://docs.zephyrproject.org/getting_started/getting_started.html

Signed-off-by: Sebastian Boe <sebastian.boe@nordicsemi.no>
2017-11-08 20:00:22 -05:00
David B. Kinder 4600c37ff1 doc: Fix misspellings in header/doxygen comments
Occasional scan for misspellings missed during PR reviews

Signed-off-by: David B. Kinder <david.b.kinder@intel.com>
2017-10-17 19:40:29 -04:00
Andrew Boie c5c104f91e kernel: fix k_thread_stack_t definition
Currently this is defined as a k_thread_stack_t pointer.
However this isn't correct, stacks are defined as arrays. Extern
references to k_thread_stack_t doesn't work properly as the compiler
treats it as a pointer to the stack array and not the array itself.

Declaring as an unsized array of k_thread_stack_t doesn't work
well either. The least amount of confusion is to leave out the
pointer/array status completely, use pointers for function prototypes,
and define K_THREAD_STACK_EXTERN() to properly create an extern
reference.

The definitions for all functions and struct that use
k_thread_stack_t need to be updated, but code that uses them should
be unchanged.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2017-10-17 08:24:29 -07:00
Anas Nashif ae2e91155e arch: riscv32: define soc family in correct Kconfig
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2017-10-03 08:43:50 -04:00
Anas Nashif 1e8afbfe5a cleanup: remove lots of references to unified kernel
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
2017-09-12 12:37:11 -04:00
Andrew Boie 1e06ffc815 zephyr: use k_thread_entry_t everywhere
In various places, a private _thread_entry_t, or the full prototype
were being used. Be consistent and use the same typedef everywhere.

Signen-off-by: Andrew Boie <andrew.p.boie@intel.com>
2017-09-11 11:18:22 -07:00
Andrew Boie 8eaff5d6d2 k_thread_abort(): assert if abort essential thread
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>
2017-09-07 16:35:16 -07:00
Andrew Boie 507852a4ad kernel: introduce opaque data type for stacks
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>
2017-08-01 16:43:15 -07:00
Jean-Paul Etienne 34862656b9 riscv32: fixed context restore upon exiting ISR
By now, t0 register restored value is overwritten
by mepc and mstatus values prior to returning from ISR.

Fixed by restoring mstatus and mepc registers before
restoring the caller-saved registers.

As t0 is a temporary register within the riscv ABI,
this issue was unnoticed for most applications, except
for computation intensive apps, like crypto tests.

Signed-off-by: Jean-Paul Etienne <fractalclone@gmail.com>
2017-06-30 06:31:51 -04:00