In a kernel build the cloning primitives are reached through a system call,
and armv7-a dispatches one by re-pointing the caller's own exception frame at
dispatch_syscall() and switching to the task's kernel stack. The snapshot the
entry point in fork.S takes for itself therefore describes the kernel-side
stub, and the frames below it are on a stack the child gets no copy of: a
child built from that snapshot resumes at a kernel address with a stack
pointer into its own user stack. It faulted with a prefetch abort at PC 0 on
qemu-armv7a:knsh, which is why the fork family had never been run there.
Record what the caller was actually doing instead. arm_syscall() stores the
exception frame of the outermost system call in xcp.sregs, mirroring
riscv_swint.c, and arm_fork() chooses where the caller's registers live:
arm_fork_syscall() when a user stack pointer is saved, rebuilding the child
from xcp.sregs so that it returns from the very same SVC
as the parent, in the same mode, on its own stack and
with no inherited system call nesting;
arm_fork_direct() otherwise -- the flat build, a kernel thread in any
build, and a build without a kernel stack, where the
call is dispatched on the caller's own stack so the
caller's frames are copied along with the kernel-side
ones.
Note that the discriminator is xcp.ustkptr rather than TCB_FLAG_SYSCALL. On
armv7-a the caller is the task that runs the kernel side of its own system
call, so being in a system call is not by itself a reason to distrust the
snapshot; the switch to the kernel stack is. Because arm_syscall() has
already re-pointed the frame by the time arm_fork() runs, the caller's PC,
CPSR and SP come from where arm_syscall() put them -- syscall[0].sysreturn,
syscall[0].cpsr and ustkptr -- and the rest from the frame itself.
Nothing selects the primitives on an ARM kernel build yet, so this commit
changes no configuration; it is what the next one needs to be correct.
Assisted-by: Claude Code:claude-opus-5
Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com>
ARM PIC has used r10 as the base register, but the tree has never been
consistent about it. Toolchain.defs gives CONFIG_BUILD_PIC
-mpic-register=r9 and CONFIG_PIC -mpic-register=r10, twenty-five lines
apart, and arm_initialstate.c sets REG_R9 from inline assembly under one
and REG_PIC under the other, with a comment reading "Set the PIC base
register (probably R10)". This settles it on r9 for all of PIC: NXFLAT,
ELF PIC and CONFIG_BUILD_PIC alike.
r9 is the right choice rather than an arbitrary one. It is the AAPCS
platform register, the "static base", and it is what GCC itself picks
for -msingle-pic-base on an EABI target; r10 is the non-EABI default.
It also removes a combination that cannot build today. Stack checking
adds -ffixed-r10 in armv7-m/Toolchain.defs and armv8-m/Toolchain.defs,
while CONFIG_PIC adds -mpic-register=r10, and GCC rejects the pair with
"unable to use 'r10' for PIC register". The comment above REG_PIC has
always said the register "can be R9 if stack checking is enabled", but
the definition was unconditionally REG_R10, so it would have named the
wrong register even had the build succeeded.
The thunk generator moves with the firmware. NXFLAT import stubs had
the register baked in as "add ip,ip,sl", so a module built for r9 would
load and then branch to a wild address on its first call out. The stubs
now come from NXFLAT_PIC_REG in the in-tree tool, which is built only
when CONFIG_NXFLAT is set, following the
CONFIG_BOARD_ETC_ROMFS_PASSWD_ENABLE precedent in tools/Unix.mk.
That leaves modules built before this change, and they are the reason
for the ABI marker. The NXFLAT header cannot carry a version: h_magic
is written by ldnxflat, which is GPL, derived from elf2flt, and stays
out of this repository, so it can never be changed in step with the
loader. The import table can, because both of its ends are in-tree --
mknxflat emits it and nxflat_bindimports() reads it -- and ldnxflat
passes it through untouched. So every module now imports
__nxflat_abi_v2, the base firmware defines it, and a module that does
not import it is refused.
Making the marker a real exported symbol rather than a name the loader
special-cases is what keeps it out of the build system's way: a board's
symbol table picks it up exactly as it picks up printf, so mksymtab.sh
and its equivalents need no change. It also gives the reverse direction
a diagnosis for free -- a module built against a newer ABI than its
firmware fails with "Exported symbol __nxflat_abi_v2 not found".
Most of the remaining churn is boards restating a default. ARCHPICFLAGS
is a "?=" default so that a board only speaks up when it differs, and
twenty-six were assigning the value the default already had. MKNXFLAT
gets the same treatment: thirteen boards named the same tool, and the
only thing that varies is ARM versus Thumb-2, which falls out of
CONFIG_ARM_THUMB. LDNXFLAT gains a default too -- it stays an
out-of-tree PATH lookup, but naming it centrally fixes boards that never
assigned it, where it expanded to nothing and handed make a recipe
beginning "-e", whose leading dash make ate as "ignore errors".
The non-ARM boards carrying -mpic-register=r10 lose it: it is an
ARM-only option, reachable only through CPICFLAGS, which is only used to
build NXFLAT modules, and no non-ARM board enables NXFLAT.
Boards keep nothing about PIC flags any more. ARCHPICFLAGS was set by
sixty-three of them and only ever fed CPICFLAGS, which is only used to
build NXFLAT modules; no board outside arch/arm enables NXFLAT, so every
non-ARM copy was setting a variable nothing read. Those are removed
rather than moved somewhere more central, which would only make dead
text look load-bearing. LDNXFLAT goes the same way as MKNXFLAT, for the
same reason: thirteen boards named the same tool that Toolchain.defs now
names once.
One of them was not merely redundant. am67/t3-gem-o1 asked for
"-mpic-register=r10 -ffixed-r10", which GCC refuses outright with
"unable to use 'r10' for PIC register" -- the very combination the
filter-out machinery in Toolchain.defs exists to prevent. It has
survived because that board does not build NXFLAT modules, so the flags
are never handed to a compiler. Renaming the register would have
carried the fault forward unchanged, so the line goes.
Tested on lm3s6965-ek:qemu-nxflat under QEMU, configured and built with
no overrides. The nxflat example runs the errno, hello and struct
modules with output identical to the same config built from master.
Built with the old out-of-tree thunk generator instead, the same
firmware refuses all three with ENOEXEC rather than locking up in a
HardFault, which is what this change is for. mps3-an547:picostest,
which is CONFIG_PIC without CONFIG_NXFLAT, builds clean and does not
build the thunk generator.
The .def files pick up two cosmetic changes here alongside the register:
a "Dyanamic" typo that codespell rejects, and a reworded comment in each
thunk_*.c. Neither appears in the emitted thunk -- both are in C
comments -- so the generated text is still what the upstream tool
produces, modulo the register itself.
BREAKING CHANGE: ARM PIC moves from r10 to r9. An NXFLAT module built
before this change has r10 baked into its import stubs and will not run
against a firmware carrying it; the two cannot be mixed. The module is
refused with ENOEXEC rather than branching to a wild address, by way of the
__nxflat_abi_v2 marker described below.
Quick fix: rebuild the module against this tree. Its source needs no
change. A board that reserved r10 by hand, or that assigned ARCHPICFLAGS
or MKNXFLAT to restate a default, should drop those assignments; nothing
else is affected, and CONFIG_PIC without CONFIG_NXFLAT needs no action.
Assisted-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com>
The register index layout for D16-D31 and FPU_CONTEXT_REGS was guarded
by CONFIG_ARM_HAVE_DPFPU32 (hardware capability) in three header files,
but all save/restore code in the corresponding .S files gates on
CONFIG_ARM_DPFPU32 (software enable).
These two macros are distinct:
CONFIG_ARM_HAVE_DPFPU32 - set by chip via 'select'; means hardware
has D16-D31 registers
CONFIG_ARM_DPFPU32 - user-selectable; means software has chosen
to use D16-D31 (requires hardware support)
When ARM_HAVE_DPFPU32=y and ARM_DPFPU32=n, the header defined
REG_FPSCR at offset 64 and FPU_CONTEXT_REGS=65, while the assembly
only saved S0-S31+FPSCR (33 words), placing FPSCR at offset 32.
This mismatch causes incorrect register access and wrong xcptcontext
sizing.
Signed-off-by: yaojiaqi <yaojiaqi@lixiang.com>
Add support to disable signals actions related struct
Co-authored-by: guoshichao <guoshichao@xiaomi.com>
Signed-off-by: Chengdong Wang <wangchengdong@lixiang.com>
The l1entry replace cause huge time when text/data is big,
Need 16KB per task to hold l1table.
Also critical_section no longer required, as table per-task maintained.
For complex goldfish emulator scarios can speed up:
enter_nsh/application_init_done,
from 23.517300/05:07.067500
to 01.501500/00:06.587300
at least 10 times faster.
As we don't have do x_NPAGES swap out etc.
Signed-off-by: buxiasen <buxiasen@xiaomi.com>
Inline & inline_function both used make confuze, let's modify all inline
in irq.h to inline_function, also clear the always_inline_funcion
declaration.
Signed-off-by: buxiasen <buxiasen@xiaomi.com>
This is continue work of https://github.com/apache/nuttx/pull/13726
We can utilize percpu storage to hold information about the
current running task. If we intend to implement this feature, we would
need to define two macros that help us manage this percpu information
effectively.
up_this_task: This macro is designed to read the contents of the percpu
register to retrieve information about the current
running task.This allows us to quickly access
task-specific data without having to disable interrupts,
access global variables and obtain the current cpu index.
up_update_task: This macro is responsible for updating the contents of
the percpu register.It is typically called during
initialization or when a context switch occurs to ensure
that the percpu register reflects the information of the
newly running task.
Signed-off-by: hujun5 <hujun5@xiaomi.com>
Most tools used for compliance and SBOM generation use SPDX identifiers
This change brings us a step closer to an easy SBOM generation.
Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
reason:
up_set_current_regs initially had two functions:
1: To mark the entry into an interrupt state.
2: To record the context before an interrupt/exception. If we switch to
a new task, we need to store the upcoming context regs by calling up_set_current_regs(regs).
Currently, we record the context in other ways, so the second function is obsolete.
Therefore, we need to rename up_set_current_regs to better reflect its actual meaning,
which is solely to mark an interrupt.
Signed-off-by: hujun5 <hujun5@xiaomi.com>
when we build mbedtls in vela with ghs compiler, the mbedtls need to
access __ARM_ARCH and __ARM_FEATURE_DSP, and to construct the inline asm
code based on these two macros.
With ghs compiler, these two macros are not defined, and will be
evaluated as 0 by default, and thus will using to wrong inline asm code,
in order to handle this issue, we need to add conversion between the ghs
and gcc with __ARM_ARCH, __ARM_FEATURE_DSP
Signed-off-by: guoshichao <guoshichao@xiaomi.com>
Some app with same code runs on different cores in AMP mode,
need the physical core on which the function is called.
Signed-off-by: hujun5 <hujun5@xiaomi.com>
Signed-off-by: fangxinyong <fangxinyong@xiaomi.com>
According to the current design on the armv7-a platform,
only fiq is processed in TEE, while irq and fiq are processed
in REE.
If we enable the irq function in TEE, when we process
some signal-related scenarios in TEE,
such as the ostest sighand testcase, this testcase will
call up_irq_enable() to enable irq interrupt in the
arm_sigdeliver() function. After the signal processing
logic is executed, irq will be disabled again.
During the interval of enabling irq, some external device
irq interrupts will be enabled, but these external device
irqs do not have corresponding handlers registered in TEE,
so an "unexpected irq isr exception" will be triggered.
Therefore, a better implementation is to keep the original
implementation of the up_irq_enable() function, that is,
to enable only fiq in TEE and to enable irq and fiq in REE.
Then for vendor-specific requirements, such as the need to
briefly enable irq during the TEE initialization process
and then disable irq before starting APz in TEE, we directly
provide a separate implementation of enabling irq in the
vendor, without modifying the implementation of the public
up_enable_irq() function.
Signed-off-by: guoshichao <guoshichao@xiaomi.com>
Purpose: make the the os crash when busyloop with interrupt disable
Follow the arm gicv2 spec, if we want to use the IRQ and FIQ
simultaneously when not using the processor Security Externsions.
We should:
1. IRQ to Group 1 and FIQ to Group 0;
2. Set CICC_CTLR.FIQEn to 1;
Then in NuttX:
1. implement the arm_decodefiq and directly crash in it;
2. provide interface to change the IRQ to FIQ, e.g. change the
watchdog IRQ to FIQ, so the watchdog can trigger even with the
interrupt disabled (up_irq_save() called);
Signed-off-by: wangbowen6 <wangbowen6@xiaomi.com>
Signed-off-by: zhangyuan21 <zhangyuan21@xiaomi.com>
Signed-off-by: ligd <liguiding1@xiaomi.com>
Current `CONFIG_PAGING` refers to an experimental implementation
to enable embedded MCUs with some limited RAM space to execute
large programs from some non-random access media.
On-demand paging should be implemented for the kernel mode with
address environment implementation enabled.
The current context save implementation saves registers of each task
to xcp context, which is unnecessary because most of the arm registers are
already saved in the task stack, this commit replace the xcp context with
stack context to improve context switching performance and reduce the tcb
space occupation of tcb instance.
Signed-off-by: chao.an <anchao@xiaomi.com>
In AArch32, the frame pointer is stored in register R11 for ARM code or register R7 for Thumb code.
In AArch64, the frame pointer is stored in register X29.
Signed-off-by: chao.an <anchao@xiaomi.com>
libs/: Remove references to CONFIG_DISABLE_SIGNALS. Signals can no longer be disabled.
syscall/: Remove references to CONFIG_DISABLE_SIGNALS. Signals can no longer be disabled.
wireless/: Remove references to CONFIG_DISABLE_SIGNALS. Signals can no longer be disabled.
Documentation/: Remove references to CONFIG_DISABLE_SIGNALS. Signals can no longer be disabled.
include/: Remove references to CONFIG_DISABLE_SIGNALS. Signals can no longer be disabled.
drivers/: Remove references to CONFIG_DISABLE_SIGNALS. Signals can no longer be disabled.
sched/: Remove references to CONFIG_DISABLE_SIGNALS. Signals can no longer be disabled.
configs: Remove references to CONFIG_DISABLE_SIGNALS. Signals can no longer be disabled.
arch/xtensa: Remove references to CONFIG_DISABLE_SIGNALS. Signals can no longer be disabled.
arch/z80: Remove references to CONFIG_DISABLE_SIGNALS. Signals can no longer be disabled.
arch/x86: Remove references to CONFIG_DISABLE_SIGNALS. Signals can no longer be disabled.
arch/renesas and arch/risc-v: Remove references to CONFIG_DISABLE_SIGNALS. Signals can no longer be disabled.
arch/or1k: Remove all references to CONFIG_DISABLE_SIGNALS. Signals are always enabled.
arch/misoc: Remove all references to CONFIG_DISABLE_SIGNALS. Signals are always enabled.
arch/mips: Remove all references to CONFIG_DISABLE_SIGNALS. Signals are always enabled.
arch/avr: Remove all references to CONFIG_DISABLE_SIGNALS. Signals are always enabled.
arch/arm: Remove all references to CONFIG_DISABLE_SIGNALS. Signals are always enabled.
