The TCB initializes the pid early, but the argvstack is not initialized
at that time. This may cause invalid addresses to be obtained when
nxsched_get_stackargs is called during task enumeration.
Initialize the argv pointer to NULL to enable safe validity checks.
Signed-off-by: hujun5 <hujun5@xiaomi.com>
Since the task and group structures are no longer allocated in the same space, the memory for group is allocated in the group_allocate() function, and no further allocation is needed during the task allocation process.
Signed-off-by: wangzhi16 <wangzhi16@xiaomi.com>
This reverts commit 29e50ffa73.
reason:
Placing the main thread and the gourd in the same memory block, and allocating and freeing memory simultaneously, presents the following two problems：
When the main thread creates a child thread and performs a detach operation, there is a possibility that the main thread may have exited, but the main thread's TCB (Transaction Control Block) may not have been released.
This could potentially cause the main thread's TCB to be double-freed. The core contradiction in this problem lies in binding the main thread's TCB (Trust Container Registry) and the group together. When releasing the main thread's TCB, an additional check is needed to ensure the main thread was the last to leave the group. If this check and the free operation are atomically guaranteed, the logic is sound, and double freeing won't occur. However, this atomicity cannot be completely guaranteed. If other free operations cause a block, problems still arise.
Signed-off-by: wangzhi16 <wangzhi16@xiaomi.com>
If the thread is blocked waiting on a event, then the
thread must be unblocked from the evnet to handle
the task cancellation.
Signed-off-by: Chengdong Wang wangchengdong@lixiang.com
Currently, there is duplicated code in nxsig_wait_irq() and nxsig_timeout().
This patch updates the input parameters of nxsig_wait_irq() so that it can
be reused in nxsig_timeout(), reducing code duplication and improving
maintainability.
Signed-off-by: Chengdong Wang <wangchengdong@lixiang.com>
Replace all nxsched_suspend/resume_*** with nxsched_switch_context
Delete nxsched_resume_scheduler in up_exit and call it uniformly in task_exit
Co-authored-by: yinshengkai <yinshengkai@xiaomi.com>
Signed-off-by: guoshengyuan1 <guoshengyuan1@xiaomi.com>
When the task has TCB_FLAG_CPU_LOCKED it is locked to the CPU regardless
of the affinity. There is no need to switch the affinity back and forth.
Signed-off-by: Jukka Laitinen <jukka.laitinen@tii.ae>
Change every occurence of up_switch_context to use this_task() as the first parameter.
"nxsched_add_readytorun" returns "true" if context switch is required. "nxsched_add_readytorun"
typically could only switch the assigned/running task to the one which is passed in as parameter.
But this is not strictly guaranteed in SMP; if other CPUs tweak with affinities or priorities,
it may be possible that the running task after the call is changed, but is some other
task from the readytorun list (and it should be, if there is higher priority one available or the
affinity of the added task prevents it to be scheduled in, but the previous head of the readytorun
list should run.
this_task() is always the correct one to switch to, since it always points to the tcb which was
just switched in by the nxsched_add_readytorun.
This is also a precursor to re-writing the SMP queue logic to remove pending lists for SMP.
Signed-off-by: Jukka Laitinen <jukka.laitinen@tii.ae>
This patch is a rework of the NuttX file descriptor implementation. The
goal is two-fold:
1. Improve POSIX compliance. The old implementation tied file description
to inode only, not the file struct. POSIX however dictates otherwise.
2. Fix a bug with descriptor duplication (dup2() and dup3()). There is
an existing race condition with this POSIX API that currently results
in a kernel side crash.
The crash occurs when a partially open / closed file descriptor is
duplicated. The reason for the crash is that even if the descriptor is
closed, the file might still be in use by the kernel (due to e.g. ongoing
write to file). The open file data is changed by file_dup3() and this
causes a crash in the device / drivers themselves as they lose access to
the inode and private data.
The fix is done by separating struct file into file and file descriptor
structs. The file struct can live on even if the descriptor is closed,
fixing the crash. This also fixes the POSIX issue, as two descriptors
can now point to the same file.
Signed-off-by: Ville Juven <ville.juven@unikie.com>
Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>
For some SMP calls it is necessary to lock the current CPU for the process
receiving the SMP call. This is done by setting the CPU affinity to the
current CPU and preventing the CPU selection algorithm from switching
CPUs.
dtcb->flags |= TCB_FLAG_CPU_LOCKED;
CPU_SET(dtcb->cpu, &dtcb->affinity);
However, this logic is currently broken, as CPU_SET is defined as:
#define CPU_SET(c,s) do { *(s) |= (1u << (c)); } while (0)
In order to assign tcb->cpu (the current CPU) to the affinity mask, the
mask must be cleared first by calling CPU_ZERO.
test:
1.use mps3-an547 build helloxx as module and run it
2.use qemu-armv7a:knsh test kernel build helloxx and run it
Signed-off-by: anjiahao <anjiahao@xiaomi.com>
There is no need for a gettid() syscall, as the thread ID is stable through
the life of the process. It is safe to put a copy of TID to TLS. This way
a user processes can access TID quickly via its own stack, instead of
having to use an expensive syscall.
Signed-off-by: Ville Juven <ville.juven@unikie.com>
reason:
The old implementation of the SMP call, even when using the "no wait" parameter,
could still result in waiting, if invoking it within a critical section
may lead to deadlocks. Therefore, in order to implement a truly asynchronous SMP
call strategy, we have added nxsched_smp_call_async.
Signed-off-by: hujun5 <hujun5@xiaomi.com>
The comment about the CPU index remaining stable is incorrect. There is no
guarantee the task does not yield during the exit process, meaning the CPU
can most definitely change. Also, there is no reason why it should not be
allowed to change.
This fixes a full system crash during process exit when the CPU changes
and we query the current task from the old CPU.
after
text data bss dec hex filename
269732 51065 63335 384132 5dc84 nuttx
before
text data bss dec hex filename
269784 51065 63335 384184 5dcb8 nuttx
size -50
Signed-off-by: hujun5 <hujun5@xiaomi.com>
reason:
In the kernel, we are planning to remove all occurrences of up_cpu_pause as one of the steps to
simplify the implementation of critical sections. The goal is to enable spin_lock_irqsave to encapsulate critical sections,
thereby facilitating the replacement of critical sections(big lock) with smaller spin_lock_irqsave(small lock)
Signed-off-by: hujun5 <hujun5@xiaomi.com>
reason:
In the kernel, we are planning to remove all occurrences of up_cpu_pause as one of the steps to
simplify the implementation of critical sections. The goal is to enable spin_lock_irqsave to encapsulate critical sections,
thereby facilitating the replacement of critical sections(big lock) with smaller spin_lock_irqsave(small lock)
Configuring NuttX and compile:
$ ./tools/configure.sh -l qemu-armv8a:nsh_smp
$ make
Running with qemu
$ qemu-system-aarch64 -cpu cortex-a53 -smp 4 -nographic
-machine virt,virtualization=on,gic-version=3
-net none -chardev stdio,id=con,mux=on -serial chardev:con
-mon chardev=con,mode=readline -kernel ./nuttx
Signed-off-by: hujun5 <hujun5@xiaomi.com>
reason:
1 To improve efficiency, we mimic Linux's behavior where preemption disabling is only applicable to the current CPU and does not affect other CPUs.
2 In the future, we will implement "spinlock+sched_lock", and use it extensively. Under such circumstances, if preemption is still globally disabled, it will seriously impact the scheduling efficiency.
3 We have removed g_cpu_lockset and used irqcount in order to eliminate the dependency of schedlock on critical sections in the future, simplify the logic, and further enhance the performance of sched_lock.
4 We set lockcount to 1 in order to lock scheduling on all CPUs during startup, without the need to provide additional functions to disable scheduling on other CPUs.
5 Cpu1~n must wait for cpu0 to enter the idle state before enabling scheduling because it prevents CPUs1~n from competing with cpu0 for the memory manager mutex, which could cause the cpu0 idle task to enter a wait state and trigger an assert.
size nuttx
before:
text data bss dec hex filename
265396 51057 63646 380099 5ccc3 nuttx
after:
text data bss dec hex filename
265184 51057 63642 379883 5cbeb nuttx
size -216
Configuring NuttX and compile:
$ ./tools/configure.sh -l qemu-armv8a:nsh_smp
$ make
Running with qemu
$ qemu-system-aarch64 -cpu cortex-a53 -smp 4 -nographic \
-machine virt,virtualization=on,gic-version=3 \
-net none -chardev stdio,id=con,mux=on -serial chardev:con \
-mon chardev=con,mode=readline -kernel ./nuttx
Signed-off-by: hujun5 <hujun5@xiaomi.com>
reason:
Currently, if we need to schedule a task to another CPU, we have to completely halt the other CPU,
manipulate the scheduling linked list, and then resume the operation of that CPU. This process is both time-consuming and unnecessary.
During this process, both the current CPU and the target CPU are inevitably subjected to busyloop.
The improved strategy is to simply send a cross-core interrupt to the target CPU.
The current CPU continues to run while the target CPU responds to the interrupt, eliminating the certainty of a busyloop occurring.
Signed-off-by: hujun5 <hujun5@xiaomi.com>
reason:
1In the scenario of active waiting, context switching is inevitable, and we can eliminate redundant judgments.
code size
before
hujun5@hujun5-OptiPlex-7070:~/downloads1/vela_sim/nuttx$ size nuttx
text data bss dec hex filename
262848 49985 63893 376726 5bf96 nuttx
after
hujun5@hujun5-OptiPlex-7070:~/downloads1/vela_sim/nuttx$ size nuttx
text data bss dec hex filename
263324 49985 63893 377202 5c172 nuttx
reduce code size by -476
Configuring NuttX and compile:
$ ./tools/configure.sh -l qemu-armv8a:nsh_smp
$ make
Running with qemu
$ qemu-system-aarch64 -cpu cortex-a53 -smp 4 -nographic \
-machine virt,virtualization=on,gic-version=3 \
-net none -chardev stdio,id=con,mux=on -serial chardev:con \
-mon chardev=con,mode=readline -kernel ./nuttx
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>
Calling malloc in the critical section may cause thread switching.
Add a retry mechanism to handle the situation where other threads have been successfully expanded.
Signed-off-by: yinshengkai <yinshengkai@xiaomi.com>
Signed-off-by: ligd <liguiding1@xiaomi.com>
Two things need to be done when vfork'ing:
- Must attach to parent's address environment (the addrenv is shared)
- Must allocate a kernel stack (where would the register context go otherwise)
Note that this code assumes the address environment is shared, since we
don't support fork() which would _clone_ the address environment instead.
Kthreads can share the group data so that to reduce overheads.
This implements shared kthread group via:
- use `tcb_s` instead of `task_tcb_s` for kthreads
- use `g_kthread_group` when creating kthreads
- use stackargs to start tasks and kthreads
see pull/12320 for test logs.
Signed-off-by: Yanfeng Liu <yfliu2008@qq.com>
we can use g_cpu_lockset to determine whether we are currently in the scheduling lock,
and all accesses and modifications to g_cpu_lockset, g_cpu_irqlock, g_cpu_irqset
are in the critical section, so we can directly operate on it.
test:
We can use qemu for testing.
compiling
make distclean -j20; ./tools/configure.sh -l qemu-armv8a:nsh_smp ;make -j20
running
qemu-system-aarch64 -cpu cortex-a53 -smp 4 -nographic -machine virt,virtualization=on,gic-version=3 -net none -chardev stdio,id=con,mux=on -serial chardev:con -mon chardev=con,mode=readline -kernel ./nuttx
Signed-off-by: hujun5 <hujun5@xiaomi.com>
sched implementation not depends on macro abstraction, so revert below commit:
This reverts commit 4e62d0005a
This reverts commit 0f0c370520
This reverts commit ad0efd04ee
Signed-off-by: chao an <anchao@lixiang.com>
This log appears for NSH internal commands in KERNEL build and
duplicates a lot with task_spawn: log. So drop it to make the
DEBUG_SCHED_INFO logging more readable.
Signed-off-by: Yanfeng Liu <yfliu2008@qq.com>
