- Save the FPU registers into the tcb so they don't get lost if the stack
frame for xcp.regs moves (as it does)
- Handle interger and FPU register save/load separately
- Integer registers are saved/loaded always, like before
- FPU registers are only saved during a context switch:
- Save ONLY if FPU is dirty
- Restore always if FPU has been used (not in FSTATE_OFF, FSTATE_INIT)
- Remove all lazy-FPU related logic from the macros, it is not needed
If a kernel stack exists, use that whenever the user process is in
privileged mode, i.e. running an exception or in system call. Previously
the exception context was stored into the user's stack, which is not ideal.
Why?
1. Because the exception entry status (REG_INT_CTX) is needed by the
kernel, and this is now in user memory which requires that the correct
user mappings are active when it is accessed.
2. The user must currently account for the exception stack frame (which
is BIG) in its own stack allocation. Moving the exception context save
to the kernel stack offloads this responsibility from the user to the
kernel, which is IMO the correct behavior.
3. The kernel access to user memory is currently allowed without condition,
however this is not ideal either. The privileged mode status CSR allows
blocking access to user memory via the STATUS_SUM-bit, which should be
disabled by default and only enabled when access to user space is really
needed. This patch allows implementing such features.
minidump will backtrace failure when use C code to save user context,
because the stack push operation in C code can disrupt the stack information.
Signed-off-by: zhangyuan21 <zhangyuan21@xiaomi.com>
Initially supporting ESP32-C3 chip, to be followed by other RISC-V-based
chips from Espressif.
Signed-off-by: Gustavo Henrique Nihei <gustavo.nihei@espressif.com>
The function is not relevant any longer, remove it. Also remove
save_addrenv_t, the parameter taken by up_addrenv_restore.
Implement addrenv_select() / addrenv_restore() to handle the temporary
instantiation of address environments, e.g. when a process is being
created.
This is preparation for moving address environments out of the group
structure into the tcb.
Why move ? Because the group is destroyed very early in the exit phase,
but the MMU mappings are needed until the context switch to the next
process is complete. Otherwise the MMU will lose its mappings and the
system will crash.
1.Move __XSTR from include/arch.h to include/irq.h
2.Move FLOAD/FSTORE and REGLOAD/REGSTORE from include/arch.h to src/common/riscv_internal.h
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
The FPU register saving upon vfork entry was missing.
Also added macro that tells the actual size of an FPU reg, instead
of just having a coefficient for qfpu/no-qfpu.
Summary:
- This commit adds support for semihosting and hostfs
Impact:
- None
Testing:
- Tested with nsh and nsh64 (defconfig will be updated later)
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
by renaming riscv_dispatch_syscall to sys_callx, so the caller
don't need the immediate step(syscallx->riscv_dispatch_syscall)
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
This implements initial support for kernel build (address environments,
page allocator) for RISC-V.
This is done a bit differently compared to the ARMV7 implementation:
- Support implemented for Sv39 MMU, however the implementation should be
extensible for other MMU types also.
- Instead of preserving and moving the L1 references around, a canonical
approach is used instead, where the page table base address register
is switched upon context switch.
- To preserve a bit of memory, only a single L1/L2 table is supported,
this gives access to 1GiB of virtual memory for each process, which
should be more than enough.
Some things worth noting:
- Assumes page pool is mapped with vaddr=paddr mappings
- The CONFIG_ARCH_XXXX_VBASE and CONFIG_ARCH_XXXX_NPAGES values are
ignored, with the exception of CONFIG_ARCH_DATA_VBASE which is used
for ARCH_DATA_RESERVE
- ARCH_DATA_RESERVE is placed at the beginning of the userspace task's
address environment
IRQ_NSTACKS, ARCH_CPU_COUNT, CONFIG_SMP_NCPUS all relate to each
other. However, a bit of clean up can be done and everything can
be merged into SMP_NCPUS.
The MPFS bootloader case works also as it requires only 1 IRQ stack
for the hart that executes as bootloader.
ESP32C3 use customized irq encoding so it's hard to share further code
with other risc-v based chips, in this patch, we keep the exception
number definition with risc-v spec.
Signed-off-by: Huang Qi <huangqi3@xiaomi.com>
- Add config "ARCH_USE_S_MODE" which controls whether the kernel
runs in M-mode or S-mode
- Add more MSTATUS and most of the SSTATUS register definitions
- Add more MIP flags for interrupt delegation
- Add handling of interrupts from S-mode
- Add handling of FPU from S-mode
- Add new context handling functions that are not dependent on the trap
handlers / ecall
NOTE: S-mode requires a companion SW (SBI) which is not yet implemented,
thus S-mode is not usable as is, yet.
