4e5c093e66
This macro is slated for complete removal, as it's not possible on arches with an MPU stack guard to know the true buffer bounds without also knowing the runtime state of its associated thread. As removing this completely would be invasive to where we are in the 1.14 release, demote to a private kernel Z_ API instead. The current way that the macro is being used internally will not cause any undue harm, we just don't want any external code depending on it. The final work to remove this (and overhaul stack specification in general) will take place in 1.15 in the context of #14269 Fixes: #14766 Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
67 lines
2.4 KiB
C
67 lines
2.4 KiB
C
/*
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* Copyright (c) 2016 Jean-Paul Etienne <fractalclone@gmail.com>
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <kernel.h>
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#include <arch/cpu.h>
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#include <kernel_structs.h>
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#include <wait_q.h>
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#include <string.h>
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void z_thread_entry_wrapper(k_thread_entry_t thread,
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void *arg1,
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void *arg2,
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void *arg3);
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void z_new_thread(struct k_thread *thread, k_thread_stack_t *stack,
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size_t stack_size, k_thread_entry_t thread_func,
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void *arg1, void *arg2, void *arg3,
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int priority, unsigned int options)
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{
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char *stack_memory = Z_THREAD_STACK_BUFFER(stack);
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Z_ASSERT_VALID_PRIO(priority, thread_func);
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struct __esf *stack_init;
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z_new_thread_init(thread, stack_memory, stack_size, priority, options);
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/* Initial stack frame for thread */
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stack_init = (struct __esf *)
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STACK_ROUND_DOWN(stack_memory +
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stack_size - sizeof(struct __esf));
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/* Setup the initial stack frame */
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stack_init->a0 = (u32_t)thread_func;
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stack_init->a1 = (u32_t)arg1;
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stack_init->a2 = (u32_t)arg2;
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stack_init->a3 = (u32_t)arg3;
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/*
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* Following the RISC-V architecture,
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* the MSTATUS register (used to globally enable/disable interrupt),
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* as well as the MEPC register (used to by the core to save the
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* value of the program counter at which an interrupt/exception occcurs)
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* need to be saved on the stack, upon an interrupt/exception
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* and restored prior to returning from the interrupt/exception.
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* This shall allow to handle nested interrupts.
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*
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* Given that context switching is performed via a system call exception
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* within the RISCV32 architecture implementation, initially set:
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* 1) MSTATUS to SOC_MSTATUS_DEF_RESTORE in the thread stack to enable
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* interrupts when the newly created thread will be scheduled;
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* 2) MEPC to the address of the z_thread_entry_wrapper in the thread
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* stack.
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* Hence, when going out of an interrupt/exception/context-switch,
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* after scheduling the newly created thread:
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* 1) interrupts will be enabled, as the MSTATUS register will be
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* restored following the MSTATUS value set within the thread stack;
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* 2) the core will jump to z_thread_entry_wrapper, as the program
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* counter will be restored following the MEPC value set within the
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* thread stack.
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*/
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stack_init->mstatus = SOC_MSTATUS_DEF_RESTORE;
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stack_init->mepc = (u32_t)z_thread_entry_wrapper;
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thread->callee_saved.sp = (u32_t)stack_init;
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}
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