dacd176991
This patch adds the code managing the syscalls. The privileged stack is setup before jumping into the real syscall. Signed-off-by: Carlo Caione <ccaione@baylibre.com>
117 lines
2.9 KiB
C
117 lines
2.9 KiB
C
/*
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* Copyright (c) 2019 Carlo Caione <ccaione@baylibre.com>
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* @file
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* @brief New thread creation for ARM64 Cortex-A
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*
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* Core thread related primitives for the ARM64 Cortex-A
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*/
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#include <kernel.h>
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#include <ksched.h>
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#include <wait_q.h>
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#include <arch/cpu.h>
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#ifdef CONFIG_USERSPACE
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static bool is_user(struct k_thread *thread)
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{
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return (thread->base.user_options & K_USER) != 0;
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}
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#endif
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void arch_new_thread(struct k_thread *thread, k_thread_stack_t *stack,
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char *stack_ptr, k_thread_entry_t entry,
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void *p1, void *p2, void *p3)
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{
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z_arch_esf_t *pInitCtx;
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pInitCtx = Z_STACK_PTR_TO_FRAME(struct __esf, stack_ptr);
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pInitCtx->x0 = (uint64_t)entry;
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pInitCtx->x1 = (uint64_t)p1;
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pInitCtx->x2 = (uint64_t)p2;
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pInitCtx->x3 = (uint64_t)p3;
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/*
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* - ELR_ELn: to be used by eret in z_arm64_exit_exc() to return
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* to z_thread_entry() with entry in x0(entry_point) and the
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* parameters already in place in x1(arg1), x2(arg2), x3(arg3).
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* - SPSR_ELn: to enable IRQs (we are masking FIQs).
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*/
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#ifdef CONFIG_USERSPACE
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/*
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* If the new thread is a user thread we jump into
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* arch_user_mode_enter() when still in EL1.
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*/
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if (is_user(thread)) {
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pInitCtx->elr = (uint64_t)arch_user_mode_enter;
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} else {
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pInitCtx->elr = (uint64_t)z_thread_entry;
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}
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pInitCtx->tpidrro_el0 = 0x0;
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thread->arch.priv_stack_start = 0;
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#else
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pInitCtx->elr = (uint64_t)z_thread_entry;
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#endif
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pInitCtx->spsr = SPSR_MODE_EL1T | DAIF_FIQ_BIT;
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/*
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* We are saving SP to pop out entry and parameters when going through
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* z_arm64_exit_exc()
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*/
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thread->callee_saved.sp = (uint64_t)pInitCtx;
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thread->switch_handle = thread;
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}
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void *z_arch_get_next_switch_handle(struct k_thread **old_thread)
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{
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*old_thread = _current;
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return z_get_next_switch_handle(*old_thread);
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}
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#ifdef CONFIG_USERSPACE
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FUNC_NORETURN void arch_user_mode_enter(k_thread_entry_t user_entry,
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void *p1, void *p2, void *p3)
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{
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z_arch_esf_t *pInitCtx;
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uintptr_t stack_ptr;
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/* Setup the private stack */
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_current->arch.priv_stack_start = (uint64_t)(_current->stack_obj);
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/* Reset the stack pointer to the base discarding any old context */
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stack_ptr = Z_STACK_PTR_ALIGN(_current->stack_info.start +
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_current->stack_info.size -
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_current->stack_info.delta);
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/*
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* Reconstruct the ESF from scratch to leverage the z_arm64_exit_exc()
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* macro that will simulate a return from exception to move from EL1t
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* to EL0t. On return we will be in userspace.
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*/
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pInitCtx = Z_STACK_PTR_TO_FRAME(struct __esf, stack_ptr);
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pInitCtx->spsr = DAIF_FIQ_BIT | SPSR_MODE_EL0T;
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pInitCtx->elr = (uint64_t)z_thread_entry;
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/* The thread will be in user context */
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pInitCtx->tpidrro_el0 = 0x1;
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pInitCtx->x0 = (uint64_t)user_entry;
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pInitCtx->x1 = (uint64_t)p1;
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pInitCtx->x2 = (uint64_t)p2;
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pInitCtx->x3 = (uint64_t)p3;
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/* All the needed information is already in the ESF */
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z_arm64_userspace_enter(pInitCtx);
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CODE_UNREACHABLE;
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}
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#endif
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