| /* |
| * Copyright (c) 2013-2014 Wind River Systems, Inc. |
| * |
| * SPDX-License-Identifier: Apache-2.0 |
| */ |
| |
| /** |
| * @file |
| * @brief New thread creation for ARM Cortex-M |
| * |
| * Core thread related primitives for the ARM Cortex-M processor architecture. |
| */ |
| |
| #include <kernel.h> |
| #include <toolchain.h> |
| #include <kernel_structs.h> |
| #include <wait_q.h> |
| |
| #ifdef CONFIG_USERSPACE |
| extern u8_t *z_priv_stack_find(void *obj); |
| #endif |
| |
| /** |
| * |
| * @brief Initialize a new thread from its stack space |
| * |
| * The control structure (thread) is put at the lower address of the stack. An |
| * initial context, to be "restored" by __pendsv(), is put at the other end of |
| * the stack, and thus reusable by the stack when not needed anymore. |
| * |
| * The initial context is an exception stack frame (ESF) since exiting the |
| * PendSV exception will want to pop an ESF. Interestingly, even if the lsb of |
| * an instruction address to jump to must always be set since the CPU always |
| * runs in thumb mode, the ESF expects the real address of the instruction, |
| * with the lsb *not* set (instructions are always aligned on 16 bit halfwords). |
| * Since the compiler automatically sets the lsb of function addresses, we have |
| * to unset it manually before storing it in the 'pc' field of the ESF. |
| * |
| * <options> is currently unused. |
| * |
| * @param stack pointer to the aligned stack memory |
| * @param stackSize size of the available stack memory in bytes |
| * @param pEntry the entry point |
| * @param parameter1 entry point to the first param |
| * @param parameter2 entry point to the second param |
| * @param parameter3 entry point to the third param |
| * @param priority thread priority |
| * @param options thread options: K_ESSENTIAL, K_FP_REGS |
| * |
| * @return N/A |
| */ |
| |
| void z_new_thread(struct k_thread *thread, k_thread_stack_t *stack, |
| size_t stackSize, k_thread_entry_t pEntry, |
| void *parameter1, void *parameter2, void *parameter3, |
| int priority, unsigned int options) |
| { |
| char *pStackMem = Z_THREAD_STACK_BUFFER(stack); |
| char *stackEnd; |
| /* Offset between the top of stack and the high end of stack area. */ |
| u32_t top_of_stack_offset = 0U; |
| |
| Z_ASSERT_VALID_PRIO(priority, pEntry); |
| |
| #if defined(CONFIG_USERSPACE) |
| /* Truncate the stack size to align with the MPU region granularity. |
| * This is done proactively to account for the case when the thread |
| * switches to user mode (thus, its stack area will need to be MPU- |
| * programmed to be assigned unprivileged RW access permission). |
| */ |
| stackSize &= ~(CONFIG_ARM_MPU_REGION_MIN_ALIGN_AND_SIZE - 1); |
| |
| #ifdef CONFIG_THREAD_USERSPACE_LOCAL_DATA |
| /* Reserve space on top of stack for local data. */ |
| u32_t p_local_data = STACK_ROUND_DOWN(pStackMem + stackSize |
| - sizeof(*thread->userspace_local_data)); |
| |
| thread->userspace_local_data = |
| (struct _thread_userspace_local_data *)(p_local_data); |
| |
| /* Top of actual stack must be moved below the user local data. */ |
| top_of_stack_offset = (u32_t) |
| (pStackMem + stackSize - ((char *)p_local_data)); |
| |
| #endif /* CONFIG_THREAD_USERSPACE_LOCAL_DATA */ |
| #endif /* CONFIG_USERSPACE */ |
| |
| #if defined(CONFIG_MPU_REQUIRES_POWER_OF_TWO_ALIGNMENT) \ |
| && defined(CONFIG_USERSPACE) |
| /* This is required to work-around the case where the thread |
| * is created without using K_THREAD_STACK_SIZEOF() macro in |
| * k_thread_create(). If K_THREAD_STACK_SIZEOF() is used, the |
| * Guard size has already been take out of stackSize. |
| */ |
| stackSize -= MPU_GUARD_ALIGN_AND_SIZE; |
| #endif |
| |
| #if defined(CONFIG_FLOAT) && defined(CONFIG_FP_SHARING) \ |
| && defined(CONFIG_MPU_STACK_GUARD) |
| /* For a thread which intends to use the FP services, it is required to |
| * allocate a wider MPU guard region, to always successfully detect an |
| * overflow of the stack. |
| * |
| * Note that the wider MPU regions requires re-adjusting the stack_info |
| * .start and .size. |
| * |
| */ |
| if ((options & K_FP_REGS) != 0) { |
| pStackMem += MPU_GUARD_ALIGN_AND_SIZE_FLOAT |
| - MPU_GUARD_ALIGN_AND_SIZE; |
| stackSize -= MPU_GUARD_ALIGN_AND_SIZE_FLOAT |
| - MPU_GUARD_ALIGN_AND_SIZE; |
| } |
| #endif |
| stackEnd = pStackMem + stackSize; |
| |
| struct __esf *pInitCtx; |
| |
| z_new_thread_init(thread, pStackMem, stackSize, priority, |
| options); |
| |
| /* Carve the thread entry struct from the "base" of the stack |
| * |
| * The initial carved stack frame only needs to contain the basic |
| * stack frame (state context), because no FP operations have been |
| * performed yet for this thread. |
| */ |
| pInitCtx = (struct __esf *)(STACK_ROUND_DOWN(stackEnd - |
| (char *)top_of_stack_offset - sizeof(struct __basic_sf))); |
| |
| #if defined(CONFIG_USERSPACE) |
| if ((options & K_USER) != 0) { |
| pInitCtx->basic.pc = (u32_t)z_arch_user_mode_enter; |
| } else { |
| pInitCtx->basic.pc = (u32_t)z_thread_entry; |
| } |
| #else |
| pInitCtx->basic.pc = (u32_t)z_thread_entry; |
| #endif |
| |
| #if defined(CONFIG_CPU_CORTEX_M) |
| /* force ARM mode by clearing LSB of address */ |
| pInitCtx->basic.pc &= 0xfffffffe; |
| #endif |
| |
| pInitCtx->basic.a1 = (u32_t)pEntry; |
| pInitCtx->basic.a2 = (u32_t)parameter1; |
| pInitCtx->basic.a3 = (u32_t)parameter2; |
| pInitCtx->basic.a4 = (u32_t)parameter3; |
| pInitCtx->basic.xpsr = |
| 0x01000000UL; /* clear all, thumb bit is 1, even if RO */ |
| |
| thread->callee_saved.psp = (u32_t)pInitCtx; |
| #if defined(CONFIG_CPU_CORTEX_R) |
| pInitCtx->basic.lr = (u32_t)pInitCtx->basic.pc; |
| thread->callee_saved.spsr = A_BIT | T_BIT | MODE_SYS; |
| thread->callee_saved.lr = (u32_t)pInitCtx->basic.pc; |
| #endif |
| thread->arch.basepri = 0; |
| |
| #if defined(CONFIG_USERSPACE) || defined(CONFIG_FP_SHARING) |
| thread->arch.mode = 0; |
| #if defined(CONFIG_USERSPACE) |
| thread->arch.priv_stack_start = 0; |
| #endif |
| #endif |
| |
| /* swap_return_value can contain garbage */ |
| |
| /* |
| * initial values in all other registers/thread entries are |
| * irrelevant. |
| */ |
| } |
| |
| #ifdef CONFIG_USERSPACE |
| |
| FUNC_NORETURN void z_arch_user_mode_enter(k_thread_entry_t user_entry, |
| void *p1, void *p2, void *p3) |
| { |
| |
| /* Set up privileged stack before entering user mode */ |
| _current->arch.priv_stack_start = |
| (u32_t)z_priv_stack_find(_current->stack_obj); |
| #if defined(CONFIG_MPU_STACK_GUARD) |
| /* Stack guard area reserved at the bottom of the thread's |
| * privileged stack. Adjust the available (writable) stack |
| * buffer area accordingly. |
| */ |
| #if defined(CONFIG_FLOAT) && defined(CONFIG_FP_SHARING) |
| _current->arch.priv_stack_start += |
| (_current->base.user_options & K_FP_REGS) ? |
| MPU_GUARD_ALIGN_AND_SIZE_FLOAT : MPU_GUARD_ALIGN_AND_SIZE; |
| #else |
| _current->arch.priv_stack_start += MPU_GUARD_ALIGN_AND_SIZE; |
| #endif /* CONFIG_FLOAT && CONFIG_FP_SHARING */ |
| #endif /* CONFIG_MPU_STACK_GUARD */ |
| |
| z_arm_userspace_enter(user_entry, p1, p2, p3, |
| (u32_t)_current->stack_info.start, |
| _current->stack_info.size); |
| CODE_UNREACHABLE; |
| } |
| |
| #endif |
| |
| #if defined(CONFIG_BUILTIN_STACK_GUARD) |
| /* |
| * @brief Configure ARM built-in stack guard |
| * |
| * This function configures per thread stack guards by reprogramming |
| * the built-in Process Stack Pointer Limit Register (PSPLIM). |
| * The functionality is meant to be used during context switch. |
| * |
| * @param thread thread info data structure. |
| */ |
| void configure_builtin_stack_guard(struct k_thread *thread) |
| { |
| #if defined(CONFIG_USERSPACE) |
| if ((thread->arch.mode & CONTROL_nPRIV_Msk) != 0) { |
| /* Only configure stack limit for threads in privileged mode |
| * (i.e supervisor threads or user threads doing system call). |
| * User threads executing in user mode do not require a stack |
| * limit protection. |
| */ |
| return; |
| } |
| u32_t guard_start = thread->arch.priv_stack_start ? |
| (u32_t)thread->arch.priv_stack_start : |
| (u32_t)thread->stack_obj; |
| |
| __ASSERT(thread->stack_info.start == ((u32_t)thread->stack_obj), |
| "stack_info.start does not point to the start of the" |
| "thread allocated area."); |
| #else |
| u32_t guard_start = thread->stack_info.start; |
| #endif |
| #if defined(CONFIG_CPU_CORTEX_M_HAS_SPLIM) |
| __set_PSPLIM(guard_start); |
| #else |
| #error "Built-in PSP limit checks not supported by HW" |
| #endif |
| } |
| #endif /* CONFIG_BUILTIN_STACK_GUARD */ |
| |
| #if defined(CONFIG_MPU_STACK_GUARD) || defined(CONFIG_USERSPACE) |
| |
| #define IS_MPU_GUARD_VIOLATION(guard_start, guard_len, fault_addr, stack_ptr) \ |
| ((fault_addr == -EINVAL) ? \ |
| ((fault_addr >= guard_start) && \ |
| (fault_addr < (guard_start + guard_len)) && \ |
| (stack_ptr < (guard_start + guard_len))) \ |
| : \ |
| (stack_ptr < (guard_start + guard_len))) |
| |
| /** |
| * @brief Assess occurrence of current thread's stack corruption |
| * |
| * This function performs an assessment whether a memory fault (on a |
| * given memory address) is the result of stack memory corruption of |
| * the current thread. |
| * |
| * Thread stack corruption for supervisor threads or user threads in |
| * privilege mode (when User Space is supported) is reported upon an |
| * attempt to access the stack guard area (if MPU Stack Guard feature |
| * is supported). Additionally the current PSP (process stack pointer) |
| * must be pointing inside or below the guard area. |
| * |
| * Thread stack corruption for user threads in user mode is reported, |
| * if the current PSP is pointing below the start of the current |
| * thread's stack. |
| * |
| * Notes: |
| * - we assume a fully descending stack, |
| * - we assume a stacking error has occurred, |
| * - the function shall be called when handling MemManage and Bus fault, |
| * and only if a Stacking error has been reported. |
| * |
| * If stack corruption is detected, the function returns the lowest |
| * allowed address where the Stack Pointer can safely point to, to |
| * prevent from errors when un-stacking the corrupted stack frame |
| * upon exception return. |
| * |
| * @param fault_addr memory address on which memory access violation |
| * has been reported. It can be invalid (-EINVAL), |
| * if only Stacking error has been reported. |
| * @param psp current address the PSP points to |
| * |
| * @return The lowest allowed stack frame pointer, if error is a |
| * thread stack corruption, otherwise return 0. |
| */ |
| u32_t z_check_thread_stack_fail(const u32_t fault_addr, const u32_t psp) |
| { |
| const struct k_thread *thread = _current; |
| |
| if (!thread) { |
| return 0; |
| } |
| |
| #if defined(CONFIG_FLOAT) && defined(CONFIG_FP_SHARING) |
| u32_t guard_len = (thread->base.user_options & K_FP_REGS) ? |
| MPU_GUARD_ALIGN_AND_SIZE_FLOAT : MPU_GUARD_ALIGN_AND_SIZE; |
| #else |
| u32_t guard_len = MPU_GUARD_ALIGN_AND_SIZE; |
| #endif /* CONFIG_FLOAT && CONFIG_FP_SHARING */ |
| |
| #if defined(CONFIG_USERSPACE) |
| if (thread->arch.priv_stack_start) { |
| /* User thread */ |
| if ((__get_CONTROL() & CONTROL_nPRIV_Msk) == 0) { |
| /* User thread in privilege mode */ |
| if (IS_MPU_GUARD_VIOLATION( |
| thread->arch.priv_stack_start - guard_len, |
| guard_len, |
| fault_addr, psp)) { |
| /* Thread's privilege stack corruption */ |
| return thread->arch.priv_stack_start; |
| } |
| } else { |
| if (psp < (u32_t)thread->stack_obj) { |
| /* Thread's user stack corruption */ |
| return (u32_t)thread->stack_obj; |
| } |
| } |
| } else { |
| /* Supervisor thread */ |
| if (IS_MPU_GUARD_VIOLATION(thread->stack_info.start - |
| guard_len, |
| guard_len, |
| fault_addr, psp)) { |
| /* Supervisor thread stack corruption */ |
| return thread->stack_info.start; |
| } |
| } |
| #else /* CONFIG_USERSPACE */ |
| if (IS_MPU_GUARD_VIOLATION(thread->stack_info.start - guard_len, |
| guard_len, |
| fault_addr, psp)) { |
| /* Thread stack corruption */ |
| return thread->stack_info.start; |
| } |
| #endif /* CONFIG_USERSPACE */ |
| |
| return 0; |
| } |
| #endif /* CONFIG_MPU_STACK_GUARD || CONFIG_USERSPACE */ |
| |
| #if defined(CONFIG_FLOAT) && defined(CONFIG_FP_SHARING) |
| int z_arch_float_disable(struct k_thread *thread) |
| { |
| if (thread != _current) { |
| return -EINVAL; |
| } |
| |
| if (z_is_in_isr()) { |
| return -EINVAL; |
| } |
| |
| /* Disable all floating point capabilities for the thread */ |
| |
| /* K_FP_REG flag is used in SWAP and stack check fail. Locking |
| * interrupts here prevents a possible context-switch or MPU |
| * fault to take an outdated thread user_options flag into |
| * account. |
| */ |
| int key = z_arch_irq_lock(); |
| |
| thread->base.user_options &= ~K_FP_REGS; |
| |
| __set_CONTROL(__get_CONTROL() & (~CONTROL_FPCA_Msk)); |
| |
| /* No need to add an ISB barrier after setting the CONTROL |
| * register; z_arch_irq_unlock() already adds one. |
| */ |
| |
| z_arch_irq_unlock(key); |
| |
| return 0; |
| } |
| #endif /* CONFIG_FLOAT && CONFIG_FP_SHARING */ |