arch: arc: add the handling of mpu stack guard exception
* mpu stack guard exception is a kind of mpu violation exception * use SW way to distingusih it from other mpu vioation exception Signed-off-by: Wayne Ren <wei.ren@synopsys.com>
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3 changed files with 108 additions and 4 deletions
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@ -43,7 +43,7 @@ void z_NanoFatalErrorHandler(unsigned int reason, const NANO_ESF *pEsf)
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break;
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#if defined(CONFIG_STACK_CANARIES) || defined(CONFIG_ARC_STACK_CHECKING) \
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|| defined(CONFIG_STACK_SENTINEL)
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|| defined(CONFIG_STACK_SENTINEL) || defined(CONFIG_MPU_STACK_GUARD)
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case _NANO_ERR_STACK_CHK_FAIL:
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printk("***** Stack Check Fail! *****\n");
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break;
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@ -21,6 +21,8 @@
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#include <exc_handle.h>
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#include <logging/log_ctrl.h>
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extern u32_t arc_exc_saved_sp;
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#ifdef CONFIG_USERSPACE
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Z_EXC_DECLARE(z_arch_user_string_nlen);
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@ -29,6 +31,98 @@ static const struct z_exc_handle exceptions[] = {
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};
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#endif
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#if defined(CONFIG_MPU_STACK_GUARD)
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#define IS_MPU_GUARD_VIOLATION(guard_start, fault_addr, stack_ptr) \
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((fault_addr >= guard_start) && \
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(fault_addr < (guard_start + STACK_GUARD_SIZE)) && \
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(stack_ptr <= (guard_start + STACK_GUARD_SIZE)))
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/**
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* @brief Assess occurrence of current thread's stack corruption
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*
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* This function performs an assessment whether a memory fault (on a
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* given memory address) is the result of stack memory corruption of
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* the current thread.
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*
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* Thread stack corruption for supervisor threads or user threads in
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* privilege mode (when User Space is supported) is reported upon an
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* attempt to access the stack guard area (if MPU Stack Guard feature
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* is supported). Additionally the current thread stack pointer
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* must be pointing inside or below the guard area.
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*
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* Thread stack corruption for user threads in user mode is reported,
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* if the current stack pointer is pointing below the start of the current
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* thread's stack.
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*
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* Notes:
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* - we assume a fully descending stack,
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* - we assume a stacking error has occurred,
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* - the function shall be called when handling MPU privilege violation
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*
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* If stack corruption is detected, the function returns the lowest
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* allowed address where the Stack Pointer can safely point to, to
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* prevent from errors when un-stacking the corrupted stack frame
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* upon exception return.
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*
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* @param fault_addr memory address on which memory access violation
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* has been reported.
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* @param sp stack pointer when exception comes out
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*
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* @return The lowest allowed stack frame pointer, if error is a
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* thread stack corruption, otherwise return 0.
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*/
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static u32_t z_check_thread_stack_fail(const u32_t fault_addr, u32_t sp)
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{
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const struct k_thread *thread = _current;
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if (!thread) {
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return 0;
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}
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#if defined(CONFIG_USERSPACE)
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if (thread->arch.priv_stack_start) {
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/* User thread */
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if (z_arc_v2_aux_reg_read(_ARC_V2_ERSTATUS)
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& _ARC_V2_STATUS32_U) {
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/* Thread's user stack corruption */
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#ifdef CONFIG_ARC_HAS_SECURE
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sp = z_arc_v2_aux_reg_read(_ARC_V2_SEC_U_SP);
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#else
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sp = z_arc_v2_aux_reg_read(_ARC_V2_USER_SP);
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#endif
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if (sp <= (u32_t)thread->stack_obj) {
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return (u32_t)thread->stack_obj;
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}
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} else {
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/* User thread in privilege mode */
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if (IS_MPU_GUARD_VIOLATION(
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thread->arch.priv_stack_start - STACK_GUARD_SIZE,
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fault_addr, sp)) {
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/* Thread's privilege stack corruption */
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return thread->arch.priv_stack_start;
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}
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}
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} else {
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/* Supervisor thread */
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if (IS_MPU_GUARD_VIOLATION((u32_t)thread->stack_obj,
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fault_addr, sp)) {
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/* Supervisor thread stack corruption */
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return (u32_t)thread->stack_obj + STACK_GUARD_SIZE;
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}
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}
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#else /* CONFIG_USERSPACE */
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if (IS_MPU_GUARD_VIOLATION(thread->stack_info.start,
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fault_addr, sp)) {
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/* Thread stack corruption */
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return thread->stack_info.start + STACK_GUARD_SIZE;
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}
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#endif /* CONFIG_USERSPACE */
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return 0;
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}
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#endif
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/*
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* @brief Fault handler
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*
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@ -82,5 +176,14 @@ void _Fault(NANO_ESF *esf)
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return;
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}
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#endif
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#ifdef CONFIG_MPU_STACK_GUARD
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if (vector == 6 && ((parameter == 4) || (parameter == 24))) {
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if (z_check_thread_stack_fail(exc_addr, arc_exc_saved_sp)) {
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z_NanoFatalErrorHandler(_NANO_ERR_STACK_CHK_FAIL, esf);
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return;
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}
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}
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#endif
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z_NanoFatalErrorHandler(_NANO_ERR_HW_EXCEPTION, esf);
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}
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@ -39,8 +39,9 @@ GTEXT(_irq_do_offload);
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#endif
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GDATA(exc_nest_count)
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GDATA(arc_exc_saved_sWWp)
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SECTION_VAR(BSS, saved_value)
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SECTION_VAR(BSS, arc_exc_saved_sp)
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.balign 4
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.word 0
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@ -65,7 +66,7 @@ SECTION_SUBSEC_FUNC(TEXT,__fault,__ev_dc_error)
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SECTION_SUBSEC_FUNC(TEXT,__fault,__ev_maligned)
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_exc_entry:
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st sp, [saved_value]
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st sp, [arc_exc_saved_sp]
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/*
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* re-use the top part of interrupt stack as exception
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* stack. If this top part is used by interrupt handling,
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@ -145,7 +146,7 @@ _exc_return_from_exc:
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sr r0, [_ARC_V2_ERET]
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_pop_irq_stack_frame
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ld sp, [saved_value]
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ld sp, [arc_exc_saved_sp]
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rtie
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