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>
This commit is contained in:
Wayne Ren 2019-03-20 17:36:20 +08:00 committed by Anas Nashif
commit eba78548da
3 changed files with 108 additions and 4 deletions

View file

@ -43,7 +43,7 @@ void z_NanoFatalErrorHandler(unsigned int reason, const NANO_ESF *pEsf)
break;
#if defined(CONFIG_STACK_CANARIES) || defined(CONFIG_ARC_STACK_CHECKING) \
|| defined(CONFIG_STACK_SENTINEL)
|| defined(CONFIG_STACK_SENTINEL) || defined(CONFIG_MPU_STACK_GUARD)
case _NANO_ERR_STACK_CHK_FAIL:
printk("***** Stack Check Fail! *****\n");
break;

View file

@ -21,6 +21,8 @@
#include <exc_handle.h>
#include <logging/log_ctrl.h>
extern u32_t arc_exc_saved_sp;
#ifdef CONFIG_USERSPACE
Z_EXC_DECLARE(z_arch_user_string_nlen);
@ -29,6 +31,98 @@ static const struct z_exc_handle exceptions[] = {
};
#endif
#if defined(CONFIG_MPU_STACK_GUARD)
#define IS_MPU_GUARD_VIOLATION(guard_start, fault_addr, stack_ptr) \
((fault_addr >= guard_start) && \
(fault_addr < (guard_start + STACK_GUARD_SIZE)) && \
(stack_ptr <= (guard_start + STACK_GUARD_SIZE)))
/**
* @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 thread 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 stack pointer 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 MPU privilege violation
*
* 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.
* @param sp stack pointer when exception comes out
*
* @return The lowest allowed stack frame pointer, if error is a
* thread stack corruption, otherwise return 0.
*/
static u32_t z_check_thread_stack_fail(const u32_t fault_addr, u32_t sp)
{
const struct k_thread *thread = _current;
if (!thread) {
return 0;
}
#if defined(CONFIG_USERSPACE)
if (thread->arch.priv_stack_start) {
/* User thread */
if (z_arc_v2_aux_reg_read(_ARC_V2_ERSTATUS)
& _ARC_V2_STATUS32_U) {
/* Thread's user stack corruption */
#ifdef CONFIG_ARC_HAS_SECURE
sp = z_arc_v2_aux_reg_read(_ARC_V2_SEC_U_SP);
#else
sp = z_arc_v2_aux_reg_read(_ARC_V2_USER_SP);
#endif
if (sp <= (u32_t)thread->stack_obj) {
return (u32_t)thread->stack_obj;
}
} else {
/* User thread in privilege mode */
if (IS_MPU_GUARD_VIOLATION(
thread->arch.priv_stack_start - STACK_GUARD_SIZE,
fault_addr, sp)) {
/* Thread's privilege stack corruption */
return thread->arch.priv_stack_start;
}
}
} else {
/* Supervisor thread */
if (IS_MPU_GUARD_VIOLATION((u32_t)thread->stack_obj,
fault_addr, sp)) {
/* Supervisor thread stack corruption */
return (u32_t)thread->stack_obj + STACK_GUARD_SIZE;
}
}
#else /* CONFIG_USERSPACE */
if (IS_MPU_GUARD_VIOLATION(thread->stack_info.start,
fault_addr, sp)) {
/* Thread stack corruption */
return thread->stack_info.start + STACK_GUARD_SIZE;
}
#endif /* CONFIG_USERSPACE */
return 0;
}
#endif
/*
* @brief Fault handler
*
@ -82,5 +176,14 @@ void _Fault(NANO_ESF *esf)
return;
}
#endif
#ifdef CONFIG_MPU_STACK_GUARD
if (vector == 6 && ((parameter == 4) || (parameter == 24))) {
if (z_check_thread_stack_fail(exc_addr, arc_exc_saved_sp)) {
z_NanoFatalErrorHandler(_NANO_ERR_STACK_CHK_FAIL, esf);
return;
}
}
#endif
z_NanoFatalErrorHandler(_NANO_ERR_HW_EXCEPTION, esf);
}

View file

@ -39,8 +39,9 @@ GTEXT(_irq_do_offload);
#endif
GDATA(exc_nest_count)
GDATA(arc_exc_saved_sWWp)
SECTION_VAR(BSS, saved_value)
SECTION_VAR(BSS, arc_exc_saved_sp)
.balign 4
.word 0
@ -65,7 +66,7 @@ SECTION_SUBSEC_FUNC(TEXT,__fault,__ev_dc_error)
SECTION_SUBSEC_FUNC(TEXT,__fault,__ev_maligned)
_exc_entry:
st sp, [saved_value]
st sp, [arc_exc_saved_sp]
/*
* re-use the top part of interrupt stack as exception
* stack. If this top part is used by interrupt handling,
@ -145,7 +146,7 @@ _exc_return_from_exc:
sr r0, [_ARC_V2_ERET]
_pop_irq_stack_frame
ld sp, [saved_value]
ld sp, [arc_exc_saved_sp]
rtie