arch: arc: implement MPU_GAP_FILLING for mpu version 3
when MPU_GAP_FILLING is configured, the default mpu entry (kernel read + kernel write) will be used to fill the gaps among mpu entires to avoid dynamic mpu region splitting. This will bring better performance in thread switch but fewer constraints on privileged codes. when MPU_GAP_FILLING is not configured, a sw-based mpu dynamic region splitting is used to bypass the limitation of no mpu region overlap in hardware. This approach will consume more hardware mpu entries and more time in thread switch. Signed-off-by: Wayne Ren <wei.ren@synopsys.com>
This commit is contained in:
Wayne Ren
Johan Hedberg
parent
85f591e866
commit
acf9675bfc
1 changed files with 194 additions and 28 deletions
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@ -28,6 +28,23 @@
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#define CALC_REGION_END_ADDR(start, size) \
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(start + size - (1 << ARC_FEATURE_MPU_ALIGNMENT_BITS))
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/* ARC MPU version 3 does not support mpu region overlap in hardware
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* so if we want to allocate MPU region dynamically, e.g. thread stack,
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* memory domain from a background region, a dynamic region splitting
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* approach is designed. pls see comments in
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* _dynamic_region_allocate_and_init
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* But this approach has an impact on performance of thread switch.
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* As a trade off, we can use the default mpu region as the background region
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* to avoid the dynamic region splitting. This will give more privilege to
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* codes in kernel mode which can access the memory region not covered by
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* explicit mpu entry. Considering memory protection is mainly used to
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* isolate malicious codes in user mode, it makes sense to get better
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* thread switch performance through default mpu region.
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* CONFIG_MPU_GAP_FILLING is used to turn this on/off.
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*
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*/
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#if defined(CONFIG_MPU_GAP_FILLING)
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#if defined(CONFIG_USERSPACE) && defined(CONFIG_MPU_STACK_GUARD)
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/* 1 for stack guard , 1 for user thread, 1 for split */
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#define MPU_REGION_NUM_FOR_THREAD 3
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@ -38,6 +55,8 @@
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#define MPU_REGION_NUM_FOR_THREAD 0
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#endif
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#define MPU_DYNAMIC_REGION_AREAS_NUM 2
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/**
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* @brief internal structure holding information of
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* memory areas where dynamic MPU programming is allowed.
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@ -49,9 +68,6 @@ struct dynamic_region_info {
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u32_t attr;
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};
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#define MPU_DYNAMIC_REGION_AREAS_NUM 2
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static u8_t static_regions_num;
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static u8_t dynamic_regions_num;
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static u8_t dynamic_region_index;
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@ -61,6 +77,9 @@ static u8_t dynamic_region_index;
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* regions may be configured.
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*/
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static struct dynamic_region_info dyn_reg_info[MPU_DYNAMIC_REGION_AREAS_NUM];
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#endif /* CONFIG_MPU_GAP_FILLING */
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static u8_t static_regions_num;
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#ifdef CONFIG_ARC_NORMAL_FIRMWARE
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/* \todo through secure service to access mpu */
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@ -236,20 +255,6 @@ static inline bool _is_user_accessible_region(u32_t r_index, int write)
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#endif /* CONFIG_ARC_NORMAL_FIRMWARE */
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/**
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* This internal function allocates a dynamic MPU region and returns
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* the index or error
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*/
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static inline int _dynamic_region_allocate_index(void)
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{
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if (dynamic_region_index >= get_num_regions()) {
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LOG_ERR("no enough mpu entries %d", dynamic_region_index);
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return -EINVAL;
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}
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return dynamic_region_index++;
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}
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/**
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* This internal function checks the area given by (start, size)
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* and returns the index if the area match one MPU entry
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@ -265,6 +270,21 @@ static inline int _get_region_index(u32_t start, u32_t size)
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return -EINVAL;
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}
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#if defined(CONFIG_MPU_GAP_FILLING)
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/**
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* This internal function allocates a dynamic MPU region and returns
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* the index or error
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*/
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static inline int _dynamic_region_allocate_index(void)
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{
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if (dynamic_region_index >= get_num_regions()) {
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LOG_ERR("no enough mpu entries %d", dynamic_region_index);
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return -EINVAL;
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}
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return dynamic_region_index++;
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}
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/* @brief allocate and init a dynamic MPU region
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*
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* This internal function performs the allocation and initialization of
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@ -409,6 +429,69 @@ static inline int _mpu_configure(u8_t type, u32_t base, u32_t size)
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return _dynamic_region_allocate_and_init(base, size, region_attr);
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}
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#else
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/**
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* This internal function is utilized by the MPU driver to parse the intent
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* type (i.e. THREAD_STACK_REGION) and return the correct region index.
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*/
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static inline int get_region_index_by_type(u32_t type)
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{
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/*
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* The new MPU regions are allocated per type after the statically
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* configured regions. The type is one-indexed rather than
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* zero-indexed.
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*
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* For ARC MPU v2, the smaller index has higher priority, so the
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* index is allocated in reverse order. Static regions start from
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* the biggest index, then thread related regions.
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*
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*/
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switch (type) {
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case THREAD_STACK_USER_REGION:
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return static_regions_num + THREAD_STACK_REGION;
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case THREAD_STACK_REGION:
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case THREAD_APP_DATA_REGION:
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case THREAD_STACK_GUARD_REGION:
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return static_regions_num + type;
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case THREAD_DOMAIN_PARTITION_REGION:
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#if defined(CONFIG_MPU_STACK_GUARD)
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return static_regions_num + type;
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#else
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/*
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* Start domain partition region from stack guard region
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* since stack guard is not enabled.
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*/
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return static_regions_num + type - 1;
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#endif
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default:
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__ASSERT(0, "Unsupported type");
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return -EINVAL;
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}
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}
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/**
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* @brief configure the base address and size for an MPU region
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*
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* @param type MPU region type
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* @param base base address in RAM
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* @param size size of the region
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*/
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static inline int _mpu_configure(u8_t type, u32_t base, u32_t size)
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{
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int region_index = get_region_index_by_type(type);
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u32_t region_attr = get_region_attr_by_type(type);
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LOG_DBG("Region info: 0x%x 0x%x", base, size);
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if (region_attr == 0U || region_index < 0) {
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return -EINVAL;
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}
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_region_init(region_index, base, size, region_attr);
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return 0;
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}
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#endif
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/* ARC Core MPU Driver API Implementation for ARC MPUv3 */
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@ -419,9 +502,9 @@ void arc_core_mpu_enable(void)
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{
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#ifdef CONFIG_ARC_SECURE_FIRMWARE
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/* the default region:
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* normal:0x000, SID:0x10000, KW:0x100 KR:0x80, KE:0x4 0
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* secure:0x8000, SID:0x10000, KW:0x100 KR:0x80
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*/
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#define MPU_ENABLE_ATTR 0x101c0
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#define MPU_ENABLE_ATTR 0x18180
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#else
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#define MPU_ENABLE_ATTR 0
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#endif
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@ -447,6 +530,7 @@ void arc_core_mpu_disable(void)
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*/
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void arc_core_mpu_configure_thread(struct k_thread *thread)
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{
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#if defined(CONFIG_MPU_GAP_FILLING)
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/* the mpu entries of ARC MPUv3 are divided into 2 parts:
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* static entries: global mpu entries, not changed in context switch
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* dynamic entries: MPU entries changed in context switch and
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@ -459,6 +543,7 @@ void arc_core_mpu_configure_thread(struct k_thread *thread)
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* entries
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*/
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_mpu_reset_dynamic_regions();
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#endif
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#if defined(CONFIG_MPU_STACK_GUARD)
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#if defined(CONFIG_USERSPACE)
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if ((thread->base.user_options & K_USER) != 0U) {
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@ -499,10 +584,6 @@ void arc_core_mpu_configure_thread(struct k_thread *thread)
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#endif
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#if defined(CONFIG_USERSPACE)
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u32_t num_partitions;
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struct k_mem_partition *pparts;
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struct k_mem_domain *mem_domain = thread->mem_domain_info.mem_domain;
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/* configure stack region of user thread */
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if (thread->base.user_options & K_USER) {
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LOG_DBG("configure user thread %p's stack", thread);
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@ -513,6 +594,11 @@ void arc_core_mpu_configure_thread(struct k_thread *thread)
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}
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}
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#if defined(CONFIG_MPU_GAP_FILLING)
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u32_t num_partitions;
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struct k_mem_partition *pparts;
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struct k_mem_domain *mem_domain = thread->mem_domain_info.mem_domain;
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/* configure thread's memory domain */
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if (mem_domain) {
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LOG_DBG("configure thread %p's domain: %p",
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@ -536,6 +622,9 @@ void arc_core_mpu_configure_thread(struct k_thread *thread)
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}
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pparts++;
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}
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#else
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arc_core_mpu_configure_mem_domain(thread);
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#endif
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#endif
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}
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@ -581,10 +670,56 @@ int arc_core_mpu_region(u32_t index, u32_t base, u32_t size,
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*
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* @param thread the thread which has memory domain
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*/
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#if defined(CONFIG_MPU_GAP_FILLING)
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void arc_core_mpu_configure_mem_domain(struct k_thread *thread)
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{
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arc_core_mpu_configure_thread(thread);
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}
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#else
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void arc_core_mpu_configure_mem_domain(struct k_thread *thread)
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{
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u32_t region_index;
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u32_t num_partitions;
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u32_t num_regions;
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struct k_mem_partition *pparts;
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struct k_mem_domain *mem_domain = NULL;
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if (thread) {
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mem_domain = thread->mem_domain_info.mem_domain;
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}
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if (mem_domain) {
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LOG_DBG("configure domain: %p", mem_domain);
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num_partitions = mem_domain->num_partitions;
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pparts = mem_domain->partitions;
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} else {
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LOG_DBG("disable domain partition regions");
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num_partitions = 0U;
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pparts = NULL;
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}
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num_regions = get_num_regions();
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region_index = get_region_index_by_type(THREAD_DOMAIN_PARTITION_REGION);
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while (num_partitions && region_index < num_regions) {
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if (pparts->size > 0) {
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LOG_DBG("set region 0x%x 0x%lx 0x%x",
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region_index, pparts->start, pparts->size);
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_region_init(region_index, pparts->start,
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pparts->size, pparts->attr);
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region_index++;
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}
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pparts++;
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num_partitions--;
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}
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while (region_index < num_regions) {
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/* clear the left mpu entries */
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_region_init(region_index, 0, 0, 0);
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region_index++;
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}
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}
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#endif
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/**
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* @brief remove MPU regions for the memory partitions of the memory domain
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@ -612,8 +747,12 @@ void arc_core_mpu_remove_mem_domain(struct k_mem_domain *mem_domain)
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index = _get_region_index(pparts->start,
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pparts->size);
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if (index > 0) {
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#if defined(CONFIG_MPU_GAP_FILLING)
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_region_set_attr(index,
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REGION_KERNEL_RAM_ATTR);
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#else
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_region_init(index, 0, 0, 0);
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#endif
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}
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}
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pparts++;
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@ -638,7 +777,11 @@ void arc_core_mpu_remove_mem_partition(struct k_mem_domain *domain,
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}
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LOG_DBG("remove region 0x%x", region_index);
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#if defined(CONFIG_MPU_GAP_FILLING)
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_region_set_attr(region_index, REGION_KERNEL_RAM_ATTR);
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#else
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_region_init(region_index, 0, 0, 0);
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#endif
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}
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/**
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@ -646,8 +789,13 @@ void arc_core_mpu_remove_mem_partition(struct k_mem_domain *domain,
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*/
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int arc_core_mpu_get_max_domain_partition_regions(void)
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{
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#if defined(CONFIG_MPU_GAP_FILLING)
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/* consider the worst case: each partition requires split */
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return (get_num_regions() - MPU_REGION_NUM_FOR_THREAD) / 2;
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#else
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return get_num_regions() -
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get_region_index_by_type(THREAD_DOMAIN_PARTITION_REGION) - 1;
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#endif
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}
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/**
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@ -704,11 +852,18 @@ static int arc_mpu_init(struct device *arg)
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return -EINVAL;
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}
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static_regions_num = 0;
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/* Disable MPU */
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arc_core_mpu_disable();
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for (i = 0U; i < mpu_config.num_regions; i++) {
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_region_init(i,
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/* skip empty region */
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if (mpu_config.mpu_regions[i].size == 0) {
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continue;
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}
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#if defined(CONFIG_MPU_GAP_FILLING)
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_region_init(static_regions_num,
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mpu_config.mpu_regions[i].base,
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mpu_config.mpu_regions[i].size,
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mpu_config.mpu_regions[i].attr);
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@ -732,11 +887,22 @@ static int arc_mpu_init(struct device *arg)
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dynamic_regions_num++;
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}
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static_regions_num++;
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#else
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/* dynamic region will be covered by default mpu setting
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* no need to configure
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*/
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if (!(mpu_config.mpu_regions[i].attr & REGION_DYNAMIC)) {
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_region_init(static_regions_num,
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mpu_config.mpu_regions[i].base,
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mpu_config.mpu_regions[i].size,
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mpu_config.mpu_regions[i].attr);
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static_regions_num++;
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}
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#endif
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}
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static_regions_num = mpu_config.num_regions;
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for (; i < num_regions; i++) {
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for (i = static_regions_num; i < num_regions; i++) {
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_region_init(i, 0, 0, 0);
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}
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