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kernel: internal APIs for thread resource pools

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Some kernel APIs may need to allocate memory in order to function
correctly, especially if they are exposed to userspace where
buffers provided by user code cannot be trusted.

Instead of simply drawing from the system heap, specific pools
may instead be assigned to threads, and any requests made on
behalf of the calling thread will draw heap memory from that pool.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2018-04-12 17:12:15 -07:00 • committed by Andrew Boie
commit 92e5bd7473
5 changed files with 92 additions and 1 deletions
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36
include/kernel.h
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@ -524,6 +524,7 @@ struct k_thread {
/* Context handle returned via _arch_switch() */
void *switch_handle;
#endif
struct k_mem_pool *resource_pool;
/* arch-specifics: must always be at the end */
struct _thread_arch arch;
@ -700,6 +701,41 @@ extern FUNC_NORETURN void k_thread_user_mode_enter(k_thread_entry_t entry,
extern void __attribute__((sentinel))
k_thread_access_grant(struct k_thread *thread, ...);
/**
* @brief Assign a resource memory pool to a thread
*
* By default, threads have no resource pool assigned unless their parent
* thread has a resource pool, in which case it is inherited. Multiple
* threads may be assigned to the same memory pool.
*
* Changing a thread's resource pool will not migrate allocations from the
* previous pool.
*
* @param thread Target thread to assign a memory pool for resource requests,
* or NULL if the thread should no longer have a memory pool.
* @param pool Memory pool to use for resources.
*/
static inline void k_thread_resource_pool_assign(struct k_thread *thread,
struct k_mem_pool *pool)
{
thread->resource_pool = pool;
}
#if (CONFIG_HEAP_MEM_POOL_SIZE > 0)
/**
* @brief Assign the system heap as a thread's resource pool
*
* Similar to k_thread_resource_pool_assign(), but the thread will use
* the kernel heap to draw memory.
*
* Use with caution, as a malicious thread could perform DoS attacks on the
* kernel heap.
*
* @param thread Target thread to assign the system heap for resource requests
*/
void k_thread_system_pool_assign(struct k_thread *thread);
#endif /* (CONFIG_HEAP_MEM_POOL_SIZE > 0) */
/**
* @brief Put the current thread to sleep.
*