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Commit c052de26 authored by Nicolas Pitre's avatar Nicolas Pitre
Browse files

ARM: bL_switcher: simplify stack isolation 



We now have a dedicated thread for each logical CPU.  That's plenty
of stack space for our needs.

Signed-off-by: default avatarNicolas Pitre <nico@linaro.org>
parent 71ce1dee

arch/arm/common/bL_switcher.c

+8 −15
Original line number Original line Diff line number Diff line
@@ -53,12 +53,6 @@ static void bL_do_switch(void *_unused) 
{

{

	unsigned mpidr, cpuid, clusterid, ob_cluster, ib_cluster;

	unsigned mpidr, cpuid, clusterid, ob_cluster, ib_cluster;





	/*

	 * We now have a piece of stack borrowed from the init task's.

	 * Let's also switch to init_mm right away to match it.

	 */

	cpu_switch_mm(init_mm.pgd, &init_mm);



	pr_debug("%s\n", __func__);

	pr_debug("%s\n", __func__);





	mpidr = read_mpidr();

	mpidr = read_mpidr();
@@ -93,22 +87,21 @@ static void bL_do_switch(void *_unused) 
}

}





/*

/*

 * Stack isolation.  To ensure 'current' remains valid, we just borrow

 * Stack isolation.  To ensure 'current' remains valid, we just use another

 * a slice of the init/idle task which should be fairly lightly used.

 * piece of our thread's stack space which should be fairly lightly used.

 * The borrowed area starts just above the thread_info structure located

 * The selected area starts just above the thread_info structure located

 * at the very bottom of the stack, aligned to a cache line.

 * at the very bottom of the stack, aligned to a cache line, and indexed

 * with the cluster number.

 */

 */

#define STACK_SIZE 256

#define STACK_SIZE 512

extern void call_with_stack(void (*fn)(void *), void *arg, void *sp);

extern void call_with_stack(void (*fn)(void *), void *arg, void *sp);

static int bL_switchpoint(unsigned long _arg)

static int bL_switchpoint(unsigned long _arg)

{

{

	unsigned int mpidr = read_mpidr();

	unsigned int mpidr = read_mpidr();

	unsigned int cpuid = MPIDR_AFFINITY_LEVEL(mpidr, 0);

	unsigned int clusterid = MPIDR_AFFINITY_LEVEL(mpidr, 1);

	unsigned int clusterid = MPIDR_AFFINITY_LEVEL(mpidr, 1);

	unsigned int cpu_index = cpuid + clusterid * MAX_CPUS_PER_CLUSTER;

	void *stack = current_thread_info() + 1;

	void *stack = &init_thread_info + 1;

	stack = PTR_ALIGN(stack, L1_CACHE_BYTES);

	stack = PTR_ALIGN(stack, L1_CACHE_BYTES);

	stack += cpu_index * STACK_SIZE + STACK_SIZE;

	stack += clusterid * STACK_SIZE + STACK_SIZE;

	call_with_stack(bL_do_switch, (void *)_arg, stack);

	call_with_stack(bL_do_switch, (void *)_arg, stack);

	BUG();

	BUG();

}

}