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authorNicolas Pitre <nicolas.pitre@linaro.org>2012-11-27 15:55:33 -0500
committerNicolas Pitre <nicolas.pitre@linaro.org>2013-05-13 19:02:04 -0400
commitfca7d749daa8a4331c59259831b7f8d3eb058367 (patch)
treeb28de8fc4081e6cdf42d8ac6dffcd0d001d0824e
parent1098727b016d60700c65c18077ab3a7837825e8f (diff)
downloadvexpress-lsk-fca7d749daa8a4331c59259831b7f8d3eb058367.tar.gz
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: Nicolas Pitre <nico@linaro.org>
-rw-r--r--arch/arm/common/bL_switcher.c23
1 files changed, 8 insertions, 15 deletions
diff --git a/arch/arm/common/bL_switcher.c b/arch/arm/common/bL_switcher.c
index 1edc400137d..b59958e7e53 100644
--- a/arch/arm/common/bL_switcher.c
+++ b/arch/arm/common/bL_switcher.c
@@ -54,12 +54,6 @@ static void bL_do_switch(void *_unused)
{
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__);
mpidr = read_mpidr();
@@ -94,22 +88,21 @@ static void bL_do_switch(void *_unused)
}
/*
- * Stack isolation. To ensure 'current' remains valid, we just borrow
- * a slice of the init/idle task which should be fairly lightly used.
- * The borrowed area starts just above the thread_info structure located
- * at the very bottom of the stack, aligned to a cache line.
+ * Stack isolation. To ensure 'current' remains valid, we just use another
+ * piece of our thread's stack space which should be fairly lightly used.
+ * The selected area starts just above the thread_info structure located
+ * 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);
static int bL_switchpoint(unsigned long _arg)
{
unsigned int mpidr = read_mpidr();
- unsigned int cpuid = MPIDR_AFFINITY_LEVEL(mpidr, 0);
unsigned int clusterid = MPIDR_AFFINITY_LEVEL(mpidr, 1);
- unsigned int cpu_index = cpuid + clusterid * MAX_CPUS_PER_CLUSTER;
- void *stack = &init_thread_info + 1;
+ void *stack = current_thread_info() + 1;
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);
BUG();
}