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authorMax Filippov <jcmvbkbc@gmail.com>2022-04-15 03:05:31 -0700
committerMax Filippov <jcmvbkbc@gmail.com>2022-05-01 19:51:23 -0700
commit11e969bc964a0e50ae64cdba092048e3937d2389 (patch)
tree99303eb470e622faf5397649005d6f221f46bdb0 /arch/xtensa/kernel/smp.c
parentf29cab2906346fa93831376256e01f5a6629f979 (diff)
downloadlwn-11e969bc964a0e50ae64cdba092048e3937d2389.tar.gz
lwn-11e969bc964a0e50ae64cdba092048e3937d2389.zip
xtensa: support coprocessors on SMP
Current coprocessor support on xtensa only works correctly on uniprocessor configurations. Make it work on SMP too and keep it lazy. Make coprocessor_owner array per-CPU and move it to struct exc_table for easy access from the fast_coprocessor exception handler. Allow task to have live coprocessors only on single CPU, record this CPU number in the struct thread_info::cp_owner_cpu. Change struct thread_info::cpenable meaning to be 'coprocessors live on cp_owner_cpu'. Introduce C-level coprocessor exception handler that flushes and releases live coprocessors of the task taking 'coprocessor disabled' exception and call it from the fast_coprocessor handler when the task has live coprocessors on other CPU. Make coprocessor_flush_all and coprocessor_release_all work correctly when called from any CPU by sending IPI to the cp_owner_cpu. Add function coprocessor_flush_release_all to do flush followed by release atomically. Add function local_coprocessors_flush_release_all to flush and release all coprocessors on the local CPU and use it to flush coprocessor contexts from the CPU that goes offline. Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Diffstat (limited to 'arch/xtensa/kernel/smp.c')
-rw-r--r--arch/xtensa/kernel/smp.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c
index 1254da07ead1..4dc109dd6214 100644
--- a/arch/xtensa/kernel/smp.c
+++ b/arch/xtensa/kernel/smp.c
@@ -30,6 +30,7 @@
#include <linux/thread_info.h>
#include <asm/cacheflush.h>
+#include <asm/coprocessor.h>
#include <asm/kdebug.h>
#include <asm/mmu_context.h>
#include <asm/mxregs.h>
@@ -272,6 +273,12 @@ int __cpu_disable(void)
*/
set_cpu_online(cpu, false);
+#if XTENSA_HAVE_COPROCESSORS
+ /*
+ * Flush coprocessor contexts that are active on the current CPU.
+ */
+ local_coprocessors_flush_release_all();
+#endif
/*
* OK - migrate IRQs away from this CPU
*/