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author | Max Filippov <jcmvbkbc@gmail.com> | 2022-04-15 03:05:31 -0700 |
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committer | Max Filippov <jcmvbkbc@gmail.com> | 2022-05-01 19:51:23 -0700 |
commit | 11e969bc964a0e50ae64cdba092048e3937d2389 (patch) | |
tree | 99303eb470e622faf5397649005d6f221f46bdb0 /arch/xtensa/kernel/smp.c | |
parent | f29cab2906346fa93831376256e01f5a6629f979 (diff) | |
download | lwn-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.c | 7 |
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 */ |