kernel/arch/xtensa/include/asm/traps.h, branch linux-rolling-stable

xtensa: add load/store exception handler

2023-06-14T04:56:27Z

Memory attached to instruction bus of the xtensa CPU is only accessible for a limited subset of opcodes. Other opcodes generate an exception with the load/store error cause code. This property complicates use of such systems. Provide a handler that recognizes and transparently fixes such exceptions. The following opcodes are recognized when used outside of FLIX bundles: l32i, l32i.n, l16ui, l16si, l8ui. Signed-off-by: Max Filippov

xtensa: move early_trap_init from kasan_early_init to init_arch

2023-06-14T04:56:27Z

There may be other users for the early traps besides KASAN. Move call to the early_trap_init from kasan_early_init. Protect init_exc_table initializer with ifdef to make sure it builds on noMMU configurations. Signed-off-by: Max Filippov

xtensa: support coprocessors on SMP

2022-05-02T02:51:23Z

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

xtensa: clean up excsave1 initialization

2022-05-02T02:51:22Z

Use xtensa_set_sr instead of inline assembly. Rename local variable exc_table in early_trap_init to avoid conflict with per-CPU variable of the same name. Signed-off-by: Max Filippov

xtensa: clean up exception handler prototypes

2022-05-02T02:51:22Z

Exception handlers are currently passed as void pointers because they may have one or two parameters. Only two handlers uses the second parameter and it is available in the struct pt_regs anyway. Make all handlers have only one parameter, introduce xtensa_exception_handler type for handlers and use it in trap_set_handler. Signed-off-by: Max Filippov

xtensa: clean up function declarations in traps.c

2022-05-02T02:51:22Z

Drop 'extern' from all function declarations and move those that need to be visible from traps.c to traps.h. Add 'asmlinkage' to declarations of fucntions defined in assembly. Add 'static' to declarations and definitions only used locally. Add argument names in declarations. Drop unused second argument from do_multihit and do_page_fault. Signed-off-by: Max Filippov

xtensa: only build windowed register support code when needed

2021-10-19T05:19:35Z

There's no need in window overflow/underflow/alloca exception handlers or window spill code when neither kernel nor userspace support windowed registers. Don't build or link it. Signed-off-by: Max Filippov

xtensa: drop unused field from the struct exc_table

2018-12-03T09:39:22Z

exc_table::syscall_save and corresponding macro EXC_TABLE_SYSCALL_SAVE have never been used by the xtensa code. Drop them. Signed-off-by: Max Filippov

xtensa: implement early_trap_init

2017-12-17T06:37:09Z

Paging on xtensa architecture requires functioning exception handling because hardware cannot transparently access page tables that are not currently mapped by TLB. Exception handling is set up late in the initialization process, but working paging is needed for KASAN. Provide early_trap_init that sets up minimal exception handling sufficient for KASAN to work. Signed-off-by: Max Filippov

xtensa: clean up exception handling structure

2017-12-17T06:37:09Z

Instead of using flat array of longs use normal C structure and generate EXC_TABLE_* constants in the asm-offsets.c Signed-off-by: Max Filippov