If ICACHE_INS is not supported, we use IPI to sync icache on each
core. But ftrace_modify_code is called from stop_machine from default
implementation of arch_ftrace_update_code and stop_machine callback
is irq_disabled. When you call ipi with irq_disabled, a deadlock will
happen.
We couldn't use icache_flush with irq_disabled, but startup make_nop
is specific case and it needn't ipi other cores.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Some CPUs don't support icache specific instructions to flush icache
lines in broadcast way. We use cpu control registers to flush local
icache and use IPI to notify other cores.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
DMA_FROM_DEVICE only need to read dma data of memory into CPU cache,
so there is no need to clear cache before. Also clear + inv for
DMA_FROM_DEVICE won't cause problem, because the memory range for dma
won't be touched by software during dma working.
Changes for V2:
- Remove clr cache and ignore the DMA_TO_DEVICE in _for_cpu.
- Change inv to wbinv cache with DMA_FROM_DEVICE in _for_device.
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Arnd Bergmann <arnd@arndb.de>
