[PATCH for-4.9 4/7] MIPS: Switch to the irq_stack in interrupts

From: Matt Redfearn When enterring interrupt context via handle_int or except_vec_vi, switch to the irq_stack of the current CPU if it is not already in use. The current stack pointer is masked with the thread size and compared to the base or the irq stack. If it does

[PATCH for-4.9 4/7] MIPS: Switch to the irq_stack in interrupts

From: Matt Redfearn When enterring interrupt context via handle_int or except_vec_vi, switch to the irq_stack of the current CPU if it is not already in use. The current stack pointer is masked with the thread size and compared to the base or the irq stack. If it does not match then the stack