[PATCH v2 4/4] RISC-V: Move to the new generic IRQ handler

Palmer Dabbelt
2018-01-25T03:08:37Z

The old mechanism for handling IRQs on RISC-V was pretty ugly: the arch
code looked at the Kconfig entry for our first-level irqchip driver and
called into it directly.

This patch uses the new 0generic IRQ handling infastructure, which
essentially just deletes a bunch of code. This does add an additional
load to the interrupt latency, but there's a lot of tuning left to be
done there on RISC-V so I think it's OK for now.

Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
---
arch/riscv/Kconfig | 1 +
arch/riscv/include/asm/Kbuild | 1 +
arch/riscv/kernel/entry.S | 5 +++--
arch/riscv/kernel/irq.c | 13 -------------
4 files changed, 5 insertions(+), 15 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 2c6adf12713a..e67f42178059 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -35,6 +35,7 @@ config RISCV
select THREAD_INFO_IN_TASK
select RISCV_IRQ_INTC
select RISCV_TIMER
+ select MULTI_IRQ_HANDLER

config MMU
def_bool y
diff --git a/arch/riscv/include/asm/Kbuild b/arch/riscv/include/asm/Kbuild
index 970460a0b492..e0d0fbe43ca2 100644
--- a/arch/riscv/include/asm/Kbuild
+++ b/arch/riscv/include/asm/Kbuild
@@ -16,6 +16,7 @@ generic-y += ftrace.h
generic-y += futex.h
generic-y += hardirq.h
generic-y += hash.h
+generic-y += handle_irq.h
generic-y += hw_irq.h
generic-y += ioctl.h
generic-y += ioctls.h
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index 7404ec222406..a79869151aea 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -166,8 +166,9 @@ ENTRY(handle_exception)
/* Handle interrupts */
slli a0, s4, 1
srli a0, a0, 1
- move a1, sp /* pt_regs */
- tail do_IRQ
+ move a0, sp /* pt_regs */
+ REG_L a1, handle_arch_irq
+ jr a1
1:
/* Handle syscalls */
li t0, EXC_SYSCALL
diff --git a/arch/riscv/kernel/irq.c b/arch/riscv/kernel/irq.c
index 328718e8026e..b74cbfbce2d0 100644
--- a/arch/riscv/kernel/irq.c
+++ b/arch/riscv/kernel/irq.c
@@ -24,16 +24,3 @@ void __init init_IRQ(void)
{
irqchip_init();
}
-
-asmlinkage void __irq_entry do_IRQ(unsigned int cause, struct pt_regs *regs)
-{
-#ifdef CONFIG_RISCV_INTC
- /*
- * FIXME: We don't want a direct call to riscv_intc_irq here. The plan
- * is to put an IRQ domain here and let the interrupt controller
- * register with that, but I poked around the arm64 code a bit and
- * there might be a better way to do it (ie, something fully generic).
- */
- riscv_intc_irq(cause, regs);
-#endif
-}
--
2.13.6