[PATCH v3 2/5] RISC-V: Move to the new GENERIC_IRQ_MULTI_HANDLER handler

From: Palmer Dabbelt
Date: Wed Mar 07 2018 - 18:57:51 EST


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 generic 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.

Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Acked-by: Stafford Horne <shorne@xxxxxxxxx>
Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxx>
---
arch/riscv/Kconfig | 1 +
arch/riscv/include/asm/Kbuild | 1 +
arch/riscv/kernel/entry.S | 7 +++----
arch/riscv/kernel/irq.c | 13 -------------
4 files changed, 5 insertions(+), 17 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 04807c7f64cc..148865de1692 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -33,6 +33,7 @@ config RISCV
select MODULES_USE_ELF_RELA if MODULES
select THREAD_INFO_IN_TASK
select RISCV_TIMER
+ select GENERIC_IRQ_MULTI_HANDLER

config MMU
def_bool y
diff --git a/arch/riscv/include/asm/Kbuild b/arch/riscv/include/asm/Kbuild
index 4286a5f83876..1e5fd280fb4d 100644
--- a/arch/riscv/include/asm/Kbuild
+++ b/arch/riscv/include/asm/Kbuild
@@ -15,6 +15,7 @@ generic-y += fcntl.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 56fa592cfa34..9aaf6c986771 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -167,10 +167,9 @@ ENTRY(handle_exception)
bge s4, zero, 1f

/* 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:
/* Exceptions run with interrupts enabled */
csrs sstatus, SR_SIE
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
-}
--
2.16.1