linux-kernel - [PATCH 13/15] irq: riscv: perform irqentry in entry code

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Date:   Thu, 21 Oct 2021 19:02:34 +0100
From:   Mark Rutland <mark.rutland@....com>
To:     linux-kernel@...r.kernel.org
Cc:     aou@...s.berkeley.edu, catalin.marinas@....com,
        deanbo422@...il.com, green.hu@...il.com, guoren@...nel.org,
        jonas@...thpole.se, kernelfans@...il.com,
        linux-arm-kernel@...ts.infradead.org, linux@...linux.org.uk,
        mark.rutland@....com, maz@...nel.org, nickhu@...estech.com,
        palmer@...belt.com, paulmck@...nel.org, paul.walmsley@...ive.com,
        peterz@...radead.org, shorne@...il.com,
        stefan.kristiansson@...nalahti.fi, tglx@...utronix.de,
        torvalds@...ux-foundation.org, tsbogend@...ha.franken.de,
        vgupta@...nel.org, will@...nel.org
Subject: [PATCH 13/15] irq: riscv: perform irqentry in entry code

In preparation for removing HANDLE_DOMAIN_IRQ_IRQENTRY, have arch/riscv
perform all the irqentry accounting in its entry code. As arch/riscv
uses GENERIC_IRQ_MULTI_HANDLER, we can use generic_handle_arch_irq() to
do so.

Since generic_handle_arch_irq() handles the irq entry and setting the
irq regs, and happens before the irqchip code calls handle_IPI(), we can
remove the redundant irq entry and irq regs manipulation from
handle_IPI().

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@....com>
Cc: Albert Ou <aou@...s.berkeley.edu>
Cc: Marc Zyngier <maz@...nel.org>
Cc: Palmer Dabbelt <palmer@...belt.com>
Cc: Paul Walmsley <paul.walmsley@...ive.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
---
 arch/riscv/Kconfig        | 1 -
 arch/riscv/kernel/entry.S | 3 +--
 arch/riscv/kernel/smp.c   | 9 +--------
 3 files changed, 2 insertions(+), 11 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 740653063a56..301a54233c7e 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -63,7 +63,6 @@ config RISCV
 	select GENERIC_SMP_IDLE_THREAD
 	select GENERIC_TIME_VSYSCALL if MMU && 64BIT
 	select HANDLE_DOMAIN_IRQ
-	select HANDLE_DOMAIN_IRQ_IRQENTRY
 	select HAVE_ARCH_AUDITSYSCALL
 	select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL
 	select HAVE_ARCH_JUMP_LABEL_RELATIVE if !XIP_KERNEL
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index 98f502654edd..64236f7efde5 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -130,8 +130,7 @@ skip_context_tracking:
 
 	/* Handle interrupts */
 	move a0, sp /* pt_regs */
-	la a1, handle_arch_irq
-	REG_L a1, (a1)
+	la a1, generic_handle_arch_irq
 	jr a1
 1:
 	/*
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 921d9d7df400..2f6da845c9ae 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -140,12 +140,9 @@ void arch_irq_work_raise(void)
 
 void handle_IPI(struct pt_regs *regs)
 {
-	struct pt_regs *old_regs = set_irq_regs(regs);
 	unsigned long *pending_ipis = &ipi_data[smp_processor_id()].bits;
 	unsigned long *stats = ipi_data[smp_processor_id()].stats;
 
-	irq_enter();
-
 	riscv_clear_ipi();
 
 	while (true) {
@@ -156,7 +153,7 @@ void handle_IPI(struct pt_regs *regs)
 
 		ops = xchg(pending_ipis, 0);
 		if (ops == 0)
-			goto done;
+			return;
 
 		if (ops & (1 << IPI_RESCHEDULE)) {
 			stats[IPI_RESCHEDULE]++;
@@ -189,10 +186,6 @@ void handle_IPI(struct pt_regs *regs)
 		/* Order data access and bit testing. */
 		mb();
 	}
-
-done:
-	irq_exit();
-	set_irq_regs(old_regs);
 }
 
 static const char * const ipi_names[] = {
-- 
2.11.0