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Message-Id: <20180906123651.28500-2-anup@brainfault.org>
Date: Thu, 6 Sep 2018 18:06:47 +0530
From: Anup Patel <anup@...infault.org>
To: Palmer Dabbelt <palmer@...ive.com>,
Albert Ou <aou@...s.berkeley.edu>,
Daniel Lezcano <daniel.lezcano@...aro.org>,
Thomas Gleixner <tglx@...utronix.de>,
Jason Cooper <jason@...edaemon.net>,
Marc Zyngier <marc.zyngier@....com>
Cc: Atish Patra <atish.patra@....com>,
Christoph Hellwig <hch@...radead.org>,
linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
Anup Patel <anup@...infault.org>
Subject: [PATCH v2 1/5] RISC-V: self-contained IPI handling routine
Currently, the IPI handling routine riscv_software_interrupt() does
not take any argument and also does not perform irq_enter()/irq_exit().
This patch makes IPI handling routine more self-contained by:
1. Passing "pt_regs *" argument
2. Explicitly doing irq_enter()/irq_exit()
3. Explicitly save/restore "pt_regs *" using set_irq_regs()
With above changes, IPI handling routine does not depend on caller
function to perform irq_enter()/irq_exit() and save/restore of
"pt_regs *" hence its more self-contained. This also enables us
to call IPI handling routine from IRQCHIP drivers.
Signed-off-by: Anup Patel <anup@...infault.org>
---
arch/riscv/include/asm/irq.h | 1 -
arch/riscv/include/asm/smp.h | 3 +++
arch/riscv/kernel/irq.c | 16 ++++++++++------
arch/riscv/kernel/smp.c | 11 +++++++++--
4 files changed, 22 insertions(+), 9 deletions(-)
diff --git a/arch/riscv/include/asm/irq.h b/arch/riscv/include/asm/irq.h
index a873a72d0f00..8d5d1a9f7fae 100644
--- a/arch/riscv/include/asm/irq.h
+++ b/arch/riscv/include/asm/irq.h
@@ -18,7 +18,6 @@
#define NR_IRQS 0
void riscv_timer_interrupt(void);
-void riscv_software_interrupt(void);
void wait_for_software_interrupt(void);
#include <asm-generic/irq.h>
diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
index 8145b8657d20..d7c3da05f200 100644
--- a/arch/riscv/include/asm/smp.h
+++ b/arch/riscv/include/asm/smp.h
@@ -51,6 +51,9 @@ void send_ipi_message(const struct cpumask *to_whom,
/* SMP initialization hook for setup_arch */
void __init setup_smp(void);
+/* Called from C code, this handles an IPI. */
+void handle_IPI(struct pt_regs *regs);
+
/* Hook for the generic smp_call_function_many() routine. */
void arch_send_call_function_ipi_mask(struct cpumask *mask);
diff --git a/arch/riscv/kernel/irq.c b/arch/riscv/kernel/irq.c
index 7e14b0d9a71d..f5073dcbc560 100644
--- a/arch/riscv/kernel/irq.c
+++ b/arch/riscv/kernel/irq.c
@@ -26,12 +26,15 @@
asmlinkage void __irq_entry do_IRQ(struct pt_regs *regs, unsigned long cause)
{
- struct pt_regs *old_regs = set_irq_regs(regs);
+ struct pt_regs *old_regs;
- irq_enter();
switch (cause & ~INTERRUPT_CAUSE_FLAG) {
case INTERRUPT_CAUSE_TIMER:
+ old_regs = set_irq_regs(regs);
+ irq_enter();
riscv_timer_interrupt();
+ irq_exit();
+ set_irq_regs(old_regs);
break;
#ifdef CONFIG_SMP
case INTERRUPT_CAUSE_SOFTWARE:
@@ -39,18 +42,19 @@ asmlinkage void __irq_entry do_IRQ(struct pt_regs *regs, unsigned long cause)
* We only use software interrupts to pass IPIs, so if a non-SMP
* system gets one, then we don't know what to do.
*/
- riscv_software_interrupt();
+ handle_IPI(regs);
break;
#endif
case INTERRUPT_CAUSE_EXTERNAL:
+ old_regs = set_irq_regs(regs);
+ irq_enter();
handle_arch_irq(regs);
+ irq_exit();
+ set_irq_regs(old_regs);
break;
default:
panic("unexpected interrupt cause");
}
- irq_exit();
-
- set_irq_regs(old_regs);
}
/*
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 629456bb6122..9e7bcf705946 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -58,10 +58,13 @@ int setup_profiling_timer(unsigned int multiplier)
return -EINVAL;
}
-void riscv_software_interrupt(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;
+ irq_enter();
+
/* Clear pending IPI */
csr_clear(sip, SIE_SSIE);
@@ -73,7 +76,7 @@ void riscv_software_interrupt(void)
ops = xchg(pending_ipis, 0);
if (ops == 0)
- return;
+ goto done;
if (ops & (1 << IPI_RESCHEDULE))
scheduler_ipi();
@@ -86,6 +89,10 @@ void riscv_software_interrupt(void)
/* Order data access and bit testing. */
mb();
}
+
+done:
+ irq_exit();
+ set_irq_regs(old_regs);
}
void
--
2.17.1
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