Unverified Commit 5cf998ba authored by Anup Patel's avatar Anup Patel Committed by Palmer Dabbelt
Browse files

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: default avatarAnup Patel <anup.patel@wdc.com>
Reviewed-by: default avatarAtish Patra <atish.patra@wdc.com>
Reviewed-by: default avatarPalmer Dabbelt <palmerdabbelt@google.com>
Acked-by: default avatarPalmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: default avatarPalmer Dabbelt <palmerdabbelt@google.com>
parent e8c7ef7d

arch/riscv/include/asm/irq.h

+0 −1
Original line number Diff line number Diff line
@@ -13,7 +13,6 @@ 
#define NR_IRQS         0



void riscv_timer_interrupt(void);

void riscv_software_interrupt(void);



#include <asm-generic/irq.h>

arch/riscv/include/asm/smp.h

+3 −0
Original line number Diff line number Diff line
@@ -28,6 +28,9 @@ void show_ipi_stats(struct seq_file *p, int prec); 
/* 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);

arch/riscv/kernel/irq.c

+10 −6
Original line number Diff line number Diff line
@@ -19,12 +19,15 @@ int arch_show_interrupts(struct seq_file *p, int prec) 


asmlinkage __visible void __irq_entry do_IRQ(struct pt_regs *regs)

{

	struct pt_regs *old_regs = set_irq_regs(regs);

	struct pt_regs *old_regs;



	irq_enter();

	switch (regs->cause & ~CAUSE_IRQ_FLAG) {

	case RV_IRQ_TIMER:

		old_regs = set_irq_regs(regs);

		irq_enter();

		riscv_timer_interrupt();

		irq_exit();

		set_irq_regs(old_regs);

		break;

#ifdef CONFIG_SMP

	case RV_IRQ_SOFT:
@@ -32,19 +35,20 @@ asmlinkage __visible void __irq_entry do_IRQ(struct pt_regs *regs) 
		 * 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 RV_IRQ_EXT:

		old_regs = set_irq_regs(regs);

		irq_enter();

		handle_arch_irq(regs);

		irq_exit();

		set_irq_regs(old_regs);

		break;

	default:

		pr_alert("unexpected interrupt cause 0x%lx", regs->cause);

		BUG();

	}

	irq_exit();



	set_irq_regs(old_regs);

}



void __init init_IRQ(void)

arch/riscv/kernel/smp.c

+9 −2
Original line number Diff line number Diff line
@@ -123,11 +123,14 @@ static inline void clear_ipi(void) 
		clint_clear_ipi(cpuid_to_hartid_map(smp_processor_id()));

}



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;

	unsigned long *stats = ipi_data[smp_processor_id()].stats;



	irq_enter();



	clear_ipi();



	while (true) {
@@ -138,7 +141,7 @@ void riscv_software_interrupt(void) 


		ops = xchg(pending_ipis, 0);

		if (ops == 0)

			return;

			goto done;



		if (ops & (1 << IPI_RESCHEDULE)) {

			stats[IPI_RESCHEDULE]++;
@@ -160,6 +163,10 @@ void riscv_software_interrupt(void) 
		/* Order data access and bit testing. */

		mb();

	}



done:

	irq_exit();

	set_irq_regs(old_regs);

}



static const char * const ipi_names[] = {

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