From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C4705225A50; Wed, 14 May 2025 10:39:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747219175; cv=none; b=WTuovkCm6P7JendnxhpKmvtTsixpT/cTAKU6mkn8bQr0Uxkn9TG8Lm8wobaPE49Z69pQ6nDJz00gPg7X/R/hfw5cqvJMy2K5F0ehPt8pL/drC10fI8yq2awmHTDIfM7fbn5AYmhLP7uhMQzcExBHzE/xeX0MJhqlG0zfbR3J6TQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747219175; c=relaxed/simple; bh=jdaKOxD2qt2jrO1zGt5BuJsLgrxKO8Tjw4sVNPmGmNE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XqVwE/cWbmzjQ4PAfqXGomeD/Jq97yg5hYmwe4OhwsZXN4H1AZ33xj2RQksfTASwKAx5caWmELLx1nOZZngoWLNEEp0fbtNzFMAkCJu4j8B3bIhCjyo4sZN41vyIjChCv4wlsICwVW+crXMvWcuiqT89tdHY51Q4hb4L7p2Gt2g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=m2sbotfm; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="m2sbotfm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BBF48C4CEE9; Wed, 14 May 2025 10:39:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747219174; bh=jdaKOxD2qt2jrO1zGt5BuJsLgrxKO8Tjw4sVNPmGmNE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=m2sbotfmS8yko3IJtk8XVsHgYCDFtBVsGhhCxwPZlon3shJEZXif2/gpZglkjaOir 5ys+PFUjoRr4jsgRlDaOsQZ8dKT7+n2DQ97IGnxK6MKxTSqwiBvNA1sCaIc0FO4jKO R8HFtSJ2mxI+TZm+NI/LZfsx9yAGU8MaWB4qbVthLFocMpXaaVyE6mQ4dIoeH6AhS8 AkaxffMkxGBqNEu15rfuGoFkQH+pKTh3/IlSITZBJzh79ateLjk3W2E0anKIbrcFy9 ut4DKOO26SynEkltCKpjgN6/WkNXhY8oxCT6CZQty64AQ4cxjQ5O85YX3wNHLCYtA/ WH8qs5ei9qPpA== Date: Wed, 14 May 2025 12:39:28 +0200 From: Lorenzo Pieralisi To: Marc Zyngier , Thomas Gleixner , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Catalin Marinas , Will Deacon Cc: Arnd Bergmann , Sascha Bischoff , Timothy Hayes , "Liam R. Howlett" , Mark Rutland , Jiri Slaby , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org Subject: Re: [PATCH v4 18/26] arm64: smp: Support non-SGIs for IPIs Message-ID: References: <20250513-gicv5-host-v4-0-b36e9b15a6c3@kernel.org> <20250513-gicv5-host-v4-18-b36e9b15a6c3@kernel.org> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250513-gicv5-host-v4-18-b36e9b15a6c3@kernel.org> On Tue, May 13, 2025 at 07:48:11PM +0200, Lorenzo Pieralisi wrote: [...] > /* > * Called from the secondary holding pen, this is the secondary CPU entry point. > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c > index 3b3f6b56e733039cad7ff5b8995db16a68f3c762..3f3712e47c94c62836fb89cd4bfb3595fbb41557 100644 > --- a/arch/arm64/kernel/smp.c > +++ b/arch/arm64/kernel/smp.c > @@ -83,7 +83,26 @@ enum ipi_msg_type { > > static int ipi_irq_base __ro_after_init; > static int nr_ipi __ro_after_init = NR_IPI; > -static struct irq_desc *ipi_desc[MAX_IPI] __ro_after_init; > + > +struct ipi_descs { > + struct irq_desc *descs[MAX_IPI]; > +}; > + > +static DEFINE_PER_CPU(struct ipi_descs, pcpu_ipi_desc); > + > +#define get_ipi_desc(__cpu, __ipi) (per_cpu_ptr(&pcpu_ipi_desc, __cpu)->descs[__ipi]) > + > +static bool percpu_ipi_descs __ro_after_init; > + > +static int ipi_to_irq(int ipi, int cpu) > +{ > + return ipi_irq_base + (cpu * nr_ipi) + ipi; > +} > + > +static int irq_to_ipi(int irq) > +{ > + return (irq - ipi_irq_base) % nr_ipi; > +} > > static bool crash_stop; > > @@ -844,7 +863,7 @@ int arch_show_interrupts(struct seq_file *p, int prec) > seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i, > prec >= 4 ? " " : ""); > for_each_online_cpu(cpu) > - seq_printf(p, "%10u ", irq_desc_kstat_cpu(ipi_desc[i], cpu)); > + seq_printf(p, "%10u ", irq_desc_kstat_cpu(get_ipi_desc(cpu, i), cpu)); > seq_printf(p, " %s\n", ipi_types[i]); > } > > @@ -919,7 +938,13 @@ static void __noreturn ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs > > static void arm64_backtrace_ipi(cpumask_t *mask) > { > - __ipi_send_mask(ipi_desc[IPI_CPU_BACKTRACE], mask); > + unsigned int cpu; > + > + if (!percpu_ipi_descs) > + __ipi_send_mask(get_ipi_desc(0, IPI_CPU_BACKTRACE), mask); > + else > + for_each_cpu(cpu, mask) > + __ipi_send_single(get_ipi_desc(cpu, IPI_CPU_BACKTRACE), cpu); > } > > void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu) > @@ -944,7 +969,7 @@ void kgdb_roundup_cpus(void) > if (cpu == this_cpu) > continue; > > - __ipi_send_single(ipi_desc[IPI_KGDB_ROUNDUP], cpu); > + __ipi_send_single(get_ipi_desc(cpu, IPI_KGDB_ROUNDUP), cpu); > } > } > #endif > @@ -1013,14 +1038,21 @@ static void do_handle_IPI(int ipinr) > > static irqreturn_t ipi_handler(int irq, void *data) > { > - do_handle_IPI(irq - ipi_irq_base); > + do_handle_IPI(irq_to_ipi(irq)); > return IRQ_HANDLED; > } > > static void smp_cross_call(const struct cpumask *target, unsigned int ipinr) > { > + unsigned int cpu; > + > trace_ipi_raise(target, ipi_types[ipinr]); > - __ipi_send_mask(ipi_desc[ipinr], target); > + > + if (!percpu_ipi_descs) > + __ipi_send_mask(get_ipi_desc(0, ipinr), target); > + else > + for_each_cpu(cpu, target) > + __ipi_send_single(get_ipi_desc(cpu, ipinr), cpu); > } > > static bool ipi_should_be_nmi(enum ipi_msg_type ipi) > @@ -1046,11 +1078,15 @@ static void ipi_setup(int cpu) > return; > > for (i = 0; i < nr_ipi; i++) { > - if (ipi_should_be_nmi(i)) { > - prepare_percpu_nmi(ipi_irq_base + i); > - enable_percpu_nmi(ipi_irq_base + i, 0); > + if (!percpu_ipi_descs) { > + if (ipi_should_be_nmi(i)) { > + prepare_percpu_nmi(ipi_irq_base + i); > + enable_percpu_nmi(ipi_irq_base + i, 0); > + } else { > + enable_percpu_irq(ipi_irq_base + i, 0); > + } > } else { > - enable_percpu_irq(ipi_irq_base + i, 0); > + enable_irq(irq_desc_get_irq(get_ipi_desc(cpu, i))); > } > } > } > @@ -1064,44 +1100,79 @@ static void ipi_teardown(int cpu) > return; > > for (i = 0; i < nr_ipi; i++) { > - if (ipi_should_be_nmi(i)) { > - disable_percpu_nmi(ipi_irq_base + i); > - teardown_percpu_nmi(ipi_irq_base + i); > + if (!percpu_ipi_descs) { > + if (ipi_should_be_nmi(i)) { > + disable_percpu_nmi(ipi_irq_base + i); > + teardown_percpu_nmi(ipi_irq_base + i); > + } else { > + disable_percpu_irq(ipi_irq_base + i); > + } > } else { > - disable_percpu_irq(ipi_irq_base + i); > + disable_irq(irq_desc_get_irq(get_ipi_desc(cpu, i))); > } > } > } > #endif > > -void __init set_smp_ipi_range(int ipi_base, int n) > +static void ipi_setup_ppi(int ipi) > +{ > + int err, irq, cpu; > + > + irq = ipi_irq_base + ipi; > + > + if (ipi_should_be_nmi(irq)) { > + err = request_percpu_nmi(irq, ipi_handler, "IPI", &irq_stat); > + WARN(err, "Could not request IRQ %d as NMI, err=%d\n", irq, err); > + } else { > + err = request_percpu_irq(irq, ipi_handler, "IPI", &irq_stat); > + WARN(err, "Could not request IRQ %d as IRQ, err=%d\n", irq, err); > + } > + > + for_each_possible_cpu(cpu) > + get_ipi_desc(cpu, ipi) = irq_to_desc(irq); > + > + irq_set_status_flags(irq, IRQ_HIDDEN); > +} > + > +static void ipi_setup_lpi(int ipi, int ncpus) > +{ > + for (int cpu = 0; cpu < ncpus; cpu++) { > + int err, irq; > + > + irq = ipi_to_irq(ipi, cpu); > + > + err = irq_force_affinity(irq, cpumask_of(cpu)); > + > + WARN(err, "Could not force affinity IRQ %d, err=%d\n", irq, err); > + > + err = request_irq(irq, ipi_handler, IRQF_NO_AUTOEN, "IPI", > + &irq_stat); Heads-up, kbuild bot (sparse) barfed (correctly) at this, because the &irq_stat pointer does not match the request_irq() void *dev_id parameter signature (it is void __percpu *). Of course, the &irq_stat parameter is unused so this is harmless. I would just pass NULL (because AFAICS irq_stat in the action handler is unused), the question is why are we passing &irq_stat in request_percpu_irq() if that's unused in ipi_handler() ? Was it used before and we removed its usage ? Should we clean it up for completeness ? Thanks, Lorenzo > + > + WARN(err, "Could not request IRQ %d, err=%d\n", irq, err); > + > + irq_set_status_flags(irq, (IRQ_HIDDEN | IRQ_NO_BALANCING_MASK)); > + > + get_ipi_desc(cpu, ipi) = irq_to_desc(irq); > + } > +} > + > +void __init set_smp_ipi_range_percpu(int ipi_base, int n, int ncpus) > { > int i; > > WARN_ON(n < MAX_IPI); > nr_ipi = min(n, MAX_IPI); > > - for (i = 0; i < nr_ipi; i++) { > - int err; > - > - if (ipi_should_be_nmi(i)) { > - err = request_percpu_nmi(ipi_base + i, ipi_handler, > - "IPI", &irq_stat); > - WARN(err, "Could not request IPI %d as NMI, err=%d\n", > - i, err); > - } else { > - err = request_percpu_irq(ipi_base + i, ipi_handler, > - "IPI", &irq_stat); > - WARN(err, "Could not request IPI %d as IRQ, err=%d\n", > - i, err); > - } > - > - ipi_desc[i] = irq_to_desc(ipi_base + i); > - irq_set_status_flags(ipi_base + i, IRQ_HIDDEN); > - } > - > + percpu_ipi_descs = !!ncpus; > ipi_irq_base = ipi_base; > > + for (i = 0; i < nr_ipi; i++) { > + if (!percpu_ipi_descs) > + ipi_setup_ppi(i); > + else > + ipi_setup_lpi(i, ncpus); > + } > + > /* Setup the boot CPU immediately */ > ipi_setup(smp_processor_id()); > } > > -- > 2.48.0 >