Patch "x86/acpi: Handle SCI interrupts above legacy space gracefully" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

x86/acpi: Handle SCI interrupts above legacy space gracefully

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
x86-acpi-handle-sci-interrupts-above-legacy-space-gracefully.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Vikas C Sajjan <[email protected]>
Date: Thu, 16 Nov 2017 21:43:44 +0530
Subject: x86/acpi: Handle SCI interrupts above legacy space gracefully

From: Vikas C Sajjan <[email protected]>

commit 252714155f04c5d16989cb3aadb85fd1b5772f99 upstream.

Platforms which support only IOAPIC mode, pass the SCI information above the legacy space (0-15) via the FADT mechanism and not via MADT.

In such cases mp_override_legacy_irq() which is invoked from acpi_sci_ioapic_setup() to register SCI interrupts fails for interrupts greater equal 16, since it is meant to handle only the legacy space and emits error "Invalid bus_irq %u for legacy override".

Add a new function to handle SCI interrupts >= 16 and invoke it conditionally in acpi_sci_ioapic_setup().

The code duplication due to this new function will be cleaned up in a separate patch.

---
 arch/x86/kernel/acpi/boot.c |   34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

@@ -429,6 +429,34 @@ static int mp_config_acpi_gsi(struct dev
 	return 0;
 }
 
+static int __init mp_register_ioapic_irq(u8 bus_irq, u8 polarity,
+						u8 trigger, u32 gsi)
+{
+	struct mpc_intsrc mp_irq;
+	int ioapic, pin;
+
+	/* Convert 'gsi' to 'ioapic.pin'(INTIN#) */
+	ioapic = mp_find_ioapic(gsi);
+	if (ioapic < 0) {
+		pr_warn("Failed to find ioapic for gsi : %u\n", gsi);
+		return ioapic;
+	}
+
+	pin = mp_find_ioapic_pin(ioapic, gsi);
+
+	mp_irq.type = MP_INTSRC;
+	mp_irq.irqtype = mp_INT;
+	mp_irq.irqflag = (trigger << 2) | polarity;
+	mp_irq.srcbus = MP_ISA_BUS;
+	mp_irq.srcbusirq = bus_irq;
+	mp_irq.dstapic = mpc_ioapic_id(ioapic);
+	mp_irq.dstirq = pin;
+
+	mp_save_irq(&mp_irq);
+
+	return 0;
+}
+
 static int __init
 acpi_parse_ioapic(struct acpi_subtable_header * header, const unsigned long end)
 {

@@ -473,7 +501,11 @@ static void __init acpi_sci_ioapic_setup
 	if (acpi_sci_flags & ACPI_MADT_POLARITY_MASK)
 		polarity = acpi_sci_flags & ACPI_MADT_POLARITY_MASK;
 
-	mp_override_legacy_irq(bus_irq, polarity, trigger, gsi);
+	if (bus_irq < NR_IRQS_LEGACY)
+		mp_override_legacy_irq(bus_irq, polarity, trigger, gsi);
+	else
+		mp_register_ioapic_irq(bus_irq, polarity, trigger, gsi);
+
 	acpi_penalize_sci_irq(bus_irq, trigger, polarity);
 
 	/*

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/x86-acpi-handle-sci-interrupts-above-legacy-space-gracefully.patch