From 71f521bbaf375b685aeea20c6b0ed8600cd6edfe Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Tue, 19 Aug 2008 20:50:03 -0700 Subject: x86, irq: get nr_irqs from madt Until now, NR_IRQS was derived from black magic defines that had to be "large enough" to both accomodate NR_CPUS and MAX_NR_IO_APICs. This resulted in a way too large irq_desc[] array on most x86 systems. Especially with larger CPU masks, the size of irq_desc can spiral out of control quickly. So be smarter about it and use precise allocation instead: determine the default maximum possible IRQ number from the ACPI MADT. Use a minimum limit of at least 32 IRQs for broken BIOSes. Signed-off-by: Yinghai Lu Signed-off-by: Ingo Molnar --- arch/x86/kernel/acpi/boot.c | 30 ++++++++++++++++++++++++++++-- 1 file changed, 28 insertions(+), 2 deletions(-) (limited to 'arch/x86/kernel/acpi') diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index eb875cdc736..3e9d163fd92 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -957,6 +957,29 @@ void __init mp_register_ioapic(int id, u32 address, u32 gsi_base) nr_ioapics++; } +int get_nr_irqs_via_madt(void) +{ + int idx; + int nr = 0; + + for (idx = 0; idx < nr_ioapics; idx++) { + if (mp_ioapic_routing[idx].gsi_end > nr) + nr = mp_ioapic_routing[idx].gsi_end; + } + + nr++; + + /* double it for hotplug and msi and nmi */ + nr <<= 1; + + /* something wrong ? */ + if (nr < 32) + nr = 32; + + return nr; + +} + static void assign_to_mp_irq(struct mp_config_intsrc *m, struct mp_config_intsrc *mp_irq) { @@ -1254,9 +1277,12 @@ static int __init acpi_parse_madt_ioapic_entries(void) return count; } + + nr_irqs = get_nr_irqs_via_madt(); + count = acpi_table_parse_madt(ACPI_MADT_TYPE_INTERRUPT_OVERRIDE, acpi_parse_int_src_ovr, - NR_IRQ_VECTORS); + nr_irqs); if (count < 0) { printk(KERN_ERR PREFIX "Error parsing interrupt source overrides entry\n"); @@ -1276,7 +1302,7 @@ static int __init acpi_parse_madt_ioapic_entries(void) count = acpi_table_parse_madt(ACPI_MADT_TYPE_NMI_SOURCE, acpi_parse_nmi_src, - NR_IRQ_VECTORS); + nr_irqs); if (count < 0) { printk(KERN_ERR PREFIX "Error parsing NMI SRC entry\n"); /* TBD: Cleanup to allow fallback to MPS */ -- cgit v1.2.3