Re: [PATCH] kexec: force x86_64 arches to boot kdump kernels on boot cpu

Vivek Goyal
2007-12-10T16:22:48Z

On Mon, Dec 10, 2007 at 10:39:59AM -0500, Neil Horman wrote:
> On Fri, Dec 07, 2007 at 12:58:32PM -0500, Neil Horman wrote:
> >
> > Ok, New patch attached. It preforms the same function as previously described,
> > but is more restricted in its application. As Yinghai pointed out, the
> > broadcast mask bit (bit 17 in the htcfg register) should only be enabled, if the
> > extened apic id bit (bit 18 in the same register) is also set. So this patch
> > now check for that bit to be turned on first. Also, this patch now adds an
> > independent quirk check for all AMD hypertransport host controllers, since its
> > possible for this misconfiguration to be present in systems other than nvidias.
> > The net effect of these changes is, that its now applicable to all AMD systems
> > containing hypertransport busses, and is only activated if extended apic ids are
> > in use, meaning that this quirk guarantees that all processors in a system are
> > elligible to receive interrupts from the ioapic, even if their apicid extends
> > beyond the nominal 4 bit limitation. Tested successfully by me.
> >
> > Thanks & Regards
> > Neil
> >
> > Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
> >
> >
> > early-quirks.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++-----
> > 1 file changed, 76 insertions(+), 7 deletions(-)
> >
> >
> >
> > diff --git a/arch/x86/kernel/early-quirks.c b/arch/x86/kernel/early-quirks.c
> > index 88bb83e..d5a7b30 100644
> > --- a/arch/x86/kernel/early-quirks.c
> > +++ b/arch/x86/kernel/early-quirks.c
> > @@ -44,6 +44,50 @@ static int __init nvidia_hpet_check(struct acpi_table_header *header)
> > #endif /* CONFIG_X86_IO_APIC */
> > #endif /* CONFIG_ACPI */
> >
> > +static void __init fix_hypertransport_config(int num, int slot, int func)
> > +{
> > + u32 htcfg;
> > + /*
> > + *we found a hypertransport bus
> > + *make sure that are broadcasting
> > + *interrupts to all cpus on the ht bus
> > + *if we're using extended apic ids
> > + */
> > + htcfg = read_pci_config(num, slot, func, 0x68);
> > + if ((htcfg & (1 << 18)) == 1) {
> > + printk(KERN_INFO "Detected use of extended apic ids on hypertransport bus\n");
> > + if ((htcfg & (1 << 17)) == 0) {
> > + printk(KERN_INFO "Enabling hypertransport extended apic interrupt broadcast\n");
> > + htcfg |= (1 << 17);
> > + write_pci_config(num, slot, func, 0x68, htcfg);
> > + }
> > + }
> > +
> > +}
> > +
> > +static void __init check_hypertransport_config()
> > +{
> > + int num, slot, func;
> > + u32 device, vendor;
> > + func = 0;
> > + for (num = 0; num < 32; num++) {
> > + for (slot = 0; slot < 32; slot++) {
> > + vendor = read_pci_config(num,slot,func,
> > + PCI_VENDOR_ID);
> > + device = read_pci_config(num,slot,func,
> > + PCI_DEVICE_ID);
> > + vendor &= 0x0000ffff;
> > + device >>= 16;
> > + if ((vendor == PCI_VENDOR_ID_AMD) &&
> > + (device == PCI_DEVICE_ID_AMD_K8_NB))
> > + fix_hypertransport_config(num,slot,func);
> > + }
> > + }
> > +
> > + return;
> > +
> > +}
> > +
> > static void __init nvidia_bugs(void)
> > {
> > #ifdef CONFIG_ACPI
> > @@ -83,6 +127,12 @@ static void __init ati_bugs(void)
> > #endif
> > }
> >
> > +static void __init amd_host_bugs(void)
> > +{
> > + printk(KERN_CRIT "IN AMD_HOST_BUGS\n");
> > + check_hypertransport_config();
> > +}
> > +
> > struct chipset {
> > u16 vendor;
> > void (*f)(void);
> > @@ -95,9 +145,16 @@ static struct chipset early_qrk[] __initdata = {
> > {}
> > };
> >
> > +static struct chipset early_host_qrk[] __initdata = {
> > + { PCI_VENDOR_ID_AMD, amd_host_bugs},
> > + {}
> > +};
> > +
> > void __init early_quirks(void)
> > {
> > int num, slot, func;
> > + u8 found_bridge = 0;
> > + u8 found_host = 0;
> >
> > if (!early_pci_allowed())
> > return;
> > @@ -115,18 +172,30 @@ void __init early_quirks(void)
> > if (class == 0xffffffff)
> > break;
> >
> > - if ((class >> 16) != PCI_CLASS_BRIDGE_PCI)
> > + class >>= 16;
> > + if ((class != PCI_CLASS_BRIDGE_PCI) &&
> > + (class != PCI_CLASS_BRIDGE_HOST))
> > continue;
> >
> > vendor = read_pci_config(num, slot, func,
> > PCI_VENDOR_ID);
> > vendor &= 0xffff;
> > -
> > - for (i = 0; early_qrk[i].f; i++)
> > - if (early_qrk[i].vendor == vendor) {
> > - early_qrk[i].f();
> > - return;
> > - }
> > + if ((class == PCI_CLASS_BRIDGE_PCI) && (!found_bridge)) {
> > + for (i = 0; early_qrk[i].f; i++)
> > + if (early_qrk[i].vendor == vendor) {
> > + early_qrk[i].f();
> > + found_bridge = 1;;
> > + }
> > + } else if (!found_host) {
> > + for (i = 0; early_host_qrk[i].f; i++)
> > + if (early_host_qrk[i].vendor == vendor) {
> > + early_host_qrk[i].f();
> > + found_host = 1;
> > + }
> > + }
> > +
> > + if (found_bridge && found_host)
> > + return;
> >
> > type = read_pci_config_byte(num, slot, func,
> > PCI_HEADER_TYPE);
> >
> > _______________________________________________
> > kexec mailing list
> > kexec@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/kexec
>
> Sorry to reply to myself, but do we have consensus on this patch? I'd like to
> figure out its disposition if possible.
>

I agree with the approach taken. Somebody needs to review the changes done
for applying early_quirks. I am not well versed with it.

Thanks
Vivek