On Fri, Nov 17, 2006 at 05:42:24PM +0530, Mohan Kumar M wrote:
> On Fri, Nov 17, 2006 at 02:36:16AM +1100, Anton Blanchard wrote:
> >
> > Hi,
> >
> > Thanks for fixing this problem. One thing I noticed in the patch:
> >
> > > + np = cpuid_to_of_node(boot_cpuid);
> > > + BUG_ON(!np);
> > > + ireg = get_property(np, "ibm,ppc-interrupt-gserver#s", &ilen);
> > > + hcpuid = get_hard_smp_processor_id(boot_cpuid);
> > > +
> > > + if (ireg[0] == hcpuid)
> > > + default_distrib_server = ireg[1];
> > > + else
> > > + default_distrib_server = ireg[3];
> >
> > While this will work on current firmware it would be more robust to loop
> > through interrupt-gserver#s until you find your cpuid. For example we
> > set up multiple interrupt-gserver#s entries in the lab so we can have
> > chip, node local and global targets:
> >
> > ibm,ppc-interrupt-server#s
> > 00000002 00000003
> >
> > ibm,ppc-interrupt-gserver#s
> > 00000002 000000ff 00000003 000000ff 00000002 000000f7
> > 00000003 000000f7 00000002 000000d7
> > 00000003 000000d7
> >
> > We always put the global target at the end (0xd7 in this case) because
> > the current code in Linux just grabs the last entry in the array to get
> > the global server. So the question is, do we look for the first or the
> > last entry that matches your cpuid to find the global server?
> >
> > It might be worth getting something added to the architecture (PAPR) to
> > clear it up. To match what current Linux does, we would want servers to
> > go from including the least to the most cpus, so the global one is at
> > the end.
> >
Hi Paul,
I updated the patch as per Anton's suggestion. Can you please consider
this patch to be merged in the powerpc git tree?
Regards,
Mohan.
>
> Thanks Anton,
>
> I have modified the patch to loop through ibm,ppc-interrupt-gserver#s
> property to find the global distribution server from the last entry
> that matches with boot cpuid. So this patch will work with above
> situation also.
>
> o The following patch allows any secondary CPU thread also to become
> boot cpu for POWER5. The patch is required to solve kdump boot issue
> when the kdump kernel is booted with parameter "maxcpus=1". XICS init
> code tries to match the current boot cpu id with "reg" property in
> each CPU node in the device tree. But CPU node is created only for
> primary thread CPU ids and "reg" property only reflects primary CPU
> ids. So when a kernel is booted on a secondary cpu thread above
> condition will never meet and the default distribution server is left
> as zero. This leads to route the interrupts to CPU 0, but which is not
> online at this time.
>
> o The patch uses ibm,ppc-interrupt-server#s to check for both primary
> and secondary CPU ids. Accordingly default distribution server value
> is initialized from "ibm,ppc-interrupt-gserver#s" property.
>
> Signed-off-by: Mohan Kumar M <[EMAIL PROTECTED]>
> ---
> arch/powerpc/platforms/pseries/xics.c | 68
> ++++++++++++++++++++++++----------
> 1 file changed, 49 insertions(+), 19 deletions(-)
>
> Index: linux-2.6.19-rc5/arch/powerpc/platforms/pseries/xics.c
> ===================================================================
> --- linux-2.6.19-rc5.orig/arch/powerpc/platforms/pseries/xics.c
> +++ linux-2.6.19-rc5/arch/powerpc/platforms/pseries/xics.c
> @@ -656,13 +656,38 @@ static void __init xics_setup_8259_casca
> set_irq_chained_handler(cascade, pseries_8259_cascade);
> }
>
> +static struct device_node *cpuid_to_of_node(int cpu)
> +{
> + struct device_node *np;
> + u32 hcpuid = get_hard_smp_processor_id(cpu);
> +
> + for_each_node_by_type(np, "cpu") {
> + int i, len;
> + const u32 *intserv;
> +
> + intserv = get_property(np, "ibm,ppc-interrupt-server#s", &len);
> +
> + if (!intserv)
> + intserv = get_property(np, "reg", &len);
> +
> + i = len / sizeof(u32);
> +
> + while (i--)
> + if (intserv[i] == hcpuid)
> + return np;
> + }
> +
> + return NULL;
> +}
> +
> void __init xics_init_IRQ(void)
> {
> - int i;
> + int i, j;
> struct device_node *np;
> u32 ilen, indx = 0;
> - const u32 *ireg;
> + const u32 *ireg, *isize;
> int found = 0;
> + u32 hcpuid;
>
> ppc64_boot_msg(0x20, "XICS Init");
>
> @@ -683,26 +708,31 @@ void __init xics_init_IRQ(void)
> xics_init_host();
>
> /* Find the server numbers for the boot cpu. */
> - for (np = of_find_node_by_type(NULL, "cpu");
> - np;
> - np = of_find_node_by_type(np, "cpu")) {
> - ireg = get_property(np, "reg", &ilen);
> - if (ireg && ireg[0] == get_hard_smp_processor_id(boot_cpuid)) {
> - ireg = get_property(np,
> - "ibm,ppc-interrupt-gserver#s", &ilen);
> - i = ilen / sizeof(int);
> - if (ireg && i > 0) {
> - default_server = ireg[0];
> - /* take last element */
> - default_distrib_server = ireg[i-1];
> - }
> - ireg = get_property(np,
> + np = cpuid_to_of_node(boot_cpuid);
> + BUG_ON(!np);
> + ireg = get_property(np, "ibm,ppc-interrupt-gserver#s", &ilen);
> + if (!ireg)
> + goto skip_gserver_check;
> + i = ilen / sizeof(int);
> + hcpuid = get_hard_smp_processor_id(boot_cpuid);
> +
> + /* Global interrupt distribution server is specified in the last
> + * entry of "ibm,ppc-interrupt-gserver#s" property. Get the last
> + * entry fom this property for current boot cpu id and use it as
> + * default distribution server
> + */
> + for (j = 0; j < i; j += 2) {
> + if (ireg[j] == hcpuid) {
> + default_server = hcpuid;
> + default_distrib_server = ireg[j+1];
> +
> + isize = get_property(np,
> "ibm,interrupt-server#-size", NULL);
> - if (ireg)
> - interrupt_server_size = *ireg;
> - break;
> + if (isize)
> + interrupt_server_size = *isize;
> }
> }
> +skip_gserver_check:
> of_node_put(np);
>
> if (firmware_has_feature(FW_FEATURE_LPAR))
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