From a5715d6dfc85e002bfad68bb2858cf5a248e2060 Mon Sep 17 00:00:00 2001 From: Mohan Kumar M Date: Fri, 17 Nov 2006 17:42:24 +0530 Subject: [PATCH] [POWERPC] pSeries/kexec: Fix for interrupt distribution This 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. We use 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. We loop through ibm,ppc-interrupt-gserver#s property to find the global distribution server from the last entry that matches with boot cpuid. Signed-off-by: Mohan Kumar M Signed-off-by: Paul Mackerras --- arch/powerpc/platforms/pseries/xics.c | 68 +++++++++++++++++++-------- 1 file changed, 49 insertions(+), 19 deletions(-) diff --git a/arch/powerpc/platforms/pseries/xics.c b/arch/powerpc/platforms/pseries/xics.c index d071abe78a..b5b2b1103d 100644 --- a/arch/powerpc/platforms/pseries/xics.c +++ b/arch/powerpc/platforms/pseries/xics.c @@ -656,13 +656,38 @@ static void __init xics_setup_8259_cascade(void) 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)) -- 2.39.5