This is an SN specific patch. Architectually, cpu_init is always called twice on cpu 0 and thus resulted in two SN_SAL_SET_CPU_NUMBER calls. This was harmless in production kernel; however, it can cause problem on booting up a crashdump kernel at Altix. Here is the patch that detects the second sn_cpu_init call and skips the second call to SN_SAL_SET_CPU_NUMBER. Signed-Off-By: Jay Lan <jlan@xxxxxxx> The patch is created off 2.6.19.
Index: linux/arch/ia64/sn/kernel/setup.c =================================================================== --- linux.orig/arch/ia64/sn/kernel/setup.c 2006-11-29 13:57:37.000000000 -0800 +++ linux/arch/ia64/sn/kernel/setup.c 2006-12-11 15:31:16.700848251 -0800 @@ -562,7 +562,7 @@ void __cpuinit sn_cpu_init(void) int slice; int cnode; int i; - static int wars_have_been_checked; + static int wars_have_been_checked, set_cpu0_number; cpuid = smp_processor_id(); if (cpuid == 0 && IS_MEDUSA()) { @@ -587,8 +587,16 @@ void __cpuinit sn_cpu_init(void) /* * Don't check status. The SAL call is not supported on all PROMs * but a failure is harmless. + * Architechtuallly, cpu_init is always called twice on cpu 0. We + * should set cpu_number on cpu 0 once. */ - (void) ia64_sn_set_cpu_number(cpuid); + if (cpuid == 0) { + if (!set_cpu0_number) { + (void) ia64_sn_set_cpu_number(cpuid); + set_cpu0_number = 1; + } + } else + (void) ia64_sn_set_cpu_number(cpuid); /* * The boot cpu makes this call again after platform initialization is
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