From 10617bbe84628eb18ab5f723d3ba35005adde143 Mon Sep 17 00:00:00 2001 From: Tony Luck Date: Tue, 12 Aug 2008 10:34:20 -0700 Subject: [IA64] Ensure cpu0 can access per-cpu variables in early boot code ia64 handles per-cpu variables a litle differently from other architectures in that it maps the physical memory allocated for each cpu at a constant virtual address (0xffffffffffff0000). This mapping is not enabled until the architecture specific cpu_init() function is run, which causes problems since some generic code is run before this point. In particular when CONFIG_PRINTK_TIME is enabled, the boot cpu will trap on the access to per-cpu memory at the first printk() call so the boot will fail without the kernel printing anything to the console. Fix this by allocating percpu memory for cpu0 in the kernel data section and doing all initialization to enable percpu access in head.S before calling any generic code. Other cpus must take care not to access per-cpu variables too early, but their code path from start_secondary() to cpu_init() is all in arch/ia64 Signed-off-by: Tony Luck --- arch/ia64/kernel/setup.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) (limited to 'arch/ia64/kernel/setup.c') diff --git a/arch/ia64/kernel/setup.c b/arch/ia64/kernel/setup.c index 593279f33e96..c27d5b2c182b 100644 --- a/arch/ia64/kernel/setup.c +++ b/arch/ia64/kernel/setup.c @@ -927,17 +927,19 @@ cpu_init (void) if (smp_processor_id() == 0) { cpu_set(0, per_cpu(cpu_sibling_map, 0)); cpu_set(0, cpu_core_map[0]); + } else { + /* + * Set ar.k3 so that assembly code in MCA handler can compute + * physical addresses of per cpu variables with a simple: + * phys = ar.k3 + &per_cpu_var + * and the alt-dtlb-miss handler can set per-cpu mapping into + * the TLB when needed. head.S already did this for cpu0. + */ + ia64_set_kr(IA64_KR_PER_CPU_DATA, + ia64_tpa(cpu_data) - (long) __per_cpu_start); } #endif - /* - * We set ar.k3 so that assembly code in MCA handler can compute - * physical addresses of per cpu variables with a simple: - * phys = ar.k3 + &per_cpu_var - */ - ia64_set_kr(IA64_KR_PER_CPU_DATA, - ia64_tpa(cpu_data) - (long) __per_cpu_start); - get_max_cacheline_size(); /* -- cgit v1.2.3