From 4ad8d38342430f8b52f7a8458dce90caf8c8ca64 Mon Sep 17 00:00:00 2001 From: Zwane Mwaikambo Date: Sat, 3 Sep 2005 15:56:51 -0700 Subject: [PATCH] i386 boottime for_each_cpu broken for_each_cpu walks through all processors in cpu_possible_map, which is defined as cpu_callout_map on i386 and isn't initialised until all processors have been booted. This breaks things which do for_each_cpu iterations early during boot. So, define cpu_possible_map as a bitmap with NR_CPUS bits populated. This was triggered by a patch i'm working on which does alloc_percpu before bringing up secondary processors. From: Alexander Nyberg i386-boottime-for_each_cpu-broken.patch i386-boottime-for_each_cpu-broken-fix.patch The SMP version of __alloc_percpu checks the cpu_possible_map before allocating memory for a certain cpu. With the above patches the BSP cpuid is never set in cpu_possible_map which breaks CONFIG_SMP on uniprocessor machines (as soon as someone tries to dereference something allocated via __alloc_percpu, which in fact is never allocated since the cpu is not set in cpu_possible_map). Signed-off-by: Zwane Mwaikambo Signed-off-by: Alexander Nyberg Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/kernel/mpparse.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'arch/i386/kernel/mpparse.c') diff --git a/arch/i386/kernel/mpparse.c b/arch/i386/kernel/mpparse.c index 788efff..5d0b9a8 100644 --- a/arch/i386/kernel/mpparse.c +++ b/arch/i386/kernel/mpparse.c @@ -122,7 +122,7 @@ static int MP_valid_apicid(int apicid, int version) static void __init MP_processor_info (struct mpc_config_processor *m) { - int ver, apicid; + int ver, apicid, cpu, found_bsp = 0; physid_mask_t tmp; if (!(m->mpc_cpuflag & CPU_ENABLED)) @@ -181,6 +181,7 @@ static void __init MP_processor_info (struct mpc_config_processor *m) if (m->mpc_cpuflag & CPU_BOOTPROCESSOR) { Dprintk(" Bootup CPU\n"); boot_cpu_physical_apicid = m->mpc_apicid; + found_bsp = 1; } if (num_processors >= NR_CPUS) { @@ -204,6 +205,11 @@ static void __init MP_processor_info (struct mpc_config_processor *m) return; } + if (found_bsp) + cpu = 0; + else + cpu = num_processors - 1; + cpu_set(cpu, cpu_possible_map); tmp = apicid_to_cpu_present(apicid); physids_or(phys_cpu_present_map, phys_cpu_present_map, tmp); -- cgit v1.1