From: Andi Kleen Date: Tue, 17 May 2005 04:53:35 +0000 (-0700) Subject: [PATCH] x86_64: Don't assume BSP has ID 0 in new smp bootup X-Git-Tag: v3.12-rc1~43151^2~237 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=18a2b6471277c9ffbaa14a0c87a11a075eb354bd;p=kernel%2Fkernel-generic.git [PATCH] x86_64: Don't assume BSP has ID 0 in new smp bootup This patch removes the assumption that LAPIC entries contain the BSP as its first entry. This is a slight improvement to the temporary fix submitted by Suresh Siddha. - Removes assumption that LAPIC entries contain BSP first. - Builds x86_acpiid_to_apicid[] and bios_cpu_apicid[] properly with BSP as first entry. - Made maxcpus=1 boot on these systems. Since the parsing earlier in arch/x86_64/kernel/mpparse.c stopped after maxcpus entries, other entries were not processed, this causes kernel not to boot on these systems. TBD: x86_acpiid_to_apicid and bios_cpu_apicid[] seem to be exactly the same. This could be removed, but might need more work to cleanup. Signed-off-by: Ashok Raj Signed-off-by: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/arch/x86_64/kernel/mpparse.c b/arch/x86_64/kernel/mpparse.c index f221231..f86d9db 100644 --- a/arch/x86_64/kernel/mpparse.c +++ b/arch/x86_64/kernel/mpparse.c @@ -107,6 +107,7 @@ static int __init mpf_checksum(unsigned char *mp, int len) static void __init MP_processor_info (struct mpc_config_processor *m) { int ver; + static int found_bsp=0; if (!(m->mpc_cpuflag & CPU_ENABLED)) return; @@ -126,11 +127,6 @@ static void __init MP_processor_info (struct mpc_config_processor *m) " Processor ignored.\n", NR_CPUS); return; } - if (num_processors >= maxcpus) { - printk(KERN_WARNING "WARNING: maxcpus limit of %i reached." - " Processor ignored.\n", maxcpus); - return; - } num_processors++; @@ -150,7 +146,19 @@ static void __init MP_processor_info (struct mpc_config_processor *m) ver = 0x10; } apic_version[m->mpc_apicid] = ver; - bios_cpu_apicid[num_processors - 1] = m->mpc_apicid; + if (m->mpc_cpuflag & CPU_BOOTPROCESSOR) { + /* + * bios_cpu_apicid is required to have processors listed + * in same order as logical cpu numbers. Hence the first + * entry is BSP, and so on. + */ + bios_cpu_apicid[0] = m->mpc_apicid; + x86_cpu_to_apicid[0] = m->mpc_apicid; + found_bsp = 1; + } else { + bios_cpu_apicid[num_processors - found_bsp] = m->mpc_apicid; + x86_cpu_to_apicid[num_processors - found_bsp] = m->mpc_apicid; + } } static void __init MP_bus_info (struct mpc_config_bus *m) diff --git a/arch/x86_64/kernel/smpboot.c b/arch/x86_64/kernel/smpboot.c index d00e494..5abdee1 100644 --- a/arch/x86_64/kernel/smpboot.c +++ b/arch/x86_64/kernel/smpboot.c @@ -645,7 +645,6 @@ static int __cpuinit do_boot_cpu(int cpu, int apicid) printk("failed fork for CPU %d\n", cpu); return PTR_ERR(idle); } - x86_cpu_to_apicid[cpu] = apicid; cpu_pda[cpu].pcurrent = idle; @@ -954,7 +953,6 @@ void __cpuinit smp_prepare_cpus(unsigned int max_cpus) GET_APIC_ID(apic_read(APIC_ID)), boot_cpu_id); /* Or can we switch back to PIC here? */ } - x86_cpu_to_apicid[0] = boot_cpu_id; /* * Now start the IO-APICs