8b28d50cdd
Only the BSP CPU was able to start its hyper-threading CPU siblings. When an AP CPU attempts this it calls start_cpu() within start_cpu(), deadlocking the system with start_cpu_lock. At the time intel_sibling_init() is run, the BSP CPU is still walking the cpu_bus linked list in lapic_cpu_init: start_other_cpus(). A sibling CPU appended at the end of this list will get started. Also fail compile with #error if SERIAL_CPU_INIT==0, as microcode updates on hyper-threading sibling CPUs must be serialized. Tested with HT-enabled P4 Xeons on dual-socket604 platform. Change-Id: I0053f58f49ed604605ce0a55e826d3e1afdc90b6 Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com> Reviewed-on: http://review.coreboot.org/775 Reviewed-by: Ronald G. Minnich <rminnich@gmail.com> Tested-by: build bot (Jenkins) Reviewed-by: Rudolf Marek <r.marek@assembler.cz>
74 lines
1.6 KiB
C
74 lines
1.6 KiB
C
#include <console/console.h>
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#include <cpu/cpu.h>
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#include <cpu/x86/lapic.h>
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#include <cpu/intel/hyperthreading.h>
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#include <device/device.h>
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#include <pc80/mc146818rtc.h>
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#include <smp/spinlock.h>
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#include <assert.h>
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#if CONFIG_SERIAL_CPU_INIT==0
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#error Intel hyper-threading requires serialized cpu init
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#endif
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static int first_time = 1;
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static int disable_siblings = !CONFIG_LOGICAL_CPUS;
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void intel_sibling_init(device_t cpu)
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{
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unsigned i, siblings;
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struct cpuid_result result;
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/* On the bootstrap processor see if I want sibling cpus enabled */
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if (first_time) {
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first_time = 0;
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get_option(&disable_siblings, "hyper_threading");
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}
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result = cpuid(1);
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/* Is hyperthreading supported */
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if (!(result.edx & (1 << 28))) {
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return;
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}
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/* See how many sibling cpus we have */
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siblings = (result.ebx >> 16) & 0xff;
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if (siblings < 1) {
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siblings = 1;
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}
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printk(BIOS_DEBUG, "CPU: %u %d siblings\n",
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cpu->path.apic.apic_id,
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siblings);
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/* See if I am a sibling cpu */
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if (cpu->path.apic.apic_id & (siblings -1)) {
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if (disable_siblings) {
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cpu->enabled = 0;
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}
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return;
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}
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/* I am the primary cpu start up my siblings */
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for(i = 1; i < siblings; i++) {
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struct device_path cpu_path;
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device_t new;
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/* Build the cpu device path */
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cpu_path.type = DEVICE_PATH_APIC;
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cpu_path.apic.apic_id = cpu->path.apic.apic_id + i;
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/* Allocate new cpu device structure iff sibling CPU
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* was not in static device tree.
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*/
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new = alloc_find_dev(cpu->bus, &cpu_path);
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if (!new) {
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continue;
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}
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printk(BIOS_DEBUG, "CPU: %u has sibling %u\n",
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cpu->path.apic.apic_id,
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new->path.apic.apic_id);
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}
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}
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