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Intel cpus: Fix deadlock on hyper-threading init 

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>
This commit is contained in:
Kyösti Mälkki 2012-03-09 17:02:37 +02:00 committed by Rudolf Marek
parent 2172f61ede
commit 8b28d50cdd
1 changed files with 9 additions and 13 deletions
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22
src/cpu/intel/hyperthreading/intel_sibling.c
View File

@ -5,6 +5,11 @@
#include <device/device.h>
#include <pc80/mc146818rtc.h>
#include <smp/spinlock.h>
#include <assert.h>
#if CONFIG_SERIAL_CPU_INIT==0
#error Intel hyper-threading requires serialized cpu init
#endif
static int first_time = 1;
static int disable_siblings = !CONFIG_LOGICAL_CPUS;
@ -30,11 +35,9 @@ void intel_sibling_init(device_t cpu)
siblings = 1;
}
#if 1
printk(BIOS_DEBUG, "CPU: %u %d siblings\n",
cpu->path.apic.apic_id,
siblings);
#endif
/* See if I am a sibling cpu */
if (cpu->path.apic.apic_id & (siblings -1)) {
@ -53,25 +56,18 @@ void intel_sibling_init(device_t cpu)
cpu_path.apic.apic_id = cpu->path.apic.apic_id + i;
/* Allocate the new cpu device structure */
new = alloc_dev(cpu->bus, &cpu_path);
/* Allocate new cpu device structure iff sibling CPU
* was not in static device tree.
*/
new = alloc_find_dev(cpu->bus, &cpu_path);
if (!new) {
continue;
}
#if 1
printk(BIOS_DEBUG, "CPU: %u has sibling %u\n",
cpu->path.apic.apic_id,
new->path.apic.apic_id);
#endif
/* Start the new cpu */
if (!start_cpu(new)) {
/* Record the error in cpu? */
printk(BIOS_ERR, "CPU %u would not start!\n",
new->path.apic.apic_id);
}
}
}