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x86/microcode: Replace the all-in-one rendevous handler

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commit 0bf8716512 upstream

with a new handler which just separates the control flow of primary and
secondary CPUs.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231002115903.433704135@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Thomas Gleixner
2023-10-02 14:00:03 +02:00
committed by Greg Kroah-Hartman
parent 058370ffef
commit 9c31ea5b1b
1 changed files with 9 additions and 42 deletions
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arch/x86/kernel/cpu/microcode/core.c
+9 -42
View File
@@ -268,7 +268,7 @@ struct microcode_ctrl {
};
static DEFINE_PER_CPU(struct microcode_ctrl, ucode_ctrl);
static atomic_t late_cpus_in, late_cpus_out;
static atomic_t late_cpus_in;
static bool wait_for_cpus(atomic_t *cnt)
{
@@ -304,7 +304,7 @@ static bool wait_for_ctrl(void)
return false;
}
static __maybe_unused void load_secondary(unsigned int cpu)
static void load_secondary(unsigned int cpu)
{
unsigned int ctrl_cpu = this_cpu_read(ucode_ctrl.ctrl_cpu);
enum ucode_state ret;
@@ -339,7 +339,7 @@ static __maybe_unused void load_secondary(unsigned int cpu)
this_cpu_write(ucode_ctrl.ctrl, SCTRL_DONE);
}
static __maybe_unused void load_primary(unsigned int cpu)
static void load_primary(unsigned int cpu)
{
struct cpumask *secondaries = topology_sibling_cpumask(cpu);
enum sibling_ctrl ctrl;
@@ -376,46 +376,14 @@ static __maybe_unused void load_primary(unsigned int cpu)
static int load_cpus_stopped(void *unused)
{
int cpu = smp_processor_id();
enum ucode_state ret;
unsigned int cpu = smp_processor_id();
/*
* Wait for all CPUs to arrive. A load will not be attempted unless all
* CPUs show up.
* */
if (!wait_for_cpus(&late_cpus_in)) {
this_cpu_write(ucode_ctrl.result, UCODE_TIMEOUT);
return 0;
}
if (this_cpu_read(ucode_ctrl.ctrl_cpu) == cpu)
load_primary(cpu);
else
load_secondary(cpu);
/*
* On an SMT system, it suffices to load the microcode on one sibling of
* the core because the microcode engine is shared between the threads.
* Synchronization still needs to take place so that no concurrent
* loading attempts happen on multiple threads of an SMT core. See
* below.
*/
if (cpumask_first(topology_sibling_cpumask(cpu)) != cpu)
goto wait_for_siblings;
ret = microcode_ops->apply_microcode(cpu);
this_cpu_write(ucode_ctrl.result, ret);
wait_for_siblings:
if (!wait_for_cpus(&late_cpus_out))
panic("Timeout during microcode update!\n");
/*
* At least one thread has completed update on each core.
* For others, simply call the update to make sure the
* per-cpu cpuinfo can be updated with right microcode
* revision.
*/
if (cpumask_first(topology_sibling_cpumask(cpu)) == cpu)
return 0;
ret = microcode_ops->apply_microcode(cpu);
this_cpu_write(ucode_ctrl.result, ret);
/* No point to wait here. The CPUs will all wait in stop_machine(). */
return 0;
}
@@ -429,7 +397,6 @@ static int load_late_stop_cpus(void)
pr_err("You should switch to early loading, if possible.\n");
atomic_set(&late_cpus_in, num_online_cpus());
atomic_set(&late_cpus_out, num_online_cpus());
/*
* Take a snapshot before the microcode update in order to compare and