6.6-stable review patch. If anyone has any objections, please let me know.
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From: Thomas Gleixner tglx@linutronix.de
commit 0bf871651211b58c7b19f40b746b646d5311e2ec 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 --- arch/x86/kernel/cpu/microcode/core.c | 51 ++++++----------------------------- 1 file changed, 9 insertions(+), 42 deletions(-)
--- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -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_secondar 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(
static int load_cpus_stopped(void *unused) { - int cpu = smp_processor_id(); - enum ucode_state ret; - - /* - * 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; - } - - /* - * 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; + unsigned int cpu = smp_processor_id();
- 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; + if (this_cpu_read(ucode_ctrl.ctrl_cpu) == cpu) + load_primary(cpu); + else + load_secondary(cpu);
- 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