--- /dev/null
+From fbe1bf1e5ff1e3b298420d7a8434983ef8d72bd1 Mon Sep 17 00:00:00 2001
+From: Linus Torvalds <torvalds@linux-foundation.org>
+Date: Sun, 15 Oct 2023 12:02:02 -0700
+Subject: Revert "x86/smp: Put CPUs into INIT on shutdown if possible"
+
+From: Linus Torvalds <torvalds@linux-foundation.org>
+
+commit fbe1bf1e5ff1e3b298420d7a8434983ef8d72bd1 upstream.
+
+This reverts commit 45e34c8af58f23db4474e2bfe79183efec09a18b, and the
+two subsequent fixes to it:
+
+ 3f874c9b2aae ("x86/smp: Don't send INIT to non-present and non-booted CPUs")
+ b1472a60a584 ("x86/smp: Don't send INIT to boot CPU")
+
+because it seems to result in hung machines at shutdown. Particularly
+some Dell machines, but Thomas says
+
+ "The rest seems to be Lenovo and Sony with Alderlake/Raptorlake CPUs -
+ at least that's what I could figure out from the various bug reports.
+
+ I don't know which CPUs the DELL machines have, so I can't say it's a
+ pattern.
+
+ I agree with the revert for now"
+
+Ashok Raj chimes in:
+
+ "There was a report (probably this same one), and it turns out it was a
+ bug in the BIOS SMI handler.
+
+ The client BIOS's were waiting for the lowest APICID to be the SMI
+ rendevous master. If this is MeteorLake, the BSP wasn't the one with
+ the lowest APIC and it triped here.
+
+ The BIOS change is also being pushed to others for assimilation :)
+
+ Server BIOS's had this correctly for a while now"
+
+and it does look likely to be some bad interaction between SMI and the
+non-BSP cores having put into INIT (and thus unresponsive until reset).
+
+Link: https://bbs.archlinux.org/viewtopic.php?pid=2124429
+Link: https://www.reddit.com/r/openSUSE/comments/16qq99b/tumbleweed_shutdown_did_not_finish_completely/
+Link: https://forum.artixlinux.org/index.php/topic,5997.0.html
+Link: https://bugzilla.redhat.com/show_bug.cgi?id=2241279
+Acked-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Ashok Raj <ashok.raj@intel.com>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/include/asm/smp.h | 2 --
+ arch/x86/kernel/smp.c | 39 +++++++--------------------------------
+ arch/x86/kernel/smpboot.c | 27 ---------------------------
+ 3 files changed, 7 insertions(+), 61 deletions(-)
+
+--- a/arch/x86/include/asm/smp.h
++++ b/arch/x86/include/asm/smp.h
+@@ -134,8 +134,6 @@ void native_send_call_func_ipi(const str
+ void native_send_call_func_single_ipi(int cpu);
+ void x86_idle_thread_init(unsigned int cpu, struct task_struct *idle);
+
+-bool smp_park_other_cpus_in_init(void);
+-
+ void smp_store_boot_cpu_info(void);
+ void smp_store_cpu_info(int id);
+
+--- a/arch/x86/kernel/smp.c
++++ b/arch/x86/kernel/smp.c
+@@ -131,7 +131,7 @@ static int smp_stop_nmi_callback(unsigne
+ }
+
+ /*
+- * Disable virtualization, APIC etc. and park the CPU in a HLT loop
++ * this function calls the 'stop' function on all other CPUs in the system.
+ */
+ DEFINE_IDTENTRY_SYSVEC(sysvec_reboot)
+ {
+@@ -172,17 +172,13 @@ static void native_stop_other_cpus(int w
+ * 2) Wait for all other CPUs to report that they reached the
+ * HLT loop in stop_this_cpu()
+ *
+- * 3) If the system uses INIT/STARTUP for CPU bringup, then
+- * send all present CPUs an INIT vector, which brings them
+- * completely out of the way.
++ * 3) If #2 timed out send an NMI to the CPUs which did not
++ * yet report
+ *
+- * 4) If #3 is not possible and #2 timed out send an NMI to the
+- * CPUs which did not yet report
+- *
+- * 5) Wait for all other CPUs to report that they reached the
++ * 4) Wait for all other CPUs to report that they reached the
+ * HLT loop in stop_this_cpu()
+ *
+- * #4 can obviously race against a CPU reaching the HLT loop late.
++ * #3 can obviously race against a CPU reaching the HLT loop late.
+ * That CPU will have reported already and the "have all CPUs
+ * reached HLT" condition will be true despite the fact that the
+ * other CPU is still handling the NMI. Again, there is no
+@@ -198,7 +194,7 @@ static void native_stop_other_cpus(int w
+ /*
+ * Don't wait longer than a second for IPI completion. The
+ * wait request is not checked here because that would
+- * prevent an NMI/INIT shutdown in case that not all
++ * prevent an NMI shutdown attempt in case that not all
+ * CPUs reach shutdown state.
+ */
+ timeout = USEC_PER_SEC;
+@@ -206,27 +202,7 @@ static void native_stop_other_cpus(int w
+ udelay(1);
+ }
+
+- /*
+- * Park all other CPUs in INIT including "offline" CPUs, if
+- * possible. That's a safe place where they can't resume execution
+- * of HLT and then execute the HLT loop from overwritten text or
+- * page tables.
+- *
+- * The only downside is a broadcast MCE, but up to the point where
+- * the kexec() kernel brought all APs online again an MCE will just
+- * make HLT resume and handle the MCE. The machine crashes and burns
+- * due to overwritten text, page tables and data. So there is a
+- * choice between fire and frying pan. The result is pretty much
+- * the same. Chose frying pan until x86 provides a sane mechanism
+- * to park a CPU.
+- */
+- if (smp_park_other_cpus_in_init())
+- goto done;
+-
+- /*
+- * If park with INIT was not possible and the REBOOT_VECTOR didn't
+- * take all secondary CPUs offline, try with the NMI.
+- */
++ /* if the REBOOT_VECTOR didn't work, try with the NMI */
+ if (!cpumask_empty(&cpus_stop_mask)) {
+ /*
+ * If NMI IPI is enabled, try to register the stop handler
+@@ -249,7 +225,6 @@ static void native_stop_other_cpus(int w
+ udelay(1);
+ }
+
+-done:
+ local_irq_save(flags);
+ disable_local_APIC();
+ mcheck_cpu_clear(this_cpu_ptr(&cpu_info));
+--- a/arch/x86/kernel/smpboot.c
++++ b/arch/x86/kernel/smpboot.c
+@@ -1346,33 +1346,6 @@ void arch_thaw_secondary_cpus_end(void)
+ cache_aps_init();
+ }
+
+-bool smp_park_other_cpus_in_init(void)
+-{
+- unsigned int cpu, this_cpu = smp_processor_id();
+- unsigned int apicid;
+-
+- if (apic->wakeup_secondary_cpu_64 || apic->wakeup_secondary_cpu)
+- return false;
+-
+- /*
+- * If this is a crash stop which does not execute on the boot CPU,
+- * then this cannot use the INIT mechanism because INIT to the boot
+- * CPU will reset the machine.
+- */
+- if (this_cpu)
+- return false;
+-
+- for_each_cpu_and(cpu, &cpus_booted_once_mask, cpu_present_mask) {
+- if (cpu == this_cpu)
+- continue;
+- apicid = apic->cpu_present_to_apicid(cpu);
+- if (apicid == BAD_APICID)
+- continue;
+- send_init_sequence(apicid);
+- }
+- return true;
+-}
+-
+ /*
+ * Early setup to make printk work.
+ */
projects / thirdparty / kernel / stable-queue.git / commitdiff
