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Date: Mon, 13 Oct 2014 09:19:48 +0200
From: Ingo Molnar <mingo@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, "H. Peter Anvin" <hpa@...or.com>,
Thomas Gleixner <tglx@...utronix.de>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] x86/boot tree changes for v3.18
Linus,
Please pull the latest x86-boot-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-boot-for-linus
# HEAD: eeeda4cd06e828b331b15741a204ff9f5874d28d x86/relocs: Make per_cpu_load_addr static
The changes in this cycle were:
- Fix rare SMP-boot hang (mostly in virtual environments)
- Fix build warning with certain (rare) toolchains
Thanks,
Ingo
------------------>
Ben Hutchings (1):
x86/relocs: Make per_cpu_load_addr static
Igor Mammedov (1):
x86/smpboot: Initialize secondary CPU only if master CPU will wait for it
arch/x86/kernel/cpu/common.c | 29 ++++++++-----
arch/x86/kernel/smpboot.c | 98 ++++++++++++++------------------------------
arch/x86/tools/relocs.c | 2 +-
arch/x86/xen/smp.c | 2 +
4 files changed, 51 insertions(+), 80 deletions(-)
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index e4ab2b42bd6f..426cfedefd04 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1266,6 +1266,19 @@ static void dbg_restore_debug_regs(void)
#define dbg_restore_debug_regs()
#endif /* ! CONFIG_KGDB */
+static void wait_for_master_cpu(int cpu)
+{
+#ifdef CONFIG_SMP
+ /*
+ * wait for ACK from master CPU before continuing
+ * with AP initialization
+ */
+ WARN_ON(cpumask_test_and_set_cpu(cpu, cpu_initialized_mask));
+ while (!cpumask_test_cpu(cpu, cpu_callout_mask))
+ cpu_relax();
+#endif
+}
+
/*
* cpu_init() initializes state that is per-CPU. Some data is already
* initialized (naturally) in the bootstrap process, such as the GDT
@@ -1281,16 +1294,17 @@ void cpu_init(void)
struct task_struct *me;
struct tss_struct *t;
unsigned long v;
- int cpu;
+ int cpu = stack_smp_processor_id();
int i;
+ wait_for_master_cpu(cpu);
+
/*
* Load microcode on this cpu if a valid microcode is available.
* This is early microcode loading procedure.
*/
load_ucode_ap();
- cpu = stack_smp_processor_id();
t = &per_cpu(init_tss, cpu);
oist = &per_cpu(orig_ist, cpu);
@@ -1302,9 +1316,6 @@ void cpu_init(void)
me = current;
- if (cpumask_test_and_set_cpu(cpu, cpu_initialized_mask))
- panic("CPU#%d already initialized!\n", cpu);
-
pr_debug("Initializing CPU#%d\n", cpu);
clear_in_cr4(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
@@ -1381,13 +1392,9 @@ void cpu_init(void)
struct tss_struct *t = &per_cpu(init_tss, cpu);
struct thread_struct *thread = &curr->thread;
- show_ucode_info_early();
+ wait_for_master_cpu(cpu);
- if (cpumask_test_and_set_cpu(cpu, cpu_initialized_mask)) {
- printk(KERN_WARNING "CPU#%d already initialized!\n", cpu);
- for (;;)
- local_irq_enable();
- }
+ show_ucode_info_early();
printk(KERN_INFO "Initializing CPU#%d\n", cpu);
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 2d872e08fab9..735c420eba2d 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -111,7 +111,6 @@ atomic_t init_deasserted;
static void smp_callin(void)
{
int cpuid, phys_id;
- unsigned long timeout;
/*
* If waken up by an INIT in an 82489DX configuration
@@ -130,37 +129,6 @@ static void smp_callin(void)
* (This works even if the APIC is not enabled.)
*/
phys_id = read_apic_id();
- if (cpumask_test_cpu(cpuid, cpu_callin_mask)) {
- panic("%s: phys CPU#%d, CPU#%d already present??\n", __func__,
- phys_id, cpuid);
- }
- pr_debug("CPU#%d (phys ID: %d) waiting for CALLOUT\n", cpuid, phys_id);
-
- /*
- * STARTUP IPIs are fragile beasts as they might sometimes
- * trigger some glue motherboard logic. Complete APIC bus
- * silence for 1 second, this overestimates the time the
- * boot CPU is spending to send the up to 2 STARTUP IPIs
- * by a factor of two. This should be enough.
- */
-
- /*
- * Waiting 2s total for startup (udelay is not yet working)
- */
- timeout = jiffies + 2*HZ;
- while (time_before(jiffies, timeout)) {
- /*
- * Has the boot CPU finished it's STARTUP sequence?
- */
- if (cpumask_test_cpu(cpuid, cpu_callout_mask))
- break;
- cpu_relax();
- }
-
- if (!time_before(jiffies, timeout)) {
- panic("%s: CPU%d started up but did not get a callout!\n",
- __func__, cpuid);
- }
/*
* the boot CPU has finished the init stage and is spinning
@@ -753,8 +721,8 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
unsigned long start_ip = real_mode_header->trampoline_start;
unsigned long boot_error = 0;
- int timeout;
int cpu0_nmi_registered = 0;
+ unsigned long timeout;
/* Just in case we booted with a single CPU. */
alternatives_enable_smp();
@@ -802,6 +770,15 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
}
/*
+ * AP might wait on cpu_callout_mask in cpu_init() with
+ * cpu_initialized_mask set if previous attempt to online
+ * it timed-out. Clear cpu_initialized_mask so that after
+ * INIT/SIPI it could start with a clean state.
+ */
+ cpumask_clear_cpu(cpu, cpu_initialized_mask);
+ smp_mb();
+
+ /*
* Wake up a CPU in difference cases:
* - Use the method in the APIC driver if it's defined
* Otherwise,
@@ -815,53 +792,38 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
if (!boot_error) {
/*
- * allow APs to start initializing.
+ * Wait 10s total for a response from AP
*/
- pr_debug("Before Callout %d\n", cpu);
- cpumask_set_cpu(cpu, cpu_callout_mask);
- pr_debug("After Callout %d\n", cpu);
+ boot_error = -1;
+ timeout = jiffies + 10*HZ;
+ while (time_before(jiffies, timeout)) {
+ if (cpumask_test_cpu(cpu, cpu_initialized_mask)) {
+ /*
+ * Tell AP to proceed with initialization
+ */
+ cpumask_set_cpu(cpu, cpu_callout_mask);
+ boot_error = 0;
+ break;
+ }
+ udelay(100);
+ schedule();
+ }
+ }
+ if (!boot_error) {
/*
- * Wait 5s total for a response
+ * Wait till AP completes initial initialization
*/
- for (timeout = 0; timeout < 50000; timeout++) {
- if (cpumask_test_cpu(cpu, cpu_callin_mask))
- break; /* It has booted */
- udelay(100);
+ while (!cpumask_test_cpu(cpu, cpu_callin_mask)) {
/*
* Allow other tasks to run while we wait for the
* AP to come online. This also gives a chance
* for the MTRR work(triggered by the AP coming online)
* to be completed in the stop machine context.
*/
+ udelay(100);
schedule();
}
-
- if (cpumask_test_cpu(cpu, cpu_callin_mask)) {
- print_cpu_msr(&cpu_data(cpu));
- pr_debug("CPU%d: has booted.\n", cpu);
- } else {
- boot_error = 1;
- if (*trampoline_status == 0xA5A5A5A5)
- /* trampoline started but...? */
- pr_err("CPU%d: Stuck ??\n", cpu);
- else
- /* trampoline code not run */
- pr_err("CPU%d: Not responding\n", cpu);
- if (apic->inquire_remote_apic)
- apic->inquire_remote_apic(apicid);
- }
- }
-
- if (boot_error) {
- /* Try to put things back the way they were before ... */
- numa_remove_cpu(cpu); /* was set by numa_add_cpu */
-
- /* was set by do_boot_cpu() */
- cpumask_clear_cpu(cpu, cpu_callout_mask);
-
- /* was set by cpu_init() */
- cpumask_clear_cpu(cpu, cpu_initialized_mask);
}
/* mark "stuck" area as not stuck */
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index bbb1d2259ecf..a5efb21d5228 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -695,7 +695,7 @@ static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
*
*/
static int per_cpu_shndx = -1;
-Elf_Addr per_cpu_load_addr;
+static Elf_Addr per_cpu_load_addr;
static void percpu_init(void)
{
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 7005974c3ff3..3631e7129e8c 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -360,6 +360,8 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
struct desc_struct *gdt;
unsigned long gdt_mfn;
+ /* used to tell cpu_init() that it can proceed with initialization */
+ cpumask_set_cpu(cpu, cpu_callout_mask);
if (cpumask_test_and_set_cpu(cpu, xen_cpu_initialized_map))
return 0;
--
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