From e94cd1503b153ea753f0c4ed9d5ed12e7abd1306 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 12 May 2023 23:07:12 +0200 Subject: [PATCH] x86/smpboot: Get rid of cpu_init_secondary() The synchronization of the AP with the control CPU is a SMP boot problem and has nothing to do with cpu_init(). Open code cpu_init_secondary() in start_secondary() and move wait_for_master_cpu() into the SMP boot code. No functional change. Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Tested-by: Michael Kelley Tested-by: Oleksandr Natalenko Tested-by: Helge Deller # parisc Tested-by: Guilherme G. Piccoli # Steam Deck Link: https://lore.kernel.org/r/20230512205255.981999763@linutronix.de --- arch/x86/include/asm/processor.h | 1 - arch/x86/kernel/cpu/common.c | 27 --------------------------- arch/x86/kernel/smpboot.c | 24 +++++++++++++++++++----- 3 files changed, 19 insertions(+), 33 deletions(-) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index a1e4fa58b357..d46300e94f85 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -551,7 +551,6 @@ extern void switch_gdt_and_percpu_base(int); extern void load_direct_gdt(int); extern void load_fixmap_gdt(int); extern void cpu_init(void); -extern void cpu_init_secondary(void); extern void cpu_init_exception_handling(void); extern void cr4_init(void); diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 80710a68ef7d..e25fb13cd6ef 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -2123,19 +2123,6 @@ 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 -} - static inline void setup_getcpu(int cpu) { unsigned long cpudata = vdso_encode_cpunode(cpu, early_cpu_to_node(cpu)); @@ -2239,8 +2226,6 @@ void cpu_init(void) struct task_struct *cur = current; int cpu = raw_smp_processor_id(); - wait_for_master_cpu(cpu); - ucode_cpu_init(cpu); #ifdef CONFIG_NUMA @@ -2293,18 +2278,6 @@ void cpu_init(void) load_fixmap_gdt(cpu); } -#ifdef CONFIG_SMP -void cpu_init_secondary(void) -{ - /* - * Relies on the BP having set-up the IDT tables, which are loaded - * on this CPU in cpu_init_exception_handling(). - */ - cpu_init_exception_handling(); - cpu_init(); -} -#endif - #ifdef CONFIG_MICROCODE_LATE_LOADING /** * store_cpu_caps() - Store a snapshot of CPU capabilities diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 0bd9c9f7861f..50eff9b7fe7f 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -220,6 +220,17 @@ static void ap_calibrate_delay(void) cpu_data(smp_processor_id()).loops_per_jiffy = loops_per_jiffy; } +static void wait_for_master_cpu(int cpu) +{ + /* + * Wait for release by control 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(); +} + /* * Activate a secondary processor. */ @@ -237,13 +248,16 @@ static void notrace start_secondary(void *unused) load_cr3(swapper_pg_dir); __flush_tlb_all(); #endif + cpu_init_exception_handling(); + /* - * Sync point with wait_cpu_initialized(). Before proceeding through - * cpu_init(), the AP will call wait_for_master_cpu() which sets its - * own bit in cpu_initialized_mask and then waits for the BSP to set - * its bit in cpu_callout_mask to release it. + * Sync point with wait_cpu_initialized(). Sets AP in + * cpu_initialized_mask and then waits for the control CPU + * to release it. */ - cpu_init_secondary(); + wait_for_master_cpu(raw_smp_processor_id()); + + cpu_init(); rcu_cpu_starting(raw_smp_processor_id()); x86_cpuinit.early_percpu_clock_init();