From bd9e0b74f52dbac6241643fadca2393808b14c7a Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Tue, 27 Jun 2006 02:53:43 -0700 Subject: [PATCH] [PATCH] x86: cpu_init(): avoid GFP_KERNEL allocation while atomic The patch fixes two issues: 1. cpu_init is called with interrupt disabled. Allocating gdt table there isn't good at runtime. 2. gdt table page cause memory leak in CPU hotplug case. Signed-off-by: Shaohua Li Cc: Ashok Raj Cc: Zachary Amsden Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/kernel/cpu/common.c | 8 +++++++- arch/i386/kernel/smpboot.c | 13 +++++++++++++ 2 files changed, 20 insertions(+), 1 deletion(-) diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c index 44f2c5f..640364d 100644 --- a/arch/i386/kernel/cpu/common.c +++ b/arch/i386/kernel/cpu/common.c @@ -613,6 +613,12 @@ void __cpuinit cpu_init(void) set_in_cr4(X86_CR4_TSD); } + /* The CPU hotplug case */ + if (cpu_gdt_descr->address) { + gdt = (struct desc_struct *)cpu_gdt_descr->address; + memset(gdt, 0, PAGE_SIZE); + goto old_gdt; + } /* * This is a horrible hack to allocate the GDT. The problem * is that cpu_init() is called really early for the boot CPU @@ -631,7 +637,7 @@ void __cpuinit cpu_init(void) local_irq_enable(); } } - +old_gdt: /* * Initialize the per-CPU GDT with the boot GDT, * and set up the GDT descriptor: diff --git a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c index bce5470..9466a3c 100644 --- a/arch/i386/kernel/smpboot.c +++ b/arch/i386/kernel/smpboot.c @@ -1056,6 +1056,7 @@ static int __cpuinit __smp_prepare_cpu(int cpu) struct warm_boot_cpu_info info; struct work_struct task; int apicid, ret; + struct Xgt_desc_struct *cpu_gdt_descr = &per_cpu(cpu_gdt_descr, cpu); apicid = x86_cpu_to_apicid[cpu]; if (apicid == BAD_APICID) { @@ -1063,6 +1064,18 @@ static int __cpuinit __smp_prepare_cpu(int cpu) goto exit; } + /* + * the CPU isn't initialized at boot time, allocate gdt table here. + * cpu_init will initialize it + */ + if (!cpu_gdt_descr->address) { + cpu_gdt_descr->address = get_zeroed_page(GFP_KERNEL); + if (!cpu_gdt_descr->address) + printk(KERN_CRIT "CPU%d failed to allocate GDT\n", cpu); + ret = -ENOMEM; + goto exit; + } + info.complete = &done; info.apicid = apicid; info.cpu = cpu; -- 2.7.4