[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 <shaohua.li@intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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 @@
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 @@
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 @@
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 @@
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;