From: Akio Takebe <takebe_akio@jp.fujitsu.com>
Subject: Re: [PATCH] kexec: framework and i386 (Take X)
Date: Mon, 05 Jun 2006 11:53:16 +0900
Message-ID: <67C6884B31A247takebe_akio@jp.fujitsu.com>
References: <20060517095213.GA31686@verge.net.au>
	<805b0fdb70b2ca542d6f9f43c0936928@cl.cam.ac.uk>
	<20060518033753.GB13670@verge.net.au>
	<20060525072017.GA25881@verge.net.au>
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To: Horms <horms@verge.net.au>, Keir Fraser <Keir.Fraser@cl.cam.ac.uk>
Cc: Ian Pratt <m+Ian.Pratt@cl.cam.ac.uk>, Kazuo Moriwaka <moriwaka@valinux.co.jp>, xen-devel@lists.xensource.com, Akio Takebe <takebe_akio@jp.fujitsu.com>, Isaku Yamahata <yamahata@valinux.co.jp>, Magnus Damm <magnus@valinux.co.jp>, Mark Williamson <mark.williamson@cl.cam.ac.uk>

Hi, Horms

When I tried your patch, I had compile errors.
If you use xchg(), you should get return value of xchg().
The above compile error occurre at the below part.

+void crash_kexec(struct cpu_user_regs *regs)
+{
+    int locked;
+
+    locked = xchg(&kexec_crash_lock, 1);
+    if (locked)
+        return;
+    __crash_kexec(regs);
+    xchg(&kexec_crash_lock, 0); <-------------this one
+}
+
+static int get_crash_note(int vcpuid, XEN_GUEST_HANDLE(void) uarg)
+{
+    struct domain *domain = current->domain;
+    unsigned long crash_note;
+    struct vcpu *vcpu;
+    int locked;
+
+    if (vcpuid < 0 || vcpuid > MAX_VIRT_CPUS)
+	return -EINVAL;
+
+    if ( ! (vcpu = domain->vcpu[vcpuid]) )
+	return -EINVAL;
+
+    locked = xchg(&kexec_crash_lock, 1);
+    if (locked)
+    {
+       printk("do_kexec: (CMD_kexec_crash_note): dump is locked\n");
+       return -EFAULT;
+    }
+    crash_note = __pa((unsigned long)per_cpu(crash_notes, vcpu->
processor));
+    xchg(&kexec_crash_lock, 0); <-------------this one
+
+    if ( unlikely(copy_to_guest(uarg, &crash_note, 1) != 0) )
+    {
+        printk("do_kexec: (CMD_kexec_crash_note): copy_to_guest failed
\n");
+        return -EFAULT;
+    }
+    
+    return 0;
+}
+
+int do_kexec(unsigned long op, int arg1, XEN_GUEST_HANDLE(void) uarg)
+{
+    xen_kexec_image_t *image;
+    int locked;
+    int *image_set;
+    int status = -EINVAL;
+
+    if ( !IS_PRIV(current->domain) )  
+        return -EPERM;
+
+    switch (op)
+    {
+    case KEXEC_CMD_kexec_crash_note:
+        return get_crash_note(arg1, uarg);
+    case KEXEC_CMD_kexec_reserve:
+	return get_reserve(uarg);
+    }
+
+    /* For all other ops, arg1 is the type of kexec, that is
+     * KEXEC_TYPE_DEFAULT or KEXEC_TYPE_CRASH */
+    if (arg1 == KEXEC_TYPE_CRASH)
+    {
+        image = &kexec_crash_image;
+        image_set = &kexec_crash_image_set;
+        locked = xchg(&kexec_crash_lock, 1);
+        if (locked)
+        {
+           printk("do_kexec: dump is locked\n");
+           return -EFAULT;
+        }
+    }
+    else
+    {
+        image = &kexec_image;
+        image_set = &kexec_image_set;
+    }
+
+    switch(op) {
+    case KEXEC_CMD_kexec:
+        BUG_ON(!*image_set);
+	status = __do_kexec(arg1, uarg, image);
+        break;
+    case KEXEC_CMD_kexec_load:
+        BUG_ON(*image_set);
+        if ( unlikely(copy_from_guest(image, uarg, 1) != 0) )
+        {
+            printk("do_kexec (CMD_kexec_load): copy_from_guest failed\n
");
+            status = -EFAULT;
+	    break;
+        }
+        *image_set = 1;
+        status = machine_kexec_load(arg1, image);
+        break;
+    case KEXEC_CMD_kexec_unload:
+        BUG_ON(!*image_set);
+        *image_set = 0;
+        machine_kexec_unload(arg1, image);
+        status = 0;
+        break;
+    }
+
+    if (arg1 == KEXEC_TYPE_CRASH)
+        xchg(&kexec_crash_lock, 0);  <-------------this one
+    return status;
+}
+


Best Regards,

Akio Takebe