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hvc_console: Better kernel console support
hvc_console has two methods to instanciate the consoles. hvc_instanciate is meant to be called at early boot, while hvc_alloc is called for more dynamically probed objects. Currently, it only deals with adding kernel consoles in the former case, which means for example that if a console only uses dynamic probing, it will never be usable as a kernel console even when specifying console=hvc0 explicitly, which could be considered annoying... More specifically, on pseries, we only do the early instanciate for the console currently used by the firmware, so if you have your firmware configured to go to a video card, for example, you cannot get your kernel console, oops messages, etc... on your serial port or hypervisor console, which would be handy to deal with oopses. This fixes it by checking if hvc_console.flags & CON_ENABLED is set when registering a new dynamic console, and if not, redo the index check and re-register the console if the index matches, allowing console=hvcN to work. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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parent
baa436b367
commit
92057a493a
1 changed files with 26 additions and 7 deletions
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@ -245,6 +245,20 @@ static void hvc_port_destruct(struct tty_port *port)
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kfree(hp);
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}
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static void hvc_check_console(int index)
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{
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/* Already enabled, bail out */
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if (hvc_console.flags & CON_ENABLED)
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return;
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/* If this index is what the user requested, then register
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* now (setup won't fail at this point). It's ok to just
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* call register again if previously .setup failed.
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*/
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if (index == hvc_console.index)
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register_console(&hvc_console);
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}
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/*
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* hvc_instantiate() is an early console discovery method which locates
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* consoles * prior to the vio subsystem discovering them. Hotplugged
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@ -275,12 +289,8 @@ int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops)
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if (last_hvc < index)
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last_hvc = index;
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/* if this index is what the user requested, then register
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* now (setup won't fail at this point). It's ok to just
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* call register again if previously .setup failed.
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*/
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if (index == hvc_console.index)
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register_console(&hvc_console);
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/* check if we need to re-register the kernel console */
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hvc_check_console(index);
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return 0;
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}
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@ -858,10 +868,15 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
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i = ++last_hvc;
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hp->index = i;
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cons_ops[i] = ops;
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vtermnos[i] = vtermno;
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list_add_tail(&(hp->next), &hvc_structs);
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spin_unlock(&hvc_structs_lock);
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/* check if we need to re-register the kernel console */
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hvc_check_console(i);
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return hp;
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}
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EXPORT_SYMBOL_GPL(hvc_alloc);
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@ -874,8 +889,12 @@ int hvc_remove(struct hvc_struct *hp)
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tty = tty_port_tty_get(&hp->port);
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spin_lock_irqsave(&hp->lock, flags);
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if (hp->index < MAX_NR_HVC_CONSOLES)
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if (hp->index < MAX_NR_HVC_CONSOLES) {
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console_lock();
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vtermnos[hp->index] = -1;
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cons_ops[hp->index] = NULL;
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console_unlock();
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}
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/* Don't whack hp->irq because tty_hangup() will need to free the irq. */
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