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sparc64: Make prom entry spinlock NMI safe. 

If we do something like try to print to the OF console from an NMI
while we're already in OpenFirmware, we'll deadlock on the spinlock.

Use a raw spinlock and disable NMIs when we take it.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2010-03-03 09:06:03 -08:00
parent c7d5a00507
commit 8a4fd1e492
1 changed files with 7 additions and 5 deletions
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12
arch/sparc/prom/p1275.c
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@ -32,10 +32,9 @@ extern void prom_cif_interface(void);
extern void prom_cif_callback(void);
/*
* This provides SMP safety on the p1275buf. prom_callback() drops this lock
* to allow recursuve acquisition.
* This provides SMP safety on the p1275buf.
*/
DEFINE_SPINLOCK(prom_entry_lock);
DEFINE_RAW_SPINLOCK(prom_entry_lock);
long p1275_cmd(const char *service, long fmt, ...)
{
@ -47,7 +46,9 @@ long p1275_cmd(const char *service, long fmt, ...)
p = p1275buf.prom_buffer;
spin_lock_irqsave(&prom_entry_lock, flags);
raw_local_save_flags(flags);
raw_local_irq_restore(PIL_NMI);
raw_spin_lock(&prom_entry_lock);
p1275buf.prom_args[0] = (unsigned long)p; /* service */
strcpy (p, service);
@ -139,7 +140,8 @@ long p1275_cmd(const char *service, long fmt, ...)
va_end(list);
x = p1275buf.prom_args [nargs + 3];
spin_unlock_irqrestore(&prom_entry_lock, flags);
raw_spin_unlock(&prom_entry_lock);
raw_local_irq_restore(flags);
return x;
}