Techwizz/kernel-fxtec-pro1x
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sparc64: Make prom entry spinlock NMI safe.

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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;
}