Commit 8a4fd1e4 authored by David S. Miller's avatar David S. Miller
Browse files

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: default avatarDavid S. Miller <davem@davemloft.net>
parent c7d5a005

arch/sparc/prom/p1275.c

+7 −5
Original line number Original line Diff line number Diff line
@@ -32,10 +32,9 @@ extern void prom_cif_interface(void); 
extern void prom_cif_callback(void);

extern void prom_cif_callback(void);





/*

/*

 * This provides SMP safety on the p1275buf. prom_callback() drops this lock

 * This provides SMP safety on the p1275buf.

 * to allow recursuve acquisition.

 */

 */

DEFINE_SPINLOCK(prom_entry_lock);

DEFINE_RAW_SPINLOCK(prom_entry_lock);





long p1275_cmd(const char *service, long fmt, ...)

long p1275_cmd(const char *service, long fmt, ...)

{

{
@@ -47,7 +46,9 @@ long p1275_cmd(const char *service, long fmt, ...) 
	

	

	p = p1275buf.prom_buffer;

	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 */

	p1275buf.prom_args[0] = (unsigned long)p;		/* service */

	strcpy (p, service);

	strcpy (p, service);
@@ -139,7 +140,8 @@ long p1275_cmd(const char *service, long fmt, ...) 
	va_end(list);

	va_end(list);

	x = p1275buf.prom_args [nargs + 3];

	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;

	return x;

}

}