linux-kernel-test/arch/sparc/prom/p1275.c
David S. Miller 8a4fd1e492 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>
2010-03-03 09:06:03 -08:00

154 lines
3.7 KiB
C

/*
* p1275.c: Sun IEEE 1275 PROM low level interface routines
*
* Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/string.h>
#include <linux/spinlock.h>
#include <asm/openprom.h>
#include <asm/oplib.h>
#include <asm/system.h>
#include <asm/spitfire.h>
#include <asm/pstate.h>
#include <asm/ldc.h>
struct {
long prom_callback; /* 0x00 */
void (*prom_cif_handler)(long *); /* 0x08 */
unsigned long prom_cif_stack; /* 0x10 */
unsigned long prom_args [23]; /* 0x18 */
char prom_buffer [3000];
} p1275buf;
extern void prom_world(int);
extern void prom_cif_interface(void);
extern void prom_cif_callback(void);
/*
* This provides SMP safety on the p1275buf.
*/
DEFINE_RAW_SPINLOCK(prom_entry_lock);
long p1275_cmd(const char *service, long fmt, ...)
{
char *p, *q;
unsigned long flags;
int nargs, nrets, i;
va_list list;
long attrs, x;
p = p1275buf.prom_buffer;
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);
p = (char *)(((long)(strchr (p, 0) + 8)) & ~7);
p1275buf.prom_args[1] = nargs = (fmt & 0x0f); /* nargs */
p1275buf.prom_args[2] = nrets = ((fmt & 0xf0) >> 4); /* nrets */
attrs = fmt >> 8;
va_start(list, fmt);
for (i = 0; i < nargs; i++, attrs >>= 3) {
switch (attrs & 0x7) {
case P1275_ARG_NUMBER:
p1275buf.prom_args[i + 3] =
(unsigned)va_arg(list, long);
break;
case P1275_ARG_IN_64B:
p1275buf.prom_args[i + 3] =
va_arg(list, unsigned long);
break;
case P1275_ARG_IN_STRING:
strcpy (p, va_arg(list, char *));
p1275buf.prom_args[i + 3] = (unsigned long)p;
p = (char *)(((long)(strchr (p, 0) + 8)) & ~7);
break;
case P1275_ARG_OUT_BUF:
(void) va_arg(list, char *);
p1275buf.prom_args[i + 3] = (unsigned long)p;
x = va_arg(list, long);
i++; attrs >>= 3;
p = (char *)(((long)(p + (int)x + 7)) & ~7);
p1275buf.prom_args[i + 3] = x;
break;
case P1275_ARG_IN_BUF:
q = va_arg(list, char *);
p1275buf.prom_args[i + 3] = (unsigned long)p;
x = va_arg(list, long);
i++; attrs >>= 3;
memcpy (p, q, (int)x);
p = (char *)(((long)(p + (int)x + 7)) & ~7);
p1275buf.prom_args[i + 3] = x;
break;
case P1275_ARG_OUT_32B:
(void) va_arg(list, char *);
p1275buf.prom_args[i + 3] = (unsigned long)p;
p += 32;
break;
case P1275_ARG_IN_FUNCTION:
p1275buf.prom_args[i + 3] =
(unsigned long)prom_cif_callback;
p1275buf.prom_callback = va_arg(list, long);
break;
}
}
va_end(list);
prom_world(1);
prom_cif_interface();
prom_world(0);
attrs = fmt >> 8;
va_start(list, fmt);
for (i = 0; i < nargs; i++, attrs >>= 3) {
switch (attrs & 0x7) {
case P1275_ARG_NUMBER:
(void) va_arg(list, long);
break;
case P1275_ARG_IN_STRING:
(void) va_arg(list, char *);
break;
case P1275_ARG_IN_FUNCTION:
(void) va_arg(list, long);
break;
case P1275_ARG_IN_BUF:
(void) va_arg(list, char *);
(void) va_arg(list, long);
i++; attrs >>= 3;
break;
case P1275_ARG_OUT_BUF:
p = va_arg(list, char *);
x = va_arg(list, long);
memcpy (p, (char *)(p1275buf.prom_args[i + 3]), (int)x);
i++; attrs >>= 3;
break;
case P1275_ARG_OUT_32B:
p = va_arg(list, char *);
memcpy (p, (char *)(p1275buf.prom_args[i + 3]), 32);
break;
}
}
va_end(list);
x = p1275buf.prom_args [nargs + 3];
raw_spin_unlock(&prom_entry_lock);
raw_local_irq_restore(flags);
return x;
}
void prom_cif_init(void *cif_handler, void *cif_stack)
{
p1275buf.prom_cif_handler = (void (*)(long *))cif_handler;
p1275buf.prom_cif_stack = (unsigned long)cif_stack;
}