int c0_compare_int_usable(void)
{
unsigned int delta;
unsigned int cnt;
#ifdef CONFIG_KVM_GUEST
return 1;
#endif
/*
* IP7 already pending? Try to clear it by acking the timer.
*/
if (c0_compare_int_pending()) {
cnt = read_c0_count();
write_c0_compare(cnt);
back_to_back_c0_hazard();
while (read_c0_count() < (cnt + COMPARE_INT_SEEN_TICKS))
if (!c0_compare_int_pending())
break;
if (c0_compare_int_pending())
return 0;
}
for (delta = 0x10; delta <= 0x400000; delta <<= 1) {
cnt = read_c0_count();
cnt += delta;
write_c0_compare(cnt);
back_to_back_c0_hazard();
if ((int)(read_c0_count() - cnt) < 0)
break;
/* increase delta if the timer was already expired */
}
while ((int)(read_c0_count() - cnt) <= 0)
; /* Wait for expiry */
while (read_c0_count() < (cnt + COMPARE_INT_SEEN_TICKS))
if (c0_compare_int_pending())
break;
if (!c0_compare_int_pending())
return 0;
cnt = read_c0_count();
write_c0_compare(cnt);
back_to_back_c0_hazard();
while (read_c0_count() < (cnt + COMPARE_INT_SEEN_TICKS))
if (!c0_compare_int_pending())
break;
if (c0_compare_int_pending())
return 0;
/*
* Feels like a real count / compare timer.
*/
return 1;
}
int c0_compare_int_usable(void)
{
unsigned int delta;
unsigned int cnt;
/*
*/
if (c0_compare_int_pending()) {
cnt = read_c0_count();
write_c0_compare(cnt);
back_to_back_c0_hazard();
while (read_c0_count() < (cnt + COMPARE_INT_SEEN_TICKS))
if (!c0_compare_int_pending())
break;
if (c0_compare_int_pending())
return 0;
}
for (delta = 0x10; delta <= 0x400000; delta <<= 1) {
cnt = read_c0_count();
cnt += delta;
write_c0_compare(cnt);
back_to_back_c0_hazard();
if ((int)(read_c0_count() - cnt) < 0)
break;
/* */
}
while ((int)(read_c0_count() - cnt) <= 0)
; /* */
while (read_c0_count() < (cnt + COMPARE_INT_SEEN_TICKS))
if (c0_compare_int_pending())
break;
if (!c0_compare_int_pending())
return 0;
cnt = read_c0_count();
write_c0_compare(cnt);
back_to_back_c0_hazard();
while (read_c0_count() < (cnt + COMPARE_INT_SEEN_TICKS))
if (!c0_compare_int_pending())
break;
if (c0_compare_int_pending())
return 0;
/*
*/
return 1;
}
static void mips_cpu_irq_disable(unsigned int irq)
{
unsigned long flags;
local_irq_save(flags);
mask_mips_irq(irq);
back_to_back_c0_hazard();
local_irq_restore(flags);
}
IMPLEMENTATION [mips32]:
#include <cstring>
#include "mipsregs.h"
#include "panic.h"
#include "warn.h"
PRIVATE
static void
Utcb_init::validate_utcb()
{
const Mword dummy = 0x12345678;
Mword old_value = 0;
Mword new_value = 0;
// TODO may need to expand validate_utcb() to catch an exception but this
// approach is sufficient for platforms which silently ignore the accesses.
// Write the test such that the exception handler can skip the faulting access
// and still detect a failure, or consider using _recover_jmpbuf.
if ((int)Config::Warn_level >= Warning)
printf("Verifying access to UTCB pointer... ");
// Detect issues with accessing the UTCB pointer early on.
old_value = read_c0_ddatalo();
write_c0_ddatalo(dummy);
back_to_back_c0_hazard();
new_value = read_c0_ddatalo();
write_c0_ddatalo(old_value);
if (dummy != new_value)
panic("UTCB pointer could not be stored in DDataLo register.\n"
"Consider using another COP0 register available to your platform.\n");
else if ((int)Config::Warn_level >= Warning)
printf("UTCB pointer stored in DDataLo\n");
}
// XXXKYMA: Store the UTCB pointer in COP0-DDataLo Register.
// This can be set in kernel mode and read in user mode.
IMPLEMENT
void
Utcb_init::init()
{
validate_utcb();
}
