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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2008 David Daney
*/
#include <linux/sched.h>
#include <asm/processor.h>
#include <asm/watch.h>
/*
* Install the watch registers for the current thread. A maximum of
* four registers are installed although the machine may have more.
*/
void mips_install_watch_registers(struct task_struct *t)
{
struct mips3264_watch_reg_state *watches = &t->thread.watch.mips3264;
unsigned int watchhi = MIPS_WATCHHI_G | /* Trap all ASIDs */
MIPS_WATCHHI_IRW; /* Clear result bits */
switch (current_cpu_data.watch_reg_use_cnt) {
default:
BUG();
case 4:
write_c0_watchlo3(watches->watchlo[3]);
write_c0_watchhi3(watchhi | watches->watchhi[3]);
/* fall through */
case 3:
write_c0_watchlo2(watches->watchlo[2]);
write_c0_watchhi2(watchhi | watches->watchhi[2]);
/* fall through */
case 2:
write_c0_watchlo1(watches->watchlo[1]);
write_c0_watchhi1(watchhi | watches->watchhi[1]);
/* fall through */
case 1:
write_c0_watchlo0(watches->watchlo[0]);
write_c0_watchhi0(watchhi | watches->watchhi[0]);
}
}
/*
* Read back the watchhi registers so the user space debugger has
* access to the I, R, and W bits. A maximum of four registers are
* read although the machine may have more.
*/
void mips_read_watch_registers(void)
{
struct mips3264_watch_reg_state *watches =
¤t->thread.watch.mips3264;
unsigned int watchhi_mask = MIPS_WATCHHI_MASK | MIPS_WATCHHI_IRW;
switch (current_cpu_data.watch_reg_use_cnt) {
default:
BUG();
case 4:
watches->watchhi[3] = (read_c0_watchhi3() & watchhi_mask);
/* fall through */
case 3:
watches->watchhi[2] = (read_c0_watchhi2() & watchhi_mask);
/* fall through */
case 2:
watches->watchhi[1] = (read_c0_watchhi1() & watchhi_mask);
/* fall through */
case 1:
watches->watchhi[0] = (read_c0_watchhi0() & watchhi_mask);
}
if (current_cpu_data.watch_reg_use_cnt == 1 &&
(watches->watchhi[0] & MIPS_WATCHHI_IRW) == 0) {
/* Pathological case of release 1 architecture that
* doesn't set the condition bits. We assume that
* since we got here, the watch condition was met and
* signal that the conditions requested in watchlo
* were met. */
watches->watchhi[0] |= (watches->watchlo[0] & MIPS_WATCHHI_IRW);
}
}
/*
* Disable all watch registers. Although only four registers are
* installed, all are cleared to eliminate the possibility of endless
* looping in the watch handler.
*/
void mips_clear_watch_registers(void)
{
switch (current_cpu_data.watch_reg_count) {
default:
BUG();
case 8:
write_c0_watchlo7(0);
/* fall through */
case 7:
write_c0_watchlo6(0);
/* fall through */
case 6:
write_c0_watchlo5(0);
/* fall through */
case 5:
write_c0_watchlo4(0);
/* fall through */
case 4:
write_c0_watchlo3(0);
/* fall through */
case 3:
write_c0_watchlo2(0);
/* fall through */
case 2:
write_c0_watchlo1(0);
/* fall through */
case 1:
write_c0_watchlo0(0);
}
}
void mips_probe_watch_registers(struct cpuinfo_mips *c)
{
unsigned int t;
if ((c->options & MIPS_CPU_WATCH) == 0)
return;
/*
* Check which of the I,R and W bits are supported, then
* disable the register.
*/
write_c0_watchlo0(MIPS_WATCHLO_IRW);
back_to_back_c0_hazard();
t = read_c0_watchlo0();
write_c0_watchlo0(0);
c->watch_reg_masks[0] = t & MIPS_WATCHLO_IRW;
/* Write the mask bits and read them back to determine which
* can be used. */
c->watch_reg_count = 1;
c->watch_reg_use_cnt = 1;
t = read_c0_watchhi0();
write_c0_watchhi0(t | MIPS_WATCHHI_MASK);
back_to_back_c0_hazard();
t = read_c0_watchhi0();
c->watch_reg_masks[0] |= (t & MIPS_WATCHHI_MASK);
if ((t & MIPS_WATCHHI_M) == 0)
return;
write_c0_watchlo1(MIPS_WATCHLO_IRW);
back_to_back_c0_hazard();
t = read_c0_watchlo1();
write_c0_watchlo1(0);
c->watch_reg_masks[1] = t & MIPS_WATCHLO_IRW;
c->watch_reg_count = 2;
c->watch_reg_use_cnt = 2;
t = read_c0_watchhi1();
write_c0_watchhi1(t | MIPS_WATCHHI_MASK);
back_to_back_c0_hazard();
t = read_c0_watchhi1();
c->watch_reg_masks[1] |= (t & MIPS_WATCHHI_MASK);
if ((t & MIPS_WATCHHI_M) == 0)
return;
write_c0_watchlo2(MIPS_WATCHLO_IRW);
back_to_back_c0_hazard();
t = read_c0_watchlo2();
write_c0_watchlo2(0);
c->watch_reg_masks[2] = t & MIPS_WATCHLO_IRW;
c->watch_reg_count = 3;
c->watch_reg_use_cnt = 3;
t = read_c0_watchhi2();
write_c0_watchhi2(t | MIPS_WATCHHI_MASK);
back_to_back_c0_hazard();
t = read_c0_watchhi2();
c->watch_reg_masks[2] |= (t & MIPS_WATCHHI_MASK);
if ((t & MIPS_WATCHHI_M) == 0)
return;
write_c0_watchlo3(MIPS_WATCHLO_IRW);
back_to_back_c0_hazard();
t = read_c0_watchlo3();
write_c0_watchlo3(0);
c->watch_reg_masks[3] = t & MIPS_WATCHLO_IRW;
c->watch_reg_count = 4;
c->watch_reg_use_cnt = 4;
t = read_c0_watchhi3();
write_c0_watchhi3(t | MIPS_WATCHHI_MASK);
back_to_back_c0_hazard();
t = read_c0_watchhi3();
c->watch_reg_masks[3] |= (t & MIPS_WATCHHI_MASK);
if ((t & MIPS_WATCHHI_M) == 0)
return;
/* We use at most 4, but probe and report up to 8. */
c->watch_reg_count = 5;
t = read_c0_watchhi4();
if ((t & MIPS_WATCHHI_M) == 0)
return;
c->watch_reg_count = 6;
t = read_c0_watchhi5();
if ((t & MIPS_WATCHHI_M) == 0)
return;
c->watch_reg_count = 7;
t = read_c0_watchhi6();
if ((t & MIPS_WATCHHI_M) == 0)
return;
c->watch_reg_count = 8;
}
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