MIPS: Add HARDWARE_WATCHPOINTS definitions and support code.
This is the main support code for the patch. Here we just add the
code, the following patches hook it up.
Signed-off-by: David Daney <ddaney@avtrex.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
create mode 100644 arch/mips/include/asm/watch.h
create mode 100644 arch/mips/kernel/watch.c
diff --git a/arch/mips/kernel/watch.c b/arch/mips/kernel/watch.c
new file mode 100644
index 0000000..c154069
--- /dev/null
+++ b/arch/mips/kernel/watch.c
@@ -0,0 +1,188 @@
+/*
+ * 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(void)
+{
+ struct mips3264_watch_reg_state *watches =
+ ¤t->thread.watch.mips3264;
+ switch (current_cpu_data.watch_reg_use_cnt) {
+ default:
+ BUG();
+ case 4:
+ write_c0_watchlo3(watches->watchlo[3]);
+ /* Write 1 to the I, R, and W bits to clear them, and
+ 1 to G so all ASIDs are trapped. */
+ write_c0_watchhi3(0x40000007 | watches->watchhi[3]);
+ case 3:
+ write_c0_watchlo2(watches->watchlo[2]);
+ write_c0_watchhi2(0x40000007 | watches->watchhi[2]);
+ case 2:
+ write_c0_watchlo1(watches->watchlo[1]);
+ write_c0_watchhi1(0x40000007 | watches->watchhi[1]);
+ case 1:
+ write_c0_watchlo0(watches->watchlo[0]);
+ write_c0_watchhi0(0x40000007 | 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;
+ switch (current_cpu_data.watch_reg_use_cnt) {
+ default:
+ BUG();
+ case 4:
+ watches->watchhi[3] = (read_c0_watchhi3() & 0x0fff);
+ case 3:
+ watches->watchhi[2] = (read_c0_watchhi2() & 0x0fff);
+ case 2:
+ watches->watchhi[1] = (read_c0_watchhi1() & 0x0fff);
+ case 1:
+ watches->watchhi[0] = (read_c0_watchhi0() & 0x0fff);
+ }
+ if (current_cpu_data.watch_reg_use_cnt == 1 &&
+ (watches->watchhi[0] & 7) == 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] & 7);
+ }
+ }
+
+/*
+ * 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);
+ case 7:
+ write_c0_watchlo6(0);
+ case 6:
+ write_c0_watchlo5(0);
+ case 5:
+ write_c0_watchlo4(0);
+ case 4:
+ write_c0_watchlo3(0);
+ case 3:
+ write_c0_watchlo2(0);
+ case 2:
+ write_c0_watchlo1(0);
+ case 1:
+ write_c0_watchlo0(0);
+ }
+}
+
+__cpuinit 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(7);
+ t = read_c0_watchlo0();
+ write_c0_watchlo0(0);
+ c->watch_reg_masks[0] = t & 7;
+
+ /* 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 | 0xff8);
+ t = read_c0_watchhi0();
+ c->watch_reg_masks[0] |= (t & 0xff8);
+ if ((t & 0x80000000) == 0)
+ return;
+
+ write_c0_watchlo1(7);
+ t = read_c0_watchlo1();
+ write_c0_watchlo1(0);
+ c->watch_reg_masks[1] = t & 7;
+
+ c->watch_reg_count = 2;
+ c->watch_reg_use_cnt = 2;
+ t = read_c0_watchhi1();
+ write_c0_watchhi1(t | 0xff8);
+ t = read_c0_watchhi1();
+ c->watch_reg_masks[1] |= (t & 0xff8);
+ if ((t & 0x80000000) == 0)
+ return;
+
+ write_c0_watchlo2(7);
+ t = read_c0_watchlo2();
+ write_c0_watchlo2(0);
+ c->watch_reg_masks[2] = t & 7;
+
+ c->watch_reg_count = 3;
+ c->watch_reg_use_cnt = 3;
+ t = read_c0_watchhi2();
+ write_c0_watchhi2(t | 0xff8);
+ t = read_c0_watchhi2();
+ c->watch_reg_masks[2] |= (t & 0xff8);
+ if ((t & 0x80000000) == 0)
+ return;
+
+ write_c0_watchlo3(7);
+ t = read_c0_watchlo3();
+ write_c0_watchlo3(0);
+ c->watch_reg_masks[3] = t & 7;
+
+ c->watch_reg_count = 4;
+ c->watch_reg_use_cnt = 4;
+ t = read_c0_watchhi3();
+ write_c0_watchhi3(t | 0xff8);
+ t = read_c0_watchhi3();
+ c->watch_reg_masks[3] |= (t & 0xff8);
+ if ((t & 0x80000000) == 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 & 0x80000000) == 0)
+ return;
+
+ c->watch_reg_count = 6;
+ t = read_c0_watchhi5();
+ if ((t & 0x80000000) == 0)
+ return;
+
+ c->watch_reg_count = 7;
+ t = read_c0_watchhi6();
+ if ((t & 0x80000000) == 0)
+ return;
+
+ c->watch_reg_count = 8;
+}