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authorDavid Daney <ddaney@avtrex.com>2008-09-23 00:11:26 -0700
committerRalf Baechle <ralf@linux-mips.org>2008-10-11 16:18:57 +0100
commit0926bf953ee79b8f139741b442e5a18520f81705 (patch)
tree5e2cbdb2060ec9324866e6a072d1d7666849445c
parent2c708cbaa6031b73be6b992adb3ec1811f91cdb1 (diff)
MIPS: Ptrace support for HARDWARE_WATCHPOINTS
This is the final part of the watch register patch. Here we hook up ptrace so that the user space debugger (gdb), can set and read the registers. Signed-off-by: David Daney <ddaney@avtrex.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
-rw-r--r--arch/mips/include/asm/ptrace.h46
-rw-r--r--arch/mips/kernel/ptrace.c100
-rw-r--r--arch/mips/kernel/ptrace32.c10
3 files changed, 155 insertions, 1 deletions
diff --git a/arch/mips/include/asm/ptrace.h b/arch/mips/include/asm/ptrace.h
index c00cca24dae..cd5e8a47812 100644
--- a/arch/mips/include/asm/ptrace.h
+++ b/arch/mips/include/asm/ptrace.h
@@ -74,11 +74,57 @@ struct pt_regs {
#define PTRACE_POKEDATA_3264 0xc3
#define PTRACE_GET_THREAD_AREA_3264 0xc4
+/* Read and write watchpoint registers. */
+enum pt_watch_style {
+ pt_watch_style_mips32,
+ pt_watch_style_mips64
+};
+struct mips32_watch_regs {
+ uint32_t watchlo[8];
+ /* Lower 16 bits of watchhi. */
+ uint16_t watchhi[8];
+ /* Valid mask and I R W bits.
+ * bit 0 -- 1 if W bit is usable.
+ * bit 1 -- 1 if R bit is usable.
+ * bit 2 -- 1 if I bit is usable.
+ * bits 3 - 11 -- Valid watchhi mask bits.
+ */
+ uint16_t watch_masks[8];
+ /* The number of valid watch register pairs. */
+ uint32_t num_valid;
+} __attribute__((aligned(8)));
+
+struct mips64_watch_regs {
+ uint64_t watchlo[8];
+ uint16_t watchhi[8];
+ uint16_t watch_masks[8];
+ uint32_t num_valid;
+} __attribute__((aligned(8)));
+
+struct pt_watch_regs {
+ enum pt_watch_style style;
+ union {
+ struct mips32_watch_regs mips32;
+ struct mips32_watch_regs mips64;
+ };
+};
+
+#define PTRACE_GET_WATCH_REGS 0xd0
+#define PTRACE_SET_WATCH_REGS 0xd1
+
#ifdef __KERNEL__
+#include <linux/compiler.h>
#include <linux/linkage.h>
#include <asm/isadep.h>
+struct task_struct;
+
+extern int ptrace_get_watch_regs(struct task_struct *child,
+ struct pt_watch_regs __user *addr);
+extern int ptrace_set_watch_regs(struct task_struct *child,
+ struct pt_watch_regs __user *addr);
+
/*
* Does the process account for user or for system time?
*/
diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
index 96ffc9c6d19..054861ccb4d 100644
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -46,7 +46,8 @@
*/
void ptrace_disable(struct task_struct *child)
{
- /* Nothing to do.. */
+ /* Don't load the watchpoint registers for the ex-child. */
+ clear_tsk_thread_flag(child, TIF_LOAD_WATCH);
}
/*
@@ -167,6 +168,93 @@ int ptrace_setfpregs(struct task_struct *child, __u32 __user *data)
return 0;
}
+int ptrace_get_watch_regs(struct task_struct *child,
+ struct pt_watch_regs __user *addr)
+{
+ enum pt_watch_style style;
+ int i;
+
+ if (!cpu_has_watch || current_cpu_data.watch_reg_use_cnt == 0)
+ return -EIO;
+ if (!access_ok(VERIFY_WRITE, addr, sizeof(struct pt_watch_regs)))
+ return -EIO;
+
+#ifdef CONFIG_32BIT
+ style = pt_watch_style_mips32;
+#define WATCH_STYLE mips32
+#else
+ style = pt_watch_style_mips64;
+#define WATCH_STYLE mips64
+#endif
+
+ __put_user(style, &addr->style);
+ __put_user(current_cpu_data.watch_reg_use_cnt,
+ &addr->WATCH_STYLE.num_valid);
+ for (i = 0; i < current_cpu_data.watch_reg_use_cnt; i++) {
+ __put_user(child->thread.watch.mips3264.watchlo[i],
+ &addr->WATCH_STYLE.watchlo[i]);
+ __put_user(child->thread.watch.mips3264.watchhi[i] & 0xfff,
+ &addr->WATCH_STYLE.watchhi[i]);
+ __put_user(current_cpu_data.watch_reg_masks[i],
+ &addr->WATCH_STYLE.watch_masks[i]);
+ }
+ for (; i < 8; i++) {
+ __put_user(0, &addr->WATCH_STYLE.watchlo[i]);
+ __put_user(0, &addr->WATCH_STYLE.watchhi[i]);
+ __put_user(0, &addr->WATCH_STYLE.watch_masks[i]);
+ }
+
+ return 0;
+}
+
+int ptrace_set_watch_regs(struct task_struct *child,
+ struct pt_watch_regs __user *addr)
+{
+ int i;
+ int watch_active = 0;
+ unsigned long lt[NUM_WATCH_REGS];
+ u16 ht[NUM_WATCH_REGS];
+
+ if (!cpu_has_watch || current_cpu_data.watch_reg_use_cnt == 0)
+ return -EIO;
+ if (!access_ok(VERIFY_READ, addr, sizeof(struct pt_watch_regs)))
+ return -EIO;
+ /* Check the values. */
+ for (i = 0; i < current_cpu_data.watch_reg_use_cnt; i++) {
+ __get_user(lt[i], &addr->WATCH_STYLE.watchlo[i]);
+#ifdef CONFIG_32BIT
+ if (lt[i] & __UA_LIMIT)
+ return -EINVAL;
+#else
+ if (test_tsk_thread_flag(child, TIF_32BIT_ADDR)) {
+ if (lt[i] & 0xffffffff80000000UL)
+ return -EINVAL;
+ } else {
+ if (lt[i] & __UA_LIMIT)
+ return -EINVAL;
+ }
+#endif
+ __get_user(ht[i], &addr->WATCH_STYLE.watchhi[i]);
+ if (ht[i] & ~0xff8)
+ return -EINVAL;
+ }
+ /* Install them. */
+ for (i = 0; i < current_cpu_data.watch_reg_use_cnt; i++) {
+ if (lt[i] & 7)
+ watch_active = 1;
+ child->thread.watch.mips3264.watchlo[i] = lt[i];
+ /* Set the G bit. */
+ child->thread.watch.mips3264.watchhi[i] = ht[i];
+ }
+
+ if (watch_active)
+ set_tsk_thread_flag(child, TIF_LOAD_WATCH);
+ else
+ clear_tsk_thread_flag(child, TIF_LOAD_WATCH);
+
+ return 0;
+}
+
long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
int ret;
@@ -440,6 +528,16 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
(unsigned long __user *) data);
break;
+ case PTRACE_GET_WATCH_REGS:
+ ret = ptrace_get_watch_regs(child,
+ (struct pt_watch_regs __user *) addr);
+ break;
+
+ case PTRACE_SET_WATCH_REGS:
+ ret = ptrace_set_watch_regs(child,
+ (struct pt_watch_regs __user *) addr);
+ break;
+
default:
ret = ptrace_request(child, request, addr, data);
break;
diff --git a/arch/mips/kernel/ptrace32.c b/arch/mips/kernel/ptrace32.c
index cac56a8c867..e45105e3ef0 100644
--- a/arch/mips/kernel/ptrace32.c
+++ b/arch/mips/kernel/ptrace32.c
@@ -387,6 +387,16 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
(unsigned long __user *) (unsigned long) data);
break;
+ case PTRACE_GET_WATCH_REGS:
+ ret = ptrace_get_watch_regs(child,
+ (struct pt_watch_regs __user *) (unsigned long) addr);
+ break;
+
+ case PTRACE_SET_WATCH_REGS:
+ ret = ptrace_set_watch_regs(child,
+ (struct pt_watch_regs __user *) (unsigned long) addr);
+ break;
+
default:
ret = ptrace_request(child, request, addr, data);
break;