linux-mips
[Top] [All Lists]

[PATCH 6/6] Ptrace support for HARDWARE_WATCHPOINTS.

To: linux-mips@linux-mips.org
Subject: [PATCH 6/6] Ptrace support for HARDWARE_WATCHPOINTS.
From: David Daney <ddaney@avtrex.com>
Date: Mon, 28 Apr 2008 18:43:26 -0700
Cc: Linux kernel <linux-kernel@vger.kernel.org>
In-reply-to: <48167832.3090103@avtrex.com>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <48167832.3090103@avtrex.com>
Sender: linux-mips-bounce@linux-mips.org
User-agent: Thunderbird 2.0.0.12 (X11/20080226)
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>
---
arch/mips/kernel/ptrace.c |   93 +++++++++++++++++++++++++++++++++++++++++++++
include/asm-mips/ptrace.h |   31 +++++++++++++++
2 files changed, 124 insertions(+), 0 deletions(-)

diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
index 35234b9..8e86134 100644
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -46,7 +46,12 @@
 */
void ptrace_disable(struct task_struct *child)
{
+#ifdef CONFIG_HARDWARE_WATCHPOINTS
+       /* Don't load the watchpoint registers for the ex-child. */
+       clear_tsk_thread_flag(child, TIF_LOAD_WATCH);
+#else
        /* Nothing to do.. */
+#endif
}

/*
@@ -167,6 +172,84 @@ int ptrace_setfpregs(struct task_struct *child, __u32 
__user *data)
        return 0;
}

+#ifdef CONFIG_HARDWARE_WATCHPOINTS
+static 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)
+               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_count,
+                  &addr->WATCH_STYLE.num_valid);
+       __put_user(current_cpu_data.watch_reg_mask,
+                  &addr->WATCH_STYLE.reg_mask);
+       __put_user(current_cpu_data.watch_reg_irw,
+                  &addr->WATCH_STYLE.irw_mask);
+       for (i = 0; i < current_cpu_data.watch_reg_count; 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]);
+       }
+
+       return 0;
+}
+
+static 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];
+       unsigned int ht[NUM_WATCH_REGS];
+
+       if (!cpu_has_watch)
+               return -EIO;
+       if (!access_ok(VERIFY_READ, addr, sizeof(struct pt_watch_regs)))
+               return -EIO;
+       /* Check the values. */
+       for (i = 0; i < NUM_WATCH_REGS; i++) {
+               __get_user(lt[i], &addr->WATCH_STYLE.watchlo[i]);
+               if (lt[i] & __UA_LIMIT)
+                       return -EINVAL;
+
+               __get_user(ht[i], &addr->WATCH_STYLE.watchhi[i]);
+               if (ht[i] & ~0xff8)
+                       return -EINVAL;
+       }
+       /* Install them. */
+       for (i = 0; i < NUM_WATCH_REGS; 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] | 0x40000000;
+       }
+
+       if (watch_active)
+               set_tsk_thread_flag(child, TIF_LOAD_WATCH);
+       else
+               clear_tsk_thread_flag(child, TIF_LOAD_WATCH);
+
+       return 0;
+}
+
+#endif /* CONFIG_HARDWARE_WATCHPOINTS */
+
long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
        int ret;
@@ -439,7 +522,17 @@ long arch_ptrace(struct task_struct *child, long request, 
long addr, long data)
                ret = put_user(task_thread_info(child)->tp_value,
                                (unsigned long __user *) data);
                break;
+#ifdef CONFIG_HARDWARE_WATCHPOINTS
+       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;
+#endif
        default:
                ret = ptrace_request(child, request, addr, data);
                break;
diff --git a/include/asm-mips/ptrace.h b/include/asm-mips/ptrace.h
index 786f7e3..d8d821d 100644
--- a/include/asm-mips/ptrace.h
+++ b/include/asm-mips/ptrace.h
@@ -71,6 +71,37 @@ 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];
+       uint32_t watchhi[8];
+       uint32_t num_valid;
+       uint32_t reg_mask;
+       uint32_t irw_mask;
+};
+struct mips64_watch_regs {
+       uint64_t watchlo[8];
+       uint32_t watchhi[8];
+       uint32_t num_valid;
+       uint32_t reg_mask;
+       uint32_t irw_mask;
+};
+
+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/linkage.h>
--
1.5.5


<Prev in Thread] Current Thread [Next in Thread>