9 files changed, 255 insertions, 32 deletions

diff --git a/arch/x86/include/asm/a.out-core.h b/arch/x86/include/asm/a.out-core.h
index bb70e397aa84..fc4685dd6e4d 100644
--- a/arch/x86/include/asm/a.out-core.h
+++ b/arch/x86/include/asm/a.out-core.h
@@ -32,10 +32,10 @@ static inline void aout_dump_thread(struct pt_regs *regs, struct user *dump)
                         >> PAGE_SHIFT;
         dump->u_dsize -= dump->u_tsize;
         dump->u_ssize = 0;
-        dump->u_debugreg[0] = current->thread.debugreg0;
-        dump->u_debugreg[1] = current->thread.debugreg1;
-        dump->u_debugreg[2] = current->thread.debugreg2;
-        dump->u_debugreg[3] = current->thread.debugreg3;
+        dump->u_debugreg[0] = current->thread.debugreg[0];
+        dump->u_debugreg[1] = current->thread.debugreg[1];
+        dump->u_debugreg[2] = current->thread.debugreg[2];
+        dump->u_debugreg[3] = current->thread.debugreg[3];
         dump->u_debugreg[4] = 0;
         dump->u_debugreg[5] = 0;
         dump->u_debugreg[6] = current->thread.debugreg6;
diff --git a/arch/x86/include/asm/debugreg.h b/arch/x86/include/asm/debugreg.h
index 3ea6f37be9e2..23439fbb1d0e 100644
--- a/arch/x86/include/asm/debugreg.h
+++ b/arch/x86/include/asm/debugreg.h
@@ -18,6 +18,7 @@
 #define DR_TRAP1        (0x2)           /* db1 */
 #define DR_TRAP2        (0x4)           /* db2 */
 #define DR_TRAP3        (0x8)           /* db3 */
+#define DR_TRAP_BITS    (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)
 
 #define DR_STEP         (0x4000)        /* single-step */
 #define DR_SWITCH       (0x8000)        /* task switch */
@@ -49,6 +50,8 @@
 
 #define DR_LOCAL_ENABLE_SHIFT 0    /* Extra shift to the local enable bit */
 #define DR_GLOBAL_ENABLE_SHIFT 1   /* Extra shift to the global enable bit */
+#define DR_LOCAL_ENABLE (0x1)      /* Local enable for reg 0 */
+#define DR_GLOBAL_ENABLE (0x2)     /* Global enable for reg 0 */
 #define DR_ENABLE_SIZE 2           /* 2 enable bits per register */
 
 #define DR_LOCAL_ENABLE_MASK (0x55)  /* Set  local bits for all 4 regs */
@@ -67,4 +70,30 @@
 #define DR_LOCAL_SLOWDOWN (0x100)   /* Local slow the pipeline */
 #define DR_GLOBAL_SLOWDOWN (0x200)  /* Global slow the pipeline */
 
+/*
+ * HW breakpoint additions
+ */
+#ifdef __KERNEL__
+
+/* For process management */
+extern void flush_thread_hw_breakpoint(struct task_struct *tsk);
+extern int copy_thread_hw_breakpoint(struct task_struct *tsk,
+                struct task_struct *child, unsigned long clone_flags);
+
+/* For CPU management */
+extern void load_debug_registers(void);
+static inline void hw_breakpoint_disable(void)
+{
+        /* Zero the control register for HW Breakpoint */
+        set_debugreg(0UL, 7);
+
+        /* Zero-out the individual HW breakpoint address registers */
+        set_debugreg(0UL, 0);
+        set_debugreg(0UL, 1);
+        set_debugreg(0UL, 2);
+        set_debugreg(0UL, 3);
+}
+
+#endif  /* __KERNEL__ */
+
 #endif /* _ASM_X86_DEBUGREG_H */
diff --git a/arch/x86/include/asm/hw_breakpoint.h b/arch/x86/include/asm/hw_breakpoint.h
new file mode 100644
index 000000000000..1acb4d45de70
--- /dev/null
+++ b/arch/x86/include/asm/hw_breakpoint.h
@@ -0,0 +1,55 @@
+#ifndef _I386_HW_BREAKPOINT_H
+#define _I386_HW_BREAKPOINT_H
+
+#ifdef  __KERNEL__
+#define __ARCH_HW_BREAKPOINT_H
+
+struct arch_hw_breakpoint {
+        char            *name; /* Contains name of the symbol to set bkpt */
+        unsigned long   address;
+        u8              len;
+        u8              type;
+};
+
+#include <linux/kdebug.h>
+#include <asm-generic/hw_breakpoint.h>
+
+/* Available HW breakpoint length encodings */
+#define HW_BREAKPOINT_LEN_1             0x40
+#define HW_BREAKPOINT_LEN_2             0x44
+#define HW_BREAKPOINT_LEN_4             0x4c
+#define HW_BREAKPOINT_LEN_EXECUTE       0x40
+
+#ifdef CONFIG_X86_64
+#define HW_BREAKPOINT_LEN_8             0x48
+#endif
+
+/* Available HW breakpoint type encodings */
+
+/* trigger on instruction execute */
+#define HW_BREAKPOINT_EXECUTE   0x80
+/* trigger on memory write */
+#define HW_BREAKPOINT_WRITE     0x81
+/* trigger on memory read or write */
+#define HW_BREAKPOINT_RW        0x83
+
+/* Total number of available HW breakpoint registers */
+#define HBP_NUM 4
+
+extern struct hw_breakpoint *hbp_kernel[HBP_NUM];
+DECLARE_PER_CPU(struct hw_breakpoint*, this_hbp_kernel[HBP_NUM]);
+extern unsigned int hbp_user_refcount[HBP_NUM];
+
+extern void arch_install_thread_hw_breakpoint(struct task_struct *tsk);
+extern void arch_uninstall_thread_hw_breakpoint(void);
+extern int arch_check_va_in_userspace(unsigned long va, u8 hbp_len);
+extern int arch_validate_hwbkpt_settings(struct hw_breakpoint *bp,
+                                                struct task_struct *tsk);
+extern void arch_update_user_hw_breakpoint(int pos, struct task_struct *tsk);
+extern void arch_flush_thread_hw_breakpoint(struct task_struct *tsk);
+extern void arch_update_kernel_hw_breakpoint(void *);
+extern int hw_breakpoint_exceptions_notify(struct notifier_block *unused,
+                                     unsigned long val, void *data);
+#endif  /* __KERNEL__ */
+#endif  /* _I386_HW_BREAKPOINT_H */
+
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 0b2fab0051e0..448b34a8e393 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -29,6 +29,7 @@ struct mm_struct;
 #include <linux/threads.h>
 #include <linux/init.h>
 
+#define HBP_NUM 4
 /*
  * Default implementation of macro that returns current
  * instruction pointer ("program counter").
@@ -431,12 +432,11 @@ struct thread_struct {
         unsigned long           fs;
         unsigned long           gs;
         /* Hardware debugging registers: */
-        unsigned long           debugreg0;
-        unsigned long           debugreg1;
-        unsigned long           debugreg2;
-        unsigned long           debugreg3;
+        unsigned long           debugreg[HBP_NUM];
         unsigned long           debugreg6;
         unsigned long           debugreg7;
+        /* Hardware breakpoint info */
+        struct hw_breakpoint    *hbp[HBP_NUM];
         /* Fault info: */
         unsigned long           cr2;
         unsigned long           trap_no;
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index fb5dfb891f0f..291527cb438a 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -106,10 +106,10 @@ void flush_thread(void)
 
         clear_tsk_thread_flag(tsk, TIF_DEBUG);
 
-        tsk->thread.debugreg0 = 0;
-        tsk->thread.debugreg1 = 0;
-        tsk->thread.debugreg2 = 0;
-        tsk->thread.debugreg3 = 0;
+        tsk->thread.debugreg[0] = 0;
+        tsk->thread.debugreg[1] = 0;
+        tsk->thread.debugreg[2] = 0;
+        tsk->thread.debugreg[3] = 0;
         tsk->thread.debugreg6 = 0;
         tsk->thread.debugreg7 = 0;
         memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
@@ -194,10 +194,10 @@ void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
                 update_debugctlmsr(next->debugctlmsr);
 
         if (test_tsk_thread_flag(next_p, TIF_DEBUG)) {
-                set_debugreg(next->debugreg0, 0);
-                set_debugreg(next->debugreg1, 1);
-                set_debugreg(next->debugreg2, 2);
-                set_debugreg(next->debugreg3, 3);
+                set_debugreg(next->debugreg[0], 0);
+                set_debugreg(next->debugreg[1], 1);
+                set_debugreg(next->debugreg[2], 2);
+                set_debugreg(next->debugreg[3], 3);
                 /* no 4 and 5 */
                 set_debugreg(next->debugreg6, 6);
                 set_debugreg(next->debugreg7, 7);
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 09ecbde91c13..313be40be55a 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -471,10 +471,10 @@ static int genregs_set(struct task_struct *target,
 static unsigned long ptrace_get_debugreg(struct task_struct *child, int n)
 {
         switch (n) {
-        case 0:         return child->thread.debugreg0;
-        case 1:         return child->thread.debugreg1;
-        case 2:         return child->thread.debugreg2;
-        case 3:         return child->thread.debugreg3;
+        case 0:         return child->thread.debugreg[0];
+        case 1:         return child->thread.debugreg[1];
+        case 2:         return child->thread.debugreg[2];
+        case 3:         return child->thread.debugreg[3];
         case 6:         return child->thread.debugreg6;
         case 7:         return child->thread.debugreg7;
         }
@@ -493,10 +493,10 @@ static int ptrace_set_debugreg(struct task_struct *child,
                 return -EIO;
 
         switch (n) {
-        case 0:         child->thread.debugreg0 = data; break;
-        case 1:         child->thread.debugreg1 = data; break;
-        case 2:         child->thread.debugreg2 = data; break;
-        case 3:         child->thread.debugreg3 = data; break;
+        case 0:         child->thread.debugreg[0] = data; break;
+        case 1:         child->thread.debugreg[1] = data; break;
+        case 2:         child->thread.debugreg[2] = data; break;
+        case 3:         child->thread.debugreg[3] = data; break;
 
         case 6:
                 if ((data & ~0xffffffffUL) != 0)
diff --git a/arch/x86/power/cpu_32.c b/arch/x86/power/cpu_32.c
index ce702c5b3a2c..519913948003 100644
--- a/arch/x86/power/cpu_32.c
+++ b/arch/x86/power/cpu_32.c
@@ -84,10 +84,10 @@ static void fix_processor_context(void)
          * Now maybe reload the debug registers
          */
         if (current->thread.debugreg7) {
-                set_debugreg(current->thread.debugreg0, 0);
-                set_debugreg(current->thread.debugreg1, 1);
-                set_debugreg(current->thread.debugreg2, 2);
-                set_debugreg(current->thread.debugreg3, 3);
+                set_debugreg(current->thread.debugreg[0], 0);
+                set_debugreg(current->thread.debugreg[1], 1);
+                set_debugreg(current->thread.debugreg[2], 2);
+                set_debugreg(current->thread.debugreg[3], 3);
                 /* no 4 and 5 */
                 set_debugreg(current->thread.debugreg6, 6);
                 set_debugreg(current->thread.debugreg7, 7);
diff --git a/arch/x86/power/cpu_64.c b/arch/x86/power/cpu_64.c
index 5343540f2607..1e3bdcc959ff 100644
--- a/arch/x86/power/cpu_64.c
+++ b/arch/x86/power/cpu_64.c
@@ -163,10 +163,10 @@ static void fix_processor_context(void)
          * Now maybe reload the debug registers
          */
         if (current->thread.debugreg7){
-                loaddebug(&current->thread, 0);
-                loaddebug(&current->thread, 1);
-                loaddebug(&current->thread, 2);
-                loaddebug(&current->thread, 3);
+                set_debugreg(current->thread.debugreg[0], 0);
+                set_debugreg(current->thread.debugreg[1], 1);
+                set_debugreg(current->thread.debugreg[2], 2);
+                set_debugreg(current->thread.debugreg[3], 3);
                 /* no 4 and 5 */
                 loaddebug(&current->thread, 6);
                 loaddebug(&current->thread, 7);
diff --git a/include/asm-generic/hw_breakpoint.h b/include/asm-generic/hw_breakpoint.h
new file mode 100644
index 000000000000..9bf2d12eb74a
--- /dev/null
+++ b/include/asm-generic/hw_breakpoint.h
@@ -0,0 +1,139 @@
+#ifndef _ASM_GENERIC_HW_BREAKPOINT_H
+#define _ASM_GENERIC_HW_BREAKPOINT_H
+
+#ifndef __ARCH_HW_BREAKPOINT_H
+#error "Please don't include this file directly"
+#endif
+
+#ifdef  __KERNEL__
+#include <linux/list.h>
+#include <linux/types.h>
+#include <linux/kallsyms.h>
+
+/**
+ * struct hw_breakpoint - unified kernel/user-space hardware breakpoint
+ * @triggered: callback invoked after target address access
+ * @info: arch-specific breakpoint info (address, length, and type)
+ *
+ * %hw_breakpoint structures are the kernel's way of representing
+ * hardware breakpoints.  These are data breakpoints
+ * (also known as "watchpoints", triggered on data access), and the breakpoint's
+ * target address can be located in either kernel space or user space.
+ *
+ * The breakpoint's address, length, and type are highly
+ * architecture-specific.  The values are encoded in the @info field; you
+ * specify them when registering the breakpoint.  To examine the encoded
+ * values use hw_breakpoint_get_{kaddress,uaddress,len,type}(), declared
+ * below.
+ *
+ * The address is specified as a regular kernel pointer (for kernel-space
+ * breakponts) or as an %__user pointer (for user-space breakpoints).
+ * With register_user_hw_breakpoint(), the address must refer to a
+ * location in user space.  The breakpoint will be active only while the
+ * requested task is running.  Conversely with
+ * register_kernel_hw_breakpoint(), the address must refer to a location
+ * in kernel space, and the breakpoint will be active on all CPUs
+ * regardless of the current task.
+ *
+ * The length is the breakpoint's extent in bytes, which is subject to
+ * certain limitations.  include/asm/hw_breakpoint.h contains macros
+ * defining the available lengths for a specific architecture.  Note that
+ * the address's alignment must match the length.  The breakpoint will
+ * catch accesses to any byte in the range from address to address +
+ * (length - 1).
+ *
+ * The breakpoint's type indicates the sort of access that will cause it
+ * to trigger.  Possible values may include:
+ *
+ *      %HW_BREAKPOINT_RW (triggered on read or write access),
+ *      %HW_BREAKPOINT_WRITE (triggered on write access), and
+ *      %HW_BREAKPOINT_READ (triggered on read access).
+ *
+ * Appropriate macros are defined in include/asm/hw_breakpoint.h; not all
+ * possibilities are available on all architectures.  Execute breakpoints
+ * must have length equal to the special value %HW_BREAKPOINT_LEN_EXECUTE.
+ *
+ * When a breakpoint gets hit, the @triggered callback is
+ * invoked in_interrupt with a pointer to the %hw_breakpoint structure and the
+ * processor registers.
+ * Data breakpoints occur after the memory access has taken place.
+ * Breakpoints are disabled during execution @triggered, to avoid
+ * recursive traps and allow unhindered access to breakpointed memory.
+ *
+ * This sample code sets a breakpoint on pid_max and registers a callback
+ * function for writes to that variable.  Note that it is not portable
+ * as written, because not all architectures support HW_BREAKPOINT_LEN_4.
+ *
+ * ----------------------------------------------------------------------
+ *
+ * #include <asm/hw_breakpoint.h>
+ *
+ * struct hw_breakpoint my_bp;
+ *
+ * static void my_triggered(struct hw_breakpoint *bp, struct pt_regs *regs)
+ * {
+ *      printk(KERN_DEBUG "Inside triggered routine of breakpoint exception\n");
+ *      dump_stack();
+ *      .......<more debugging output>........
+ * }
+ *
+ * static struct hw_breakpoint my_bp;
+ *
+ * static int init_module(void)
+ * {
+ *      ..........<do anything>............
+ *      my_bp.info.type = HW_BREAKPOINT_WRITE;
+ *      my_bp.info.len = HW_BREAKPOINT_LEN_4;
+ *
+ *      my_bp.installed = (void *)my_bp_installed;
+ *
+ *      rc = register_kernel_hw_breakpoint(&my_bp);
+ *      ..........<do anything>............
+ * }
+ *
+ * static void cleanup_module(void)
+ * {
+ *      ..........<do anything>............
+ *      unregister_kernel_hw_breakpoint(&my_bp);
+ *      ..........<do anything>............
+ * }
+ *
+ * ----------------------------------------------------------------------
+ */
+struct hw_breakpoint {
+        void (*triggered)(struct hw_breakpoint *, struct pt_regs *);
+        struct arch_hw_breakpoint info;
+};
+
+/*
+ * len and type values are defined in include/asm/hw_breakpoint.h.
+ * Available values vary according to the architecture.  On i386 the
+ * possibilities are:
+ *
+ *      HW_BREAKPOINT_LEN_1
+ *      HW_BREAKPOINT_LEN_2
+ *      HW_BREAKPOINT_LEN_4
+ *      HW_BREAKPOINT_RW
+ *      HW_BREAKPOINT_READ
+ *
+ * On other architectures HW_BREAKPOINT_LEN_8 may be available, and the
+ * 1-, 2-, and 4-byte lengths may be unavailable.  There also may be
+ * HW_BREAKPOINT_WRITE.  You can use #ifdef to check at compile time.
+ */
+
+extern int register_user_hw_breakpoint(struct task_struct *tsk,
+                                        struct hw_breakpoint *bp);
+extern int modify_user_hw_breakpoint(struct task_struct *tsk,
+                                        struct hw_breakpoint *bp);
+extern void unregister_user_hw_breakpoint(struct task_struct *tsk,
+                                                struct hw_breakpoint *bp);
+/*
+ * Kernel breakpoints are not associated with any particular thread.
+ */
+extern int register_kernel_hw_breakpoint(struct hw_breakpoint *bp);
+extern void unregister_kernel_hw_breakpoint(struct hw_breakpoint *bp);
+
+extern unsigned int hbp_kernel_pos;
+
+#endif  /* __KERNEL__ */
+#endif  /* _ASM_GENERIC_HW_BREAKPOINT_H */