Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[safe/jmp/linux-2.6] / arch / x86 / kernel / hw_breakpoint.c

diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c
index e622620..dca2802 100644 (file)
--- a/arch/x86/kernel/hw_breakpoint.c
+++ b/arch/x86/kernel/hw_breakpoint.c
@@ -16,6 +16,10 @@
  * Copyright (C) 2007 Alan Stern
  * Copyright (C) 2009 IBM Corporation
  * Copyright (C) 2009 Frederic Weisbecker <fweisbec@gmail.com>
+ *
+ * Authors: Alan Stern <stern@rowland.harvard.edu>
+ *          K.Prasad <prasad@linux.vnet.ibm.com>
+ *          Frederic Weisbecker <fweisbec@gmail.com>
  */
 
 /*
@@ -42,7 +46,8 @@
 #include <asm/debugreg.h>
 
 /* Per cpu debug control register value */
-DEFINE_PER_CPU(unsigned long, dr7);
+DEFINE_PER_CPU(unsigned long, cpu_dr7);
+EXPORT_PER_CPU_SYMBOL(cpu_dr7);
 
 /* Per cpu debug address registers values */
 static DEFINE_PER_CPU(unsigned long, cpu_debugreg[HBP_NUM]);
@@ -54,22 +59,28 @@ static DEFINE_PER_CPU(unsigned long, cpu_debugreg[HBP_NUM]);
 static DEFINE_PER_CPU(struct perf_event *, bp_per_reg[HBP_NUM]);
 
 
-/*
- * Encode the length, type, Exact, and Enable bits for a particular breakpoint
- * as stored in debug register 7.
- */
-unsigned long encode_dr7(int drnum, unsigned int len, unsigned int type)
+static inline unsigned long
+__encode_dr7(int drnum, unsigned int len, unsigned int type)
 {
        unsigned long bp_info;
 
        bp_info = (len | type) & 0xf;
        bp_info <<= (DR_CONTROL_SHIFT + drnum * DR_CONTROL_SIZE);
-       bp_info |= (DR_GLOBAL_ENABLE << (drnum * DR_ENABLE_SIZE)) |
-                               DR_GLOBAL_SLOWDOWN;
+       bp_info |= (DR_GLOBAL_ENABLE << (drnum * DR_ENABLE_SIZE));
+
        return bp_info;
 }
 
 /*
+ * Encode the length, type, Exact, and Enable bits for a particular breakpoint
+ * as stored in debug register 7.
+ */
+unsigned long encode_dr7(int drnum, unsigned int len, unsigned int type)
+{
+       return __encode_dr7(drnum, len, type) | DR_GLOBAL_SLOWDOWN;
+}
+
+/*
  * Decode the length and type bits for a particular breakpoint as
  * stored in debug register 7.  Return the "enabled" status.
  */
@@ -113,7 +124,7 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
        set_debugreg(info->address, i);
        __get_cpu_var(cpu_debugreg[i]) = info->address;
 
-       dr7 = &__get_cpu_var(dr7);
+       dr7 = &__get_cpu_var(cpu_dr7);
        *dr7 |= encode_dr7(i, info->len, info->type);
 
        set_debugreg(*dr7, 7);
@@ -148,8 +159,8 @@ void arch_uninstall_hw_breakpoint(struct perf_event *bp)
        if (WARN_ONCE(i == HBP_NUM, "Can't find any breakpoint slot"))
                return;
 
-       dr7 = &__get_cpu_var(dr7);
-       *dr7 &= ~encode_dr7(i, info->len, info->type);
+       dr7 = &__get_cpu_var(cpu_dr7);
+       *dr7 &= ~__encode_dr7(i, info->len, info->type);
 
        set_debugreg(*dr7, 7);
 }
@@ -201,25 +212,6 @@ static int arch_check_va_in_kernelspace(unsigned long va, u8 hbp_len)
        return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE);
 }
 
-/*
- * Store a breakpoint's encoded address, length, and type.
- */
-static int arch_store_info(struct perf_event *bp)
-{
-       struct arch_hw_breakpoint *info = counter_arch_bp(bp);
-       /*
-        * For kernel-addresses, either the address or symbol name can be
-        * specified.
-        */
-       if (info->name)
-               info->address = (unsigned long)
-                               kallsyms_lookup_name(info->name);
-       if (info->address)
-               return 0;
-
-       return -EINVAL;
-}
-
 int arch_bp_generic_fields(int x86_len, int x86_type,
                           int *gen_len, int *gen_type)
 {
@@ -351,11 +343,13 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp,
                return ret;
        }
 
-       if (bp->callback)
-               ret = arch_store_info(bp);
-
-       if (ret < 0)
-               return ret;
+       /*
+        * For kernel-addresses, either the address or symbol name can be
+        * specified.
+        */
+       if (info->name)
+               info->address = (unsigned long)
+                               kallsyms_lookup_name(info->name);
        /*
         * Check that the low-order bits of the address are appropriate
         * for the alignment implied by len.
@@ -376,6 +370,42 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp,
 }
 
 /*
+ * Dump the debug register contents to the user.
+ * We can't dump our per cpu values because it
+ * may contain cpu wide breakpoint, something that
+ * doesn't belong to the current task.
+ *
+ * TODO: include non-ptrace user breakpoints (perf)
+ */
+void aout_dump_debugregs(struct user *dump)
+{
+       int i;
+       int dr7 = 0;
+       struct perf_event *bp;
+       struct arch_hw_breakpoint *info;
+       struct thread_struct *thread = &current->thread;
+
+       for (i = 0; i < HBP_NUM; i++) {
+               bp = thread->ptrace_bps[i];
+
+               if (bp && !bp->attr.disabled) {
+                       dump->u_debugreg[i] = bp->attr.bp_addr;
+                       info = counter_arch_bp(bp);
+                       dr7 |= encode_dr7(i, info->len, info->type);
+               } else {
+                       dump->u_debugreg[i] = 0;
+               }
+       }
+
+       dump->u_debugreg[4] = 0;
+       dump->u_debugreg[5] = 0;
+       dump->u_debugreg[6] = current->thread.debugreg6;
+
+       dump->u_debugreg[7] = dr7;
+}
+EXPORT_SYMBOL_GPL(aout_dump_debugregs);
+
+/*
  * Release the user breakpoints used by ptrace
  */
 void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
@@ -389,7 +419,6 @@ void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
        }
 }
 
-#ifdef CONFIG_KVM
 void hw_breakpoint_restore(void)
 {
        set_debugreg(__get_cpu_var(cpu_debugreg[0]), 0);
@@ -397,10 +426,9 @@ void hw_breakpoint_restore(void)
        set_debugreg(__get_cpu_var(cpu_debugreg[2]), 2);
        set_debugreg(__get_cpu_var(cpu_debugreg[3]), 3);
        set_debugreg(current->thread.debugreg6, 6);
-       set_debugreg(__get_cpu_var(dr7), 7);
+       set_debugreg(__get_cpu_var(cpu_dr7), 7);
 }
 EXPORT_SYMBOL_GPL(hw_breakpoint_restore);
-#endif
 
 /*
  * Handle debug exception notifications.
@@ -458,8 +486,6 @@ static int __kprobes hw_breakpoint_handler(struct die_args *args)
                rcu_read_lock();
 
                bp = per_cpu(bp_per_reg[i], cpu);
-               if (bp)
-                       rc = NOTIFY_DONE;
                /*
                 * Reset the 'i'th TRAP bit in dr6 to denote completion of
                 * exception handling
@@ -474,11 +500,17 @@ static int __kprobes hw_breakpoint_handler(struct die_args *args)
                        break;
                }
 
-               (bp->callback)(bp, args->regs);
+               perf_bp_event(bp, args->regs);
 
                rcu_read_unlock();
        }
-       if (dr6 & (~DR_TRAP_BITS))
+       /*
+        * Further processing in do_debug() is needed for a) user-space
+        * breakpoints (to generate signals) and b) when the system has
+        * taken exception due to multiple causes
+        */
+       if ((current->thread.debugreg6 & DR_TRAP_BITS) ||
+           (dr6 & (~DR_TRAP_BITS)))
                rc = NOTIFY_DONE;
 
        set_debugreg(dr7, 7);