Merge branch 'tracing/hw-breakpoints' into perf/core

Conflicts:
	arch/x86/kernel/kprobes.c
	kernel/trace/Makefile

Merge reason: hw-breakpoints perf integration is looking
              good in testing and in reviews, plus conflicts
              are mounting up - so merge & resolve.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/Kconfig

@@ -126,4 +126,11 @@ config HAVE_DMA_API_DEBUG
 config HAVE_DEFAULT_NO_SPIN_MUTEXES
 	bool
 
+config HAVE_HW_BREAKPOINT
+	bool
+	depends on HAVE_PERF_EVENTS
+	select ANON_INODES
+	select PERF_EVENTS
+
+
 source "kernel/gcov/Kconfig"

arch/x86/Kconfig

@@ -49,6 +49,7 @@ config X86
 	select HAVE_KERNEL_GZIP
 	select HAVE_KERNEL_BZIP2
 	select HAVE_KERNEL_LZMA
+	select HAVE_HW_BREAKPOINT
 	select HAVE_ARCH_KMEMCHECK
 
 config OUTPUT_FORMAT

arch/x86/include/asm/Kbuild

@@ -10,6 +10,7 @@ header-y += ptrace-abi.h
 header-y += sigcontext32.h
 header-y += ucontext.h
 header-y += processor-flags.h
+header-y += hw_breakpoint.h
 
 unifdef-y += e820.h
 unifdef-y += ist.h

arch/x86/include/asm/a.out-core.h

@@ -17,6 +17,7 @@
 
 #include <linux/user.h>
 #include <linux/elfcore.h>
+#include <asm/debugreg.h>
 
 /*
  * fill in the user structure for an a.out core dump
@@ -32,14 +33,7 @@ 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[4] = 0;
-	dump->u_debugreg[5] = 0;
-	dump->u_debugreg[6] = current->thread.debugreg6;
-	dump->u_debugreg[7] = current->thread.debugreg7;
+	aout_dump_debugregs(dump);
 
 	if (dump->start_stack < TASK_SIZE)
 		dump->u_ssize = ((unsigned long)(TASK_SIZE - dump->start_stack))

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 +70,34 @@
 #define DR_LOCAL_SLOWDOWN (0x100)   /* Local slow the pipeline */
 #define DR_GLOBAL_SLOWDOWN (0x200)  /* Global slow the pipeline */
 
+/*
+ * HW breakpoint additions
+ */
+#ifdef __KERNEL__
+
+DECLARE_PER_CPU(unsigned long, dr7);
+
+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);
+}
+
+static inline int hw_breakpoint_active(void)
+{
+	return __get_cpu_var(dr7) & DR_GLOBAL_ENABLE_MASK;
+}
+
+extern void aout_dump_debugregs(struct user *dump);
+
+extern void hw_breakpoint_restore(void);
+
+#endif	/* __KERNEL__ */
+
 #endif /* _ASM_X86_DEBUGREG_H */

arch/x86/include/asm/hw_breakpoint.h

@@ -0,0 +1,73 @@
+#ifndef	_I386_HW_BREAKPOINT_H
+#define	_I386_HW_BREAKPOINT_H
+
+#ifdef	__KERNEL__
+#define	__ARCH_HW_BREAKPOINT_H
+
+/*
+ * The name should probably be something dealt in
+ * a higher level. While dealing with the user
+ * (display/resolving)
+ */
+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 <linux/percpu.h>
+#include <linux/list.h>
+
+/* Available HW breakpoint length encodings */
+#define X86_BREAKPOINT_LEN_1		0x40
+#define X86_BREAKPOINT_LEN_2		0x44
+#define X86_BREAKPOINT_LEN_4		0x4c
+#define X86_BREAKPOINT_LEN_EXECUTE	0x40
+
+#ifdef CONFIG_X86_64
+#define X86_BREAKPOINT_LEN_8		0x48
+#endif
+
+/* Available HW breakpoint type encodings */
+
+/* trigger on instruction execute */
+#define X86_BREAKPOINT_EXECUTE	0x80
+/* trigger on memory write */
+#define X86_BREAKPOINT_WRITE	0x81
+/* trigger on memory read or write */
+#define X86_BREAKPOINT_RW	0x83
+
+/* Total number of available HW breakpoint registers */
+#define HBP_NUM 4
+
+struct perf_event;
+struct pmu;
+
+extern int arch_check_va_in_userspace(unsigned long va, u8 hbp_len);
+extern int arch_validate_hwbkpt_settings(struct perf_event *bp,
+					 struct task_struct *tsk);
+extern int hw_breakpoint_exceptions_notify(struct notifier_block *unused,
+					   unsigned long val, void *data);
+
+
+int arch_install_hw_breakpoint(struct perf_event *bp);
+void arch_uninstall_hw_breakpoint(struct perf_event *bp);
+void hw_breakpoint_pmu_read(struct perf_event *bp);
+void hw_breakpoint_pmu_unthrottle(struct perf_event *bp);
+
+extern void
+arch_fill_perf_breakpoint(struct perf_event *bp);
+
+unsigned long encode_dr7(int drnum, unsigned int len, unsigned int type);
+int decode_dr7(unsigned long dr7, int bpnum, unsigned *len, unsigned *type);
+
+extern int arch_bp_generic_fields(int x86_len, int x86_type,
+				  int *gen_len, int *gen_type);
+
+extern struct pmu perf_ops_bp;
+
+#endif	/* __KERNEL__ */
+#endif	/* _I386_HW_BREAKPOINT_H */
+

arch/x86/include/asm/processor.h

@@ -30,6 +30,7 @@ struct mm_struct;
 #include <linux/math64.h>
 #include <linux/init.h>
 
+#define HBP_NUM 4
 /*
  * Default implementation of macro that returns current
  * instruction pointer ("program counter").
@@ -422,6 +423,8 @@ extern unsigned int xstate_size;
 extern void free_thread_xstate(struct task_struct *);
 extern struct kmem_cache *task_xstate_cachep;
 
+struct perf_event;
+
 struct thread_struct {
 	/* Cached TLS descriptors: */
 	struct desc_struct	tls_array[GDT_ENTRY_TLS_ENTRIES];
@@ -443,13 +446,10 @@ struct thread_struct {
 	unsigned long		fs;
 #endif
 	unsigned long		gs;
-	/* Hardware debugging registers: */
-	unsigned long		debugreg0;
-	unsigned long		debugreg1;
-	unsigned long		debugreg2;
-	unsigned long		debugreg3;
-	unsigned long		debugreg6;
-	unsigned long		debugreg7;
+	/* Save middle states of ptrace breakpoints */
+	struct perf_event	*ptrace_bps[HBP_NUM];
+	/* Debug status used for traps, single steps, etc... */
+	unsigned long           debugreg6;
 	/* Fault info: */
 	unsigned long		cr2;
 	unsigned long		trap_no;

arch/x86/kernel/Makefile

@@ -40,7 +40,7 @@ obj-$(CONFIG_X86_64)	+= sys_x86_64.o x8664_ksyms_64.o
 obj-$(CONFIG_X86_64)	+= syscall_64.o vsyscall_64.o
 obj-y			+= bootflag.o e820.o
 obj-y			+= pci-dma.o quirks.o i8237.o topology.o kdebugfs.o
-obj-y			+= alternative.o i8253.o pci-nommu.o
+obj-y			+= alternative.o i8253.o pci-nommu.o hw_breakpoint.o
 obj-y			+= tsc.o io_delay.o rtc.o
 
 obj-$(CONFIG_X86_TRAMPOLINE)	+= trampoline.o